diff --git a/.cirrus.yml b/.cirrus.yml new file mode 100644 index 0000000000000..506a860336354 --- /dev/null +++ b/.cirrus.yml @@ -0,0 +1,198 @@ +env: + WIDEMUL: auto + STATICPRECOMPUTATION: yes + ECMULTGENPRECISION: auto + ASM: no + BUILD: check + WITH_VALGRIND: yes + RUN_VALGRIND: no + EXTRAFLAGS: + HOST: + ECDH: no + RECOVERY: no + SCHNORRSIG: no + EXPERIMENTAL: no + CTIMETEST: yes + BENCH: yes + ITERS: 2 + MAKEFLAGS: -j2 + +cat_logs_snippet: &CAT_LOGS + always: + cat_tests_log_script: + - cat tests.log || true + cat_exhaustive_tests_log_script: + - cat exhaustive_tests.log || true + cat_valgrind_ctime_test_log_script: + - cat valgrind_ctime_test.log || true + cat_bench_log_script: + - cat bench.log || true + on_failure: + cat_config_log_script: + - cat config.log || true + cat_test_env_script: + - cat test_env.log || true + cat_ci_env_script: + - env + +merge_base_script_snippet: &MERGE_BASE + merge_base_script: + - if [ "$CIRRUS_PR" = "" ]; then exit 0; fi + - git fetch $CIRRUS_REPO_CLONE_URL $CIRRUS_BASE_BRANCH + - git config --global user.email "ci@ci.ci" + - git config --global user.name "ci" + - git merge FETCH_HEAD # Merge base to detect silent merge conflicts + +task: + name: "x86_64: Linux (Debian stable)" + container: + dockerfile: ci/linux-debian.Dockerfile + # Reduce number of CPUs to be able to do more builds in parallel. + cpu: 1 + # More than enough for our scripts. + memory: 1G + matrix: &ENV_MATRIX + - env: {WIDEMUL: int64, RECOVERY: yes} + - env: {WIDEMUL: int64, ECDH: yes, EXPERIMENTAL: yes, SCHNORRSIG: yes} + - env: {WIDEMUL: int128} + - env: {WIDEMUL: int128, RECOVERY: yes, EXPERIMENTAL: yes, SCHNORRSIG: yes} + - env: {WIDEMUL: int128, ECDH: yes, EXPERIMENTAL: yes, SCHNORRSIG: yes} + - env: {WIDEMUL: int128, ASM: x86_64} + - env: { RECOVERY: yes, EXPERIMENTAL: yes, SCHNORRSIG: yes} + - env: { STATICPRECOMPUTATION: no} + - env: {BUILD: distcheck, WITH_VALGRIND: no, CTIMETEST: no, BENCH: no} + - env: {CPPFLAGS: -DDETERMINISTIC} + - env: {CFLAGS: -O0, CTIMETEST: no} + - env: + CFLAGS: "-fsanitize=undefined -fno-omit-frame-pointer" + LDFLAGS: "-fsanitize=undefined -fno-omit-frame-pointer" + UBSAN_OPTIONS: "print_stacktrace=1:halt_on_error=1" + ASM: x86_64 + ECDH: yes + RECOVERY: yes + EXPERIMENTAL: yes + SCHNORRSIG: yes + CTIMETEST: no + - env: { ECMULTGENPRECISION: 2 } + - env: { ECMULTGENPRECISION: 8 } + - env: + RUN_VALGRIND: yes + ASM: x86_64 + ECDH: yes + RECOVERY: yes + EXPERIMENTAL: yes + SCHNORRSIG: yes + EXTRAFLAGS: "--disable-openssl-tests" + BUILD: + matrix: + - env: + CC: gcc + - env: + CC: clang + << : *MERGE_BASE + test_script: + - ./ci/cirrus.sh + << : *CAT_LOGS + +task: + name: "i686: Linux (Debian stable)" + container: + dockerfile: ci/linux-debian.Dockerfile + cpu: 1 + memory: 1G + env: + HOST: i686-linux-gnu + ECDH: yes + RECOVERY: yes + EXPERIMENTAL: yes + SCHNORRSIG: yes + matrix: + - env: + CC: i686-linux-gnu-gcc + - env: + CC: clang --target=i686-pc-linux-gnu -isystem /usr/i686-linux-gnu/include + test_script: + - ./ci/cirrus.sh + << : *CAT_LOGS + +task: + name: "x86_64: macOS Catalina" + macos_instance: + image: catalina-base + env: + HOMEBREW_NO_AUTO_UPDATE: 1 + HOMEBREW_NO_INSTALL_CLEANUP: 1 + # Cirrus gives us a fixed number of 12 virtual CPUs. Not that we even have that many jobs at the moment... + MAKEFLAGS: -j13 + matrix: + << : *ENV_MATRIX + matrix: + - env: + CC: gcc-9 + - env: + CC: clang + # Update Command Line Tools + # Uncomment this if the Command Line Tools on the CirrusCI macOS image are too old to brew valgrind. + # See https://apple.stackexchange.com/a/195963 for the implementation. + ## update_clt_script: + ## - system_profiler SPSoftwareDataType + ## - touch /tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress + ## - |- + ## PROD=$(softwareupdate -l | grep "*.*Command Line" | tail -n 1 | awk -F"*" '{print $2}' | sed -e 's/^ *//' | sed 's/Label: //g' | tr -d '\n') + ## # For debugging + ## - softwareupdate -l && echo "PROD: $PROD" + ## - softwareupdate -i "$PROD" --verbose + ## - rm /tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress + ## + brew_valgrind_pre_script: + - brew config + - brew tap --shallow LouisBrunner/valgrind + # Fetch valgrind source but don't build it yet. + - brew fetch --HEAD LouisBrunner/valgrind/valgrind + brew_valgrind_cache: + # This is $(brew --cellar valgrind) but command substition does not work here. + folder: /usr/local/Cellar/valgrind + # Rebuild cache if ... + fingerprint_script: + # ... macOS version changes: + - sw_vers + # ... brew changes: + - brew config + # ... valgrind changes: + - git -C "$(brew --cache)/valgrind--git" rev-parse HEAD + populate_script: + # If there's no hit in the cache, build and install valgrind. + - brew install --HEAD LouisBrunner/valgrind/valgrind + brew_valgrind_post_script: + # If we have restored valgrind from the cache, tell brew to create symlink to the PATH. + # If we haven't restored from cached (and just run brew install), this is a no-op. + - brew link valgrind + brew_script: + - brew install automake libtool gcc@9 + << : *MERGE_BASE + test_script: + - ./ci/cirrus.sh + << : *CAT_LOGS + +task: + name: "s390x (big-endian): Linux (Debian stable, QEMU)" + container: + dockerfile: ci/linux-debian.Dockerfile + cpu: 1 + memory: 1G + env: + QEMU_CMD: qemu-s390x + HOST: s390x-linux-gnu + BUILD: + WITH_VALGRIND: no + ECDH: yes + RECOVERY: yes + EXPERIMENTAL: yes + SCHNORRSIG: yes + CTIMETEST: no + << : *MERGE_BASE + test_script: + # https://sourceware.org/bugzilla/show_bug.cgi?id=27008 + - rm /etc/ld.so.cache + - ./ci/cirrus.sh + << : *CAT_LOGS diff --git a/.travis.yml b/.travis.yml deleted file mode 100644 index ce8d6391b2f21..0000000000000 --- a/.travis.yml +++ /dev/null @@ -1,108 +0,0 @@ -language: c -os: - - linux - - osx - -dist: bionic -# Valgrind currently supports upto macOS 10.13, the latest xcode of that version is 10.1 -osx_image: xcode10.1 -addons: - apt: - packages: - - libgmp-dev - - valgrind - - libtool-bin -compiler: - - clang - - gcc -env: - global: - - WIDEMUL=auto BIGNUM=auto STATICPRECOMPUTATION=yes ECMULTGENPRECISION=auto ASM=no BUILD=check WITH_VALGRIND=yes RUN_VALGRIND=no EXTRAFLAGS= HOST= ECDH=no RECOVERY=no SCHNORRSIG=no EXPERIMENTAL=no CTIMETEST=yes BENCH=yes ITERS=2 - matrix: - - WIDEMUL=int64 RECOVERY=yes - - WIDEMUL=int64 ECDH=yes EXPERIMENTAL=yes SCHNORRSIG=yes - - WIDEMUL=int128 - - WIDEMUL=int128 RECOVERY=yes EXPERIMENTAL=yes SCHNORRSIG=yes - - WIDEMUL=int128 ECDH=yes EXPERIMENTAL=yes SCHNORRSIG=yes - - WIDEMUL=int128 ASM=x86_64 - - BIGNUM=no - - BIGNUM=no RECOVERY=yes EXPERIMENTAL=yes SCHNORRSIG=yes - - BIGNUM=no STATICPRECOMPUTATION=no - - BUILD=distcheck WITH_VALGRIND=no CTIMETEST=no BENCH=no - - CPPFLAGS=-DDETERMINISTIC - - CFLAGS=-O0 CTIMETEST=no - - ECMULTGENPRECISION=2 - - ECMULTGENPRECISION=8 - - RUN_VALGRIND=yes BIGNUM=no ASM=x86_64 ECDH=yes RECOVERY=yes EXPERIMENTAL=yes SCHNORRSIG=yes EXTRAFLAGS="--disable-openssl-tests" BUILD= -matrix: - fast_finish: true - include: - - compiler: clang - os: linux - env: HOST=i686-linux-gnu - addons: - apt: - packages: - - gcc-multilib - - libgmp-dev:i386 - - valgrind - - libtool-bin - - libc6-dbg:i386 - - compiler: clang - env: HOST=i686-linux-gnu - os: linux - addons: - apt: - packages: - - gcc-multilib - - valgrind - - libtool-bin - - libc6-dbg:i386 - - compiler: gcc - env: HOST=i686-linux-gnu - os: linux - addons: - apt: - packages: - - gcc-multilib - - valgrind - - libtool-bin - - libc6-dbg:i386 - - compiler: gcc - os: linux - env: HOST=i686-linux-gnu - addons: - apt: - packages: - - gcc-multilib - - libgmp-dev:i386 - - valgrind - - libtool-bin - - libc6-dbg:i386 - # S390x build (big endian system) - - compiler: gcc - env: HOST=s390x-unknown-linux-gnu ECDH=yes RECOVERY=yes EXPERIMENTAL=yes SCHNORRSIG=yes CTIMETEST= - arch: s390x - -# We use this to install macOS dependencies instead of the built in `homebrew` plugin, -# because in xcode earlier than 11 they have a bug requiring updating the system which overall takes ~8 minutes. -# https://travis-ci.community/t/macos-build-fails-because-of-homebrew-bundle-unknown-command/7296 -before_install: - - if [ "${TRAVIS_OS_NAME}" = "osx" ]; then HOMEBREW_NO_AUTO_UPDATE=1 brew install gmp valgrind gcc@9; fi - -before_script: ./autogen.sh - -# travis auto terminates jobs that go for 10 minutes without printing to stdout, but travis_wait doesn't work well with forking programs like valgrind (https://docs.travis-ci.com/user/common-build-problems/#build-times-out-because-no-output-was-received https://github.com/bitcoin-core/secp256k1/pull/750#issuecomment-623476860) -script: - - function keep_alive() { while true; do echo -en "\a"; sleep 60; done } - - keep_alive & - - ./contrib/travis.sh - - kill %keep_alive - -after_script: - - cat ./tests.log - - cat ./exhaustive_tests.log - - cat ./valgrind_ctime_test.log - - cat ./bench.log - - $CC --version - - valgrind --version diff --git a/Makefile.am b/Makefile.am index 023fa6067fbba..58c9635e53e74 100644 --- a/Makefile.am +++ b/Makefile.am @@ -14,8 +14,6 @@ noinst_HEADERS += src/scalar_8x32_impl.h noinst_HEADERS += src/scalar_low_impl.h noinst_HEADERS += src/group.h noinst_HEADERS += src/group_impl.h -noinst_HEADERS += src/num_gmp.h -noinst_HEADERS += src/num_gmp_impl.h noinst_HEADERS += src/ecdsa.h noinst_HEADERS += src/ecdsa_impl.h noinst_HEADERS += src/eckey.h @@ -26,14 +24,16 @@ noinst_HEADERS += src/ecmult_const.h noinst_HEADERS += src/ecmult_const_impl.h noinst_HEADERS += src/ecmult_gen.h noinst_HEADERS += src/ecmult_gen_impl.h -noinst_HEADERS += src/num.h -noinst_HEADERS += src/num_impl.h noinst_HEADERS += src/field_10x26.h noinst_HEADERS += src/field_10x26_impl.h noinst_HEADERS += src/field_5x52.h noinst_HEADERS += src/field_5x52_impl.h noinst_HEADERS += src/field_5x52_int128_impl.h noinst_HEADERS += src/field_5x52_asm_impl.h +noinst_HEADERS += src/modinv32.h +noinst_HEADERS += src/modinv32_impl.h +noinst_HEADERS += src/modinv64.h +noinst_HEADERS += src/modinv64_impl.h noinst_HEADERS += src/assumptions.h noinst_HEADERS += src/util.h noinst_HEADERS += src/scratch.h diff --git a/README.md b/README.md index e070937235c36..197a56fff842a 100644 --- a/README.md +++ b/README.md @@ -1,7 +1,7 @@ libsecp256k1 ============ -[![Build Status](https://travis-ci.org/bitcoin-core/secp256k1.svg?branch=master)](https://travis-ci.org/bitcoin-core/secp256k1) +[![Build Status](https://api.cirrus-ci.com/github/bitcoin-core/secp256k1.svg?branch=master)](https://cirrus-ci.com/github/bitcoin-core/secp256k1) Optimized C library for ECDSA signatures and secret/public key operations on curve secp256k1. @@ -34,11 +34,11 @@ Implementation details * Optimized implementation of arithmetic modulo the curve's field size (2^256 - 0x1000003D1). * Using 5 52-bit limbs (including hand-optimized assembly for x86_64, by Diederik Huys). * Using 10 26-bit limbs (including hand-optimized assembly for 32-bit ARM, by Wladimir J. van der Laan). - * Field inverses and square roots using a sliding window over blocks of 1s (by Peter Dettman). * Scalar operations * Optimized implementation without data-dependent branches of arithmetic modulo the curve's order. * Using 4 64-bit limbs (relying on __int128 support in the compiler). * Using 8 32-bit limbs. +* Modular inverses (both field elements and scalars) based on [safegcd](https://gcd.cr.yp.to/index.html) with some modifications, and a variable-time variant (by Peter Dettman). * Group operations * Point addition formula specifically simplified for the curve equation (y^2 = x^3 + 7). * Use addition between points in Jacobian and affine coordinates where possible. diff --git a/build-aux/m4/ax_prog_cc_for_build.m4 b/build-aux/m4/ax_prog_cc_for_build.m4 index 77fd346a79a6f..7bcbf3200cfa2 100644 --- a/build-aux/m4/ax_prog_cc_for_build.m4 +++ b/build-aux/m4/ax_prog_cc_for_build.m4 @@ -1,5 +1,5 @@ # =========================================================================== -# http://www.gnu.org/software/autoconf-archive/ax_prog_cc_for_build.html +# https://www.gnu.org/software/autoconf-archive/ax_prog_cc_for_build.html # =========================================================================== # # SYNOPSIS diff --git a/build-aux/m4/bitcoin_secp.m4 b/build-aux/m4/bitcoin_secp.m4 index ece3d655edc30..e57888ca18968 100644 --- a/build-aux/m4/bitcoin_secp.m4 +++ b/build-aux/m4/bitcoin_secp.m4 @@ -75,15 +75,10 @@ if test x"$has_libcrypto" = x"yes" && test x"$has_openssl_ec" = x; then fi ]) -dnl -AC_DEFUN([SECP_GMP_CHECK],[ -if test x"$has_gmp" != x"yes"; then +AC_DEFUN([SECP_VALGRIND_CHECK],[ +if test x"$has_valgrind" != x"yes"; then CPPFLAGS_TEMP="$CPPFLAGS" - CPPFLAGS="$GMP_CPPFLAGS $CPPFLAGS" - LIBS_TEMP="$LIBS" - LIBS="$GMP_LIBS $LIBS" - AC_CHECK_HEADER(gmp.h,[AC_CHECK_LIB(gmp, __gmpz_init,[has_gmp=yes; GMP_LIBS="$GMP_LIBS -lgmp"; AC_DEFINE(HAVE_LIBGMP,1,[Define this symbol if libgmp is installed])])]) - CPPFLAGS="$CPPFLAGS_TEMP" - LIBS="$LIBS_TEMP" + CPPFLAGS="$VALGRIND_CPPFLAGS $CPPFLAGS" + AC_CHECK_HEADER([valgrind/memcheck.h], [has_valgrind=yes; AC_DEFINE(HAVE_VALGRIND,1,[Define this symbol if valgrind is installed])]) fi ]) diff --git a/contrib/travis.sh b/ci/cirrus.sh similarity index 62% rename from contrib/travis.sh rename to ci/cirrus.sh index 24cc9315cb116..f26ca98d1de39 100755 --- a/contrib/travis.sh +++ b/ci/cirrus.sh @@ -3,45 +3,63 @@ set -e set -x -if [ "$HOST" = "i686-linux-gnu" ] -then - export CC="$CC -m32" -fi -if [ "$TRAVIS_OS_NAME" = "osx" ] && [ "$TRAVIS_COMPILER" = "gcc" ] -then - export CC="gcc-9" -fi +export LC_ALL=C + +env >> test_env.log + +$CC -v || true +valgrind --version || true + +./autogen.sh ./configure \ --enable-experimental="$EXPERIMENTAL" \ - --with-test-override-wide-multiply="$WIDEMUL" --with-bignum="$BIGNUM" --with-asm="$ASM" \ + --with-test-override-wide-multiply="$WIDEMUL" --with-asm="$ASM" \ --enable-ecmult-static-precomputation="$STATICPRECOMPUTATION" --with-ecmult-gen-precision="$ECMULTGENPRECISION" \ --enable-module-ecdh="$ECDH" --enable-module-recovery="$RECOVERY" \ --enable-module-schnorrsig="$SCHNORRSIG" \ --with-valgrind="$WITH_VALGRIND" \ --host="$HOST" $EXTRAFLAGS +# We have set "-j" in MAKEFLAGS. +make + +# Print information about binaries so that we can see that the architecture is correct +file *tests || true +file bench_* || true +file .libs/* || true + if [ -n "$BUILD" ] then - make -j2 "$BUILD" + make "$BUILD" fi + if [ "$RUN_VALGRIND" = "yes" ] then - make -j2 - # the `--error-exitcode` is required to make the test fail if valgrind found errors, otherwise it'll return 0 (http://valgrind.org/docs/manual/manual-core.html) + # the `--error-exitcode` is required to make the test fail if valgrind found errors, otherwise it'll return 0 (https://www.valgrind.org/docs/manual/manual-core.html) valgrind --error-exitcode=42 ./tests 16 valgrind --error-exitcode=42 ./exhaustive_tests fi + +if [ -n "$QEMU_CMD" ] +then + $QEMU_CMD ./tests 16 + $QEMU_CMD ./exhaustive_tests +fi + if [ "$BENCH" = "yes" ] then + # Using the local `libtool` because on macOS the system's libtool has nothing to do with GNU libtool + EXEC='./libtool --mode=execute' + if [ -n "$QEMU_CMD" ] + then + EXEC="$EXEC $QEMU_CMD" + fi if [ "$RUN_VALGRIND" = "yes" ] then - # Using the local `libtool` because on macOS the system's libtool has nothing to do with GNU libtool - EXEC='./libtool --mode=execute valgrind --error-exitcode=42' - else - EXEC= + EXEC="$EXEC valgrind --error-exitcode=42" fi - # This limits the iterations in the benchmarks below to ITER(set in .travis.yml) iterations. + # This limits the iterations in the benchmarks below to ITER iterations. export SECP256K1_BENCH_ITERS="$ITERS" { $EXEC ./bench_ecmult diff --git a/ci/linux-debian.Dockerfile b/ci/linux-debian.Dockerfile new file mode 100644 index 0000000000000..5967cf8b31160 --- /dev/null +++ b/ci/linux-debian.Dockerfile @@ -0,0 +1,13 @@ +FROM debian:stable + +RUN dpkg --add-architecture i386 +RUN dpkg --add-architecture s390x +RUN apt-get update + +# dkpg-dev: to make pkg-config work in cross-builds +RUN apt-get install --no-install-recommends --no-upgrade -y \ + git ca-certificates \ + make automake libtool pkg-config dpkg-dev valgrind qemu-user \ + gcc clang libc6-dbg \ + gcc-i686-linux-gnu libc6-dev-i386-cross libc6-dbg:i386 \ + gcc-s390x-linux-gnu libc6-dev-s390x-cross libc6-dbg:s390x diff --git a/configure.ac b/configure.ac index eb3b449becaad..1ed991afa7714 100644 --- a/configure.ac +++ b/configure.ac @@ -14,7 +14,7 @@ AM_INIT_AUTOMAKE([foreign subdir-objects]) : ${CFLAGS="-g"} LT_INIT -dnl make the compilation flags quiet unless V=1 is used +# Make the compilation flags quiet unless V=1 is used. m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])]) PKG_PROG_PKG_CONFIG @@ -22,9 +22,16 @@ PKG_PROG_PKG_CONFIG AC_PATH_TOOL(AR, ar) AC_PATH_TOOL(RANLIB, ranlib) AC_PATH_TOOL(STRIP, strip) -AX_PROG_CC_FOR_BUILD +# Save definition of AC_PROG_CC because AM_PROG_CC_C_O in automake<=1.13 will +# redefine AC_PROG_CC to exit with an error, which avoids the user calling it +# accidently and screwing up the effect of AM_PROG_CC_C_O. However, we'll need +# AC_PROG_CC later on in AX_PROG_CC_FOR_BUILD, where its usage is fine, and +# we'll carefully make sure not to call AC_PROG_CC anywhere else. +m4_copy([AC_PROG_CC], [saved_AC_PROG_CC]) AM_PROG_CC_C_O +# Restore AC_PROG_CC +m4_rename_force([saved_AC_PROG_CC], [AC_PROG_CC]) AC_PROG_CC_C89 if test x"$ac_cv_prog_cc_c89" = x"no"; then @@ -37,25 +44,23 @@ case $host_os in if test x$cross_compiling != xyes; then AC_PATH_PROG([BREW],brew,) if test x$BREW != x; then - dnl These Homebrew packages may be keg-only, meaning that they won't be found - dnl in expected paths because they may conflict with system files. Ask - dnl Homebrew where each one is located, then adjust paths accordingly. - + # These Homebrew packages may be keg-only, meaning that they won't be found + # in expected paths because they may conflict with system files. Ask + # Homebrew where each one is located, then adjust paths accordingly. openssl_prefix=`$BREW --prefix openssl 2>/dev/null` - gmp_prefix=`$BREW --prefix gmp 2>/dev/null` + valgrind_prefix=`$BREW --prefix valgrind 2>/dev/null` if test x$openssl_prefix != x; then PKG_CONFIG_PATH="$openssl_prefix/lib/pkgconfig:$PKG_CONFIG_PATH" export PKG_CONFIG_PATH CRYPTO_CPPFLAGS="-I$openssl_prefix/include" fi - if test x$gmp_prefix != x; then - GMP_CPPFLAGS="-I$gmp_prefix/include" - GMP_LIBS="-L$gmp_prefix/lib" + if test x$valgrind_prefix != x; then + VALGRIND_CPPFLAGS="-I$valgrind_prefix/include" fi else AC_PATH_PROG([PORT],port,) - dnl if homebrew isn't installed and macports is, add the macports default paths - dnl as a last resort. + # If homebrew isn't installed and macports is, add the macports default paths + # as a last resort. if test x$PORT != x; then CPPFLAGS="$CPPFLAGS -isystem /opt/local/include" LDFLAGS="$LDFLAGS -L/opt/local/lib" @@ -77,6 +82,15 @@ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[char foo;]])], CFLAGS="$saved_CFLAGS" ]) +saved_CFLAGS="$CFLAGS" +CFLAGS="-Wconditional-uninitialized $CFLAGS" +AC_MSG_CHECKING([if ${CC} supports -Wconditional-uninitialized]) +AC_COMPILE_IFELSE([AC_LANG_SOURCE([[char foo;]])], + [ AC_MSG_RESULT([yes]) ], + [ AC_MSG_RESULT([no]) + CFLAGS="$saved_CFLAGS" + ]) + saved_CFLAGS="$CFLAGS" CFLAGS="-fvisibility=hidden $CFLAGS" AC_MSG_CHECKING([if ${CC} supports -fvisibility=hidden]) @@ -86,6 +100,10 @@ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[char foo;]])], CFLAGS="$saved_CFLAGS" ]) +### +### Define config arguments +### + AC_ARG_ENABLE(benchmark, AS_HELP_STRING([--enable-benchmark],[compile benchmark [default=yes]]), [use_benchmark=$enableval], @@ -146,13 +164,10 @@ AC_ARG_ENABLE(external_default_callbacks, [use_external_default_callbacks=$enableval], [use_external_default_callbacks=no]) -dnl Test-only override of the (autodetected by the C code) "widemul" setting. -dnl Legal values are int64 (for [u]int64_t), int128 (for [unsigned] __int128), and auto (the default). +# Test-only override of the (autodetected by the C code) "widemul" setting. +# Legal values are int64 (for [u]int64_t), int128 (for [unsigned] __int128), and auto (the default). AC_ARG_WITH([test-override-wide-multiply], [] ,[set_widemul=$withval], [set_widemul=auto]) -AC_ARG_WITH([bignum], [AS_HELP_STRING([--with-bignum=gmp|no|auto], -[bignum implementation to use [default=auto]])],[req_bignum=$withval], [req_bignum=auto]) - AC_ARG_WITH([asm], [AS_HELP_STRING([--with-asm=x86_64|arm|no|auto], [assembly optimizations to use (experimental: arm) [default=auto]])],[req_asm=$withval], [req_asm=auto]) @@ -177,15 +192,22 @@ AC_ARG_WITH([valgrind], [AS_HELP_STRING([--with-valgrind=yes|no|auto], )], [req_valgrind=$withval], [req_valgrind=auto]) +### +### Handle config options (except for modules) +### + if test x"$req_valgrind" = x"no"; then enable_valgrind=no else - AC_CHECK_HEADER([valgrind/memcheck.h], [enable_valgrind=yes], [ + SECP_VALGRIND_CHECK + if test x"$has_valgrind" != x"yes"; then if test x"$req_valgrind" = x"yes"; then AC_MSG_ERROR([Valgrind support explicitly requested but valgrind/memcheck.h header not available]) fi enable_valgrind=no - ], []) + else + enable_valgrind=yes + fi fi AM_CONDITIONAL([VALGRIND_ENABLED],[test "$enable_valgrind" = "yes"]) @@ -197,61 +219,6 @@ else CFLAGS="-O2 $CFLAGS" fi -if test x"$use_ecmult_static_precomputation" != x"no"; then - # Temporarily switch to an environment for the native compiler - save_cross_compiling=$cross_compiling - cross_compiling=no - SAVE_CC="$CC" - CC="$CC_FOR_BUILD" - SAVE_CFLAGS="$CFLAGS" - CFLAGS="$CFLAGS_FOR_BUILD" - SAVE_CPPFLAGS="$CPPFLAGS" - CPPFLAGS="$CPPFLAGS_FOR_BUILD" - SAVE_LDFLAGS="$LDFLAGS" - LDFLAGS="$LDFLAGS_FOR_BUILD" - - warn_CFLAGS_FOR_BUILD="-Wall -Wextra -Wno-unused-function" - saved_CFLAGS="$CFLAGS" - CFLAGS="$warn_CFLAGS_FOR_BUILD $CFLAGS" - AC_MSG_CHECKING([if native ${CC_FOR_BUILD} supports ${warn_CFLAGS_FOR_BUILD}]) - AC_COMPILE_IFELSE([AC_LANG_SOURCE([[char foo;]])], - [ AC_MSG_RESULT([yes]) ], - [ AC_MSG_RESULT([no]) - CFLAGS="$saved_CFLAGS" - ]) - - AC_MSG_CHECKING([for working native compiler: ${CC_FOR_BUILD}]) - AC_RUN_IFELSE( - [AC_LANG_PROGRAM([], [])], - [working_native_cc=yes], - [working_native_cc=no],[:]) - - CFLAGS_FOR_BUILD="$CFLAGS" - - # Restore the environment - cross_compiling=$save_cross_compiling - CC="$SAVE_CC" - CFLAGS="$SAVE_CFLAGS" - CPPFLAGS="$SAVE_CPPFLAGS" - LDFLAGS="$SAVE_LDFLAGS" - - if test x"$working_native_cc" = x"no"; then - AC_MSG_RESULT([no]) - set_precomp=no - m4_define([please_set_for_build], [Please set CC_FOR_BUILD, CFLAGS_FOR_BUILD, CPPFLAGS_FOR_BUILD, and/or LDFLAGS_FOR_BUILD.]) - if test x"$use_ecmult_static_precomputation" = x"yes"; then - AC_MSG_ERROR([native compiler ${CC_FOR_BUILD} does not produce working binaries. please_set_for_build]) - else - AC_MSG_WARN([Disabling statically generated ecmult table because the native compiler ${CC_FOR_BUILD} does not produce working binaries. please_set_for_build]) - fi - else - AC_MSG_RESULT([yes]) - set_precomp=yes - fi -else - set_precomp=no -fi - if test x"$req_asm" = x"auto"; then SECP_64BIT_ASM_CHECK if test x"$has_64bit_asm" = x"yes"; then @@ -279,33 +246,7 @@ else esac fi -if test x"$req_bignum" = x"auto"; then - SECP_GMP_CHECK - if test x"$has_gmp" = x"yes"; then - set_bignum=gmp - fi - - if test x"$set_bignum" = x; then - set_bignum=no - fi -else - set_bignum=$req_bignum - case $set_bignum in - gmp) - SECP_GMP_CHECK - if test x"$has_gmp" != x"yes"; then - AC_MSG_ERROR([gmp bignum explicitly requested but libgmp not available]) - fi - ;; - no) - ;; - *) - AC_MSG_ERROR([invalid bignum implementation selection]) - ;; - esac -fi - -# select assembly optimization +# Select assembly optimization use_external_asm=no case $set_asm in @@ -322,7 +263,12 @@ no) ;; esac -# select wide multiplication implementation +if test x"$use_external_asm" = x"yes"; then + AC_DEFINE(USE_EXTERNAL_ASM, 1, [Define this symbol if an external (non-inline) assembly implementation is used]) +fi + + +# Select wide multiplication implementation case $set_widemul in int128) AC_DEFINE(USE_FORCE_WIDEMUL_INT128, 1, [Define this symbol to force the use of the (unsigned) __int128 based wide multiplication implementation]) @@ -337,25 +283,7 @@ auto) ;; esac -# select bignum implementation -case $set_bignum in -gmp) - AC_DEFINE(HAVE_LIBGMP, 1, [Define this symbol if libgmp is installed]) - AC_DEFINE(USE_NUM_GMP, 1, [Define this symbol to use the gmp implementation for num]) - AC_DEFINE(USE_FIELD_INV_NUM, 1, [Define this symbol to use the num-based field inverse implementation]) - AC_DEFINE(USE_SCALAR_INV_NUM, 1, [Define this symbol to use the num-based scalar inverse implementation]) - ;; -no) - AC_DEFINE(USE_NUM_NONE, 1, [Define this symbol to use no num implementation]) - AC_DEFINE(USE_FIELD_INV_BUILTIN, 1, [Define this symbol to use the native field inverse implementation]) - AC_DEFINE(USE_SCALAR_INV_BUILTIN, 1, [Define this symbol to use the native scalar inverse implementation]) - ;; -*) - AC_MSG_ERROR([invalid bignum implementation]) - ;; -esac - -#set ecmult window size +# Set ecmult window size if test x"$req_ecmult_window" = x"auto"; then set_ecmult_window=15 else @@ -377,7 +305,7 @@ case $set_ecmult_window in ;; esac -#set ecmult gen precision +# Set ecmult gen precision if test x"$req_ecmult_gen_precision" = x"auto"; then set_ecmult_gen_precision=4 else @@ -419,15 +347,93 @@ else enable_openssl_tests=no fi -if test x"$set_bignum" = x"gmp"; then - SECP_LIBS="$SECP_LIBS $GMP_LIBS" - SECP_INCLUDES="$SECP_INCLUDES $GMP_CPPFLAGS" +if test x"$enable_valgrind" = x"yes"; then + SECP_INCLUDES="$SECP_INCLUDES $VALGRIND_CPPFLAGS" +fi + +# Handle static precomputation (after everything which modifies CFLAGS and friends) +if test x"$use_ecmult_static_precomputation" != x"no"; then + if test x"$cross_compiling" = x"no"; then + set_precomp=yes + if test x"${CC_FOR_BUILD+x}${CFLAGS_FOR_BUILD+x}${CPPFLAGS_FOR_BUILD+x}${LDFLAGS_FOR_BUILD+x}" != x; then + AC_MSG_WARN([CC_FOR_BUILD, CFLAGS_FOR_BUILD, CPPFLAGS_FOR_BUILD, and/or LDFLAGS_FOR_BUILD is set but ignored because we are not cross-compiling.]) + fi + # If we're not cross-compiling, simply use the same compiler for building the static precompation code. + CC_FOR_BUILD="$CC" + CFLAGS_FOR_BUILD="$CFLAGS" + CPPFLAGS_FOR_BUILD="$CPPFLAGS" + LDFLAGS_FOR_BUILD="$LDFLAGS" + else + AX_PROG_CC_FOR_BUILD + + # Temporarily switch to an environment for the native compiler + save_cross_compiling=$cross_compiling + cross_compiling=no + SAVE_CC="$CC" + CC="$CC_FOR_BUILD" + SAVE_CFLAGS="$CFLAGS" + CFLAGS="$CFLAGS_FOR_BUILD" + SAVE_CPPFLAGS="$CPPFLAGS" + CPPFLAGS="$CPPFLAGS_FOR_BUILD" + SAVE_LDFLAGS="$LDFLAGS" + LDFLAGS="$LDFLAGS_FOR_BUILD" + + warn_CFLAGS_FOR_BUILD="-Wall -Wextra -Wno-unused-function" + saved_CFLAGS="$CFLAGS" + CFLAGS="$warn_CFLAGS_FOR_BUILD $CFLAGS" + AC_MSG_CHECKING([if native ${CC_FOR_BUILD} supports ${warn_CFLAGS_FOR_BUILD}]) + AC_COMPILE_IFELSE([AC_LANG_SOURCE([[char foo;]])], + [ AC_MSG_RESULT([yes]) ], + [ AC_MSG_RESULT([no]) + CFLAGS="$saved_CFLAGS" + ]) + + AC_MSG_CHECKING([for working native compiler: ${CC_FOR_BUILD}]) + AC_RUN_IFELSE( + [AC_LANG_PROGRAM([], [])], + [working_native_cc=yes], + [working_native_cc=no],[:]) + + CFLAGS_FOR_BUILD="$CFLAGS" + + # Restore the environment + cross_compiling=$save_cross_compiling + CC="$SAVE_CC" + CFLAGS="$SAVE_CFLAGS" + CPPFLAGS="$SAVE_CPPFLAGS" + LDFLAGS="$SAVE_LDFLAGS" + + if test x"$working_native_cc" = x"no"; then + AC_MSG_RESULT([no]) + set_precomp=no + m4_define([please_set_for_build], [Please set CC_FOR_BUILD, CFLAGS_FOR_BUILD, CPPFLAGS_FOR_BUILD, and/or LDFLAGS_FOR_BUILD.]) + if test x"$use_ecmult_static_precomputation" = x"yes"; then + AC_MSG_ERROR([native compiler ${CC_FOR_BUILD} does not produce working binaries. please_set_for_build]) + else + AC_MSG_WARN([Disabling statically generated ecmult table because the native compiler ${CC_FOR_BUILD} does not produce working binaries. please_set_for_build]) + fi + else + AC_MSG_RESULT([yes]) + set_precomp=yes + fi + fi + + AC_SUBST(CC_FOR_BUILD) + AC_SUBST(CFLAGS_FOR_BUILD) + AC_SUBST(CPPFLAGS_FOR_BUILD) + AC_SUBST(LDFLAGS_FOR_BUILD) +else + set_precomp=no fi if test x"$set_precomp" = x"yes"; then AC_DEFINE(USE_ECMULT_STATIC_PRECOMPUTATION, 1, [Define this symbol to use a statically generated ecmult table]) fi +### +### Handle module options +### + if test x"$enable_module_ecdh" = x"yes"; then AC_DEFINE(ENABLE_MODULE_ECDH, 1, [Define this symbol to enable the ECDH module]) fi @@ -447,14 +453,14 @@ if test x"$enable_module_extrakeys" = x"yes"; then AC_DEFINE(ENABLE_MODULE_EXTRAKEYS, 1, [Define this symbol to enable the extrakeys module]) fi -if test x"$use_external_asm" = x"yes"; then - AC_DEFINE(USE_EXTERNAL_ASM, 1, [Define this symbol if an external (non-inline) assembly implementation is used]) -fi - if test x"$use_external_default_callbacks" = x"yes"; then AC_DEFINE(USE_EXTERNAL_DEFAULT_CALLBACKS, 1, [Define this symbol if an external implementation of the default callbacks is used]) fi +### +### Check for --enable-experimental if necessary +### + if test x"$enable_experimental" = x"yes"; then AC_MSG_NOTICE([******]) AC_MSG_NOTICE([WARNING: experimental build]) @@ -474,6 +480,10 @@ else fi fi +### +### Generate output +### + AC_CONFIG_HEADERS([src/libsecp256k1-config.h]) AC_CONFIG_FILES([Makefile libsecp256k1.pc]) AC_SUBST(SECP_INCLUDES) @@ -492,7 +502,7 @@ AM_CONDITIONAL([ENABLE_MODULE_SCHNORRSIG], [test x"$enable_module_schnorrsig" = AM_CONDITIONAL([USE_EXTERNAL_ASM], [test x"$use_external_asm" = x"yes"]) AM_CONDITIONAL([USE_ASM_ARM], [test x"$set_asm" = x"arm"]) -dnl make sure nothing new is exported so that we don't break the cache +# Make sure nothing new is exported so that we don't break the cache. PKGCONFIG_PATH_TEMP="$PKG_CONFIG_PATH" unset PKG_CONFIG_PATH PKG_CONFIG_PATH="$PKGCONFIG_PATH_TEMP" @@ -513,10 +523,9 @@ echo " module extrakeys = $enable_module_extrakeys" echo " module schnorrsig = $enable_module_schnorrsig" echo echo " asm = $set_asm" -echo " bignum = $set_bignum" echo " ecmult window size = $set_ecmult_window" echo " ecmult gen prec. bits = $set_ecmult_gen_precision" -dnl Hide test-only options unless they're used. +# Hide test-only options unless they're used. if test x"$set_widemul" != xauto; then echo " wide multiplication = $set_widemul" fi @@ -527,3 +536,9 @@ echo " CFLAGS = $CFLAGS" echo " CPPFLAGS = $CPPFLAGS" echo " LDFLAGS = $LDFLAGS" echo +if test x"$set_precomp" = x"yes"; then +echo " CC_FOR_BUILD = $CC_FOR_BUILD" +echo " CFLAGS_FOR_BUILD = $CFLAGS_FOR_BUILD" +echo " CPPFLAGS_FOR_BUILD = $CPPFLAGS_FOR_BUILD" +echo " LDFLAGS_FOR_BUILD = $LDFLAGS_FOR_BUILD" +fi diff --git a/contrib/lax_der_parsing.c b/contrib/lax_der_parsing.c index f71db4b53524c..c1627e37e9e11 100644 --- a/contrib/lax_der_parsing.c +++ b/contrib/lax_der_parsing.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include #include diff --git a/contrib/lax_der_parsing.h b/contrib/lax_der_parsing.h index 7eaf63bf6a0ee..6b7255e28f5bc 100644 --- a/contrib/lax_der_parsing.h +++ b/contrib/lax_der_parsing.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ /**** * Please do not link this file directly. It is not part of the libsecp256k1 diff --git a/contrib/lax_der_privatekey_parsing.c b/contrib/lax_der_privatekey_parsing.c index c2e63b4b8d7b3..429760fbb6d19 100644 --- a/contrib/lax_der_privatekey_parsing.c +++ b/contrib/lax_der_privatekey_parsing.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014, 2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014, 2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include #include diff --git a/contrib/lax_der_privatekey_parsing.h b/contrib/lax_der_privatekey_parsing.h index fece261fb9ed2..602c7c556ad15 100644 --- a/contrib/lax_der_privatekey_parsing.h +++ b/contrib/lax_der_privatekey_parsing.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014, 2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014, 2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ /**** * Please do not link this file directly. It is not part of the libsecp256k1 diff --git a/doc/safegcd_implementation.md b/doc/safegcd_implementation.md new file mode 100644 index 0000000000000..3ae556f9a7240 --- /dev/null +++ b/doc/safegcd_implementation.md @@ -0,0 +1,765 @@ +# The safegcd implementation in libsecp256k1 explained + +This document explains the modular inverse implementation in the `src/modinv*.h` files. It is based +on the paper +["Fast constant-time gcd computation and modular inversion"](https://gcd.cr.yp.to/papers.html#safegcd) +by Daniel J. Bernstein and Bo-Yin Yang. The references below are for the Date: 2019.04.13 version. + +The actual implementation is in C of course, but for demonstration purposes Python3 is used here. +Most implementation aspects and optimizations are explained, except those that depend on the specific +number representation used in the C code. + +## 1. Computing the Greatest Common Divisor (GCD) using divsteps + +The algorithm from the paper (section 11), at a very high level, is this: + +```python +def gcd(f, g): + """Compute the GCD of an odd integer f and another integer g.""" + assert f & 1 # require f to be odd + delta = 1 # additional state variable + while g != 0: + assert f & 1 # f will be odd in every iteration + if delta > 0 and g & 1: + delta, f, g = 1 - delta, g, (g - f) // 2 + elif g & 1: + delta, f, g = 1 + delta, f, (g + f) // 2 + else: + delta, f, g = 1 + delta, f, (g ) // 2 + return abs(f) +``` + +It computes the greatest common divisor of an odd integer *f* and any integer *g*. Its inner loop +keeps rewriting the variables *f* and *g* alongside a state variable *δ* that starts at *1*, until +*g=0* is reached. At that point, *|f|* gives the GCD. Each of the transitions in the loop is called a +"division step" (referred to as divstep in what follows). + +For example, *gcd(21, 14)* would be computed as: +- Start with *δ=1 f=21 g=14* +- Take the third branch: *δ=2 f=21 g=7* +- Take the first branch: *δ=-1 f=7 g=-7* +- Take the second branch: *δ=0 f=7 g=0* +- The answer *|f| = 7*. + +Why it works: +- Divsteps can be decomposed into two steps (see paragraph 8.2 in the paper): + - (a) If *g* is odd, replace *(f,g)* with *(g,g-f)* or (f,g+f), resulting in an even *g*. + - (b) Replace *(f,g)* with *(f,g/2)* (where *g* is guaranteed to be even). +- Neither of those two operations change the GCD: + - For (a), assume *gcd(f,g)=c*, then it must be the case that *f=a c* and *g=b c* for some integers *a* + and *b*. As *(g,g-f)=(b c,(b-a)c)* and *(f,f+g)=(a c,(a+b)c)*, the result clearly still has + common factor *c*. Reasoning in the other direction shows that no common factor can be added by + doing so either. + - For (b), we know that *f* is odd, so *gcd(f,g)* clearly has no factor *2*, and we can remove + it from *g*. +- The algorithm will eventually converge to *g=0*. This is proven in the paper (see theorem G.3). +- It follows that eventually we find a final value *f'* for which *gcd(f,g) = gcd(f',0)*. As the + gcd of *f'* and *0* is *|f'|* by definition, that is our answer. + +Compared to more [traditional GCD algorithms](https://en.wikipedia.org/wiki/Euclidean_algorithm), this one has the property of only ever looking at +the low-order bits of the variables to decide the next steps, and being easy to make +constant-time (in more low-level languages than Python). The *δ* parameter is necessary to +guide the algorithm towards shrinking the numbers' magnitudes without explicitly needing to look +at high order bits. + +Properties that will become important later: +- Performing more divsteps than needed is not a problem, as *f* does not change anymore after *g=0*. +- Only even numbers are divided by *2*. This means that when reasoning about it algebraically we + do not need to worry about rounding. +- At every point during the algorithm's execution the next *N* steps only depend on the bottom *N* + bits of *f* and *g*, and on *δ*. + + +## 2. From GCDs to modular inverses + +We want an algorithm to compute the inverse *a* of *x* modulo *M*, i.e. the number a such that *a x=1 +mod M*. This inverse only exists if the GCD of *x* and *M* is *1*, but that is always the case if *M* is +prime and *0 < x < M*. In what follows, assume that the modular inverse exists. +It turns out this inverse can be computed as a side effect of computing the GCD by keeping track +of how the internal variables can be written as linear combinations of the inputs at every step +(see the [extended Euclidean algorithm](https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm)). +Since the GCD is *1*, such an algorithm will compute numbers *a* and *b* such that a x + b M = 1*. +Taking that expression *mod M* gives *a x mod M = 1*, and we see that *a* is the modular inverse of *x +mod M*. + +A similar approach can be used to calculate modular inverses using the divsteps-based GCD +algorithm shown above, if the modulus *M* is odd. To do so, compute *gcd(f=M,g=x)*, while keeping +track of extra variables *d* and *e*, for which at every step *d = f/x (mod M)* and *e = g/x (mod M)*. +*f/x* here means the number which multiplied with *x* gives *f mod M*. As *f* and *g* are initialized to *M* +and *x* respectively, *d* and *e* just start off being *0* (*M/x mod M = 0/x mod M = 0*) and *1* (*x/x mod M += 1*). + +```python +def div2(M, x): + """Helper routine to compute x/2 mod M (where M is odd).""" + assert M & 1 + if x & 1: # If x is odd, make it even by adding M. + x += M + # x must be even now, so a clean division by 2 is possible. + return x // 2 + +def modinv(M, x): + """Compute the inverse of x mod M (given that it exists, and M is odd).""" + assert M & 1 + delta, f, g, d, e = 1, M, x, 0, 1 + while g != 0: + # Note that while division by two for f and g is only ever done on even inputs, this is + # not true for d and e, so we need the div2 helper function. + if delta > 0 and g & 1: + delta, f, g, d, e = 1 - delta, g, (g - f) // 2, e, div2(M, e - d) + elif g & 1: + delta, f, g, d, e = 1 + delta, f, (g + f) // 2, d, div2(M, e + d) + else: + delta, f, g, d, e = 1 + delta, f, (g ) // 2, d, div2(M, e ) + # Verify that the invariants d=f/x mod M, e=g/x mod M are maintained. + assert f % M == (d * x) % M + assert g % M == (e * x) % M + assert f == 1 or f == -1 # |f| is the GCD, it must be 1 + # Because of invariant d = f/x (mod M), 1/x = d/f (mod M). As |f|=1, d/f = d*f. + return (d * f) % M +``` + +Also note that this approach to track *d* and *e* throughout the computation to determine the inverse +is different from the paper. There (see paragraph 12.1 in the paper) a transition matrix for the +entire computation is determined (see section 3 below) and the inverse is computed from that. +The approach here avoids the need for 2x2 matrix multiplications of various sizes, and appears to +be faster at the level of optimization we're able to do in C. + + +## 3. Batching multiple divsteps + +Every divstep can be expressed as a matrix multiplication, applying a transition matrix *(1/2 t)* +to both vectors *[f, g]* and *[d, e]* (see paragraph 8.1 in the paper): + +``` + t = [ u, v ] + [ q, r ] + + [ out_f ] = (1/2 * t) * [ in_f ] + [ out_g ] = [ in_g ] + + [ out_d ] = (1/2 * t) * [ in_d ] (mod M) + [ out_e ] [ in_e ] +``` + +where *(u, v, q, r)* is *(0, 2, -1, 1)*, *(2, 0, 1, 1)*, or *(2, 0, 0, 1)*, depending on which branch is +taken. As above, the resulting *f* and *g* are always integers. + +Performing multiple divsteps corresponds to a multiplication with the product of all the +individual divsteps' transition matrices. As each transition matrix consists of integers +divided by *2*, the product of these matrices will consist of integers divided by *2N* (see also +theorem 9.2 in the paper). These divisions are expensive when updating *d* and *e*, so we delay +them: we compute the integer coefficients of the combined transition matrix scaled by *2N*, and +do one division by *2N* as a final step: + +```python +def divsteps_n_matrix(delta, f, g): + """Compute delta and transition matrix t after N divsteps (multiplied by 2^N).""" + u, v, q, r = 1, 0, 0, 1 # start with identity matrix + for _ in range(N): + if delta > 0 and g & 1: + delta, f, g, u, v, q, r = 1 - delta, g, (g - f) // 2, 2*q, 2*r, q-u, r-v + elif g & 1: + delta, f, g, u, v, q, r = 1 + delta, f, (g + f) // 2, 2*u, 2*v, q+u, r+v + else: + delta, f, g, u, v, q, r = 1 + delta, f, (g ) // 2, 2*u, 2*v, q , r + return delta, (u, v, q, r) +``` + +As the branches in the divsteps are completely determined by the bottom *N* bits of *f* and *g*, this +function to compute the transition matrix only needs to see those bottom bits. Furthermore all +intermediate results and outputs fit in *(N+1)*-bit numbers (unsigned for *f* and *g*; signed for *u*, *v*, +*q*, and *r*) (see also paragraph 8.3 in the paper). This means that an implementation using 64-bit +integers could set *N=62* and compute the full transition matrix for 62 steps at once without any +big integer arithmetic at all. This is the reason why this algorithm is efficient: it only needs +to update the full-size *f*, *g*, *d*, and *e* numbers once every *N* steps. + +We still need functions to compute: + +``` + [ out_f ] = (1/2^N * [ u, v ]) * [ in_f ] + [ out_g ] ( [ q, r ]) [ in_g ] + + [ out_d ] = (1/2^N * [ u, v ]) * [ in_d ] (mod M) + [ out_e ] ( [ q, r ]) [ in_e ] +``` + +Because the divsteps transformation only ever divides even numbers by two, the result of *t [f,g]* is always even. When *t* is a composition of *N* divsteps, it follows that the resulting *f* +and *g* will be multiple of *2N*, and division by *2N* is simply shifting them down: + +```python +def update_fg(f, g, t): + """Multiply matrix t/2^N with [f, g].""" + u, v, q, r = t + cf, cg = u*f + v*g, q*f + r*g + # (t / 2^N) should cleanly apply to [f,g] so the result of t*[f,g] should have N zero + # bottom bits. + assert cf % 2**N == 0 + assert cg % 2**N == 0 + return cf >> N, cg >> N +``` + +The same is not true for *d* and *e*, and we need an equivalent of the `div2` function for division by *2N mod M*. +This is easy if we have precomputed *1/M mod 2N* (which always exists for odd *M*): + +```python +def div2n(M, Mi, x): + """Compute x/2^N mod M, given Mi = 1/M mod 2^N.""" + assert (M * Mi) % 2**N == 1 + # Find a factor m such that m*M has the same bottom N bits as x. We want: + # (m * M) mod 2^N = x mod 2^N + # <=> m mod 2^N = (x / M) mod 2^N + # <=> m mod 2^N = (x * Mi) mod 2^N + m = (Mi * x) % 2**N + # Subtract that multiple from x, cancelling its bottom N bits. + x -= m * M + # Now a clean division by 2^N is possible. + assert x % 2**N == 0 + return (x >> N) % M + +def update_de(d, e, t, M, Mi): + """Multiply matrix t/2^N with [d, e], modulo M.""" + u, v, q, r = t + cd, ce = u*d + v*e, q*d + r*e + return div2n(M, Mi, cd), div2n(M, Mi, ce) +``` + +With all of those, we can write a version of `modinv` that performs *N* divsteps at once: + +```python3 +def modinv(M, Mi, x): + """Compute the modular inverse of x mod M, given Mi=1/M mod 2^N.""" + assert M & 1 + delta, f, g, d, e = 1, M, x, 0, 1 + while g != 0: + # Compute the delta and transition matrix t for the next N divsteps (this only needs + # (N+1)-bit signed integer arithmetic). + delta, t = divsteps_n_matrix(delta, f % 2**N, g % 2**N) + # Apply the transition matrix t to [f, g]: + f, g = update_fg(f, g, t) + # Apply the transition matrix t to [d, e]: + d, e = update_de(d, e, t, M, Mi) + return (d * f) % M +``` + +This means that in practice we'll always perform a multiple of *N* divsteps. This is not a problem +because once *g=0*, further divsteps do not affect *f*, *g*, *d*, or *e* anymore (only *δ* keeps +increasing). For variable time code such excess iterations will be mostly optimized away in later +sections. + + +## 4. Avoiding modulus operations + +So far, there are two places where we compute a remainder of big numbers modulo *M*: at the end of +`div2n` in every `update_de`, and at the very end of `modinv` after potentially negating *d* due to the +sign of *f*. These are relatively expensive operations when done generically. + +To deal with the modulus operation in `div2n`, we simply stop requiring *d* and *e* to be in range +*[0,M)* all the time. Let's start by inlining `div2n` into `update_de`, and dropping the modulus +operation at the end: + +```python +def update_de(d, e, t, M, Mi): + """Multiply matrix t/2^N with [d, e] mod M, given Mi=1/M mod 2^N.""" + u, v, q, r = t + cd, ce = u*d + v*e, q*d + r*e + # Cancel out bottom N bits of cd and ce. + md = -((Mi * cd) % 2**N) + me = -((Mi * ce) % 2**N) + cd += md * M + ce += me * M + # And cleanly divide by 2**N. + return cd >> N, ce >> N +``` + +Let's look at bounds on the ranges of these numbers. It can be shown that *|u|+|v|* and *|q|+|r|* +never exceed *2N* (see paragraph 8.3 in the paper), and thus a multiplication with *t* will have +outputs whose absolute values are at most *2N* times the maximum absolute input value. In case the +inputs *d* and *e* are in *(-M,M)*, which is certainly true for the initial values *d=0* and *e=1* assuming +*M > 1*, the multiplication results in numbers in range *(-2NM,2NM)*. Subtracting less than *2N* +times *M* to cancel out *N* bits brings that up to *(-2N+1M,2NM)*, and +dividing by *2N* at the end takes it to *(-2M,M)*. Another application of `update_de` would take that +to *(-3M,2M)*, and so forth. This progressive expansion of the variables' ranges can be +counteracted by incrementing *d* and *e* by *M* whenever they're negative: + +```python + ... + if d < 0: + d += M + if e < 0: + e += M + cd, ce = u*d + v*e, q*d + r*e + # Cancel out bottom N bits of cd and ce. + ... +``` + +With inputs in *(-2M,M)*, they will first be shifted into range *(-M,M)*, which means that the +output will again be in *(-2M,M)*, and this remains the case regardless of how many `update_de` +invocations there are. In what follows, we will try to make this more efficient. + +Note that increasing *d* by *M* is equal to incrementing *cd* by *u M* and *ce* by *q M*. Similarly, +increasing *e* by *M* is equal to incrementing *cd* by *v M* and *ce* by *r M*. So we could instead write: + +```python + ... + cd, ce = u*d + v*e, q*d + r*e + # Perform the equivalent of incrementing d, e by M when they're negative. + if d < 0: + cd += u*M + ce += q*M + if e < 0: + cd += v*M + ce += r*M + # Cancel out bottom N bits of cd and ce. + md = -((Mi * cd) % 2**N) + me = -((Mi * ce) % 2**N) + cd += md * M + ce += me * M + ... +``` + +Now note that we have two steps of corrections to *cd* and *ce* that add multiples of *M*: this +increment, and the decrement that cancels out bottom bits. The second one depends on the first +one, but they can still be efficiently combined by only computing the bottom bits of *cd* and *ce* +at first, and using that to compute the final *md*, *me* values: + +```python +def update_de(d, e, t, M, Mi): + """Multiply matrix t/2^N with [d, e], modulo M.""" + u, v, q, r = t + md, me = 0, 0 + # Compute what multiples of M to add to cd and ce. + if d < 0: + md += u + me += q + if e < 0: + md += v + me += r + # Compute bottom N bits of t*[d,e] + M*[md,me]. + cd, ce = (u*d + v*e + md*M) % 2**N, (q*d + r*e + me*M) % 2**N + # Correct md and me such that the bottom N bits of t*[d,e] + M*[md,me] are zero. + md -= (Mi * cd) % 2**N + me -= (Mi * ce) % 2**N + # Do the full computation. + cd, ce = u*d + v*e + md*M, q*d + r*e + me*M + # And cleanly divide by 2**N. + return cd >> N, ce >> N +``` + +One last optimization: we can avoid the *md M* and *me M* multiplications in the bottom bits of *cd* +and *ce* by moving them to the *md* and *me* correction: + +```python + ... + # Compute bottom N bits of t*[d,e]. + cd, ce = (u*d + v*e) % 2**N, (q*d + r*e) % 2**N + # Correct md and me such that the bottom N bits of t*[d,e]+M*[md,me] are zero. + # Note that this is not the same as {md = (-Mi * cd) % 2**N} etc. That would also result in N + # zero bottom bits, but isn't guaranteed to be a reduction of [0,2^N) compared to the + # previous md and me values, and thus would violate our bounds analysis. + md -= (Mi*cd + md) % 2**N + me -= (Mi*ce + me) % 2**N + ... +``` + +The resulting function takes *d* and *e* in range *(-2M,M)* as inputs, and outputs values in the same +range. That also means that the *d* value at the end of `modinv` will be in that range, while we want +a result in *[0,M)*. To do that, we need a normalization function. It's easy to integrate the +conditional negation of *d* (based on the sign of *f*) into it as well: + +```python +def normalize(sign, v, M): + """Compute sign*v mod M, where v is in range (-2*M,M); output in [0,M).""" + assert sign == 1 or sign == -1 + # v in (-2*M,M) + if v < 0: + v += M + # v in (-M,M). Now multiply v with sign (which can only be 1 or -1). + if sign == -1: + v = -v + # v in (-M,M) + if v < 0: + v += M + # v in [0,M) + return v +``` + +And calling it in `modinv` is simply: + +```python + ... + return normalize(f, d, M) +``` + + +## 5. Constant-time operation + +The primary selling point of the algorithm is fast constant-time operation. What code flow still +depends on the input data so far? + +- the number of iterations of the while *g ≠ 0* loop in `modinv` +- the branches inside `divsteps_n_matrix` +- the sign checks in `update_de` +- the sign checks in `normalize` + +To make the while loop in `modinv` constant time it can be replaced with a constant number of +iterations. The paper proves (Theorem 11.2) that *741* divsteps are sufficient for any *256*-bit +inputs, and [safegcd-bounds](https://github.com/sipa/safegcd-bounds) shows that the slightly better bound *724* is +sufficient even. Given that every loop iteration performs *N* divsteps, it will run a total of +*⌈724/N⌉* times. + +To deal with the branches in `divsteps_n_matrix` we will replace them with constant-time bitwise +operations (and hope the C compiler isn't smart enough to turn them back into branches; see +`valgrind_ctime_test.c` for automated tests that this isn't the case). To do so, observe that a +divstep can be written instead as (compare to the inner loop of `gcd` in section 1). + +```python + x = -f if delta > 0 else f # set x equal to (input) -f or f + if g & 1: + g += x # set g to (input) g-f or g+f + if delta > 0: + delta = -delta + f += g # set f to (input) g (note that g was set to g-f before) + delta += 1 + g >>= 1 +``` + +To convert the above to bitwise operations, we rely on a trick to negate conditionally: per the +definition of negative numbers in two's complement, (*-v == ~v + 1*) holds for every number *v*. As +*-1* in two's complement is all *1* bits, bitflipping can be expressed as xor with *-1*. It follows +that *-v == (v ^ -1) - (-1)*. Thus, if we have a variable *c* that takes on values *0* or *-1*, then +*(v ^ c) - c* is *v* if *c=0* and *-v* if *c=-1*. + +Using this we can write: + +```python + x = -f if delta > 0 else f +``` + +in constant-time form as: + +```python + c1 = (-delta) >> 63 + # Conditionally negate f based on c1: + x = (f ^ c1) - c1 +``` + +To use that trick, we need a helper mask variable *c1* that resolves the condition *δ>0* to *-1* +(if true) or *0* (if false). We compute *c1* using right shifting, which is equivalent to dividing by +the specified power of *2* and rounding down (in Python, and also in C under the assumption of a typical two's complement system; see +`assumptions.h` for tests that this is the case). Right shifting by *63* thus maps all +numbers in range *[-263,0)* to *-1*, and numbers in range *[0,263)* to *0*. + +Using the facts that *x&0=0* and *x&(-1)=x* (on two's complement systems again), we can write: + +```python + if g & 1: + g += x +``` + +as: + +```python + # Compute c2=0 if g is even and c2=-1 if g is odd. + c2 = -(g & 1) + # This masks out x if g is even, and leaves x be if g is odd. + g += x & c2 +``` + +Using the conditional negation trick again we can write: + +```python + if g & 1: + if delta > 0: + delta = -delta +``` + +as: + +```python + # Compute c3=-1 if g is odd and delta>0, and 0 otherwise. + c3 = c1 & c2 + # Conditionally negate delta based on c3: + delta = (delta ^ c3) - c3 +``` + +Finally: + +```python + if g & 1: + if delta > 0: + f += g +``` + +becomes: + +```python + f += g & c3 +``` + +It turns out that this can be implemented more efficiently by applying the substitution +*η=-δ*. In this representation, negating *δ* corresponds to negating *η*, and incrementing +*δ* corresponds to decrementing *η*. This allows us to remove the negation in the *c1* +computation: + +```python + # Compute a mask c1 for eta < 0, and compute the conditional negation x of f: + c1 = eta >> 63 + x = (f ^ c1) - c1 + # Compute a mask c2 for odd g, and conditionally add x to g: + c2 = -(g & 1) + g += x & c2 + # Compute a mask c for (eta < 0) and odd (input) g, and use it to conditionally negate eta, + # and add g to f: + c3 = c1 & c2 + eta = (eta ^ c3) - c3 + f += g & c3 + # Incrementing delta corresponds to decrementing eta. + eta -= 1 + g >>= 1 +``` + +A variant of divsteps with better worst-case performance can be used instead: starting *δ* at +*1/2* instead of *1*. This reduces the worst case number of iterations to *590* for *256*-bit inputs +(which can be shown using convex hull analysis). In this case, the substitution *ζ=-(δ+1/2)* +is used instead to keep the variable integral. Incrementing *δ* by *1* still translates to +decrementing *ζ* by *1*, but negating *δ* now corresponds to going from *ζ* to *-(ζ+1)*, or +*~ζ*. Doing that conditionally based on *c3* is simply: + +```python + ... + c3 = c1 & c2 + zeta ^= c3 + ... +``` + +By replacing the loop in `divsteps_n_matrix` with a variant of the divstep code above (extended to +also apply all *f* operations to *u*, *v* and all *g* operations to *q*, *r*), a constant-time version of +`divsteps_n_matrix` is obtained. The full code will be in section 7. + +These bit fiddling tricks can also be used to make the conditional negations and additions in +`update_de` and `normalize` constant-time. + + +## 6. Variable-time optimizations + +In section 5, we modified the `divsteps_n_matrix` function (and a few others) to be constant time. +Constant time operations are only necessary when computing modular inverses of secret data. In +other cases, it slows down calculations unnecessarily. In this section, we will construct a +faster non-constant time `divsteps_n_matrix` function. + +To do so, first consider yet another way of writing the inner loop of divstep operations in +`gcd` from section 1. This decomposition is also explained in the paper in section 8.2. We use +the original version with initial *δ=1* and *η=-δ* here. + +```python +for _ in range(N): + if g & 1 and eta < 0: + eta, f, g = -eta, g, -f + if g & 1: + g += f + eta -= 1 + g >>= 1 +``` + +Whenever *g* is even, the loop only shifts *g* down and decreases *η*. When *g* ends in multiple zero +bits, these iterations can be consolidated into one step. This requires counting the bottom zero +bits efficiently, which is possible on most platforms; it is abstracted here as the function +`count_trailing_zeros`. + +```python +def count_trailing_zeros(v): + """For a non-zero value v, find z such that v=(d<>= zeros + i -= zeros + if i == 0: + break + # We know g is odd now + if eta < 0: + eta, f, g = -eta, g, -f + g += f + # g is even now, and the eta decrement and g shift will happen in the next loop. +``` + +We can now remove multiple bottom *0* bits from *g* at once, but still need a full iteration whenever +there is a bottom *1* bit. In what follows, we will get rid of multiple *1* bits simultaneously as +well. + +Observe that as long as *η ≥ 0*, the loop does not modify *f*. Instead, it cancels out bottom +bits of *g* and shifts them out, and decreases *η* and *i* accordingly - interrupting only when *η* +becomes negative, or when *i* reaches *0*. Combined, this is equivalent to adding a multiple of *f* to +*g* to cancel out multiple bottom bits, and then shifting them out. + +It is easy to find what that multiple is: we want a number *w* such that *g+w f* has a few bottom +zero bits. If that number of bits is *L*, we want *g+w f mod 2L = 0*, or *w = -g/f mod 2L*. Since *f* +is odd, such a *w* exists for any *L*. *L* cannot be more than *i* steps (as we'd finish the loop before +doing more) or more than *η+1* steps (as we'd run `eta, f, g = -eta, g, f` at that point), but +apart from that, we're only limited by the complexity of computing *w*. + +This code demonstrates how to cancel up to 4 bits per step: + +```python +NEGINV16 = [15, 5, 3, 9, 7, 13, 11, 1] # NEGINV16[n//2] = (-n)^-1 mod 16, for odd n +i = N +while True: + zeros = min(i, count_trailing_zeros(g)) + eta -= zeros + g >>= zeros + i -= zeros + if i == 0: + break + # We know g is odd now + if eta < 0: + eta, f, g = -eta, g, f + # Compute limit on number of bits to cancel + limit = min(min(eta + 1, i), 4) + # Compute w = -g/f mod 2**limit, using the table value for -1/f mod 2**4. Note that f is + # always odd, so its inverse modulo a power of two always exists. + w = (g * NEGINV16[(f & 15) // 2]) % (2**limit) + # As w = -g/f mod (2**limit), g+w*f mod 2**limit = 0 mod 2**limit. + g += w * f + assert g % (2**limit) == 0 + # The next iteration will now shift out at least limit bottom zero bits from g. +``` + +By using a bigger table more bits can be cancelled at once. The table can also be implemented +as a formula. Several formulas are known for computing modular inverses modulo powers of two; +some can be found in Hacker's Delight second edition by Henry S. Warren, Jr. pages 245-247. +Here we need the negated modular inverse, which is a simple transformation of those: + +- Instead of a 3-bit table: + - *-f* or *f ^ 6* +- Instead of a 4-bit table: + - *1 - f(f + 1)* + - *-(f + (((f + 1) & 4) << 1))* +- For larger tables the following technique can be used: if *w=-1/f mod 2L*, then *w(w f+2)* is + *-1/f mod 22L*. This allows extending the previous formulas (or tables). In particular we + have this 6-bit function (based on the 3-bit function above): + - *f(f2 - 2)* + +This loop, again extended to also handle *u*, *v*, *q*, and *r* alongside *f* and *g*, placed in +`divsteps_n_matrix`, gives a significantly faster, but non-constant time version. + + +## 7. Final Python version + +All together we need the following functions: + +- A way to compute the transition matrix in constant time, using the `divsteps_n_matrix` function + from section 2, but with its loop replaced by a variant of the constant-time divstep from + section 5, extended to handle *u*, *v*, *q*, *r*: + +```python +def divsteps_n_matrix(zeta, f, g): + """Compute zeta and transition matrix t after N divsteps (multiplied by 2^N).""" + u, v, q, r = 1, 0, 0, 1 # start with identity matrix + for _ in range(N): + c1 = zeta >> 63 + # Compute x, y, z as conditionally-negated versions of f, u, v. + x, y, z = (f ^ c1) - c1, (u ^ c1) - c1, (v ^ c1) - c1 + c2 = -(g & 1) + # Conditionally add x, y, z to g, q, r. + g, q, r = g + (x & c2), q + (y & c2), r + (z & c2) + c1 &= c2 # reusing c1 here for the earlier c3 variable + zeta = (zeta ^ c1) - 1 # inlining the unconditional zeta decrement here + # Conditionally add g, q, r to f, u, v. + f, u, v = f + (g & c1), u + (q & c1), v + (r & c1) + # When shifting g down, don't shift q, r, as we construct a transition matrix multiplied + # by 2^N. Instead, shift f's coefficients u and v up. + g, u, v = g >> 1, u << 1, v << 1 + return zeta, (u, v, q, r) +``` + +- The functions to update *f* and *g*, and *d* and *e*, from section 2 and section 4, with the constant-time + changes to `update_de` from section 5: + +```python +def update_fg(f, g, t): + """Multiply matrix t/2^N with [f, g].""" + u, v, q, r = t + cf, cg = u*f + v*g, q*f + r*g + return cf >> N, cg >> N + +def update_de(d, e, t, M, Mi): + """Multiply matrix t/2^N with [d, e], modulo M.""" + u, v, q, r = t + d_sign, e_sign = d >> 257, e >> 257 + md, me = (u & d_sign) + (v & e_sign), (q & d_sign) + (r & e_sign) + cd, ce = (u*d + v*e) % 2**N, (q*d + r*e) % 2**N + md -= (Mi*cd + md) % 2**N + me -= (Mi*ce + me) % 2**N + cd, ce = u*d + v*e + M*md, q*d + r*e + M*me + return cd >> N, ce >> N +``` + +- The `normalize` function from section 4, made constant time as well: + +```python +def normalize(sign, v, M): + """Compute sign*v mod M, where v in (-2*M,M); output in [0,M).""" + v_sign = v >> 257 + # Conditionally add M to v. + v += M & v_sign + c = (sign - 1) >> 1 + # Conditionally negate v. + v = (v ^ c) - c + v_sign = v >> 257 + # Conditionally add M to v again. + v += M & v_sign + return v +``` + +- And finally the `modinv` function too, adapted to use *ζ* instead of *δ*, and using the fixed + iteration count from section 5: + +```python +def modinv(M, Mi, x): + """Compute the modular inverse of x mod M, given Mi=1/M mod 2^N.""" + zeta, f, g, d, e = -1, M, x, 0, 1 + for _ in range((590 + N - 1) // N): + zeta, t = divsteps_n_matrix(zeta, f % 2**N, g % 2**N) + f, g = update_fg(f, g, t) + d, e = update_de(d, e, t, M, Mi) + return normalize(f, d, M) +``` + +- To get a variable time version, replace the `divsteps_n_matrix` function with one that uses the + divsteps loop from section 5, and a `modinv` version that calls it without the fixed iteration + count: + +```python +NEGINV16 = [15, 5, 3, 9, 7, 13, 11, 1] # NEGINV16[n//2] = (-n)^-1 mod 16, for odd n +def divsteps_n_matrix_var(eta, f, g): + """Compute eta and transition matrix t after N divsteps (multiplied by 2^N).""" + u, v, q, r = 1, 0, 0, 1 + i = N + while True: + zeros = min(i, count_trailing_zeros(g)) + eta, i = eta - zeros, i - zeros + g, u, v = g >> zeros, u << zeros, v << zeros + if i == 0: + break + if eta < 0: + eta, f, u, v, g, q, r = -eta, g, q, r, -f, -u, -v + limit = min(min(eta + 1, i), 4) + w = (g * NEGINV16[(f & 15) // 2]) % (2**limit) + g, q, r = g + w*f, q + w*u, r + w*v + return eta, (u, v, q, r) + +def modinv_var(M, Mi, x): + """Compute the modular inverse of x mod M, given Mi = 1/M mod 2^N.""" + eta, f, g, d, e = -1, M, x, 0, 1 + while g != 0: + eta, t = divsteps_n_matrix_var(eta, f % 2**N, g % 2**N) + f, g = update_fg(f, g, t) + d, e = update_de(d, e, t, M, Mi) + return normalize(f, d, Mi) +``` diff --git a/include/secp256k1.h b/include/secp256k1.h index 2178c8e2d6f18..d368488af21c4 100644 --- a/include/secp256k1.h +++ b/include/secp256k1.h @@ -11,7 +11,7 @@ extern "C" { * * 1. Context pointers go first, followed by output arguments, combined * output/input arguments, and finally input-only arguments. - * 2. Array lengths always immediately the follow the argument whose length + * 2. Array lengths always immediately follow the argument whose length * they describe, even if this violates rule 1. * 3. Within the OUT/OUTIN/IN groups, pointers to data that is typically generated * later go first. This means: signatures, public nonces, secret nonces, @@ -452,7 +452,14 @@ SECP256K1_API int secp256k1_ecdsa_signature_serialize_compact( * 0: incorrect or unparseable signature * Args: ctx: a secp256k1 context object, initialized for verification. * In: sig: the signature being verified (cannot be NULL) - * msg32: the 32-byte message hash being verified (cannot be NULL) + * msghash32: the 32-byte message hash being verified (cannot be NULL). + * The verifier must make sure to apply a cryptographic + * hash function to the message by itself and not accept an + * msghash32 value directly. Otherwise, it would be easy to + * create a "valid" signature without knowledge of the + * secret key. See also + * https://bitcoin.stackexchange.com/a/81116/35586 for more + * background on this topic. * pubkey: pointer to an initialized public key to verify with (cannot be NULL) * * To avoid accepting malleable signatures, only ECDSA signatures in lower-S @@ -467,7 +474,7 @@ SECP256K1_API int secp256k1_ecdsa_signature_serialize_compact( SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify( const secp256k1_context* ctx, const secp256k1_ecdsa_signature *sig, - const unsigned char *msg32, + const unsigned char *msghash32, const secp256k1_pubkey *pubkey ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4); @@ -532,12 +539,12 @@ SECP256K1_API extern const secp256k1_nonce_function secp256k1_nonce_function_def * * Returns: 1: signature created * 0: the nonce generation function failed, or the secret key was invalid. - * Args: ctx: pointer to a context object, initialized for signing (cannot be NULL) - * Out: sig: pointer to an array where the signature will be placed (cannot be NULL) - * In: msg32: the 32-byte message hash being signed (cannot be NULL) - * seckey: pointer to a 32-byte secret key (cannot be NULL) - * noncefp:pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used - * ndata: pointer to arbitrary data used by the nonce generation function (can be NULL) + * Args: ctx: pointer to a context object, initialized for signing (cannot be NULL) + * Out: sig: pointer to an array where the signature will be placed (cannot be NULL) + * In: msghash32: the 32-byte message hash being signed (cannot be NULL) + * seckey: pointer to a 32-byte secret key (cannot be NULL) + * noncefp: pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used + * ndata: pointer to arbitrary data used by the nonce generation function (can be NULL) * * The created signature is always in lower-S form. See * secp256k1_ecdsa_signature_normalize for more details. @@ -545,7 +552,7 @@ SECP256K1_API extern const secp256k1_nonce_function secp256k1_nonce_function_def SECP256K1_API int secp256k1_ecdsa_sign( const secp256k1_context* ctx, secp256k1_ecdsa_signature *sig, - const unsigned char *msg32, + const unsigned char *msghash32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void *ndata @@ -626,7 +633,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_negate( * invalid according to secp256k1_ec_seckey_verify, this * function returns 0. seckey will be set to some unspecified * value if this function returns 0. (cannot be NULL) - * In: tweak: pointer to a 32-byte tweak. If the tweak is invalid according to + * In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according to * secp256k1_ec_seckey_verify, this function returns 0. For * uniformly random 32-byte arrays the chance of being invalid * is negligible (around 1 in 2^128) (cannot be NULL). @@ -634,7 +641,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_negate( SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_add( const secp256k1_context* ctx, unsigned char *seckey, - const unsigned char *tweak + const unsigned char *tweak32 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); /** Same as secp256k1_ec_seckey_tweak_add, but DEPRECATED. Will be removed in @@ -642,7 +649,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_add( SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add( const secp256k1_context* ctx, unsigned char *seckey, - const unsigned char *tweak + const unsigned char *tweak32 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); /** Tweak a public key by adding tweak times the generator to it. @@ -654,7 +661,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add( * (cannot be NULL). * In/Out: pubkey: pointer to a public key object. pubkey will be set to an * invalid value if this function returns 0 (cannot be NULL). - * In: tweak: pointer to a 32-byte tweak. If the tweak is invalid according to + * In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according to * secp256k1_ec_seckey_verify, this function returns 0. For * uniformly random 32-byte arrays the chance of being invalid * is negligible (around 1 in 2^128) (cannot be NULL). @@ -662,7 +669,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add( SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add( const secp256k1_context* ctx, secp256k1_pubkey *pubkey, - const unsigned char *tweak + const unsigned char *tweak32 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); /** Tweak a secret key by multiplying it by a tweak. @@ -673,7 +680,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add( * invalid according to secp256k1_ec_seckey_verify, this * function returns 0. seckey will be set to some unspecified * value if this function returns 0. (cannot be NULL) - * In: tweak: pointer to a 32-byte tweak. If the tweak is invalid according to + * In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according to * secp256k1_ec_seckey_verify, this function returns 0. For * uniformly random 32-byte arrays the chance of being invalid * is negligible (around 1 in 2^128) (cannot be NULL). @@ -681,7 +688,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add( SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_mul( const secp256k1_context* ctx, unsigned char *seckey, - const unsigned char *tweak + const unsigned char *tweak32 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); /** Same as secp256k1_ec_seckey_tweak_mul, but DEPRECATED. Will be removed in @@ -689,7 +696,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_mul( SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_mul( const secp256k1_context* ctx, unsigned char *seckey, - const unsigned char *tweak + const unsigned char *tweak32 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); /** Tweak a public key by multiplying it by a tweak value. @@ -699,7 +706,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_mul( * (cannot be NULL). * In/Out: pubkey: pointer to a public key object. pubkey will be set to an * invalid value if this function returns 0 (cannot be NULL). - * In: tweak: pointer to a 32-byte tweak. If the tweak is invalid according to + * In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according to * secp256k1_ec_seckey_verify, this function returns 0. For * uniformly random 32-byte arrays the chance of being invalid * is negligible (around 1 in 2^128) (cannot be NULL). @@ -707,7 +714,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_mul( SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_mul( const secp256k1_context* ctx, secp256k1_pubkey *pubkey, - const unsigned char *tweak + const unsigned char *tweak32 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); /** Updates the context randomization to protect against side-channel leakage. diff --git a/include/secp256k1_extrakeys.h b/include/secp256k1_extrakeys.h index 0c5dff2c942b6..6fc7b290f8cae 100644 --- a/include/secp256k1_extrakeys.h +++ b/include/secp256k1_extrakeys.h @@ -165,6 +165,19 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_create( const unsigned char *seckey ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); +/** Get the secret key from a keypair. + * + * Returns: 0 if the arguments are invalid. 1 otherwise. + * Args: ctx: pointer to a context object (cannot be NULL) + * Out: seckey: pointer to a 32-byte buffer for the secret key (cannot be NULL) + * In: keypair: pointer to a keypair (cannot be NULL) + */ +SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_sec( + const secp256k1_context* ctx, + unsigned char *seckey, + const secp256k1_keypair *keypair +) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); + /** Get the public key from a keypair. * * Returns: 0 if the arguments are invalid. 1 otherwise. diff --git a/include/secp256k1_recovery.h b/include/secp256k1_recovery.h index f8ccaecd3dfb1..aa16532ce8614 100644 --- a/include/secp256k1_recovery.h +++ b/include/secp256k1_recovery.h @@ -71,17 +71,17 @@ SECP256K1_API int secp256k1_ecdsa_recoverable_signature_serialize_compact( * * Returns: 1: signature created * 0: the nonce generation function failed, or the secret key was invalid. - * Args: ctx: pointer to a context object, initialized for signing (cannot be NULL) - * Out: sig: pointer to an array where the signature will be placed (cannot be NULL) - * In: msg32: the 32-byte message hash being signed (cannot be NULL) - * seckey: pointer to a 32-byte secret key (cannot be NULL) - * noncefp:pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used - * ndata: pointer to arbitrary data used by the nonce generation function (can be NULL) + * Args: ctx: pointer to a context object, initialized for signing (cannot be NULL) + * Out: sig: pointer to an array where the signature will be placed (cannot be NULL) + * In: msghash32: the 32-byte message hash being signed (cannot be NULL) + * seckey: pointer to a 32-byte secret key (cannot be NULL) + * noncefp: pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used + * ndata: pointer to arbitrary data used by the nonce generation function (can be NULL) */ SECP256K1_API int secp256k1_ecdsa_sign_recoverable( const secp256k1_context* ctx, secp256k1_ecdsa_recoverable_signature *sig, - const unsigned char *msg32, + const unsigned char *msghash32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void *ndata @@ -91,16 +91,16 @@ SECP256K1_API int secp256k1_ecdsa_sign_recoverable( * * Returns: 1: public key successfully recovered (which guarantees a correct signature). * 0: otherwise. - * Args: ctx: pointer to a context object, initialized for verification (cannot be NULL) - * Out: pubkey: pointer to the recovered public key (cannot be NULL) - * In: sig: pointer to initialized signature that supports pubkey recovery (cannot be NULL) - * msg32: the 32-byte message hash assumed to be signed (cannot be NULL) + * Args: ctx: pointer to a context object, initialized for verification (cannot be NULL) + * Out: pubkey: pointer to the recovered public key (cannot be NULL) + * In: sig: pointer to initialized signature that supports pubkey recovery (cannot be NULL) + * msghash32: the 32-byte message hash assumed to be signed (cannot be NULL) */ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_recover( const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const secp256k1_ecdsa_recoverable_signature *sig, - const unsigned char *msg32 + const unsigned char *msghash32 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4); #ifdef __cplusplus diff --git a/sage/gen_exhaustive_groups.sage b/sage/gen_exhaustive_groups.sage index 3c3c984811e3a..01d15dcdeac56 100644 --- a/sage/gen_exhaustive_groups.sage +++ b/sage/gen_exhaustive_groups.sage @@ -1,9 +1,4 @@ -# Define field size and field -P = 2^256 - 2^32 - 977 -F = GF(P) -BETA = F(0x7ae96a2b657c07106e64479eac3434e99cf0497512f58995c1396c28719501ee) - -assert(BETA != F(1) and BETA^3 == F(1)) +load("secp256k1_params.sage") orders_done = set() results = {} diff --git a/sage/gen_split_lambda_constants.sage b/sage/gen_split_lambda_constants.sage new file mode 100644 index 0000000000000..7d4359e0f6482 --- /dev/null +++ b/sage/gen_split_lambda_constants.sage @@ -0,0 +1,114 @@ +""" Generates the constants used in secp256k1_scalar_split_lambda. + +See the comments for secp256k1_scalar_split_lambda in src/scalar_impl.h for detailed explanations. +""" + +load("secp256k1_params.sage") + +def inf_norm(v): + """Returns the infinity norm of a vector.""" + return max(map(abs, v)) + +def gauss_reduction(i1, i2): + v1, v2 = i1.copy(), i2.copy() + while True: + if inf_norm(v2) < inf_norm(v1): + v1, v2 = v2, v1 + # This is essentially + # m = round((v1[0]*v2[0] + v1[1]*v2[1]) / (inf_norm(v1)**2)) + # (rounding to the nearest integer) without relying on floating point arithmetic. + m = ((v1[0]*v2[0] + v1[1]*v2[1]) + (inf_norm(v1)**2) // 2) // (inf_norm(v1)**2) + if m == 0: + return v1, v2 + v2[0] -= m*v1[0] + v2[1] -= m*v1[1] + +def find_split_constants_gauss(): + """Find constants for secp256k1_scalar_split_lamdba using gauss reduction.""" + (v11, v12), (v21, v22) = gauss_reduction([0, N], [1, int(LAMBDA)]) + + # We use related vectors in secp256k1_scalar_split_lambda. + A1, B1 = -v21, -v11 + A2, B2 = v22, -v21 + + return A1, B1, A2, B2 + +def find_split_constants_explicit_tof(): + """Find constants for secp256k1_scalar_split_lamdba using the trace of Frobenius. + + See Benjamin Smith: "Easy scalar decompositions for efficient scalar multiplication on + elliptic curves and genus 2 Jacobians" (https://eprint.iacr.org/2013/672), Example 2 + """ + assert P % 3 == 1 # The paper says P % 3 == 2 but that appears to be a mistake, see [10]. + assert C.j_invariant() == 0 + + t = C.trace_of_frobenius() + + c = Integer(sqrt((4*P - t**2)/3)) + A1 = Integer((t - c)/2 - 1) + B1 = c + + A2 = Integer((t + c)/2 - 1) + B2 = Integer(1 - (t - c)/2) + + # We use a negated b values in secp256k1_scalar_split_lambda. + B1, B2 = -B1, -B2 + + return A1, B1, A2, B2 + +A1, B1, A2, B2 = find_split_constants_explicit_tof() + +# For extra fun, use an independent method to recompute the constants. +assert (A1, B1, A2, B2) == find_split_constants_gauss() + +# PHI : Z[l] -> Z_n where phi(a + b*l) == a + b*lambda mod n. +def PHI(a,b): + return Z(a + LAMBDA*b) + +# Check that (A1, B1) and (A2, B2) are in the kernel of PHI. +assert PHI(A1, B1) == Z(0) +assert PHI(A2, B2) == Z(0) + +# Check that the parallelogram generated by (A1, A2) and (B1, B2) +# is a fundamental domain by containing exactly N points. +# Since the LHS is the determinant and N != 0, this also checks that +# (A1, A2) and (B1, B2) are linearly independent. By the previous +# assertions, (A1, A2) and (B1, B2) are a basis of the kernel. +assert A1*B2 - B1*A2 == N + +# Check that their components are short enough. +assert (A1 + A2)/2 < sqrt(N) +assert B1 < sqrt(N) +assert B2 < sqrt(N) + +G1 = round((2**384)*B2/N) +G2 = round((2**384)*(-B1)/N) + +def rnddiv2(v): + if v & 1: + v += 1 + return v >> 1 + +def scalar_lambda_split(k): + """Equivalent to secp256k1_scalar_lambda_split().""" + c1 = rnddiv2((k * G1) >> 383) + c2 = rnddiv2((k * G2) >> 383) + c1 = (c1 * -B1) % N + c2 = (c2 * -B2) % N + r2 = (c1 + c2) % N + r1 = (k + r2 * -LAMBDA) % N + return (r1, r2) + +# The result of scalar_lambda_split can depend on the representation of k (mod n). +SPECIAL = (2**383) // G2 + 1 +assert scalar_lambda_split(SPECIAL) != scalar_lambda_split(SPECIAL + N) + +print(' A1 =', hex(A1)) +print(' -B1 =', hex(-B1)) +print(' A2 =', hex(A2)) +print(' -B2 =', hex(-B2)) +print(' =', hex(Z(-B2))) +print(' -LAMBDA =', hex(-LAMBDA)) + +print(' G1 =', hex(G1)) +print(' G2 =', hex(G2)) diff --git a/sage/group_prover.sage b/sage/group_prover.sage index 8521f07999322..b200bfeae3d1c 100644 --- a/sage/group_prover.sage +++ b/sage/group_prover.sage @@ -42,7 +42,7 @@ # as we assume that all constraints in it are complementary with each other. # # Based on the sage verification scripts used in the Explicit-Formulas Database -# by Tanja Lange and others, see http://hyperelliptic.org/EFD +# by Tanja Lange and others, see https://hyperelliptic.org/EFD class fastfrac: """Fractions over rings.""" @@ -65,7 +65,7 @@ class fastfrac: return self.top in I and self.bot not in I def reduce(self,assumeZero): - zero = self.R.ideal(map(numerator, assumeZero)) + zero = self.R.ideal(list(map(numerator, assumeZero))) return fastfrac(self.R, zero.reduce(self.top)) / fastfrac(self.R, zero.reduce(self.bot)) def __add__(self,other): @@ -100,7 +100,7 @@ class fastfrac: """Multiply something else with a fraction.""" return self.__mul__(other) - def __div__(self,other): + def __truediv__(self,other): """Divide two fractions.""" if parent(other) == ZZ: return fastfrac(self.R,self.top,self.bot * other) @@ -108,6 +108,11 @@ class fastfrac: return fastfrac(self.R,self.top * other.bot,self.bot * other.top) return NotImplemented + # Compatibility wrapper for Sage versions based on Python 2 + def __div__(self,other): + """Divide two fractions.""" + return self.__truediv__(other) + def __pow__(self,other): """Compute a power of a fraction.""" if parent(other) == ZZ: @@ -175,7 +180,7 @@ class constraints: def conflicts(R, con): """Check whether any of the passed non-zero assumptions is implied by the zero assumptions""" - zero = R.ideal(map(numerator, con.zero)) + zero = R.ideal(list(map(numerator, con.zero))) if 1 in zero: return True # First a cheap check whether any of the individual nonzero terms conflict on @@ -195,7 +200,7 @@ def conflicts(R, con): def get_nonzero_set(R, assume): """Calculate a simple set of nonzero expressions""" - zero = R.ideal(map(numerator, assume.zero)) + zero = R.ideal(list(map(numerator, assume.zero))) nonzero = set() for nz in map(numerator, assume.nonzero): for (f,n) in nz.factor(): @@ -208,7 +213,7 @@ def get_nonzero_set(R, assume): def prove_nonzero(R, exprs, assume): """Check whether an expression is provably nonzero, given assumptions""" - zero = R.ideal(map(numerator, assume.zero)) + zero = R.ideal(list(map(numerator, assume.zero))) nonzero = get_nonzero_set(R, assume) expl = set() ok = True @@ -250,7 +255,7 @@ def prove_zero(R, exprs, assume): r, e = prove_nonzero(R, dict(map(lambda x: (fastfrac(R, x.bot, 1), exprs[x]), exprs)), assume) if not r: return (False, map(lambda x: "Possibly zero denominator: %s" % x, e)) - zero = R.ideal(map(numerator, assume.zero)) + zero = R.ideal(list(map(numerator, assume.zero))) nonzero = prod(x for x in assume.nonzero) expl = [] for expr in exprs: @@ -265,8 +270,8 @@ def describe_extra(R, assume, assumeExtra): """Describe what assumptions are added, given existing assumptions""" zerox = assume.zero.copy() zerox.update(assumeExtra.zero) - zero = R.ideal(map(numerator, assume.zero)) - zeroextra = R.ideal(map(numerator, zerox)) + zero = R.ideal(list(map(numerator, assume.zero))) + zeroextra = R.ideal(list(map(numerator, zerox))) nonzero = get_nonzero_set(R, assume) ret = set() # Iterate over the extra zero expressions diff --git a/sage/secp256k1.sage b/sage/prove_group_implementations.sage similarity index 100% rename from sage/secp256k1.sage rename to sage/prove_group_implementations.sage diff --git a/sage/secp256k1_params.sage b/sage/secp256k1_params.sage new file mode 100644 index 0000000000000..4e000726ed366 --- /dev/null +++ b/sage/secp256k1_params.sage @@ -0,0 +1,36 @@ +"""Prime order of finite field underlying secp256k1 (2^256 - 2^32 - 977)""" +P = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F + +"""Finite field underlying secp256k1""" +F = FiniteField(P) + +"""Elliptic curve secp256k1: y^2 = x^3 + 7""" +C = EllipticCurve([F(0), F(7)]) + +"""Base point of secp256k1""" +G = C.lift_x(0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798) + +"""Prime order of secp256k1""" +N = C.order() + +"""Finite field of scalars of secp256k1""" +Z = FiniteField(N) + +""" Beta value of secp256k1 non-trivial endomorphism: lambda * (x, y) = (beta * x, y)""" +BETA = F(2)^((P-1)/3) + +""" Lambda value of secp256k1 non-trivial endomorphism: lambda * (x, y) = (beta * x, y)""" +LAMBDA = Z(3)^((N-1)/3) + +assert is_prime(P) +assert is_prime(N) + +assert BETA != F(1) +assert BETA^3 == F(1) +assert BETA^2 + BETA + 1 == 0 + +assert LAMBDA != Z(1) +assert LAMBDA^3 == Z(1) +assert LAMBDA^2 + LAMBDA + 1 == 0 + +assert Integer(LAMBDA)*G == C(BETA*G[0], G[1]) diff --git a/sage/weierstrass_prover.sage b/sage/weierstrass_prover.sage index 03ef2ec901ea9..b770c6dafe2f0 100644 --- a/sage/weierstrass_prover.sage +++ b/sage/weierstrass_prover.sage @@ -175,24 +175,24 @@ laws_jacobian_weierstrass = { def check_exhaustive_jacobian_weierstrass(name, A, B, branches, formula, p): """Verify an implementation of addition of Jacobian points on a Weierstrass curve, by executing and validating the result for every possible addition in a prime field""" F = Integers(p) - print "Formula %s on Z%i:" % (name, p) + print("Formula %s on Z%i:" % (name, p)) points = [] - for x in xrange(0, p): - for y in xrange(0, p): + for x in range(0, p): + for y in range(0, p): point = affinepoint(F(x), F(y)) r, e = concrete_verify(on_weierstrass_curve(A, B, point)) if r: points.append(point) - for za in xrange(1, p): - for zb in xrange(1, p): + for za in range(1, p): + for zb in range(1, p): for pa in points: for pb in points: - for ia in xrange(2): - for ib in xrange(2): + for ia in range(2): + for ib in range(2): pA = jacobianpoint(pa.x * F(za)^2, pa.y * F(za)^3, F(za), ia) pB = jacobianpoint(pb.x * F(zb)^2, pb.y * F(zb)^3, F(zb), ib) - for branch in xrange(0, branches): + for branch in range(0, branches): assumeAssert, assumeBranch, pC = formula(branch, pA, pB) pC.X = F(pC.X) pC.Y = F(pC.Y) @@ -206,13 +206,13 @@ def check_exhaustive_jacobian_weierstrass(name, A, B, branches, formula, p): r, e = concrete_verify(assumeLaw) if r: if match: - print " multiple branches for (%s,%s,%s,%s) + (%s,%s,%s,%s)" % (pA.X, pA.Y, pA.Z, pA.Infinity, pB.X, pB.Y, pB.Z, pB.Infinity) + print(" multiple branches for (%s,%s,%s,%s) + (%s,%s,%s,%s)" % (pA.X, pA.Y, pA.Z, pA.Infinity, pB.X, pB.Y, pB.Z, pB.Infinity)) else: match = True r, e = concrete_verify(require) if not r: - print " failure in branch %i for (%s,%s,%s,%s) + (%s,%s,%s,%s) = (%s,%s,%s,%s): %s" % (branch, pA.X, pA.Y, pA.Z, pA.Infinity, pB.X, pB.Y, pB.Z, pB.Infinity, pC.X, pC.Y, pC.Z, pC.Infinity, e) - print + print(" failure in branch %i for (%s,%s,%s,%s) + (%s,%s,%s,%s) = (%s,%s,%s,%s): %s" % (branch, pA.X, pA.Y, pA.Z, pA.Infinity, pB.X, pB.Y, pB.Z, pB.Infinity, pC.X, pC.Y, pC.Z, pC.Infinity, e)) + print() def check_symbolic_function(R, assumeAssert, assumeBranch, f, A, B, pa, pb, pA, pB, pC): @@ -242,9 +242,9 @@ def check_symbolic_jacobian_weierstrass(name, A, B, branches, formula): for key in laws_jacobian_weierstrass: res[key] = [] - print ("Formula " + name + ":") + print("Formula " + name + ":") count = 0 - for branch in xrange(branches): + for branch in range(branches): assumeFormula, assumeBranch, pC = formula(branch, pA, pB) pC.X = lift(pC.X) pC.Y = lift(pC.Y) @@ -255,10 +255,10 @@ def check_symbolic_jacobian_weierstrass(name, A, B, branches, formula): res[key].append((check_symbolic_function(R, assumeFormula, assumeBranch, laws_jacobian_weierstrass[key], A, B, pa, pb, pA, pB, pC), branch)) for key in res: - print " %s:" % key + print(" %s:" % key) val = res[key] for x in val: if x[0] is not None: - print " branch %i: %s" % (x[1], x[0]) + print(" branch %i: %s" % (x[1], x[0])) - print + print() diff --git a/src/asm/field_10x26_arm.s b/src/asm/field_10x26_arm.s index 9a5bd06721778..5f68cefc46cde 100644 --- a/src/asm/field_10x26_arm.s +++ b/src/asm/field_10x26_arm.s @@ -1,9 +1,9 @@ @ vim: set tabstop=8 softtabstop=8 shiftwidth=8 noexpandtab syntax=armasm: -/********************************************************************** - * Copyright (c) 2014 Wladimir J. van der Laan * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Wladimir J. van der Laan * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ /* ARM implementation of field_10x26 inner loops. diff --git a/src/assumptions.h b/src/assumptions.h index 77204de2b89cf..6dc527b288939 100644 --- a/src/assumptions.h +++ b/src/assumptions.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2020 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2020 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ASSUMPTIONS_H #define SECP256K1_ASSUMPTIONS_H diff --git a/src/basic-config.h b/src/basic-config.h index b0d82e89b412d..6f7693cb8fd04 100644 --- a/src/basic-config.h +++ b/src/basic-config.h @@ -1,33 +1,16 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_BASIC_CONFIG_H #define SECP256K1_BASIC_CONFIG_H #ifdef USE_BASIC_CONFIG -#undef USE_ASM_X86_64 -#undef USE_ECMULT_STATIC_PRECOMPUTATION -#undef USE_EXTERNAL_ASM -#undef USE_EXTERNAL_DEFAULT_CALLBACKS -#undef USE_FIELD_INV_BUILTIN -#undef USE_FIELD_INV_NUM -#undef USE_NUM_GMP -#undef USE_NUM_NONE -#undef USE_SCALAR_INV_BUILTIN -#undef USE_SCALAR_INV_NUM -#undef USE_FORCE_WIDEMUL_INT64 -#undef USE_FORCE_WIDEMUL_INT128 -#undef ECMULT_WINDOW_SIZE - -#define USE_NUM_NONE 1 -#define USE_FIELD_INV_BUILTIN 1 -#define USE_SCALAR_INV_BUILTIN 1 -#define USE_WIDEMUL_64 1 #define ECMULT_WINDOW_SIZE 15 +#define ECMULT_GEN_PREC_BITS 4 #endif /* USE_BASIC_CONFIG */ diff --git a/src/bench.h b/src/bench.h index 9bfed903e04e4..63c55df44d059 100644 --- a/src/bench.h +++ b/src/bench.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_BENCH_H #define SECP256K1_BENCH_H diff --git a/src/bench_ecdh.c b/src/bench_ecdh.c index f099d33884bcf..ab4b8f4244f2b 100644 --- a/src/bench_ecdh.c +++ b/src/bench_ecdh.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include diff --git a/src/bench_ecmult.c b/src/bench_ecmult.c index facd07ef31b3e..204e85a5dde13 100644 --- a/src/bench_ecmult.c +++ b/src/bench_ecmult.c @@ -1,15 +1,14 @@ -/********************************************************************** - * Copyright (c) 2017 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2017 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include #include "include/secp256k1.h" #include "util.h" #include "hash_impl.h" -#include "num_impl.h" #include "field_impl.h" #include "group_impl.h" #include "scalar_impl.h" diff --git a/src/bench_internal.c b/src/bench_internal.c index 5f2b7a9759319..73b8a24ccbfaf 100644 --- a/src/bench_internal.c +++ b/src/bench_internal.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014-2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014-2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include #include "include/secp256k1.h" @@ -10,7 +10,6 @@ #include "assumptions.h" #include "util.h" #include "hash_impl.h" -#include "num_impl.h" #include "field_impl.h" #include "group_impl.h" #include "scalar_impl.h" @@ -99,15 +98,6 @@ void bench_scalar_negate(void* arg, int iters) { } } -void bench_scalar_sqr(void* arg, int iters) { - int i; - bench_inv *data = (bench_inv*)arg; - - for (i = 0; i < iters; i++) { - secp256k1_scalar_sqr(&data->scalar[0], &data->scalar[0]); - } -} - void bench_scalar_mul(void* arg, int iters) { int i; bench_inv *data = (bench_inv*)arg; @@ -255,26 +245,6 @@ void bench_group_add_affine_var(void* arg, int iters) { } } -void bench_group_jacobi_var(void* arg, int iters) { - int i, j = 0; - bench_inv *data = (bench_inv*)arg; - - for (i = 0; i < iters; i++) { - j += secp256k1_gej_has_quad_y_var(&data->gej[0]); - /* Vary the Y and Z coordinates of the input (the X coordinate doesn't matter to - secp256k1_gej_has_quad_y_var). Note that the resulting coordinates will - generally not correspond to a point on the curve, but this is not a problem - for the code being benchmarked here. Adding and normalizing have less - overhead than EC operations (which could guarantee the point remains on the - curve). */ - secp256k1_fe_add(&data->gej[0].y, &data->fe[1]); - secp256k1_fe_add(&data->gej[0].z, &data->fe[2]); - secp256k1_fe_normalize_var(&data->gej[0].y); - secp256k1_fe_normalize_var(&data->gej[0].z); - } - CHECK(j <= iters); -} - void bench_group_to_affine_var(void* arg, int iters) { int i; bench_inv *data = (bench_inv*)arg; @@ -282,8 +252,10 @@ void bench_group_to_affine_var(void* arg, int iters) { for (i = 0; i < iters; ++i) { secp256k1_ge_set_gej_var(&data->ge[1], &data->gej[0]); /* Use the output affine X/Y coordinates to vary the input X/Y/Z coordinates. - Similar to bench_group_jacobi_var, this approach does not result in - coordinates of points on the curve. */ + Note that the resulting coordinates will generally not correspond to a point + on the curve, but this is not a problem for the code being benchmarked here. + Adding and normalizing have less overhead than EC operations (which could + guarantee the point remains on the curve). */ secp256k1_fe_add(&data->gej[0].x, &data->ge[1].y); secp256k1_fe_add(&data->gej[0].y, &data->fe[2]); secp256k1_fe_add(&data->gej[0].z, &data->ge[1].x); @@ -369,35 +341,16 @@ void bench_context_sign(void* arg, int iters) { } } -#ifndef USE_NUM_NONE -void bench_num_jacobi(void* arg, int iters) { - int i, j = 0; - bench_inv *data = (bench_inv*)arg; - secp256k1_num nx, na, norder; - - secp256k1_scalar_get_num(&nx, &data->scalar[0]); - secp256k1_scalar_order_get_num(&norder); - secp256k1_scalar_get_num(&na, &data->scalar[1]); - - for (i = 0; i < iters; i++) { - j += secp256k1_num_jacobi(&nx, &norder); - secp256k1_num_add(&nx, &nx, &na); - } - CHECK(j <= iters); -} -#endif - int main(int argc, char **argv) { bench_inv data; int iters = get_iters(20000); if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "add")) run_benchmark("scalar_add", bench_scalar_add, bench_setup, NULL, &data, 10, iters*100); if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "negate")) run_benchmark("scalar_negate", bench_scalar_negate, bench_setup, NULL, &data, 10, iters*100); - if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "sqr")) run_benchmark("scalar_sqr", bench_scalar_sqr, bench_setup, NULL, &data, 10, iters*10); if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "mul")) run_benchmark("scalar_mul", bench_scalar_mul, bench_setup, NULL, &data, 10, iters*10); if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "split")) run_benchmark("scalar_split", bench_scalar_split, bench_setup, NULL, &data, 10, iters); - if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "inverse")) run_benchmark("scalar_inverse", bench_scalar_inverse, bench_setup, NULL, &data, 10, 2000); - if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "inverse")) run_benchmark("scalar_inverse_var", bench_scalar_inverse_var, bench_setup, NULL, &data, 10, 2000); + if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "inverse")) run_benchmark("scalar_inverse", bench_scalar_inverse, bench_setup, NULL, &data, 10, iters); + if (have_flag(argc, argv, "scalar") || have_flag(argc, argv, "inverse")) run_benchmark("scalar_inverse_var", bench_scalar_inverse_var, bench_setup, NULL, &data, 10, iters); if (have_flag(argc, argv, "field") || have_flag(argc, argv, "normalize")) run_benchmark("field_normalize", bench_field_normalize, bench_setup, NULL, &data, 10, iters*100); if (have_flag(argc, argv, "field") || have_flag(argc, argv, "normalize")) run_benchmark("field_normalize_weak", bench_field_normalize_weak, bench_setup, NULL, &data, 10, iters*100); @@ -411,7 +364,6 @@ int main(int argc, char **argv) { if (have_flag(argc, argv, "group") || have_flag(argc, argv, "add")) run_benchmark("group_add_var", bench_group_add_var, bench_setup, NULL, &data, 10, iters*10); if (have_flag(argc, argv, "group") || have_flag(argc, argv, "add")) run_benchmark("group_add_affine", bench_group_add_affine, bench_setup, NULL, &data, 10, iters*10); if (have_flag(argc, argv, "group") || have_flag(argc, argv, "add")) run_benchmark("group_add_affine_var", bench_group_add_affine_var, bench_setup, NULL, &data, 10, iters*10); - if (have_flag(argc, argv, "group") || have_flag(argc, argv, "jacobi")) run_benchmark("group_jacobi_var", bench_group_jacobi_var, bench_setup, NULL, &data, 10, iters); if (have_flag(argc, argv, "group") || have_flag(argc, argv, "to_affine")) run_benchmark("group_to_affine_var", bench_group_to_affine_var, bench_setup, NULL, &data, 10, iters); if (have_flag(argc, argv, "ecmult") || have_flag(argc, argv, "wnaf")) run_benchmark("wnaf_const", bench_wnaf_const, bench_setup, NULL, &data, 10, iters); @@ -424,8 +376,5 @@ int main(int argc, char **argv) { if (have_flag(argc, argv, "context") || have_flag(argc, argv, "verify")) run_benchmark("context_verify", bench_context_verify, bench_setup, NULL, &data, 10, 1 + iters/1000); if (have_flag(argc, argv, "context") || have_flag(argc, argv, "sign")) run_benchmark("context_sign", bench_context_sign, bench_setup, NULL, &data, 10, 1 + iters/100); -#ifndef USE_NUM_NONE - if (have_flag(argc, argv, "num") || have_flag(argc, argv, "jacobi")) run_benchmark("num_jacobi", bench_num_jacobi, bench_setup, NULL, &data, 10, iters*10); -#endif return 0; } diff --git a/src/bench_recover.c b/src/bench_recover.c index e952ed1215ed1..3f6270ce84fd5 100644 --- a/src/bench_recover.c +++ b/src/bench_recover.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014-2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014-2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include "include/secp256k1.h" #include "include/secp256k1_recovery.h" diff --git a/src/bench_schnorrsig.c b/src/bench_schnorrsig.c index 315f5af28e709..f7f591c41dcea 100644 --- a/src/bench_schnorrsig.c +++ b/src/bench_schnorrsig.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include #include diff --git a/src/bench_sign.c b/src/bench_sign.c index c6b2942cc0c9b..933f367c4b6a6 100644 --- a/src/bench_sign.c +++ b/src/bench_sign.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include "include/secp256k1.h" #include "util.h" @@ -12,11 +12,11 @@ typedef struct { secp256k1_context* ctx; unsigned char msg[32]; unsigned char key[32]; -} bench_sign; +} bench_sign_data; static void bench_sign_setup(void* arg) { int i; - bench_sign *data = (bench_sign*)arg; + bench_sign_data *data = (bench_sign_data*)arg; for (i = 0; i < 32; i++) { data->msg[i] = i + 1; @@ -28,7 +28,7 @@ static void bench_sign_setup(void* arg) { static void bench_sign_run(void* arg, int iters) { int i; - bench_sign *data = (bench_sign*)arg; + bench_sign_data *data = (bench_sign_data*)arg; unsigned char sig[74]; for (i = 0; i < iters; i++) { @@ -45,7 +45,7 @@ static void bench_sign_run(void* arg, int iters) { } int main(void) { - bench_sign data; + bench_sign_data data; int iters = get_iters(20000); diff --git a/src/bench_verify.c b/src/bench_verify.c index 272d3e5cc4b4c..c56aefd3699c0 100644 --- a/src/bench_verify.c +++ b/src/bench_verify.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include #include @@ -29,11 +29,11 @@ typedef struct { #ifdef ENABLE_OPENSSL_TESTS EC_GROUP* ec_group; #endif -} benchmark_verify_t; +} bench_verify_data; -static void benchmark_verify(void* arg, int iters) { +static void bench_verify(void* arg, int iters) { int i; - benchmark_verify_t* data = (benchmark_verify_t*)arg; + bench_verify_data* data = (bench_verify_data*)arg; for (i = 0; i < iters; i++) { secp256k1_pubkey pubkey; @@ -51,9 +51,9 @@ static void benchmark_verify(void* arg, int iters) { } #ifdef ENABLE_OPENSSL_TESTS -static void benchmark_verify_openssl(void* arg, int iters) { +static void bench_verify_openssl(void* arg, int iters) { int i; - benchmark_verify_t* data = (benchmark_verify_t*)arg; + bench_verify_data* data = (bench_verify_data*)arg; for (i = 0; i < iters; i++) { data->sig[data->siglen - 1] ^= (i & 0xFF); @@ -84,7 +84,7 @@ int main(void) { int i; secp256k1_pubkey pubkey; secp256k1_ecdsa_signature sig; - benchmark_verify_t data; + bench_verify_data data; int iters = get_iters(20000); @@ -103,10 +103,10 @@ int main(void) { data.pubkeylen = 33; CHECK(secp256k1_ec_pubkey_serialize(data.ctx, data.pubkey, &data.pubkeylen, &pubkey, SECP256K1_EC_COMPRESSED) == 1); - run_benchmark("ecdsa_verify", benchmark_verify, NULL, NULL, &data, 10, iters); + run_benchmark("ecdsa_verify", bench_verify, NULL, NULL, &data, 10, iters); #ifdef ENABLE_OPENSSL_TESTS data.ec_group = EC_GROUP_new_by_curve_name(NID_secp256k1); - run_benchmark("ecdsa_verify_openssl", benchmark_verify_openssl, NULL, NULL, &data, 10, iters); + run_benchmark("ecdsa_verify_openssl", bench_verify_openssl, NULL, NULL, &data, 10, iters); EC_GROUP_free(data.ec_group); #endif diff --git a/src/ecdsa.h b/src/ecdsa.h index 80590c7cc862d..d5e54d8ce6197 100644 --- a/src/ecdsa.h +++ b/src/ecdsa.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECDSA_H #define SECP256K1_ECDSA_H diff --git a/src/ecdsa_impl.h b/src/ecdsa_impl.h index 5f54b59faa693..156a33d112865 100644 --- a/src/ecdsa_impl.h +++ b/src/ecdsa_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013-2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013-2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECDSA_IMPL_H diff --git a/src/eckey.h b/src/eckey.h index b621f1e6c39d9..5be3a64b84043 100644 --- a/src/eckey.h +++ b/src/eckey.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECKEY_H #define SECP256K1_ECKEY_H diff --git a/src/eckey_impl.h b/src/eckey_impl.h index e2e72d93039a7..a39cb79653c38 100644 --- a/src/eckey_impl.h +++ b/src/eckey_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECKEY_IMPL_H #define SECP256K1_ECKEY_IMPL_H diff --git a/src/ecmult.h b/src/ecmult.h index 09e8146414b61..7ab617e20e421 100644 --- a/src/ecmult.h +++ b/src/ecmult.h @@ -1,13 +1,12 @@ -/********************************************************************** - * Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECMULT_H #define SECP256K1_ECMULT_H -#include "num.h" #include "group.h" #include "scalar.h" #include "scratch.h" diff --git a/src/ecmult_const.h b/src/ecmult_const.h index 03bb33257d532..d6f0ea22275a6 100644 --- a/src/ecmult_const.h +++ b/src/ecmult_const.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECMULT_CONST_H #define SECP256K1_ECMULT_CONST_H diff --git a/src/ecmult_const_impl.h b/src/ecmult_const_impl.h index bb9511108be7e..0e1fb965cbdef 100644 --- a/src/ecmult_const_impl.h +++ b/src/ecmult_const_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Pieter Wuille, Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECMULT_CONST_IMPL_H #define SECP256K1_ECMULT_CONST_IMPL_H diff --git a/src/ecmult_gen.h b/src/ecmult_gen.h index 30815e5aa10e7..539618dcbb872 100644 --- a/src/ecmult_gen.h +++ b/src/ecmult_gen.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECMULT_GEN_H #define SECP256K1_ECMULT_GEN_H diff --git a/src/ecmult_gen_impl.h b/src/ecmult_gen_impl.h index 30ac16518bf48..384a67faeda7a 100644 --- a/src/ecmult_gen_impl.h +++ b/src/ecmult_gen_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014, 2015 Pieter Wuille, Gregory Maxwell * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014, 2015 Pieter Wuille, Gregory Maxwell * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_ECMULT_GEN_IMPL_H #define SECP256K1_ECMULT_GEN_IMPL_H @@ -144,7 +144,7 @@ static void secp256k1_ecmult_gen(const secp256k1_ecmult_gen_context *ctx, secp25 * (https://cryptojedi.org/peter/data/chesrump-20130822.pdf) and * "Cache Attacks and Countermeasures: the Case of AES", RSA 2006, * by Dag Arne Osvik, Adi Shamir, and Eran Tromer - * (http://www.tau.ac.il/~tromer/papers/cache.pdf) + * (https://www.tau.ac.il/~tromer/papers/cache.pdf) */ secp256k1_ge_storage_cmov(&adds, &(*ctx->prec)[j][i], i == bits); } diff --git a/src/ecmult_impl.h b/src/ecmult_impl.h index a9e8b3c76c4c6..5c2edac68fc69 100644 --- a/src/ecmult_impl.h +++ b/src/ecmult_impl.h @@ -1,8 +1,8 @@ -/***************************************************************************** - * Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra, Jonas Nick * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php. * - *****************************************************************************/ +/****************************************************************************** + * Copyright (c) 2013, 2014, 2017 Pieter Wuille, Andrew Poelstra, Jonas Nick * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php. * + ******************************************************************************/ #ifndef SECP256K1_ECMULT_IMPL_H #define SECP256K1_ECMULT_IMPL_H @@ -595,11 +595,11 @@ static int secp256k1_ecmult_strauss_batch(const secp256k1_callback* error_callba scalars = (secp256k1_scalar*)secp256k1_scratch_alloc(error_callback, scratch, n_points * sizeof(secp256k1_scalar)); state.prej = (secp256k1_gej*)secp256k1_scratch_alloc(error_callback, scratch, n_points * ECMULT_TABLE_SIZE(WINDOW_A) * sizeof(secp256k1_gej)); state.zr = (secp256k1_fe*)secp256k1_scratch_alloc(error_callback, scratch, n_points * ECMULT_TABLE_SIZE(WINDOW_A) * sizeof(secp256k1_fe)); - state.pre_a = (secp256k1_ge*)secp256k1_scratch_alloc(error_callback, scratch, n_points * 2 * ECMULT_TABLE_SIZE(WINDOW_A) * sizeof(secp256k1_ge)); - state.pre_a_lam = state.pre_a + n_points * ECMULT_TABLE_SIZE(WINDOW_A); + state.pre_a = (secp256k1_ge*)secp256k1_scratch_alloc(error_callback, scratch, n_points * ECMULT_TABLE_SIZE(WINDOW_A) * sizeof(secp256k1_ge)); + state.pre_a_lam = (secp256k1_ge*)secp256k1_scratch_alloc(error_callback, scratch, n_points * ECMULT_TABLE_SIZE(WINDOW_A) * sizeof(secp256k1_ge)); state.ps = (struct secp256k1_strauss_point_state*)secp256k1_scratch_alloc(error_callback, scratch, n_points * sizeof(struct secp256k1_strauss_point_state)); - if (points == NULL || scalars == NULL || state.prej == NULL || state.zr == NULL || state.pre_a == NULL) { + if (points == NULL || scalars == NULL || state.prej == NULL || state.zr == NULL || state.pre_a == NULL || state.pre_a_lam == NULL || state.ps == NULL) { secp256k1_scratch_apply_checkpoint(error_callback, scratch, scratch_checkpoint); return 0; } diff --git a/src/field.h b/src/field.h index aca1fb72c5084..854aaebabc966 100644 --- a/src/field.h +++ b/src/field.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_FIELD_H #define SECP256K1_FIELD_H @@ -43,13 +43,12 @@ static void secp256k1_fe_normalize_weak(secp256k1_fe *r); /** Normalize a field element, without constant-time guarantee. */ static void secp256k1_fe_normalize_var(secp256k1_fe *r); -/** Verify whether a field element represents zero i.e. would normalize to a zero value. The field - * implementation may optionally normalize the input, but this should not be relied upon. */ -static int secp256k1_fe_normalizes_to_zero(secp256k1_fe *r); +/** Verify whether a field element represents zero i.e. would normalize to a zero value. */ +static int secp256k1_fe_normalizes_to_zero(const secp256k1_fe *r); -/** Verify whether a field element represents zero i.e. would normalize to a zero value. The field - * implementation may optionally normalize the input, but this should not be relied upon. */ -static int secp256k1_fe_normalizes_to_zero_var(secp256k1_fe *r); +/** Verify whether a field element represents zero i.e. would normalize to a zero value, + * without constant-time guarantee. */ +static int secp256k1_fe_normalizes_to_zero_var(const secp256k1_fe *r); /** Set a field element equal to a small integer. Resulting field element is normalized. */ static void secp256k1_fe_set_int(secp256k1_fe *r, int a); @@ -104,9 +103,6 @@ static void secp256k1_fe_sqr(secp256k1_fe *r, const secp256k1_fe *a); * itself. */ static int secp256k1_fe_sqrt(secp256k1_fe *r, const secp256k1_fe *a); -/** Checks whether a field element is a quadratic residue. */ -static int secp256k1_fe_is_quad_var(const secp256k1_fe *a); - /** Sets a field element to be the (modular) inverse of another. Requires the input's magnitude to be * at most 8. The output magnitude is 1 (but not guaranteed to be normalized). */ static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *a); @@ -114,11 +110,6 @@ static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *a); /** Potentially faster version of secp256k1_fe_inv, without constant-time guarantee. */ static void secp256k1_fe_inv_var(secp256k1_fe *r, const secp256k1_fe *a); -/** Calculate the (modular) inverses of a batch of field elements. Requires the inputs' magnitudes to be - * at most 8. The output magnitudes are 1 (but not guaranteed to be normalized). The inputs and - * outputs must not overlap in memory. */ -static void secp256k1_fe_inv_all_var(secp256k1_fe *r, const secp256k1_fe *a, size_t len); - /** Convert a field element to the storage type. */ static void secp256k1_fe_to_storage(secp256k1_fe_storage *r, const secp256k1_fe *a); diff --git a/src/field_10x26.h b/src/field_10x26.h index 5ff03c8abcc05..9eb65607f12cb 100644 --- a/src/field_10x26.h +++ b/src/field_10x26.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_FIELD_REPR_H #define SECP256K1_FIELD_REPR_H diff --git a/src/field_10x26_impl.h b/src/field_10x26_impl.h index 651500ee8eb90..7a38c117f194b 100644 --- a/src/field_10x26_impl.h +++ b/src/field_10x26_impl.h @@ -1,14 +1,15 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_FIELD_REPR_IMPL_H #define SECP256K1_FIELD_REPR_IMPL_H #include "util.h" #include "field.h" +#include "modinv32_impl.h" #ifdef VERIFY static void secp256k1_fe_verify(const secp256k1_fe *a) { @@ -181,7 +182,7 @@ static void secp256k1_fe_normalize_var(secp256k1_fe *r) { #endif } -static int secp256k1_fe_normalizes_to_zero(secp256k1_fe *r) { +static int secp256k1_fe_normalizes_to_zero(const secp256k1_fe *r) { uint32_t t0 = r->n[0], t1 = r->n[1], t2 = r->n[2], t3 = r->n[3], t4 = r->n[4], t5 = r->n[5], t6 = r->n[6], t7 = r->n[7], t8 = r->n[8], t9 = r->n[9]; @@ -210,7 +211,7 @@ static int secp256k1_fe_normalizes_to_zero(secp256k1_fe *r) { return (z0 == 0) | (z1 == 0x3FFFFFFUL); } -static int secp256k1_fe_normalizes_to_zero_var(secp256k1_fe *r) { +static int secp256k1_fe_normalizes_to_zero_var(const secp256k1_fe *r) { uint32_t t0, t1, t2, t3, t4, t5, t6, t7, t8, t9; uint32_t z0, z1; uint32_t x; @@ -1164,4 +1165,92 @@ static SECP256K1_INLINE void secp256k1_fe_from_storage(secp256k1_fe *r, const se #endif } +static void secp256k1_fe_from_signed30(secp256k1_fe *r, const secp256k1_modinv32_signed30 *a) { + const uint32_t M26 = UINT32_MAX >> 6; + const uint32_t a0 = a->v[0], a1 = a->v[1], a2 = a->v[2], a3 = a->v[3], a4 = a->v[4], + a5 = a->v[5], a6 = a->v[6], a7 = a->v[7], a8 = a->v[8]; + + /* The output from secp256k1_modinv32{_var} should be normalized to range [0,modulus), and + * have limbs in [0,2^30). The modulus is < 2^256, so the top limb must be below 2^(256-30*8). + */ + VERIFY_CHECK(a0 >> 30 == 0); + VERIFY_CHECK(a1 >> 30 == 0); + VERIFY_CHECK(a2 >> 30 == 0); + VERIFY_CHECK(a3 >> 30 == 0); + VERIFY_CHECK(a4 >> 30 == 0); + VERIFY_CHECK(a5 >> 30 == 0); + VERIFY_CHECK(a6 >> 30 == 0); + VERIFY_CHECK(a7 >> 30 == 0); + VERIFY_CHECK(a8 >> 16 == 0); + + r->n[0] = a0 & M26; + r->n[1] = (a0 >> 26 | a1 << 4) & M26; + r->n[2] = (a1 >> 22 | a2 << 8) & M26; + r->n[3] = (a2 >> 18 | a3 << 12) & M26; + r->n[4] = (a3 >> 14 | a4 << 16) & M26; + r->n[5] = (a4 >> 10 | a5 << 20) & M26; + r->n[6] = (a5 >> 6 | a6 << 24) & M26; + r->n[7] = (a6 >> 2 ) & M26; + r->n[8] = (a6 >> 28 | a7 << 2) & M26; + r->n[9] = (a7 >> 24 | a8 << 6); + +#ifdef VERIFY + r->magnitude = 1; + r->normalized = 1; + secp256k1_fe_verify(r); +#endif +} + +static void secp256k1_fe_to_signed30(secp256k1_modinv32_signed30 *r, const secp256k1_fe *a) { + const uint32_t M30 = UINT32_MAX >> 2; + const uint64_t a0 = a->n[0], a1 = a->n[1], a2 = a->n[2], a3 = a->n[3], a4 = a->n[4], + a5 = a->n[5], a6 = a->n[6], a7 = a->n[7], a8 = a->n[8], a9 = a->n[9]; + +#ifdef VERIFY + VERIFY_CHECK(a->normalized); +#endif + + r->v[0] = (a0 | a1 << 26) & M30; + r->v[1] = (a1 >> 4 | a2 << 22) & M30; + r->v[2] = (a2 >> 8 | a3 << 18) & M30; + r->v[3] = (a3 >> 12 | a4 << 14) & M30; + r->v[4] = (a4 >> 16 | a5 << 10) & M30; + r->v[5] = (a5 >> 20 | a6 << 6) & M30; + r->v[6] = (a6 >> 24 | a7 << 2 + | a8 << 28) & M30; + r->v[7] = (a8 >> 2 | a9 << 24) & M30; + r->v[8] = a9 >> 6; +} + +static const secp256k1_modinv32_modinfo secp256k1_const_modinfo_fe = { + {{-0x3D1, -4, 0, 0, 0, 0, 0, 0, 65536}}, + 0x2DDACACFL +}; + +static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *x) { + secp256k1_fe tmp; + secp256k1_modinv32_signed30 s; + + tmp = *x; + secp256k1_fe_normalize(&tmp); + secp256k1_fe_to_signed30(&s, &tmp); + secp256k1_modinv32(&s, &secp256k1_const_modinfo_fe); + secp256k1_fe_from_signed30(r, &s); + + VERIFY_CHECK(secp256k1_fe_normalizes_to_zero(r) == secp256k1_fe_normalizes_to_zero(&tmp)); +} + +static void secp256k1_fe_inv_var(secp256k1_fe *r, const secp256k1_fe *x) { + secp256k1_fe tmp; + secp256k1_modinv32_signed30 s; + + tmp = *x; + secp256k1_fe_normalize_var(&tmp); + secp256k1_fe_to_signed30(&s, &tmp); + secp256k1_modinv32_var(&s, &secp256k1_const_modinfo_fe); + secp256k1_fe_from_signed30(r, &s); + + VERIFY_CHECK(secp256k1_fe_normalizes_to_zero(r) == secp256k1_fe_normalizes_to_zero(&tmp)); +} + #endif /* SECP256K1_FIELD_REPR_IMPL_H */ diff --git a/src/field_5x52.h b/src/field_5x52.h index 6a068484c28a0..50ee3f9ec96b7 100644 --- a/src/field_5x52.h +++ b/src/field_5x52.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_FIELD_REPR_H #define SECP256K1_FIELD_REPR_H diff --git a/src/field_5x52_asm_impl.h b/src/field_5x52_asm_impl.h index 1fc3171f6b0ed..a2118044ab381 100644 --- a/src/field_5x52_asm_impl.h +++ b/src/field_5x52_asm_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013-2014 Diederik Huys, Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013-2014 Diederik Huys, Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ /** * Changelog: diff --git a/src/field_5x52_impl.h b/src/field_5x52_impl.h index 71a38f915b2f4..60ded927f6e83 100644 --- a/src/field_5x52_impl.h +++ b/src/field_5x52_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_FIELD_REPR_IMPL_H #define SECP256K1_FIELD_REPR_IMPL_H @@ -13,6 +13,7 @@ #include "util.h" #include "field.h" +#include "modinv64_impl.h" #if defined(USE_ASM_X86_64) #include "field_5x52_asm_impl.h" @@ -161,7 +162,7 @@ static void secp256k1_fe_normalize_var(secp256k1_fe *r) { #endif } -static int secp256k1_fe_normalizes_to_zero(secp256k1_fe *r) { +static int secp256k1_fe_normalizes_to_zero(const secp256k1_fe *r) { uint64_t t0 = r->n[0], t1 = r->n[1], t2 = r->n[2], t3 = r->n[3], t4 = r->n[4]; /* z0 tracks a possible raw value of 0, z1 tracks a possible raw value of P */ @@ -184,7 +185,7 @@ static int secp256k1_fe_normalizes_to_zero(secp256k1_fe *r) { return (z0 == 0) | (z1 == 0xFFFFFFFFFFFFFULL); } -static int secp256k1_fe_normalizes_to_zero_var(secp256k1_fe *r) { +static int secp256k1_fe_normalizes_to_zero_var(const secp256k1_fe *r) { uint64_t t0, t1, t2, t3, t4; uint64_t z0, z1; uint64_t x; @@ -498,4 +499,80 @@ static SECP256K1_INLINE void secp256k1_fe_from_storage(secp256k1_fe *r, const se #endif } +static void secp256k1_fe_from_signed62(secp256k1_fe *r, const secp256k1_modinv64_signed62 *a) { + const uint64_t M52 = UINT64_MAX >> 12; + const uint64_t a0 = a->v[0], a1 = a->v[1], a2 = a->v[2], a3 = a->v[3], a4 = a->v[4]; + + /* The output from secp256k1_modinv64{_var} should be normalized to range [0,modulus), and + * have limbs in [0,2^62). The modulus is < 2^256, so the top limb must be below 2^(256-62*4). + */ + VERIFY_CHECK(a0 >> 62 == 0); + VERIFY_CHECK(a1 >> 62 == 0); + VERIFY_CHECK(a2 >> 62 == 0); + VERIFY_CHECK(a3 >> 62 == 0); + VERIFY_CHECK(a4 >> 8 == 0); + + r->n[0] = a0 & M52; + r->n[1] = (a0 >> 52 | a1 << 10) & M52; + r->n[2] = (a1 >> 42 | a2 << 20) & M52; + r->n[3] = (a2 >> 32 | a3 << 30) & M52; + r->n[4] = (a3 >> 22 | a4 << 40); + +#ifdef VERIFY + r->magnitude = 1; + r->normalized = 1; + secp256k1_fe_verify(r); +#endif +} + +static void secp256k1_fe_to_signed62(secp256k1_modinv64_signed62 *r, const secp256k1_fe *a) { + const uint64_t M62 = UINT64_MAX >> 2; + const uint64_t a0 = a->n[0], a1 = a->n[1], a2 = a->n[2], a3 = a->n[3], a4 = a->n[4]; + +#ifdef VERIFY + VERIFY_CHECK(a->normalized); +#endif + + r->v[0] = (a0 | a1 << 52) & M62; + r->v[1] = (a1 >> 10 | a2 << 42) & M62; + r->v[2] = (a2 >> 20 | a3 << 32) & M62; + r->v[3] = (a3 >> 30 | a4 << 22) & M62; + r->v[4] = a4 >> 40; +} + +static const secp256k1_modinv64_modinfo secp256k1_const_modinfo_fe = { + {{-0x1000003D1LL, 0, 0, 0, 256}}, + 0x27C7F6E22DDACACFLL +}; + +static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *x) { + secp256k1_fe tmp; + secp256k1_modinv64_signed62 s; + + tmp = *x; + secp256k1_fe_normalize(&tmp); + secp256k1_fe_to_signed62(&s, &tmp); + secp256k1_modinv64(&s, &secp256k1_const_modinfo_fe); + secp256k1_fe_from_signed62(r, &s); + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_fe_normalizes_to_zero(r) == secp256k1_fe_normalizes_to_zero(&tmp)); +#endif +} + +static void secp256k1_fe_inv_var(secp256k1_fe *r, const secp256k1_fe *x) { + secp256k1_fe tmp; + secp256k1_modinv64_signed62 s; + + tmp = *x; + secp256k1_fe_normalize_var(&tmp); + secp256k1_fe_to_signed62(&s, &tmp); + secp256k1_modinv64_var(&s, &secp256k1_const_modinfo_fe); + secp256k1_fe_from_signed62(r, &s); + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_fe_normalizes_to_zero(r) == secp256k1_fe_normalizes_to_zero(&tmp)); +#endif +} + #endif /* SECP256K1_FIELD_REPR_IMPL_H */ diff --git a/src/field_5x52_int128_impl.h b/src/field_5x52_int128_impl.h index bcbfb92ac265b..314002ee3950f 100644 --- a/src/field_5x52_int128_impl.h +++ b/src/field_5x52_int128_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_FIELD_INNER5X52_IMPL_H #define SECP256K1_FIELD_INNER5X52_IMPL_H diff --git a/src/field_impl.h b/src/field_impl.h index 18e4d2f30ea66..374284a1f4ce9 100644 --- a/src/field_impl.h +++ b/src/field_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_FIELD_IMPL_H #define SECP256K1_FIELD_IMPL_H @@ -12,7 +12,6 @@ #endif #include "util.h" -#include "num.h" #if defined(SECP256K1_WIDEMUL_INT128) #include "field_5x52_impl.h" @@ -136,185 +135,6 @@ static int secp256k1_fe_sqrt(secp256k1_fe *r, const secp256k1_fe *a) { return secp256k1_fe_equal(&t1, a); } -static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *a) { - secp256k1_fe x2, x3, x6, x9, x11, x22, x44, x88, x176, x220, x223, t1; - int j; - - /** The binary representation of (p - 2) has 5 blocks of 1s, with lengths in - * { 1, 2, 22, 223 }. Use an addition chain to calculate 2^n - 1 for each block: - * [1], [2], 3, 6, 9, 11, [22], 44, 88, 176, 220, [223] - */ - - secp256k1_fe_sqr(&x2, a); - secp256k1_fe_mul(&x2, &x2, a); - - secp256k1_fe_sqr(&x3, &x2); - secp256k1_fe_mul(&x3, &x3, a); - - x6 = x3; - for (j=0; j<3; j++) { - secp256k1_fe_sqr(&x6, &x6); - } - secp256k1_fe_mul(&x6, &x6, &x3); - - x9 = x6; - for (j=0; j<3; j++) { - secp256k1_fe_sqr(&x9, &x9); - } - secp256k1_fe_mul(&x9, &x9, &x3); - - x11 = x9; - for (j=0; j<2; j++) { - secp256k1_fe_sqr(&x11, &x11); - } - secp256k1_fe_mul(&x11, &x11, &x2); - - x22 = x11; - for (j=0; j<11; j++) { - secp256k1_fe_sqr(&x22, &x22); - } - secp256k1_fe_mul(&x22, &x22, &x11); - - x44 = x22; - for (j=0; j<22; j++) { - secp256k1_fe_sqr(&x44, &x44); - } - secp256k1_fe_mul(&x44, &x44, &x22); - - x88 = x44; - for (j=0; j<44; j++) { - secp256k1_fe_sqr(&x88, &x88); - } - secp256k1_fe_mul(&x88, &x88, &x44); - - x176 = x88; - for (j=0; j<88; j++) { - secp256k1_fe_sqr(&x176, &x176); - } - secp256k1_fe_mul(&x176, &x176, &x88); - - x220 = x176; - for (j=0; j<44; j++) { - secp256k1_fe_sqr(&x220, &x220); - } - secp256k1_fe_mul(&x220, &x220, &x44); - - x223 = x220; - for (j=0; j<3; j++) { - secp256k1_fe_sqr(&x223, &x223); - } - secp256k1_fe_mul(&x223, &x223, &x3); - - /* The final result is then assembled using a sliding window over the blocks. */ - - t1 = x223; - for (j=0; j<23; j++) { - secp256k1_fe_sqr(&t1, &t1); - } - secp256k1_fe_mul(&t1, &t1, &x22); - for (j=0; j<5; j++) { - secp256k1_fe_sqr(&t1, &t1); - } - secp256k1_fe_mul(&t1, &t1, a); - for (j=0; j<3; j++) { - secp256k1_fe_sqr(&t1, &t1); - } - secp256k1_fe_mul(&t1, &t1, &x2); - for (j=0; j<2; j++) { - secp256k1_fe_sqr(&t1, &t1); - } - secp256k1_fe_mul(r, a, &t1); -} - -static void secp256k1_fe_inv_var(secp256k1_fe *r, const secp256k1_fe *a) { -#if defined(USE_FIELD_INV_BUILTIN) - secp256k1_fe_inv(r, a); -#elif defined(USE_FIELD_INV_NUM) - secp256k1_num n, m; - static const secp256k1_fe negone = SECP256K1_FE_CONST( - 0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL, - 0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFEUL, 0xFFFFFC2EUL - ); - /* secp256k1 field prime, value p defined in "Standards for Efficient Cryptography" (SEC2) 2.7.1. */ - static const unsigned char prime[32] = { - 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, - 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, - 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, - 0xFF,0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F - }; - unsigned char b[32]; - int res; - secp256k1_fe c = *a; - secp256k1_fe_normalize_var(&c); - secp256k1_fe_get_b32(b, &c); - secp256k1_num_set_bin(&n, b, 32); - secp256k1_num_set_bin(&m, prime, 32); - secp256k1_num_mod_inverse(&n, &n, &m); - secp256k1_num_get_bin(b, 32, &n); - res = secp256k1_fe_set_b32(r, b); - (void)res; - VERIFY_CHECK(res); - /* Verify the result is the (unique) valid inverse using non-GMP code. */ - secp256k1_fe_mul(&c, &c, r); - secp256k1_fe_add(&c, &negone); - CHECK(secp256k1_fe_normalizes_to_zero_var(&c)); -#else -#error "Please select field inverse implementation" -#endif -} - -static void secp256k1_fe_inv_all_var(secp256k1_fe *r, const secp256k1_fe *a, size_t len) { - secp256k1_fe u; - size_t i; - if (len < 1) { - return; - } - - VERIFY_CHECK((r + len <= a) || (a + len <= r)); - - r[0] = a[0]; - - i = 0; - while (++i < len) { - secp256k1_fe_mul(&r[i], &r[i - 1], &a[i]); - } - - secp256k1_fe_inv_var(&u, &r[--i]); - - while (i > 0) { - size_t j = i--; - secp256k1_fe_mul(&r[j], &r[i], &u); - secp256k1_fe_mul(&u, &u, &a[j]); - } - - r[0] = u; -} - -static int secp256k1_fe_is_quad_var(const secp256k1_fe *a) { -#ifndef USE_NUM_NONE - unsigned char b[32]; - secp256k1_num n; - secp256k1_num m; - /* secp256k1 field prime, value p defined in "Standards for Efficient Cryptography" (SEC2) 2.7.1. */ - static const unsigned char prime[32] = { - 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, - 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, - 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, - 0xFF,0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F - }; - - secp256k1_fe c = *a; - secp256k1_fe_normalize_var(&c); - secp256k1_fe_get_b32(b, &c); - secp256k1_num_set_bin(&n, b, 32); - secp256k1_num_set_bin(&m, prime, 32); - return secp256k1_num_jacobi(&n, &m) >= 0; -#else - secp256k1_fe r; - return secp256k1_fe_sqrt(&r, a); -#endif -} - static const secp256k1_fe secp256k1_fe_one = SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1); #endif /* SECP256K1_FIELD_IMPL_H */ diff --git a/src/gen_context.c b/src/gen_context.c index 8b7729aee4c8d..024c55726170f 100644 --- a/src/gen_context.c +++ b/src/gen_context.c @@ -1,16 +1,17 @@ -/********************************************************************** - * Copyright (c) 2013, 2014, 2015 Thomas Daede, Cory Fields * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014, 2015 Thomas Daede, Cory Fields * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ -// Autotools creates libsecp256k1-config.h, of which ECMULT_GEN_PREC_BITS is needed. -// ifndef guard so downstream users can define their own if they do not use autotools. +/* Autotools creates libsecp256k1-config.h, of which ECMULT_GEN_PREC_BITS is needed. + ifndef guard so downstream users can define their own if they do not use autotools. */ #if !defined(ECMULT_GEN_PREC_BITS) #include "libsecp256k1-config.h" #endif -#define USE_BASIC_CONFIG 1 -#include "basic-config.h" + +/* We can't require the precomputed tables when creating them. */ +#undef USE_ECMULT_STATIC_PRECOMPUTATION #include "include/secp256k1.h" #include "assumptions.h" @@ -47,8 +48,8 @@ int main(int argc, char **argv) { return -1; } - fprintf(fp, "#ifndef _SECP256K1_ECMULT_STATIC_CONTEXT_\n"); - fprintf(fp, "#define _SECP256K1_ECMULT_STATIC_CONTEXT_\n"); + fprintf(fp, "#ifndef SECP256K1_ECMULT_STATIC_CONTEXT_H\n"); + fprintf(fp, "#define SECP256K1_ECMULT_STATIC_CONTEXT_H\n"); fprintf(fp, "#include \"src/group.h\"\n"); fprintf(fp, "#define SC SECP256K1_GE_STORAGE_CONST\n"); fprintf(fp, "#if ECMULT_GEN_PREC_N != %d || ECMULT_GEN_PREC_G != %d\n", ECMULT_GEN_PREC_N, ECMULT_GEN_PREC_G); diff --git a/src/group.h b/src/group.h index 36e39ecf0f159..b9cd334dae26c 100644 --- a/src/group.h +++ b/src/group.h @@ -1,13 +1,12 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_GROUP_H #define SECP256K1_GROUP_H -#include "num.h" #include "field.h" /** A group element of the secp256k1 curve, in affine coordinates. */ @@ -43,12 +42,6 @@ typedef struct { /** Set a group element equal to the point with given X and Y coordinates */ static void secp256k1_ge_set_xy(secp256k1_ge *r, const secp256k1_fe *x, const secp256k1_fe *y); -/** Set a group element (affine) equal to the point with the given X coordinate - * and a Y coordinate that is a quadratic residue modulo p. The return value - * is true iff a coordinate with the given X coordinate exists. - */ -static int secp256k1_ge_set_xquad(secp256k1_ge *r, const secp256k1_fe *x); - /** Set a group element (affine) equal to the point with the given X coordinate, and given oddness * for Y. Return value indicates whether the result is valid. */ static int secp256k1_ge_set_xo_var(secp256k1_ge *r, const secp256k1_fe *x, int odd); @@ -62,9 +55,12 @@ static int secp256k1_ge_is_valid_var(const secp256k1_ge *a); /** Set r equal to the inverse of a (i.e., mirrored around the X axis) */ static void secp256k1_ge_neg(secp256k1_ge *r, const secp256k1_ge *a); -/** Set a group element equal to another which is given in jacobian coordinates */ +/** Set a group element equal to another which is given in jacobian coordinates. Constant time. */ static void secp256k1_ge_set_gej(secp256k1_ge *r, secp256k1_gej *a); +/** Set a group element equal to another which is given in jacobian coordinates. */ +static void secp256k1_ge_set_gej_var(secp256k1_ge *r, secp256k1_gej *a); + /** Set a batch of group elements equal to the inputs given in jacobian coordinates */ static void secp256k1_ge_set_all_gej_var(secp256k1_ge *r, const secp256k1_gej *a, size_t len); @@ -93,9 +89,6 @@ static void secp256k1_gej_neg(secp256k1_gej *r, const secp256k1_gej *a); /** Check whether a group element is the point at infinity. */ static int secp256k1_gej_is_infinity(const secp256k1_gej *a); -/** Check whether a group element's y coordinate is a quadratic residue. */ -static int secp256k1_gej_has_quad_y_var(const secp256k1_gej *a); - /** Set r equal to the double of a. Constant time. */ static void secp256k1_gej_double(secp256k1_gej *r, const secp256k1_gej *a); diff --git a/src/group_impl.h b/src/group_impl.h index a5fbc91a0f88d..19ebd8f44ee38 100644 --- a/src/group_impl.h +++ b/src/group_impl.h @@ -1,13 +1,12 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_GROUP_IMPL_H #define SECP256K1_GROUP_IMPL_H -#include "num.h" #include "field.h" #include "group.h" @@ -207,18 +206,14 @@ static void secp256k1_ge_clear(secp256k1_ge *r) { secp256k1_fe_clear(&r->y); } -static int secp256k1_ge_set_xquad(secp256k1_ge *r, const secp256k1_fe *x) { +static int secp256k1_ge_set_xo_var(secp256k1_ge *r, const secp256k1_fe *x, int odd) { secp256k1_fe x2, x3; r->x = *x; secp256k1_fe_sqr(&x2, x); secp256k1_fe_mul(&x3, x, &x2); r->infinity = 0; secp256k1_fe_add(&x3, &secp256k1_fe_const_b); - return secp256k1_fe_sqrt(&r->y, &x3); -} - -static int secp256k1_ge_set_xo_var(secp256k1_ge *r, const secp256k1_fe *x, int odd) { - if (!secp256k1_ge_set_xquad(r, x)) { + if (!secp256k1_fe_sqrt(&r->y, &x3)) { return 0; } secp256k1_fe_normalize_var(&r->y); @@ -591,7 +586,7 @@ static void secp256k1_gej_add_ge(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_fe_cmov(&n, &m, degenerate); /* n = M^3 * Malt (2) */ secp256k1_fe_sqr(&t, &rr_alt); /* t = Ralt^2 (1) */ secp256k1_fe_mul(&r->z, &a->z, &m_alt); /* r->z = Malt*Z (1) */ - infinity = secp256k1_fe_normalizes_to_zero(&r->z) * (1 - a->infinity); + infinity = secp256k1_fe_normalizes_to_zero(&r->z) & ~a->infinity; secp256k1_fe_mul_int(&r->z, 2); /* r->z = Z3 = 2*Malt*Z (2) */ secp256k1_fe_negate(&q, &q, 1); /* q = -Q (2) */ secp256k1_fe_add(&t, &q); /* t = Ralt^2-Q (3) */ @@ -655,26 +650,12 @@ static void secp256k1_ge_mul_lambda(secp256k1_ge *r, const secp256k1_ge *a) { secp256k1_fe_mul(&r->x, &r->x, &beta); } -static int secp256k1_gej_has_quad_y_var(const secp256k1_gej *a) { - secp256k1_fe yz; - - if (a->infinity) { - return 0; - } - - /* We rely on the fact that the Jacobi symbol of 1 / a->z^3 is the same as - * that of a->z. Thus a->y / a->z^3 is a quadratic residue iff a->y * a->z - is */ - secp256k1_fe_mul(&yz, &a->y, &a->z); - return secp256k1_fe_is_quad_var(&yz); -} - static int secp256k1_ge_is_in_correct_subgroup(const secp256k1_ge* ge) { #ifdef EXHAUSTIVE_TEST_ORDER secp256k1_gej out; int i; - /* A very simple EC multiplication ladder that avoids a dependecy on ecmult. */ + /* A very simple EC multiplication ladder that avoids a dependency on ecmult. */ secp256k1_gej_set_infinity(&out); for (i = 0; i < 32; ++i) { secp256k1_gej_double_var(&out, &out, NULL); diff --git a/src/hash.h b/src/hash.h index de26e4b89f8cb..0947a096943a9 100644 --- a/src/hash.h +++ b/src/hash.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_HASH_H #define SECP256K1_HASH_H diff --git a/src/hash_impl.h b/src/hash_impl.h index 409772587bebb..f8cd3a1634113 100644 --- a/src/hash_impl.h +++ b/src/hash_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_HASH_IMPL_H #define SECP256K1_HASH_IMPL_H diff --git a/src/modinv32.h b/src/modinv32.h new file mode 100644 index 0000000000000..0efdda9ab5e2e --- /dev/null +++ b/src/modinv32.h @@ -0,0 +1,42 @@ +/*********************************************************************** + * Copyright (c) 2020 Peter Dettman * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + **********************************************************************/ + +#ifndef SECP256K1_MODINV32_H +#define SECP256K1_MODINV32_H + +#if defined HAVE_CONFIG_H +#include "libsecp256k1-config.h" +#endif + +#include "util.h" + +/* A signed 30-bit limb representation of integers. + * + * Its value is sum(v[i] * 2^(30*i), i=0..8). */ +typedef struct { + int32_t v[9]; +} secp256k1_modinv32_signed30; + +typedef struct { + /* The modulus in signed30 notation, must be odd and in [3, 2^256]. */ + secp256k1_modinv32_signed30 modulus; + + /* modulus^{-1} mod 2^30 */ + uint32_t modulus_inv30; +} secp256k1_modinv32_modinfo; + +/* Replace x with its modular inverse mod modinfo->modulus. x must be in range [0, modulus). + * If x is zero, the result will be zero as well. If not, the inverse must exist (i.e., the gcd of + * x and modulus must be 1). These rules are automatically satisfied if the modulus is prime. + * + * On output, all of x's limbs will be in [0, 2^30). + */ +static void secp256k1_modinv32_var(secp256k1_modinv32_signed30 *x, const secp256k1_modinv32_modinfo *modinfo); + +/* Same as secp256k1_modinv32_var, but constant time in x (not in the modulus). */ +static void secp256k1_modinv32(secp256k1_modinv32_signed30 *x, const secp256k1_modinv32_modinfo *modinfo); + +#endif /* SECP256K1_MODINV32_H */ diff --git a/src/modinv32_impl.h b/src/modinv32_impl.h new file mode 100644 index 0000000000000..661c5fc04c988 --- /dev/null +++ b/src/modinv32_impl.h @@ -0,0 +1,587 @@ +/*********************************************************************** + * Copyright (c) 2020 Peter Dettman * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + **********************************************************************/ + +#ifndef SECP256K1_MODINV32_IMPL_H +#define SECP256K1_MODINV32_IMPL_H + +#include "modinv32.h" + +#include "util.h" + +#include + +/* This file implements modular inversion based on the paper "Fast constant-time gcd computation and + * modular inversion" by Daniel J. Bernstein and Bo-Yin Yang. + * + * For an explanation of the algorithm, see doc/safegcd_implementation.md. This file contains an + * implementation for N=30, using 30-bit signed limbs represented as int32_t. + */ + +#ifdef VERIFY +static const secp256k1_modinv32_signed30 SECP256K1_SIGNED30_ONE = {{1}}; + +/* Compute a*factor and put it in r. All but the top limb in r will be in range [0,2^30). */ +static void secp256k1_modinv32_mul_30(secp256k1_modinv32_signed30 *r, const secp256k1_modinv32_signed30 *a, int alen, int32_t factor) { + const int32_t M30 = (int32_t)(UINT32_MAX >> 2); + int64_t c = 0; + int i; + for (i = 0; i < 8; ++i) { + if (i < alen) c += (int64_t)a->v[i] * factor; + r->v[i] = (int32_t)c & M30; c >>= 30; + } + if (8 < alen) c += (int64_t)a->v[8] * factor; + VERIFY_CHECK(c == (int32_t)c); + r->v[8] = (int32_t)c; +} + +/* Return -1 for ab*factor. A consists of alen limbs; b has 9. */ +static int secp256k1_modinv32_mul_cmp_30(const secp256k1_modinv32_signed30 *a, int alen, const secp256k1_modinv32_signed30 *b, int32_t factor) { + int i; + secp256k1_modinv32_signed30 am, bm; + secp256k1_modinv32_mul_30(&am, a, alen, 1); /* Normalize all but the top limb of a. */ + secp256k1_modinv32_mul_30(&bm, b, 9, factor); + for (i = 0; i < 8; ++i) { + /* Verify that all but the top limb of a and b are normalized. */ + VERIFY_CHECK(am.v[i] >> 30 == 0); + VERIFY_CHECK(bm.v[i] >> 30 == 0); + } + for (i = 8; i >= 0; --i) { + if (am.v[i] < bm.v[i]) return -1; + if (am.v[i] > bm.v[i]) return 1; + } + return 0; +} +#endif + +/* Take as input a signed30 number in range (-2*modulus,modulus), and add a multiple of the modulus + * to it to bring it to range [0,modulus). If sign < 0, the input will also be negated in the + * process. The input must have limbs in range (-2^30,2^30). The output will have limbs in range + * [0,2^30). */ +static void secp256k1_modinv32_normalize_30(secp256k1_modinv32_signed30 *r, int32_t sign, const secp256k1_modinv32_modinfo *modinfo) { + const int32_t M30 = (int32_t)(UINT32_MAX >> 2); + int32_t r0 = r->v[0], r1 = r->v[1], r2 = r->v[2], r3 = r->v[3], r4 = r->v[4], + r5 = r->v[5], r6 = r->v[6], r7 = r->v[7], r8 = r->v[8]; + int32_t cond_add, cond_negate; + +#ifdef VERIFY + /* Verify that all limbs are in range (-2^30,2^30). */ + int i; + for (i = 0; i < 9; ++i) { + VERIFY_CHECK(r->v[i] >= -M30); + VERIFY_CHECK(r->v[i] <= M30); + } + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(r, 9, &modinfo->modulus, -2) > 0); /* r > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(r, 9, &modinfo->modulus, 1) < 0); /* r < modulus */ +#endif + + /* In a first step, add the modulus if the input is negative, and then negate if requested. + * This brings r from range (-2*modulus,modulus) to range (-modulus,modulus). As all input + * limbs are in range (-2^30,2^30), this cannot overflow an int32_t. Note that the right + * shifts below are signed sign-extending shifts (see assumptions.h for tests that that is + * indeed the behavior of the right shift operator). */ + cond_add = r8 >> 31; + r0 += modinfo->modulus.v[0] & cond_add; + r1 += modinfo->modulus.v[1] & cond_add; + r2 += modinfo->modulus.v[2] & cond_add; + r3 += modinfo->modulus.v[3] & cond_add; + r4 += modinfo->modulus.v[4] & cond_add; + r5 += modinfo->modulus.v[5] & cond_add; + r6 += modinfo->modulus.v[6] & cond_add; + r7 += modinfo->modulus.v[7] & cond_add; + r8 += modinfo->modulus.v[8] & cond_add; + cond_negate = sign >> 31; + r0 = (r0 ^ cond_negate) - cond_negate; + r1 = (r1 ^ cond_negate) - cond_negate; + r2 = (r2 ^ cond_negate) - cond_negate; + r3 = (r3 ^ cond_negate) - cond_negate; + r4 = (r4 ^ cond_negate) - cond_negate; + r5 = (r5 ^ cond_negate) - cond_negate; + r6 = (r6 ^ cond_negate) - cond_negate; + r7 = (r7 ^ cond_negate) - cond_negate; + r8 = (r8 ^ cond_negate) - cond_negate; + /* Propagate the top bits, to bring limbs back to range (-2^30,2^30). */ + r1 += r0 >> 30; r0 &= M30; + r2 += r1 >> 30; r1 &= M30; + r3 += r2 >> 30; r2 &= M30; + r4 += r3 >> 30; r3 &= M30; + r5 += r4 >> 30; r4 &= M30; + r6 += r5 >> 30; r5 &= M30; + r7 += r6 >> 30; r6 &= M30; + r8 += r7 >> 30; r7 &= M30; + + /* In a second step add the modulus again if the result is still negative, bringing r to range + * [0,modulus). */ + cond_add = r8 >> 31; + r0 += modinfo->modulus.v[0] & cond_add; + r1 += modinfo->modulus.v[1] & cond_add; + r2 += modinfo->modulus.v[2] & cond_add; + r3 += modinfo->modulus.v[3] & cond_add; + r4 += modinfo->modulus.v[4] & cond_add; + r5 += modinfo->modulus.v[5] & cond_add; + r6 += modinfo->modulus.v[6] & cond_add; + r7 += modinfo->modulus.v[7] & cond_add; + r8 += modinfo->modulus.v[8] & cond_add; + /* And propagate again. */ + r1 += r0 >> 30; r0 &= M30; + r2 += r1 >> 30; r1 &= M30; + r3 += r2 >> 30; r2 &= M30; + r4 += r3 >> 30; r3 &= M30; + r5 += r4 >> 30; r4 &= M30; + r6 += r5 >> 30; r5 &= M30; + r7 += r6 >> 30; r6 &= M30; + r8 += r7 >> 30; r7 &= M30; + + r->v[0] = r0; + r->v[1] = r1; + r->v[2] = r2; + r->v[3] = r3; + r->v[4] = r4; + r->v[5] = r5; + r->v[6] = r6; + r->v[7] = r7; + r->v[8] = r8; + +#ifdef VERIFY + VERIFY_CHECK(r0 >> 30 == 0); + VERIFY_CHECK(r1 >> 30 == 0); + VERIFY_CHECK(r2 >> 30 == 0); + VERIFY_CHECK(r3 >> 30 == 0); + VERIFY_CHECK(r4 >> 30 == 0); + VERIFY_CHECK(r5 >> 30 == 0); + VERIFY_CHECK(r6 >> 30 == 0); + VERIFY_CHECK(r7 >> 30 == 0); + VERIFY_CHECK(r8 >> 30 == 0); + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(r, 9, &modinfo->modulus, 0) >= 0); /* r >= 0 */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(r, 9, &modinfo->modulus, 1) < 0); /* r < modulus */ +#endif +} + +/* Data type for transition matrices (see section 3 of explanation). + * + * t = [ u v ] + * [ q r ] + */ +typedef struct { + int32_t u, v, q, r; +} secp256k1_modinv32_trans2x2; + +/* Compute the transition matrix and zeta for 30 divsteps. + * + * Input: zeta: initial zeta + * f0: bottom limb of initial f + * g0: bottom limb of initial g + * Output: t: transition matrix + * Return: final zeta + * + * Implements the divsteps_n_matrix function from the explanation. + */ +static int32_t secp256k1_modinv32_divsteps_30(int32_t zeta, uint32_t f0, uint32_t g0, secp256k1_modinv32_trans2x2 *t) { + /* u,v,q,r are the elements of the transformation matrix being built up, + * starting with the identity matrix. Semantically they are signed integers + * in range [-2^30,2^30], but here represented as unsigned mod 2^32. This + * permits left shifting (which is UB for negative numbers). The range + * being inside [-2^31,2^31) means that casting to signed works correctly. + */ + uint32_t u = 1, v = 0, q = 0, r = 1; + uint32_t c1, c2, f = f0, g = g0, x, y, z; + int i; + + for (i = 0; i < 30; ++i) { + VERIFY_CHECK((f & 1) == 1); /* f must always be odd */ + VERIFY_CHECK((u * f0 + v * g0) == f << i); + VERIFY_CHECK((q * f0 + r * g0) == g << i); + /* Compute conditional masks for (zeta < 0) and for (g & 1). */ + c1 = zeta >> 31; + c2 = -(g & 1); + /* Compute x,y,z, conditionally negated versions of f,u,v. */ + x = (f ^ c1) - c1; + y = (u ^ c1) - c1; + z = (v ^ c1) - c1; + /* Conditionally add x,y,z to g,q,r. */ + g += x & c2; + q += y & c2; + r += z & c2; + /* In what follows, c1 is a condition mask for (zeta < 0) and (g & 1). */ + c1 &= c2; + /* Conditionally change zeta into -zeta-2 or zeta-1. */ + zeta = (zeta ^ c1) - 1; + /* Conditionally add g,q,r to f,u,v. */ + f += g & c1; + u += q & c1; + v += r & c1; + /* Shifts */ + g >>= 1; + u <<= 1; + v <<= 1; + /* Bounds on zeta that follow from the bounds on iteration count (max 20*30 divsteps). */ + VERIFY_CHECK(zeta >= -601 && zeta <= 601); + } + /* Return data in t and return value. */ + t->u = (int32_t)u; + t->v = (int32_t)v; + t->q = (int32_t)q; + t->r = (int32_t)r; + /* The determinant of t must be a power of two. This guarantees that multiplication with t + * does not change the gcd of f and g, apart from adding a power-of-2 factor to it (which + * will be divided out again). As each divstep's individual matrix has determinant 2, the + * aggregate of 30 of them will have determinant 2^30. */ + VERIFY_CHECK((int64_t)t->u * t->r - (int64_t)t->v * t->q == ((int64_t)1) << 30); + return zeta; +} + +/* Compute the transition matrix and eta for 30 divsteps (variable time). + * + * Input: eta: initial eta + * f0: bottom limb of initial f + * g0: bottom limb of initial g + * Output: t: transition matrix + * Return: final eta + * + * Implements the divsteps_n_matrix_var function from the explanation. + */ +static int32_t secp256k1_modinv32_divsteps_30_var(int32_t eta, uint32_t f0, uint32_t g0, secp256k1_modinv32_trans2x2 *t) { + /* inv256[i] = -(2*i+1)^-1 (mod 256) */ + static const uint8_t inv256[128] = { + 0xFF, 0x55, 0x33, 0x49, 0xC7, 0x5D, 0x3B, 0x11, 0x0F, 0xE5, 0xC3, 0x59, + 0xD7, 0xED, 0xCB, 0x21, 0x1F, 0x75, 0x53, 0x69, 0xE7, 0x7D, 0x5B, 0x31, + 0x2F, 0x05, 0xE3, 0x79, 0xF7, 0x0D, 0xEB, 0x41, 0x3F, 0x95, 0x73, 0x89, + 0x07, 0x9D, 0x7B, 0x51, 0x4F, 0x25, 0x03, 0x99, 0x17, 0x2D, 0x0B, 0x61, + 0x5F, 0xB5, 0x93, 0xA9, 0x27, 0xBD, 0x9B, 0x71, 0x6F, 0x45, 0x23, 0xB9, + 0x37, 0x4D, 0x2B, 0x81, 0x7F, 0xD5, 0xB3, 0xC9, 0x47, 0xDD, 0xBB, 0x91, + 0x8F, 0x65, 0x43, 0xD9, 0x57, 0x6D, 0x4B, 0xA1, 0x9F, 0xF5, 0xD3, 0xE9, + 0x67, 0xFD, 0xDB, 0xB1, 0xAF, 0x85, 0x63, 0xF9, 0x77, 0x8D, 0x6B, 0xC1, + 0xBF, 0x15, 0xF3, 0x09, 0x87, 0x1D, 0xFB, 0xD1, 0xCF, 0xA5, 0x83, 0x19, + 0x97, 0xAD, 0x8B, 0xE1, 0xDF, 0x35, 0x13, 0x29, 0xA7, 0x3D, 0x1B, 0xF1, + 0xEF, 0xC5, 0xA3, 0x39, 0xB7, 0xCD, 0xAB, 0x01 + }; + + /* Transformation matrix; see comments in secp256k1_modinv32_divsteps_30. */ + uint32_t u = 1, v = 0, q = 0, r = 1; + uint32_t f = f0, g = g0, m; + uint16_t w; + int i = 30, limit, zeros; + + for (;;) { + /* Use a sentinel bit to count zeros only up to i. */ + zeros = secp256k1_ctz32_var(g | (UINT32_MAX << i)); + /* Perform zeros divsteps at once; they all just divide g by two. */ + g >>= zeros; + u <<= zeros; + v <<= zeros; + eta -= zeros; + i -= zeros; + /* We're done once we've done 30 divsteps. */ + if (i == 0) break; + VERIFY_CHECK((f & 1) == 1); + VERIFY_CHECK((g & 1) == 1); + VERIFY_CHECK((u * f0 + v * g0) == f << (30 - i)); + VERIFY_CHECK((q * f0 + r * g0) == g << (30 - i)); + /* Bounds on eta that follow from the bounds on iteration count (max 25*30 divsteps). */ + VERIFY_CHECK(eta >= -751 && eta <= 751); + /* If eta is negative, negate it and replace f,g with g,-f. */ + if (eta < 0) { + uint32_t tmp; + eta = -eta; + tmp = f; f = g; g = -tmp; + tmp = u; u = q; q = -tmp; + tmp = v; v = r; r = -tmp; + } + /* eta is now >= 0. In what follows we're going to cancel out the bottom bits of g. No more + * than i can be cancelled out (as we'd be done before that point), and no more than eta+1 + * can be done as its sign will flip once that happens. */ + limit = ((int)eta + 1) > i ? i : ((int)eta + 1); + /* m is a mask for the bottom min(limit, 8) bits (our table only supports 8 bits). */ + VERIFY_CHECK(limit > 0 && limit <= 30); + m = (UINT32_MAX >> (32 - limit)) & 255U; + /* Find what multiple of f must be added to g to cancel its bottom min(limit, 8) bits. */ + w = (g * inv256[(f >> 1) & 127]) & m; + /* Do so. */ + g += f * w; + q += u * w; + r += v * w; + VERIFY_CHECK((g & m) == 0); + } + /* Return data in t and return value. */ + t->u = (int32_t)u; + t->v = (int32_t)v; + t->q = (int32_t)q; + t->r = (int32_t)r; + /* The determinant of t must be a power of two. This guarantees that multiplication with t + * does not change the gcd of f and g, apart from adding a power-of-2 factor to it (which + * will be divided out again). As each divstep's individual matrix has determinant 2, the + * aggregate of 30 of them will have determinant 2^30. */ + VERIFY_CHECK((int64_t)t->u * t->r - (int64_t)t->v * t->q == ((int64_t)1) << 30); + return eta; +} + +/* Compute (t/2^30) * [d, e] mod modulus, where t is a transition matrix for 30 divsteps. + * + * On input and output, d and e are in range (-2*modulus,modulus). All output limbs will be in range + * (-2^30,2^30). + * + * This implements the update_de function from the explanation. + */ +static void secp256k1_modinv32_update_de_30(secp256k1_modinv32_signed30 *d, secp256k1_modinv32_signed30 *e, const secp256k1_modinv32_trans2x2 *t, const secp256k1_modinv32_modinfo* modinfo) { + const int32_t M30 = (int32_t)(UINT32_MAX >> 2); + const int32_t u = t->u, v = t->v, q = t->q, r = t->r; + int32_t di, ei, md, me, sd, se; + int64_t cd, ce; + int i; +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(d, 9, &modinfo->modulus, -2) > 0); /* d > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(d, 9, &modinfo->modulus, 1) < 0); /* d < modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(e, 9, &modinfo->modulus, -2) > 0); /* e > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(e, 9, &modinfo->modulus, 1) < 0); /* e < modulus */ + VERIFY_CHECK((labs(u) + labs(v)) >= 0); /* |u|+|v| doesn't overflow */ + VERIFY_CHECK((labs(q) + labs(r)) >= 0); /* |q|+|r| doesn't overflow */ + VERIFY_CHECK((labs(u) + labs(v)) <= M30 + 1); /* |u|+|v| <= 2^30 */ + VERIFY_CHECK((labs(q) + labs(r)) <= M30 + 1); /* |q|+|r| <= 2^30 */ +#endif + /* [md,me] start as zero; plus [u,q] if d is negative; plus [v,r] if e is negative. */ + sd = d->v[8] >> 31; + se = e->v[8] >> 31; + md = (u & sd) + (v & se); + me = (q & sd) + (r & se); + /* Begin computing t*[d,e]. */ + di = d->v[0]; + ei = e->v[0]; + cd = (int64_t)u * di + (int64_t)v * ei; + ce = (int64_t)q * di + (int64_t)r * ei; + /* Correct md,me so that t*[d,e]+modulus*[md,me] has 30 zero bottom bits. */ + md -= (modinfo->modulus_inv30 * (uint32_t)cd + md) & M30; + me -= (modinfo->modulus_inv30 * (uint32_t)ce + me) & M30; + /* Update the beginning of computation for t*[d,e]+modulus*[md,me] now md,me are known. */ + cd += (int64_t)modinfo->modulus.v[0] * md; + ce += (int64_t)modinfo->modulus.v[0] * me; + /* Verify that the low 30 bits of the computation are indeed zero, and then throw them away. */ + VERIFY_CHECK(((int32_t)cd & M30) == 0); cd >>= 30; + VERIFY_CHECK(((int32_t)ce & M30) == 0); ce >>= 30; + /* Now iteratively compute limb i=1..8 of t*[d,e]+modulus*[md,me], and store them in output + * limb i-1 (shifting down by 30 bits). */ + for (i = 1; i < 9; ++i) { + di = d->v[i]; + ei = e->v[i]; + cd += (int64_t)u * di + (int64_t)v * ei; + ce += (int64_t)q * di + (int64_t)r * ei; + cd += (int64_t)modinfo->modulus.v[i] * md; + ce += (int64_t)modinfo->modulus.v[i] * me; + d->v[i - 1] = (int32_t)cd & M30; cd >>= 30; + e->v[i - 1] = (int32_t)ce & M30; ce >>= 30; + } + /* What remains is limb 9 of t*[d,e]+modulus*[md,me]; store it as output limb 8. */ + d->v[8] = (int32_t)cd; + e->v[8] = (int32_t)ce; +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(d, 9, &modinfo->modulus, -2) > 0); /* d > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(d, 9, &modinfo->modulus, 1) < 0); /* d < modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(e, 9, &modinfo->modulus, -2) > 0); /* e > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(e, 9, &modinfo->modulus, 1) < 0); /* e < modulus */ +#endif +} + +/* Compute (t/2^30) * [f, g], where t is a transition matrix for 30 divsteps. + * + * This implements the update_fg function from the explanation. + */ +static void secp256k1_modinv32_update_fg_30(secp256k1_modinv32_signed30 *f, secp256k1_modinv32_signed30 *g, const secp256k1_modinv32_trans2x2 *t) { + const int32_t M30 = (int32_t)(UINT32_MAX >> 2); + const int32_t u = t->u, v = t->v, q = t->q, r = t->r; + int32_t fi, gi; + int64_t cf, cg; + int i; + /* Start computing t*[f,g]. */ + fi = f->v[0]; + gi = g->v[0]; + cf = (int64_t)u * fi + (int64_t)v * gi; + cg = (int64_t)q * fi + (int64_t)r * gi; + /* Verify that the bottom 30 bits of the result are zero, and then throw them away. */ + VERIFY_CHECK(((int32_t)cf & M30) == 0); cf >>= 30; + VERIFY_CHECK(((int32_t)cg & M30) == 0); cg >>= 30; + /* Now iteratively compute limb i=1..8 of t*[f,g], and store them in output limb i-1 (shifting + * down by 30 bits). */ + for (i = 1; i < 9; ++i) { + fi = f->v[i]; + gi = g->v[i]; + cf += (int64_t)u * fi + (int64_t)v * gi; + cg += (int64_t)q * fi + (int64_t)r * gi; + f->v[i - 1] = (int32_t)cf & M30; cf >>= 30; + g->v[i - 1] = (int32_t)cg & M30; cg >>= 30; + } + /* What remains is limb 9 of t*[f,g]; store it as output limb 8. */ + f->v[8] = (int32_t)cf; + g->v[8] = (int32_t)cg; +} + +/* Compute (t/2^30) * [f, g], where t is a transition matrix for 30 divsteps. + * + * Version that operates on a variable number of limbs in f and g. + * + * This implements the update_fg function from the explanation in modinv64_impl.h. + */ +static void secp256k1_modinv32_update_fg_30_var(int len, secp256k1_modinv32_signed30 *f, secp256k1_modinv32_signed30 *g, const secp256k1_modinv32_trans2x2 *t) { + const int32_t M30 = (int32_t)(UINT32_MAX >> 2); + const int32_t u = t->u, v = t->v, q = t->q, r = t->r; + int32_t fi, gi; + int64_t cf, cg; + int i; + VERIFY_CHECK(len > 0); + /* Start computing t*[f,g]. */ + fi = f->v[0]; + gi = g->v[0]; + cf = (int64_t)u * fi + (int64_t)v * gi; + cg = (int64_t)q * fi + (int64_t)r * gi; + /* Verify that the bottom 62 bits of the result are zero, and then throw them away. */ + VERIFY_CHECK(((int32_t)cf & M30) == 0); cf >>= 30; + VERIFY_CHECK(((int32_t)cg & M30) == 0); cg >>= 30; + /* Now iteratively compute limb i=1..len of t*[f,g], and store them in output limb i-1 (shifting + * down by 30 bits). */ + for (i = 1; i < len; ++i) { + fi = f->v[i]; + gi = g->v[i]; + cf += (int64_t)u * fi + (int64_t)v * gi; + cg += (int64_t)q * fi + (int64_t)r * gi; + f->v[i - 1] = (int32_t)cf & M30; cf >>= 30; + g->v[i - 1] = (int32_t)cg & M30; cg >>= 30; + } + /* What remains is limb (len) of t*[f,g]; store it as output limb (len-1). */ + f->v[len - 1] = (int32_t)cf; + g->v[len - 1] = (int32_t)cg; +} + +/* Compute the inverse of x modulo modinfo->modulus, and replace x with it (constant time in x). */ +static void secp256k1_modinv32(secp256k1_modinv32_signed30 *x, const secp256k1_modinv32_modinfo *modinfo) { + /* Start with d=0, e=1, f=modulus, g=x, zeta=-1. */ + secp256k1_modinv32_signed30 d = {{0}}; + secp256k1_modinv32_signed30 e = {{1}}; + secp256k1_modinv32_signed30 f = modinfo->modulus; + secp256k1_modinv32_signed30 g = *x; + int i; + int32_t zeta = -1; /* zeta = -(delta+1/2); delta is initially 1/2. */ + + /* Do 20 iterations of 30 divsteps each = 600 divsteps. 590 suffices for 256-bit inputs. */ + for (i = 0; i < 20; ++i) { + /* Compute transition matrix and new zeta after 30 divsteps. */ + secp256k1_modinv32_trans2x2 t; + zeta = secp256k1_modinv32_divsteps_30(zeta, f.v[0], g.v[0], &t); + /* Update d,e using that transition matrix. */ + secp256k1_modinv32_update_de_30(&d, &e, &t, modinfo); + /* Update f,g using that transition matrix. */ +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, 9, &modinfo->modulus, -1) > 0); /* f > -modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, 9, &modinfo->modulus, 1) <= 0); /* f <= modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, 9, &modinfo->modulus, -1) > 0); /* g > -modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, 9, &modinfo->modulus, 1) < 0); /* g < modulus */ +#endif + secp256k1_modinv32_update_fg_30(&f, &g, &t); +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, 9, &modinfo->modulus, -1) > 0); /* f > -modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, 9, &modinfo->modulus, 1) <= 0); /* f <= modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, 9, &modinfo->modulus, -1) > 0); /* g > -modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, 9, &modinfo->modulus, 1) < 0); /* g < modulus */ +#endif + } + + /* At this point sufficient iterations have been performed that g must have reached 0 + * and (if g was not originally 0) f must now equal +/- GCD of the initial f, g + * values i.e. +/- 1, and d now contains +/- the modular inverse. */ +#ifdef VERIFY + /* g == 0 */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, 9, &SECP256K1_SIGNED30_ONE, 0) == 0); + /* |f| == 1, or (x == 0 and d == 0 and |f|=modulus) */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, 9, &SECP256K1_SIGNED30_ONE, -1) == 0 || + secp256k1_modinv32_mul_cmp_30(&f, 9, &SECP256K1_SIGNED30_ONE, 1) == 0 || + (secp256k1_modinv32_mul_cmp_30(x, 9, &SECP256K1_SIGNED30_ONE, 0) == 0 && + secp256k1_modinv32_mul_cmp_30(&d, 9, &SECP256K1_SIGNED30_ONE, 0) == 0 && + (secp256k1_modinv32_mul_cmp_30(&f, 9, &modinfo->modulus, 1) == 0 || + secp256k1_modinv32_mul_cmp_30(&f, 9, &modinfo->modulus, -1) == 0))); +#endif + + /* Optionally negate d, normalize to [0,modulus), and return it. */ + secp256k1_modinv32_normalize_30(&d, f.v[8], modinfo); + *x = d; +} + +/* Compute the inverse of x modulo modinfo->modulus, and replace x with it (variable time). */ +static void secp256k1_modinv32_var(secp256k1_modinv32_signed30 *x, const secp256k1_modinv32_modinfo *modinfo) { + /* Start with d=0, e=1, f=modulus, g=x, eta=-1. */ + secp256k1_modinv32_signed30 d = {{0, 0, 0, 0, 0, 0, 0, 0, 0}}; + secp256k1_modinv32_signed30 e = {{1, 0, 0, 0, 0, 0, 0, 0, 0}}; + secp256k1_modinv32_signed30 f = modinfo->modulus; + secp256k1_modinv32_signed30 g = *x; +#ifdef VERIFY + int i = 0; +#endif + int j, len = 9; + int32_t eta = -1; /* eta = -delta; delta is initially 1 (faster for the variable-time code) */ + int32_t cond, fn, gn; + + /* Do iterations of 30 divsteps each until g=0. */ + while (1) { + /* Compute transition matrix and new eta after 30 divsteps. */ + secp256k1_modinv32_trans2x2 t; + eta = secp256k1_modinv32_divsteps_30_var(eta, f.v[0], g.v[0], &t); + /* Update d,e using that transition matrix. */ + secp256k1_modinv32_update_de_30(&d, &e, &t, modinfo); + /* Update f,g using that transition matrix. */ +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, len, &modinfo->modulus, -1) > 0); /* f > -modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, len, &modinfo->modulus, 1) <= 0); /* f <= modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, len, &modinfo->modulus, -1) > 0); /* g > -modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, len, &modinfo->modulus, 1) < 0); /* g < modulus */ +#endif + secp256k1_modinv32_update_fg_30_var(len, &f, &g, &t); + /* If the bottom limb of g is 0, there is a chance g=0. */ + if (g.v[0] == 0) { + cond = 0; + /* Check if all other limbs are also 0. */ + for (j = 1; j < len; ++j) { + cond |= g.v[j]; + } + /* If so, we're done. */ + if (cond == 0) break; + } + + /* Determine if len>1 and limb (len-1) of both f and g is 0 or -1. */ + fn = f.v[len - 1]; + gn = g.v[len - 1]; + cond = ((int32_t)len - 2) >> 31; + cond |= fn ^ (fn >> 31); + cond |= gn ^ (gn >> 31); + /* If so, reduce length, propagating the sign of f and g's top limb into the one below. */ + if (cond == 0) { + f.v[len - 2] |= (uint32_t)fn << 30; + g.v[len - 2] |= (uint32_t)gn << 30; + --len; + } +#ifdef VERIFY + VERIFY_CHECK(++i < 25); /* We should never need more than 25*30 = 750 divsteps */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, len, &modinfo->modulus, -1) > 0); /* f > -modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, len, &modinfo->modulus, 1) <= 0); /* f <= modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, len, &modinfo->modulus, -1) > 0); /* g > -modulus */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, len, &modinfo->modulus, 1) < 0); /* g < modulus */ +#endif + } + + /* At this point g is 0 and (if g was not originally 0) f must now equal +/- GCD of + * the initial f, g values i.e. +/- 1, and d now contains +/- the modular inverse. */ +#ifdef VERIFY + /* g == 0 */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&g, len, &SECP256K1_SIGNED30_ONE, 0) == 0); + /* |f| == 1, or (x == 0 and d == 0 and |f|=modulus) */ + VERIFY_CHECK(secp256k1_modinv32_mul_cmp_30(&f, len, &SECP256K1_SIGNED30_ONE, -1) == 0 || + secp256k1_modinv32_mul_cmp_30(&f, len, &SECP256K1_SIGNED30_ONE, 1) == 0 || + (secp256k1_modinv32_mul_cmp_30(x, 9, &SECP256K1_SIGNED30_ONE, 0) == 0 && + secp256k1_modinv32_mul_cmp_30(&d, 9, &SECP256K1_SIGNED30_ONE, 0) == 0 && + (secp256k1_modinv32_mul_cmp_30(&f, len, &modinfo->modulus, 1) == 0 || + secp256k1_modinv32_mul_cmp_30(&f, len, &modinfo->modulus, -1) == 0))); +#endif + + /* Optionally negate d, normalize to [0,modulus), and return it. */ + secp256k1_modinv32_normalize_30(&d, f.v[len - 1], modinfo); + *x = d; +} + +#endif /* SECP256K1_MODINV32_IMPL_H */ diff --git a/src/modinv64.h b/src/modinv64.h new file mode 100644 index 0000000000000..da506dfa9f722 --- /dev/null +++ b/src/modinv64.h @@ -0,0 +1,46 @@ +/*********************************************************************** + * Copyright (c) 2020 Peter Dettman * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + **********************************************************************/ + +#ifndef SECP256K1_MODINV64_H +#define SECP256K1_MODINV64_H + +#if defined HAVE_CONFIG_H +#include "libsecp256k1-config.h" +#endif + +#include "util.h" + +#ifndef SECP256K1_WIDEMUL_INT128 +#error "modinv64 requires 128-bit wide multiplication support" +#endif + +/* A signed 62-bit limb representation of integers. + * + * Its value is sum(v[i] * 2^(62*i), i=0..4). */ +typedef struct { + int64_t v[5]; +} secp256k1_modinv64_signed62; + +typedef struct { + /* The modulus in signed62 notation, must be odd and in [3, 2^256]. */ + secp256k1_modinv64_signed62 modulus; + + /* modulus^{-1} mod 2^62 */ + uint64_t modulus_inv62; +} secp256k1_modinv64_modinfo; + +/* Replace x with its modular inverse mod modinfo->modulus. x must be in range [0, modulus). + * If x is zero, the result will be zero as well. If not, the inverse must exist (i.e., the gcd of + * x and modulus must be 1). These rules are automatically satisfied if the modulus is prime. + * + * On output, all of x's limbs will be in [0, 2^62). + */ +static void secp256k1_modinv64_var(secp256k1_modinv64_signed62 *x, const secp256k1_modinv64_modinfo *modinfo); + +/* Same as secp256k1_modinv64_var, but constant time in x (not in the modulus). */ +static void secp256k1_modinv64(secp256k1_modinv64_signed62 *x, const secp256k1_modinv64_modinfo *modinfo); + +#endif /* SECP256K1_MODINV64_H */ diff --git a/src/modinv64_impl.h b/src/modinv64_impl.h new file mode 100644 index 0000000000000..0743a9c8210d2 --- /dev/null +++ b/src/modinv64_impl.h @@ -0,0 +1,593 @@ +/*********************************************************************** + * Copyright (c) 2020 Peter Dettman * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + **********************************************************************/ + +#ifndef SECP256K1_MODINV64_IMPL_H +#define SECP256K1_MODINV64_IMPL_H + +#include "modinv64.h" + +#include "util.h" + +/* This file implements modular inversion based on the paper "Fast constant-time gcd computation and + * modular inversion" by Daniel J. Bernstein and Bo-Yin Yang. + * + * For an explanation of the algorithm, see doc/safegcd_implementation.md. This file contains an + * implementation for N=62, using 62-bit signed limbs represented as int64_t. + */ + +#ifdef VERIFY +/* Helper function to compute the absolute value of an int64_t. + * (we don't use abs/labs/llabs as it depends on the int sizes). */ +static int64_t secp256k1_modinv64_abs(int64_t v) { + VERIFY_CHECK(v > INT64_MIN); + if (v < 0) return -v; + return v; +} + +static const secp256k1_modinv64_signed62 SECP256K1_SIGNED62_ONE = {{1}}; + +/* Compute a*factor and put it in r. All but the top limb in r will be in range [0,2^62). */ +static void secp256k1_modinv64_mul_62(secp256k1_modinv64_signed62 *r, const secp256k1_modinv64_signed62 *a, int alen, int64_t factor) { + const int64_t M62 = (int64_t)(UINT64_MAX >> 2); + int128_t c = 0; + int i; + for (i = 0; i < 4; ++i) { + if (i < alen) c += (int128_t)a->v[i] * factor; + r->v[i] = (int64_t)c & M62; c >>= 62; + } + if (4 < alen) c += (int128_t)a->v[4] * factor; + VERIFY_CHECK(c == (int64_t)c); + r->v[4] = (int64_t)c; +} + +/* Return -1 for ab*factor. A has alen limbs; b has 5. */ +static int secp256k1_modinv64_mul_cmp_62(const secp256k1_modinv64_signed62 *a, int alen, const secp256k1_modinv64_signed62 *b, int64_t factor) { + int i; + secp256k1_modinv64_signed62 am, bm; + secp256k1_modinv64_mul_62(&am, a, alen, 1); /* Normalize all but the top limb of a. */ + secp256k1_modinv64_mul_62(&bm, b, 5, factor); + for (i = 0; i < 4; ++i) { + /* Verify that all but the top limb of a and b are normalized. */ + VERIFY_CHECK(am.v[i] >> 62 == 0); + VERIFY_CHECK(bm.v[i] >> 62 == 0); + } + for (i = 4; i >= 0; --i) { + if (am.v[i] < bm.v[i]) return -1; + if (am.v[i] > bm.v[i]) return 1; + } + return 0; +} +#endif + +/* Take as input a signed62 number in range (-2*modulus,modulus), and add a multiple of the modulus + * to it to bring it to range [0,modulus). If sign < 0, the input will also be negated in the + * process. The input must have limbs in range (-2^62,2^62). The output will have limbs in range + * [0,2^62). */ +static void secp256k1_modinv64_normalize_62(secp256k1_modinv64_signed62 *r, int64_t sign, const secp256k1_modinv64_modinfo *modinfo) { + const int64_t M62 = (int64_t)(UINT64_MAX >> 2); + int64_t r0 = r->v[0], r1 = r->v[1], r2 = r->v[2], r3 = r->v[3], r4 = r->v[4]; + int64_t cond_add, cond_negate; + +#ifdef VERIFY + /* Verify that all limbs are in range (-2^62,2^62). */ + int i; + for (i = 0; i < 5; ++i) { + VERIFY_CHECK(r->v[i] >= -M62); + VERIFY_CHECK(r->v[i] <= M62); + } + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(r, 5, &modinfo->modulus, -2) > 0); /* r > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(r, 5, &modinfo->modulus, 1) < 0); /* r < modulus */ +#endif + + /* In a first step, add the modulus if the input is negative, and then negate if requested. + * This brings r from range (-2*modulus,modulus) to range (-modulus,modulus). As all input + * limbs are in range (-2^62,2^62), this cannot overflow an int64_t. Note that the right + * shifts below are signed sign-extending shifts (see assumptions.h for tests that that is + * indeed the behavior of the right shift operator). */ + cond_add = r4 >> 63; + r0 += modinfo->modulus.v[0] & cond_add; + r1 += modinfo->modulus.v[1] & cond_add; + r2 += modinfo->modulus.v[2] & cond_add; + r3 += modinfo->modulus.v[3] & cond_add; + r4 += modinfo->modulus.v[4] & cond_add; + cond_negate = sign >> 63; + r0 = (r0 ^ cond_negate) - cond_negate; + r1 = (r1 ^ cond_negate) - cond_negate; + r2 = (r2 ^ cond_negate) - cond_negate; + r3 = (r3 ^ cond_negate) - cond_negate; + r4 = (r4 ^ cond_negate) - cond_negate; + /* Propagate the top bits, to bring limbs back to range (-2^62,2^62). */ + r1 += r0 >> 62; r0 &= M62; + r2 += r1 >> 62; r1 &= M62; + r3 += r2 >> 62; r2 &= M62; + r4 += r3 >> 62; r3 &= M62; + + /* In a second step add the modulus again if the result is still negative, bringing + * r to range [0,modulus). */ + cond_add = r4 >> 63; + r0 += modinfo->modulus.v[0] & cond_add; + r1 += modinfo->modulus.v[1] & cond_add; + r2 += modinfo->modulus.v[2] & cond_add; + r3 += modinfo->modulus.v[3] & cond_add; + r4 += modinfo->modulus.v[4] & cond_add; + /* And propagate again. */ + r1 += r0 >> 62; r0 &= M62; + r2 += r1 >> 62; r1 &= M62; + r3 += r2 >> 62; r2 &= M62; + r4 += r3 >> 62; r3 &= M62; + + r->v[0] = r0; + r->v[1] = r1; + r->v[2] = r2; + r->v[3] = r3; + r->v[4] = r4; + +#ifdef VERIFY + VERIFY_CHECK(r0 >> 62 == 0); + VERIFY_CHECK(r1 >> 62 == 0); + VERIFY_CHECK(r2 >> 62 == 0); + VERIFY_CHECK(r3 >> 62 == 0); + VERIFY_CHECK(r4 >> 62 == 0); + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(r, 5, &modinfo->modulus, 0) >= 0); /* r >= 0 */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(r, 5, &modinfo->modulus, 1) < 0); /* r < modulus */ +#endif +} + +/* Data type for transition matrices (see section 3 of explanation). + * + * t = [ u v ] + * [ q r ] + */ +typedef struct { + int64_t u, v, q, r; +} secp256k1_modinv64_trans2x2; + +/* Compute the transition matrix and eta for 59 divsteps (where zeta=-(delta+1/2)). + * Note that the transformation matrix is scaled by 2^62 and not 2^59. + * + * Input: zeta: initial zeta + * f0: bottom limb of initial f + * g0: bottom limb of initial g + * Output: t: transition matrix + * Return: final zeta + * + * Implements the divsteps_n_matrix function from the explanation. + */ +static int64_t secp256k1_modinv64_divsteps_59(int64_t zeta, uint64_t f0, uint64_t g0, secp256k1_modinv64_trans2x2 *t) { + /* u,v,q,r are the elements of the transformation matrix being built up, + * starting with the identity matrix times 8 (because the caller expects + * a result scaled by 2^62). Semantically they are signed integers + * in range [-2^62,2^62], but here represented as unsigned mod 2^64. This + * permits left shifting (which is UB for negative numbers). The range + * being inside [-2^63,2^63) means that casting to signed works correctly. + */ + uint64_t u = 8, v = 0, q = 0, r = 8; + uint64_t c1, c2, f = f0, g = g0, x, y, z; + int i; + + for (i = 3; i < 62; ++i) { + VERIFY_CHECK((f & 1) == 1); /* f must always be odd */ + VERIFY_CHECK((u * f0 + v * g0) == f << i); + VERIFY_CHECK((q * f0 + r * g0) == g << i); + /* Compute conditional masks for (zeta < 0) and for (g & 1). */ + c1 = zeta >> 63; + c2 = -(g & 1); + /* Compute x,y,z, conditionally negated versions of f,u,v. */ + x = (f ^ c1) - c1; + y = (u ^ c1) - c1; + z = (v ^ c1) - c1; + /* Conditionally add x,y,z to g,q,r. */ + g += x & c2; + q += y & c2; + r += z & c2; + /* In what follows, c1 is a condition mask for (zeta < 0) and (g & 1). */ + c1 &= c2; + /* Conditionally change zeta into -zeta-2 or zeta-1. */ + zeta = (zeta ^ c1) - 1; + /* Conditionally add g,q,r to f,u,v. */ + f += g & c1; + u += q & c1; + v += r & c1; + /* Shifts */ + g >>= 1; + u <<= 1; + v <<= 1; + /* Bounds on zeta that follow from the bounds on iteration count (max 10*59 divsteps). */ + VERIFY_CHECK(zeta >= -591 && zeta <= 591); + } + /* Return data in t and return value. */ + t->u = (int64_t)u; + t->v = (int64_t)v; + t->q = (int64_t)q; + t->r = (int64_t)r; + /* The determinant of t must be a power of two. This guarantees that multiplication with t + * does not change the gcd of f and g, apart from adding a power-of-2 factor to it (which + * will be divided out again). As each divstep's individual matrix has determinant 2, the + * aggregate of 59 of them will have determinant 2^59. Multiplying with the initial + * 8*identity (which has determinant 2^6) means the overall outputs has determinant + * 2^65. */ + VERIFY_CHECK((int128_t)t->u * t->r - (int128_t)t->v * t->q == ((int128_t)1) << 65); + return zeta; +} + +/* Compute the transition matrix and eta for 62 divsteps (variable time, eta=-delta). + * + * Input: eta: initial eta + * f0: bottom limb of initial f + * g0: bottom limb of initial g + * Output: t: transition matrix + * Return: final eta + * + * Implements the divsteps_n_matrix_var function from the explanation. + */ +static int64_t secp256k1_modinv64_divsteps_62_var(int64_t eta, uint64_t f0, uint64_t g0, secp256k1_modinv64_trans2x2 *t) { + /* Transformation matrix; see comments in secp256k1_modinv64_divsteps_62. */ + uint64_t u = 1, v = 0, q = 0, r = 1; + uint64_t f = f0, g = g0, m; + uint32_t w; + int i = 62, limit, zeros; + + for (;;) { + /* Use a sentinel bit to count zeros only up to i. */ + zeros = secp256k1_ctz64_var(g | (UINT64_MAX << i)); + /* Perform zeros divsteps at once; they all just divide g by two. */ + g >>= zeros; + u <<= zeros; + v <<= zeros; + eta -= zeros; + i -= zeros; + /* We're done once we've done 62 divsteps. */ + if (i == 0) break; + VERIFY_CHECK((f & 1) == 1); + VERIFY_CHECK((g & 1) == 1); + VERIFY_CHECK((u * f0 + v * g0) == f << (62 - i)); + VERIFY_CHECK((q * f0 + r * g0) == g << (62 - i)); + /* Bounds on eta that follow from the bounds on iteration count (max 12*62 divsteps). */ + VERIFY_CHECK(eta >= -745 && eta <= 745); + /* If eta is negative, negate it and replace f,g with g,-f. */ + if (eta < 0) { + uint64_t tmp; + eta = -eta; + tmp = f; f = g; g = -tmp; + tmp = u; u = q; q = -tmp; + tmp = v; v = r; r = -tmp; + /* Use a formula to cancel out up to 6 bits of g. Also, no more than i can be cancelled + * out (as we'd be done before that point), and no more than eta+1 can be done as its + * will flip again once that happens. */ + limit = ((int)eta + 1) > i ? i : ((int)eta + 1); + VERIFY_CHECK(limit > 0 && limit <= 62); + /* m is a mask for the bottom min(limit, 6) bits. */ + m = (UINT64_MAX >> (64 - limit)) & 63U; + /* Find what multiple of f must be added to g to cancel its bottom min(limit, 6) + * bits. */ + w = (f * g * (f * f - 2)) & m; + } else { + /* In this branch, use a simpler formula that only lets us cancel up to 4 bits of g, as + * eta tends to be smaller here. */ + limit = ((int)eta + 1) > i ? i : ((int)eta + 1); + VERIFY_CHECK(limit > 0 && limit <= 62); + /* m is a mask for the bottom min(limit, 4) bits. */ + m = (UINT64_MAX >> (64 - limit)) & 15U; + /* Find what multiple of f must be added to g to cancel its bottom min(limit, 4) + * bits. */ + w = f + (((f + 1) & 4) << 1); + w = (-w * g) & m; + } + g += f * w; + q += u * w; + r += v * w; + VERIFY_CHECK((g & m) == 0); + } + /* Return data in t and return value. */ + t->u = (int64_t)u; + t->v = (int64_t)v; + t->q = (int64_t)q; + t->r = (int64_t)r; + /* The determinant of t must be a power of two. This guarantees that multiplication with t + * does not change the gcd of f and g, apart from adding a power-of-2 factor to it (which + * will be divided out again). As each divstep's individual matrix has determinant 2, the + * aggregate of 62 of them will have determinant 2^62. */ + VERIFY_CHECK((int128_t)t->u * t->r - (int128_t)t->v * t->q == ((int128_t)1) << 62); + return eta; +} + +/* Compute (t/2^62) * [d, e] mod modulus, where t is a transition matrix scaled by 2^62. + * + * On input and output, d and e are in range (-2*modulus,modulus). All output limbs will be in range + * (-2^62,2^62). + * + * This implements the update_de function from the explanation. + */ +static void secp256k1_modinv64_update_de_62(secp256k1_modinv64_signed62 *d, secp256k1_modinv64_signed62 *e, const secp256k1_modinv64_trans2x2 *t, const secp256k1_modinv64_modinfo* modinfo) { + const int64_t M62 = (int64_t)(UINT64_MAX >> 2); + const int64_t d0 = d->v[0], d1 = d->v[1], d2 = d->v[2], d3 = d->v[3], d4 = d->v[4]; + const int64_t e0 = e->v[0], e1 = e->v[1], e2 = e->v[2], e3 = e->v[3], e4 = e->v[4]; + const int64_t u = t->u, v = t->v, q = t->q, r = t->r; + int64_t md, me, sd, se; + int128_t cd, ce; +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(d, 5, &modinfo->modulus, -2) > 0); /* d > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(d, 5, &modinfo->modulus, 1) < 0); /* d < modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(e, 5, &modinfo->modulus, -2) > 0); /* e > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(e, 5, &modinfo->modulus, 1) < 0); /* e < modulus */ + VERIFY_CHECK((secp256k1_modinv64_abs(u) + secp256k1_modinv64_abs(v)) >= 0); /* |u|+|v| doesn't overflow */ + VERIFY_CHECK((secp256k1_modinv64_abs(q) + secp256k1_modinv64_abs(r)) >= 0); /* |q|+|r| doesn't overflow */ + VERIFY_CHECK((secp256k1_modinv64_abs(u) + secp256k1_modinv64_abs(v)) <= M62 + 1); /* |u|+|v| <= 2^62 */ + VERIFY_CHECK((secp256k1_modinv64_abs(q) + secp256k1_modinv64_abs(r)) <= M62 + 1); /* |q|+|r| <= 2^62 */ +#endif + /* [md,me] start as zero; plus [u,q] if d is negative; plus [v,r] if e is negative. */ + sd = d4 >> 63; + se = e4 >> 63; + md = (u & sd) + (v & se); + me = (q & sd) + (r & se); + /* Begin computing t*[d,e]. */ + cd = (int128_t)u * d0 + (int128_t)v * e0; + ce = (int128_t)q * d0 + (int128_t)r * e0; + /* Correct md,me so that t*[d,e]+modulus*[md,me] has 62 zero bottom bits. */ + md -= (modinfo->modulus_inv62 * (uint64_t)cd + md) & M62; + me -= (modinfo->modulus_inv62 * (uint64_t)ce + me) & M62; + /* Update the beginning of computation for t*[d,e]+modulus*[md,me] now md,me are known. */ + cd += (int128_t)modinfo->modulus.v[0] * md; + ce += (int128_t)modinfo->modulus.v[0] * me; + /* Verify that the low 62 bits of the computation are indeed zero, and then throw them away. */ + VERIFY_CHECK(((int64_t)cd & M62) == 0); cd >>= 62; + VERIFY_CHECK(((int64_t)ce & M62) == 0); ce >>= 62; + /* Compute limb 1 of t*[d,e]+modulus*[md,me], and store it as output limb 0 (= down shift). */ + cd += (int128_t)u * d1 + (int128_t)v * e1; + ce += (int128_t)q * d1 + (int128_t)r * e1; + if (modinfo->modulus.v[1]) { /* Optimize for the case where limb of modulus is zero. */ + cd += (int128_t)modinfo->modulus.v[1] * md; + ce += (int128_t)modinfo->modulus.v[1] * me; + } + d->v[0] = (int64_t)cd & M62; cd >>= 62; + e->v[0] = (int64_t)ce & M62; ce >>= 62; + /* Compute limb 2 of t*[d,e]+modulus*[md,me], and store it as output limb 1. */ + cd += (int128_t)u * d2 + (int128_t)v * e2; + ce += (int128_t)q * d2 + (int128_t)r * e2; + if (modinfo->modulus.v[2]) { /* Optimize for the case where limb of modulus is zero. */ + cd += (int128_t)modinfo->modulus.v[2] * md; + ce += (int128_t)modinfo->modulus.v[2] * me; + } + d->v[1] = (int64_t)cd & M62; cd >>= 62; + e->v[1] = (int64_t)ce & M62; ce >>= 62; + /* Compute limb 3 of t*[d,e]+modulus*[md,me], and store it as output limb 2. */ + cd += (int128_t)u * d3 + (int128_t)v * e3; + ce += (int128_t)q * d3 + (int128_t)r * e3; + if (modinfo->modulus.v[3]) { /* Optimize for the case where limb of modulus is zero. */ + cd += (int128_t)modinfo->modulus.v[3] * md; + ce += (int128_t)modinfo->modulus.v[3] * me; + } + d->v[2] = (int64_t)cd & M62; cd >>= 62; + e->v[2] = (int64_t)ce & M62; ce >>= 62; + /* Compute limb 4 of t*[d,e]+modulus*[md,me], and store it as output limb 3. */ + cd += (int128_t)u * d4 + (int128_t)v * e4; + ce += (int128_t)q * d4 + (int128_t)r * e4; + cd += (int128_t)modinfo->modulus.v[4] * md; + ce += (int128_t)modinfo->modulus.v[4] * me; + d->v[3] = (int64_t)cd & M62; cd >>= 62; + e->v[3] = (int64_t)ce & M62; ce >>= 62; + /* What remains is limb 5 of t*[d,e]+modulus*[md,me]; store it as output limb 4. */ + d->v[4] = (int64_t)cd; + e->v[4] = (int64_t)ce; +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(d, 5, &modinfo->modulus, -2) > 0); /* d > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(d, 5, &modinfo->modulus, 1) < 0); /* d < modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(e, 5, &modinfo->modulus, -2) > 0); /* e > -2*modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(e, 5, &modinfo->modulus, 1) < 0); /* e < modulus */ +#endif +} + +/* Compute (t/2^62) * [f, g], where t is a transition matrix scaled by 2^62. + * + * This implements the update_fg function from the explanation. + */ +static void secp256k1_modinv64_update_fg_62(secp256k1_modinv64_signed62 *f, secp256k1_modinv64_signed62 *g, const secp256k1_modinv64_trans2x2 *t) { + const int64_t M62 = (int64_t)(UINT64_MAX >> 2); + const int64_t f0 = f->v[0], f1 = f->v[1], f2 = f->v[2], f3 = f->v[3], f4 = f->v[4]; + const int64_t g0 = g->v[0], g1 = g->v[1], g2 = g->v[2], g3 = g->v[3], g4 = g->v[4]; + const int64_t u = t->u, v = t->v, q = t->q, r = t->r; + int128_t cf, cg; + /* Start computing t*[f,g]. */ + cf = (int128_t)u * f0 + (int128_t)v * g0; + cg = (int128_t)q * f0 + (int128_t)r * g0; + /* Verify that the bottom 62 bits of the result are zero, and then throw them away. */ + VERIFY_CHECK(((int64_t)cf & M62) == 0); cf >>= 62; + VERIFY_CHECK(((int64_t)cg & M62) == 0); cg >>= 62; + /* Compute limb 1 of t*[f,g], and store it as output limb 0 (= down shift). */ + cf += (int128_t)u * f1 + (int128_t)v * g1; + cg += (int128_t)q * f1 + (int128_t)r * g1; + f->v[0] = (int64_t)cf & M62; cf >>= 62; + g->v[0] = (int64_t)cg & M62; cg >>= 62; + /* Compute limb 2 of t*[f,g], and store it as output limb 1. */ + cf += (int128_t)u * f2 + (int128_t)v * g2; + cg += (int128_t)q * f2 + (int128_t)r * g2; + f->v[1] = (int64_t)cf & M62; cf >>= 62; + g->v[1] = (int64_t)cg & M62; cg >>= 62; + /* Compute limb 3 of t*[f,g], and store it as output limb 2. */ + cf += (int128_t)u * f3 + (int128_t)v * g3; + cg += (int128_t)q * f3 + (int128_t)r * g3; + f->v[2] = (int64_t)cf & M62; cf >>= 62; + g->v[2] = (int64_t)cg & M62; cg >>= 62; + /* Compute limb 4 of t*[f,g], and store it as output limb 3. */ + cf += (int128_t)u * f4 + (int128_t)v * g4; + cg += (int128_t)q * f4 + (int128_t)r * g4; + f->v[3] = (int64_t)cf & M62; cf >>= 62; + g->v[3] = (int64_t)cg & M62; cg >>= 62; + /* What remains is limb 5 of t*[f,g]; store it as output limb 4. */ + f->v[4] = (int64_t)cf; + g->v[4] = (int64_t)cg; +} + +/* Compute (t/2^62) * [f, g], where t is a transition matrix for 62 divsteps. + * + * Version that operates on a variable number of limbs in f and g. + * + * This implements the update_fg function from the explanation. + */ +static void secp256k1_modinv64_update_fg_62_var(int len, secp256k1_modinv64_signed62 *f, secp256k1_modinv64_signed62 *g, const secp256k1_modinv64_trans2x2 *t) { + const int64_t M62 = (int64_t)(UINT64_MAX >> 2); + const int64_t u = t->u, v = t->v, q = t->q, r = t->r; + int64_t fi, gi; + int128_t cf, cg; + int i; + VERIFY_CHECK(len > 0); + /* Start computing t*[f,g]. */ + fi = f->v[0]; + gi = g->v[0]; + cf = (int128_t)u * fi + (int128_t)v * gi; + cg = (int128_t)q * fi + (int128_t)r * gi; + /* Verify that the bottom 62 bits of the result are zero, and then throw them away. */ + VERIFY_CHECK(((int64_t)cf & M62) == 0); cf >>= 62; + VERIFY_CHECK(((int64_t)cg & M62) == 0); cg >>= 62; + /* Now iteratively compute limb i=1..len of t*[f,g], and store them in output limb i-1 (shifting + * down by 62 bits). */ + for (i = 1; i < len; ++i) { + fi = f->v[i]; + gi = g->v[i]; + cf += (int128_t)u * fi + (int128_t)v * gi; + cg += (int128_t)q * fi + (int128_t)r * gi; + f->v[i - 1] = (int64_t)cf & M62; cf >>= 62; + g->v[i - 1] = (int64_t)cg & M62; cg >>= 62; + } + /* What remains is limb (len) of t*[f,g]; store it as output limb (len-1). */ + f->v[len - 1] = (int64_t)cf; + g->v[len - 1] = (int64_t)cg; +} + +/* Compute the inverse of x modulo modinfo->modulus, and replace x with it (constant time in x). */ +static void secp256k1_modinv64(secp256k1_modinv64_signed62 *x, const secp256k1_modinv64_modinfo *modinfo) { + /* Start with d=0, e=1, f=modulus, g=x, zeta=-1. */ + secp256k1_modinv64_signed62 d = {{0, 0, 0, 0, 0}}; + secp256k1_modinv64_signed62 e = {{1, 0, 0, 0, 0}}; + secp256k1_modinv64_signed62 f = modinfo->modulus; + secp256k1_modinv64_signed62 g = *x; + int i; + int64_t zeta = -1; /* zeta = -(delta+1/2); delta starts at 1/2. */ + + /* Do 10 iterations of 59 divsteps each = 590 divsteps. This suffices for 256-bit inputs. */ + for (i = 0; i < 10; ++i) { + /* Compute transition matrix and new zeta after 59 divsteps. */ + secp256k1_modinv64_trans2x2 t; + zeta = secp256k1_modinv64_divsteps_59(zeta, f.v[0], g.v[0], &t); + /* Update d,e using that transition matrix. */ + secp256k1_modinv64_update_de_62(&d, &e, &t, modinfo); + /* Update f,g using that transition matrix. */ +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, 5, &modinfo->modulus, -1) > 0); /* f > -modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, 5, &modinfo->modulus, 1) <= 0); /* f <= modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, 5, &modinfo->modulus, -1) > 0); /* g > -modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, 5, &modinfo->modulus, 1) < 0); /* g < modulus */ +#endif + secp256k1_modinv64_update_fg_62(&f, &g, &t); +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, 5, &modinfo->modulus, -1) > 0); /* f > -modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, 5, &modinfo->modulus, 1) <= 0); /* f <= modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, 5, &modinfo->modulus, -1) > 0); /* g > -modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, 5, &modinfo->modulus, 1) < 0); /* g < modulus */ +#endif + } + + /* At this point sufficient iterations have been performed that g must have reached 0 + * and (if g was not originally 0) f must now equal +/- GCD of the initial f, g + * values i.e. +/- 1, and d now contains +/- the modular inverse. */ +#ifdef VERIFY + /* g == 0 */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, 5, &SECP256K1_SIGNED62_ONE, 0) == 0); + /* |f| == 1, or (x == 0 and d == 0 and |f|=modulus) */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, 5, &SECP256K1_SIGNED62_ONE, -1) == 0 || + secp256k1_modinv64_mul_cmp_62(&f, 5, &SECP256K1_SIGNED62_ONE, 1) == 0 || + (secp256k1_modinv64_mul_cmp_62(x, 5, &SECP256K1_SIGNED62_ONE, 0) == 0 && + secp256k1_modinv64_mul_cmp_62(&d, 5, &SECP256K1_SIGNED62_ONE, 0) == 0 && + (secp256k1_modinv64_mul_cmp_62(&f, 5, &modinfo->modulus, 1) == 0 || + secp256k1_modinv64_mul_cmp_62(&f, 5, &modinfo->modulus, -1) == 0))); +#endif + + /* Optionally negate d, normalize to [0,modulus), and return it. */ + secp256k1_modinv64_normalize_62(&d, f.v[4], modinfo); + *x = d; +} + +/* Compute the inverse of x modulo modinfo->modulus, and replace x with it (variable time). */ +static void secp256k1_modinv64_var(secp256k1_modinv64_signed62 *x, const secp256k1_modinv64_modinfo *modinfo) { + /* Start with d=0, e=1, f=modulus, g=x, eta=-1. */ + secp256k1_modinv64_signed62 d = {{0, 0, 0, 0, 0}}; + secp256k1_modinv64_signed62 e = {{1, 0, 0, 0, 0}}; + secp256k1_modinv64_signed62 f = modinfo->modulus; + secp256k1_modinv64_signed62 g = *x; +#ifdef VERIFY + int i = 0; +#endif + int j, len = 5; + int64_t eta = -1; /* eta = -delta; delta is initially 1 */ + int64_t cond, fn, gn; + + /* Do iterations of 62 divsteps each until g=0. */ + while (1) { + /* Compute transition matrix and new eta after 62 divsteps. */ + secp256k1_modinv64_trans2x2 t; + eta = secp256k1_modinv64_divsteps_62_var(eta, f.v[0], g.v[0], &t); + /* Update d,e using that transition matrix. */ + secp256k1_modinv64_update_de_62(&d, &e, &t, modinfo); + /* Update f,g using that transition matrix. */ +#ifdef VERIFY + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, len, &modinfo->modulus, -1) > 0); /* f > -modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, len, &modinfo->modulus, 1) <= 0); /* f <= modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, len, &modinfo->modulus, -1) > 0); /* g > -modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, len, &modinfo->modulus, 1) < 0); /* g < modulus */ +#endif + secp256k1_modinv64_update_fg_62_var(len, &f, &g, &t); + /* If the bottom limb of g is zero, there is a chance that g=0. */ + if (g.v[0] == 0) { + cond = 0; + /* Check if the other limbs are also 0. */ + for (j = 1; j < len; ++j) { + cond |= g.v[j]; + } + /* If so, we're done. */ + if (cond == 0) break; + } + + /* Determine if len>1 and limb (len-1) of both f and g is 0 or -1. */ + fn = f.v[len - 1]; + gn = g.v[len - 1]; + cond = ((int64_t)len - 2) >> 63; + cond |= fn ^ (fn >> 63); + cond |= gn ^ (gn >> 63); + /* If so, reduce length, propagating the sign of f and g's top limb into the one below. */ + if (cond == 0) { + f.v[len - 2] |= (uint64_t)fn << 62; + g.v[len - 2] |= (uint64_t)gn << 62; + --len; + } +#ifdef VERIFY + VERIFY_CHECK(++i < 12); /* We should never need more than 12*62 = 744 divsteps */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, len, &modinfo->modulus, -1) > 0); /* f > -modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, len, &modinfo->modulus, 1) <= 0); /* f <= modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, len, &modinfo->modulus, -1) > 0); /* g > -modulus */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, len, &modinfo->modulus, 1) < 0); /* g < modulus */ +#endif + } + + /* At this point g is 0 and (if g was not originally 0) f must now equal +/- GCD of + * the initial f, g values i.e. +/- 1, and d now contains +/- the modular inverse. */ +#ifdef VERIFY + /* g == 0 */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&g, len, &SECP256K1_SIGNED62_ONE, 0) == 0); + /* |f| == 1, or (x == 0 and d == 0 and |f|=modulus) */ + VERIFY_CHECK(secp256k1_modinv64_mul_cmp_62(&f, len, &SECP256K1_SIGNED62_ONE, -1) == 0 || + secp256k1_modinv64_mul_cmp_62(&f, len, &SECP256K1_SIGNED62_ONE, 1) == 0 || + (secp256k1_modinv64_mul_cmp_62(x, 5, &SECP256K1_SIGNED62_ONE, 0) == 0 && + secp256k1_modinv64_mul_cmp_62(&d, 5, &SECP256K1_SIGNED62_ONE, 0) == 0 && + (secp256k1_modinv64_mul_cmp_62(&f, len, &modinfo->modulus, 1) == 0 || + secp256k1_modinv64_mul_cmp_62(&f, len, &modinfo->modulus, -1) == 0))); +#endif + + /* Optionally negate d, normalize to [0,modulus), and return it. */ + secp256k1_modinv64_normalize_62(&d, f.v[len - 1], modinfo); + *x = d; +} + +#endif /* SECP256K1_MODINV64_IMPL_H */ diff --git a/src/modules/ecdh/main_impl.h b/src/modules/ecdh/main_impl.h index 07a25b80d4ab6..1ac67086becca 100644 --- a/src/modules/ecdh/main_impl.h +++ b/src/modules/ecdh/main_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_MODULE_ECDH_MAIN_H #define SECP256K1_MODULE_ECDH_MAIN_H diff --git a/src/modules/ecdh/tests_impl.h b/src/modules/ecdh/tests_impl.h index e8d2aeab9a59b..be07447a4b995 100644 --- a/src/modules/ecdh/tests_impl.h +++ b/src/modules/ecdh/tests_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_MODULE_ECDH_TESTS_H #define SECP256K1_MODULE_ECDH_TESTS_H diff --git a/src/modules/extrakeys/main_impl.h b/src/modules/extrakeys/main_impl.h index 5378d2f301bc9..7390b227182fe 100644 --- a/src/modules/extrakeys/main_impl.h +++ b/src/modules/extrakeys/main_impl.h @@ -1,11 +1,11 @@ -/********************************************************************** - * Copyright (c) 2020 Jonas Nick * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2020 Jonas Nick * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ -#ifndef _SECP256K1_MODULE_EXTRAKEYS_MAIN_ -#define _SECP256K1_MODULE_EXTRAKEYS_MAIN_ +#ifndef SECP256K1_MODULE_EXTRAKEYS_MAIN_H +#define SECP256K1_MODULE_EXTRAKEYS_MAIN_H #include "include/secp256k1.h" #include "include/secp256k1_extrakeys.h" @@ -180,12 +180,22 @@ int secp256k1_keypair_create(const secp256k1_context* ctx, secp256k1_keypair *ke ret = secp256k1_ec_pubkey_create_helper(&ctx->ecmult_gen_ctx, &sk, &pk, seckey32); secp256k1_keypair_save(keypair, &sk, &pk); - memczero(keypair, sizeof(*keypair), !ret); + secp256k1_memczero(keypair, sizeof(*keypair), !ret); secp256k1_scalar_clear(&sk); return ret; } +int secp256k1_keypair_sec(const secp256k1_context* ctx, unsigned char *seckey, const secp256k1_keypair *keypair) { + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(seckey != NULL); + memset(seckey, 0, 32); + ARG_CHECK(keypair != NULL); + + memcpy(seckey, &keypair->data[0], 32); + return 1; +} + int secp256k1_keypair_pub(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const secp256k1_keypair *keypair) { VERIFY_CHECK(ctx != NULL); ARG_CHECK(pubkey != NULL); diff --git a/src/modules/extrakeys/tests_exhaustive_impl.h b/src/modules/extrakeys/tests_exhaustive_impl.h index 0e29bc6b09d95..0aca4fb72d781 100644 --- a/src/modules/extrakeys/tests_exhaustive_impl.h +++ b/src/modules/extrakeys/tests_exhaustive_impl.h @@ -1,11 +1,11 @@ -/********************************************************************** - * Copyright (c) 2020 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2020 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ -#ifndef _SECP256K1_MODULE_EXTRAKEYS_TESTS_EXHAUSTIVE_ -#define _SECP256K1_MODULE_EXTRAKEYS_TESTS_EXHAUSTIVE_ +#ifndef SECP256K1_MODULE_EXTRAKEYS_TESTS_EXHAUSTIVE_H +#define SECP256K1_MODULE_EXTRAKEYS_TESTS_EXHAUSTIVE_H #include "src/modules/extrakeys/main_impl.h" #include "include/secp256k1_extrakeys.h" diff --git a/src/modules/extrakeys/tests_impl.h b/src/modules/extrakeys/tests_impl.h index 5ee135849ef21..9473a7dd4852e 100644 --- a/src/modules/extrakeys/tests_impl.h +++ b/src/modules/extrakeys/tests_impl.h @@ -1,11 +1,11 @@ -/********************************************************************** - * Copyright (c) 2020 Jonas Nick * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2020 Jonas Nick * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ -#ifndef _SECP256K1_MODULE_EXTRAKEYS_TESTS_ -#define _SECP256K1_MODULE_EXTRAKEYS_TESTS_ +#ifndef SECP256K1_MODULE_EXTRAKEYS_TESTS_H +#define SECP256K1_MODULE_EXTRAKEYS_TESTS_H #include "secp256k1_extrakeys.h" @@ -311,6 +311,7 @@ void test_xonly_pubkey_tweak_recursive(void) { void test_keypair(void) { unsigned char sk[32]; + unsigned char sk_tmp[32]; unsigned char zeros96[96] = { 0 }; unsigned char overflows[32]; secp256k1_keypair keypair; @@ -396,6 +397,28 @@ void test_keypair(void) { CHECK(secp256k1_memcmp_var(&xonly_pk, &xonly_pk_tmp, sizeof(pk)) == 0); CHECK(pk_parity == pk_parity_tmp); + /* Test keypair_seckey */ + ecount = 0; + secp256k1_testrand256(sk); + CHECK(secp256k1_keypair_create(ctx, &keypair, sk) == 1); + CHECK(secp256k1_keypair_sec(none, sk_tmp, &keypair) == 1); + CHECK(secp256k1_keypair_sec(none, NULL, &keypair) == 0); + CHECK(ecount == 1); + CHECK(secp256k1_keypair_sec(none, sk_tmp, NULL) == 0); + CHECK(ecount == 2); + CHECK(secp256k1_memcmp_var(zeros96, sk_tmp, sizeof(sk_tmp)) == 0); + + /* keypair returns the same seckey it got */ + CHECK(secp256k1_keypair_create(sign, &keypair, sk) == 1); + CHECK(secp256k1_keypair_sec(none, sk_tmp, &keypair) == 1); + CHECK(secp256k1_memcmp_var(sk, sk_tmp, sizeof(sk_tmp)) == 0); + + + /* Using an invalid keypair is fine for keypair_seckey */ + memset(&keypair, 0, sizeof(keypair)); + CHECK(secp256k1_keypair_sec(none, sk_tmp, &keypair) == 1); + CHECK(secp256k1_memcmp_var(zeros96, sk_tmp, sizeof(sk_tmp)) == 0); + secp256k1_context_destroy(none); secp256k1_context_destroy(sign); secp256k1_context_destroy(verify); @@ -484,6 +507,7 @@ void test_keypair_add(void) { secp256k1_pubkey output_pk_xy; secp256k1_pubkey output_pk_expected; unsigned char pk32[32]; + unsigned char sk32[32]; int pk_parity; secp256k1_testrand256(tweak); @@ -501,7 +525,8 @@ void test_keypair_add(void) { CHECK(secp256k1_memcmp_var(&output_pk_xy, &output_pk_expected, sizeof(output_pk_xy)) == 0); /* Check that the secret key in the keypair is tweaked correctly */ - CHECK(secp256k1_ec_pubkey_create(ctx, &output_pk_expected, &keypair.data[0]) == 1); + CHECK(secp256k1_keypair_sec(none, sk32, &keypair) == 1); + CHECK(secp256k1_ec_pubkey_create(ctx, &output_pk_expected, sk32) == 1); CHECK(secp256k1_memcmp_var(&output_pk_xy, &output_pk_expected, sizeof(output_pk_xy)) == 0); } secp256k1_context_destroy(none); diff --git a/src/modules/recovery/main_impl.h b/src/modules/recovery/main_impl.h index e2576aa953e5c..7a440a729bf96 100644 --- a/src/modules/recovery/main_impl.h +++ b/src/modules/recovery/main_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013-2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013-2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_MODULE_RECOVERY_MAIN_H #define SECP256K1_MODULE_RECOVERY_MAIN_H @@ -120,34 +120,34 @@ static int secp256k1_ecdsa_sig_recover(const secp256k1_ecmult_context *ctx, cons return !secp256k1_gej_is_infinity(&qj); } -int secp256k1_ecdsa_sign_recoverable(const secp256k1_context* ctx, secp256k1_ecdsa_recoverable_signature *signature, const unsigned char *msg32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) { +int secp256k1_ecdsa_sign_recoverable(const secp256k1_context* ctx, secp256k1_ecdsa_recoverable_signature *signature, const unsigned char *msghash32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) { secp256k1_scalar r, s; int ret, recid; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)); - ARG_CHECK(msg32 != NULL); + ARG_CHECK(msghash32 != NULL); ARG_CHECK(signature != NULL); ARG_CHECK(seckey != NULL); - ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, &recid, msg32, seckey, noncefp, noncedata); + ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, &recid, msghash32, seckey, noncefp, noncedata); secp256k1_ecdsa_recoverable_signature_save(signature, &r, &s, recid); return ret; } -int secp256k1_ecdsa_recover(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const secp256k1_ecdsa_recoverable_signature *signature, const unsigned char *msg32) { +int secp256k1_ecdsa_recover(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const secp256k1_ecdsa_recoverable_signature *signature, const unsigned char *msghash32) { secp256k1_ge q; secp256k1_scalar r, s; secp256k1_scalar m; int recid; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); - ARG_CHECK(msg32 != NULL); + ARG_CHECK(msghash32 != NULL); ARG_CHECK(signature != NULL); ARG_CHECK(pubkey != NULL); secp256k1_ecdsa_recoverable_signature_load(ctx, &r, &s, &recid, signature); VERIFY_CHECK(recid >= 0 && recid < 4); /* should have been caught in parse_compact */ - secp256k1_scalar_set_b32(&m, msg32, NULL); + secp256k1_scalar_set_b32(&m, msghash32, NULL); if (secp256k1_ecdsa_sig_recover(&ctx->ecmult_ctx, &r, &s, &q, &m, recid)) { secp256k1_pubkey_save(pubkey, &q); return 1; diff --git a/src/modules/recovery/tests_exhaustive_impl.h b/src/modules/recovery/tests_exhaustive_impl.h index a2f381d77a120..0ba9409c691d0 100644 --- a/src/modules/recovery/tests_exhaustive_impl.h +++ b/src/modules/recovery/tests_exhaustive_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2016 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2016 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_MODULE_RECOVERY_EXHAUSTIVE_TESTS_H #define SECP256K1_MODULE_RECOVERY_EXHAUSTIVE_TESTS_H diff --git a/src/modules/recovery/tests_impl.h b/src/modules/recovery/tests_impl.h index 09cae384035ff..40dba87ce39a7 100644 --- a/src/modules/recovery/tests_impl.h +++ b/src/modules/recovery/tests_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013-2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013-2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_MODULE_RECOVERY_TESTS_H #define SECP256K1_MODULE_RECOVERY_TESTS_H diff --git a/src/modules/schnorrsig/main_impl.h b/src/modules/schnorrsig/main_impl.h index b0d8481f9be34..22e1b33a5a48e 100644 --- a/src/modules/schnorrsig/main_impl.h +++ b/src/modules/schnorrsig/main_impl.h @@ -1,11 +1,11 @@ -/********************************************************************** - * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ -#ifndef _SECP256K1_MODULE_SCHNORRSIG_MAIN_ -#define _SECP256K1_MODULE_SCHNORRSIG_MAIN_ +#ifndef SECP256K1_MODULE_SCHNORRSIG_MAIN_H +#define SECP256K1_MODULE_SCHNORRSIG_MAIN_H #include "include/secp256k1.h" #include "include/secp256k1_schnorrsig.h" @@ -179,7 +179,7 @@ int secp256k1_schnorrsig_sign(const secp256k1_context* ctx, unsigned char *sig64 secp256k1_scalar_add(&e, &e, &k); secp256k1_scalar_get_b32(&sig64[32], &e); - memczero(sig64, 64, !ret); + secp256k1_memczero(sig64, 64, !ret); secp256k1_scalar_clear(&k); secp256k1_scalar_clear(&sk); memset(seckey, 0, sizeof(seckey)); diff --git a/src/modules/schnorrsig/tests_exhaustive_impl.h b/src/modules/schnorrsig/tests_exhaustive_impl.h index 4bf0bc1680fee..b4a428729f9a0 100644 --- a/src/modules/schnorrsig/tests_exhaustive_impl.h +++ b/src/modules/schnorrsig/tests_exhaustive_impl.h @@ -1,11 +1,11 @@ -/********************************************************************** - * Copyright (c) 2020 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2020 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ -#ifndef _SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_ -#define _SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_ +#ifndef SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_H +#define SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_H #include "include/secp256k1_schnorrsig.h" #include "src/modules/schnorrsig/main_impl.h" diff --git a/src/modules/schnorrsig/tests_impl.h b/src/modules/schnorrsig/tests_impl.h index f522fcb3208ff..338462fc9dfb9 100644 --- a/src/modules/schnorrsig/tests_impl.h +++ b/src/modules/schnorrsig/tests_impl.h @@ -1,11 +1,11 @@ -/********************************************************************** - * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ - -#ifndef _SECP256K1_MODULE_SCHNORRSIG_TESTS_ -#define _SECP256K1_MODULE_SCHNORRSIG_TESTS_ +/*********************************************************************** + * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ + +#ifndef SECP256K1_MODULE_SCHNORRSIG_TESTS_H +#define SECP256K1_MODULE_SCHNORRSIG_TESTS_H #include "secp256k1_schnorrsig.h" diff --git a/src/num.h b/src/num.h deleted file mode 100644 index 49f2dd791d569..0000000000000 --- a/src/num.h +++ /dev/null @@ -1,74 +0,0 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ - -#ifndef SECP256K1_NUM_H -#define SECP256K1_NUM_H - -#ifndef USE_NUM_NONE - -#if defined HAVE_CONFIG_H -#include "libsecp256k1-config.h" -#endif - -#if defined(USE_NUM_GMP) -#include "num_gmp.h" -#else -#error "Please select num implementation" -#endif - -/** Copy a number. */ -static void secp256k1_num_copy(secp256k1_num *r, const secp256k1_num *a); - -/** Convert a number's absolute value to a binary big-endian string. - * There must be enough place. */ -static void secp256k1_num_get_bin(unsigned char *r, unsigned int rlen, const secp256k1_num *a); - -/** Set a number to the value of a binary big-endian string. */ -static void secp256k1_num_set_bin(secp256k1_num *r, const unsigned char *a, unsigned int alen); - -/** Compute a modular inverse. The input must be less than the modulus. */ -static void secp256k1_num_mod_inverse(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *m); - -/** Compute the jacobi symbol (a|b). b must be positive and odd. */ -static int secp256k1_num_jacobi(const secp256k1_num *a, const secp256k1_num *b); - -/** Compare the absolute value of two numbers. */ -static int secp256k1_num_cmp(const secp256k1_num *a, const secp256k1_num *b); - -/** Test whether two number are equal (including sign). */ -static int secp256k1_num_eq(const secp256k1_num *a, const secp256k1_num *b); - -/** Add two (signed) numbers. */ -static void secp256k1_num_add(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b); - -/** Subtract two (signed) numbers. */ -static void secp256k1_num_sub(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b); - -/** Multiply two (signed) numbers. */ -static void secp256k1_num_mul(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b); - -/** Replace a number by its remainder modulo m. M's sign is ignored. The result is a number between 0 and m-1, - even if r was negative. */ -static void secp256k1_num_mod(secp256k1_num *r, const secp256k1_num *m); - -/** Right-shift the passed number by bits bits. */ -static void secp256k1_num_shift(secp256k1_num *r, int bits); - -/** Check whether a number is zero. */ -static int secp256k1_num_is_zero(const secp256k1_num *a); - -/** Check whether a number is one. */ -static int secp256k1_num_is_one(const secp256k1_num *a); - -/** Check whether a number is strictly negative. */ -static int secp256k1_num_is_neg(const secp256k1_num *a); - -/** Change a number's sign. */ -static void secp256k1_num_negate(secp256k1_num *r); - -#endif - -#endif /* SECP256K1_NUM_H */ diff --git a/src/num_gmp.h b/src/num_gmp.h deleted file mode 100644 index 3619844bd5127..0000000000000 --- a/src/num_gmp.h +++ /dev/null @@ -1,20 +0,0 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ - -#ifndef SECP256K1_NUM_REPR_H -#define SECP256K1_NUM_REPR_H - -#include - -#define NUM_LIMBS ((256+GMP_NUMB_BITS-1)/GMP_NUMB_BITS) - -typedef struct { - mp_limb_t data[2*NUM_LIMBS]; - int neg; - int limbs; -} secp256k1_num; - -#endif /* SECP256K1_NUM_REPR_H */ diff --git a/src/num_gmp_impl.h b/src/num_gmp_impl.h deleted file mode 100644 index 0ae2a8ba0ecb7..0000000000000 --- a/src/num_gmp_impl.h +++ /dev/null @@ -1,288 +0,0 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ - -#ifndef SECP256K1_NUM_REPR_IMPL_H -#define SECP256K1_NUM_REPR_IMPL_H - -#include -#include -#include - -#include "util.h" -#include "num.h" - -#ifdef VERIFY -static void secp256k1_num_sanity(const secp256k1_num *a) { - VERIFY_CHECK(a->limbs == 1 || (a->limbs > 1 && a->data[a->limbs-1] != 0)); -} -#else -#define secp256k1_num_sanity(a) do { } while(0) -#endif - -static void secp256k1_num_copy(secp256k1_num *r, const secp256k1_num *a) { - *r = *a; -} - -static void secp256k1_num_get_bin(unsigned char *r, unsigned int rlen, const secp256k1_num *a) { - unsigned char tmp[65]; - int len = 0; - int shift = 0; - if (a->limbs>1 || a->data[0] != 0) { - len = mpn_get_str(tmp, 256, (mp_limb_t*)a->data, a->limbs); - } - while (shift < len && tmp[shift] == 0) shift++; - VERIFY_CHECK(len-shift <= (int)rlen); - memset(r, 0, rlen - len + shift); - if (len > shift) { - memcpy(r + rlen - len + shift, tmp + shift, len - shift); - } - memset(tmp, 0, sizeof(tmp)); -} - -static void secp256k1_num_set_bin(secp256k1_num *r, const unsigned char *a, unsigned int alen) { - int len; - VERIFY_CHECK(alen > 0); - VERIFY_CHECK(alen <= 64); - len = mpn_set_str(r->data, a, alen, 256); - if (len == 0) { - r->data[0] = 0; - len = 1; - } - VERIFY_CHECK(len <= NUM_LIMBS*2); - r->limbs = len; - r->neg = 0; - while (r->limbs > 1 && r->data[r->limbs-1]==0) { - r->limbs--; - } -} - -static void secp256k1_num_add_abs(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b) { - mp_limb_t c = mpn_add(r->data, a->data, a->limbs, b->data, b->limbs); - r->limbs = a->limbs; - if (c != 0) { - VERIFY_CHECK(r->limbs < 2*NUM_LIMBS); - r->data[r->limbs++] = c; - } -} - -static void secp256k1_num_sub_abs(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b) { - mp_limb_t c = mpn_sub(r->data, a->data, a->limbs, b->data, b->limbs); - (void)c; - VERIFY_CHECK(c == 0); - r->limbs = a->limbs; - while (r->limbs > 1 && r->data[r->limbs-1]==0) { - r->limbs--; - } -} - -static void secp256k1_num_mod(secp256k1_num *r, const secp256k1_num *m) { - secp256k1_num_sanity(r); - secp256k1_num_sanity(m); - - if (r->limbs >= m->limbs) { - mp_limb_t t[2*NUM_LIMBS]; - mpn_tdiv_qr(t, r->data, 0, r->data, r->limbs, m->data, m->limbs); - memset(t, 0, sizeof(t)); - r->limbs = m->limbs; - while (r->limbs > 1 && r->data[r->limbs-1]==0) { - r->limbs--; - } - } - - if (r->neg && (r->limbs > 1 || r->data[0] != 0)) { - secp256k1_num_sub_abs(r, m, r); - r->neg = 0; - } -} - -static void secp256k1_num_mod_inverse(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *m) { - int i; - mp_limb_t g[NUM_LIMBS+1]; - mp_limb_t u[NUM_LIMBS+1]; - mp_limb_t v[NUM_LIMBS+1]; - mp_size_t sn; - mp_size_t gn; - secp256k1_num_sanity(a); - secp256k1_num_sanity(m); - - /** mpn_gcdext computes: (G,S) = gcdext(U,V), where - * * G = gcd(U,V) - * * G = U*S + V*T - * * U has equal or more limbs than V, and V has no padding - * If we set U to be (a padded version of) a, and V = m: - * G = a*S + m*T - * G = a*S mod m - * Assuming G=1: - * S = 1/a mod m - */ - VERIFY_CHECK(m->limbs <= NUM_LIMBS); - VERIFY_CHECK(m->data[m->limbs-1] != 0); - for (i = 0; i < m->limbs; i++) { - u[i] = (i < a->limbs) ? a->data[i] : 0; - v[i] = m->data[i]; - } - sn = NUM_LIMBS+1; - gn = mpn_gcdext(g, r->data, &sn, u, m->limbs, v, m->limbs); - (void)gn; - VERIFY_CHECK(gn == 1); - VERIFY_CHECK(g[0] == 1); - r->neg = a->neg ^ m->neg; - if (sn < 0) { - mpn_sub(r->data, m->data, m->limbs, r->data, -sn); - r->limbs = m->limbs; - while (r->limbs > 1 && r->data[r->limbs-1]==0) { - r->limbs--; - } - } else { - r->limbs = sn; - } - memset(g, 0, sizeof(g)); - memset(u, 0, sizeof(u)); - memset(v, 0, sizeof(v)); -} - -static int secp256k1_num_jacobi(const secp256k1_num *a, const secp256k1_num *b) { - int ret; - mpz_t ga, gb; - secp256k1_num_sanity(a); - secp256k1_num_sanity(b); - VERIFY_CHECK(!b->neg && (b->limbs > 0) && (b->data[0] & 1)); - - mpz_inits(ga, gb, NULL); - - mpz_import(gb, b->limbs, -1, sizeof(mp_limb_t), 0, 0, b->data); - mpz_import(ga, a->limbs, -1, sizeof(mp_limb_t), 0, 0, a->data); - if (a->neg) { - mpz_neg(ga, ga); - } - - ret = mpz_jacobi(ga, gb); - - mpz_clears(ga, gb, NULL); - - return ret; -} - -static int secp256k1_num_is_one(const secp256k1_num *a) { - return (a->limbs == 1 && a->data[0] == 1); -} - -static int secp256k1_num_is_zero(const secp256k1_num *a) { - return (a->limbs == 1 && a->data[0] == 0); -} - -static int secp256k1_num_is_neg(const secp256k1_num *a) { - return (a->limbs > 1 || a->data[0] != 0) && a->neg; -} - -static int secp256k1_num_cmp(const secp256k1_num *a, const secp256k1_num *b) { - if (a->limbs > b->limbs) { - return 1; - } - if (a->limbs < b->limbs) { - return -1; - } - return mpn_cmp(a->data, b->data, a->limbs); -} - -static int secp256k1_num_eq(const secp256k1_num *a, const secp256k1_num *b) { - if (a->limbs > b->limbs) { - return 0; - } - if (a->limbs < b->limbs) { - return 0; - } - if ((a->neg && !secp256k1_num_is_zero(a)) != (b->neg && !secp256k1_num_is_zero(b))) { - return 0; - } - return mpn_cmp(a->data, b->data, a->limbs) == 0; -} - -static void secp256k1_num_subadd(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b, int bneg) { - if (!(b->neg ^ bneg ^ a->neg)) { /* a and b have the same sign */ - r->neg = a->neg; - if (a->limbs >= b->limbs) { - secp256k1_num_add_abs(r, a, b); - } else { - secp256k1_num_add_abs(r, b, a); - } - } else { - if (secp256k1_num_cmp(a, b) > 0) { - r->neg = a->neg; - secp256k1_num_sub_abs(r, a, b); - } else { - r->neg = b->neg ^ bneg; - secp256k1_num_sub_abs(r, b, a); - } - } -} - -static void secp256k1_num_add(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b) { - secp256k1_num_sanity(a); - secp256k1_num_sanity(b); - secp256k1_num_subadd(r, a, b, 0); -} - -static void secp256k1_num_sub(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b) { - secp256k1_num_sanity(a); - secp256k1_num_sanity(b); - secp256k1_num_subadd(r, a, b, 1); -} - -static void secp256k1_num_mul(secp256k1_num *r, const secp256k1_num *a, const secp256k1_num *b) { - mp_limb_t tmp[2*NUM_LIMBS+1]; - secp256k1_num_sanity(a); - secp256k1_num_sanity(b); - - VERIFY_CHECK(a->limbs + b->limbs <= 2*NUM_LIMBS+1); - if ((a->limbs==1 && a->data[0]==0) || (b->limbs==1 && b->data[0]==0)) { - r->limbs = 1; - r->neg = 0; - r->data[0] = 0; - return; - } - if (a->limbs >= b->limbs) { - mpn_mul(tmp, a->data, a->limbs, b->data, b->limbs); - } else { - mpn_mul(tmp, b->data, b->limbs, a->data, a->limbs); - } - r->limbs = a->limbs + b->limbs; - if (r->limbs > 1 && tmp[r->limbs - 1]==0) { - r->limbs--; - } - VERIFY_CHECK(r->limbs <= 2*NUM_LIMBS); - mpn_copyi(r->data, tmp, r->limbs); - r->neg = a->neg ^ b->neg; - memset(tmp, 0, sizeof(tmp)); -} - -static void secp256k1_num_shift(secp256k1_num *r, int bits) { - if (bits % GMP_NUMB_BITS) { - /* Shift within limbs. */ - mpn_rshift(r->data, r->data, r->limbs, bits % GMP_NUMB_BITS); - } - if (bits >= GMP_NUMB_BITS) { - int i; - /* Shift full limbs. */ - for (i = 0; i < r->limbs; i++) { - int index = i + (bits / GMP_NUMB_BITS); - if (index < r->limbs && index < 2*NUM_LIMBS) { - r->data[i] = r->data[index]; - } else { - r->data[i] = 0; - } - } - } - while (r->limbs>1 && r->data[r->limbs-1]==0) { - r->limbs--; - } -} - -static void secp256k1_num_negate(secp256k1_num *r) { - r->neg ^= 1; -} - -#endif /* SECP256K1_NUM_REPR_IMPL_H */ diff --git a/src/num_impl.h b/src/num_impl.h deleted file mode 100644 index c45193b033dab..0000000000000 --- a/src/num_impl.h +++ /dev/null @@ -1,24 +0,0 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ - -#ifndef SECP256K1_NUM_IMPL_H -#define SECP256K1_NUM_IMPL_H - -#if defined HAVE_CONFIG_H -#include "libsecp256k1-config.h" -#endif - -#include "num.h" - -#if defined(USE_NUM_GMP) -#include "num_gmp_impl.h" -#elif defined(USE_NUM_NONE) -/* Nothing. */ -#else -#error "Please select num implementation" -#endif - -#endif /* SECP256K1_NUM_IMPL_H */ diff --git a/src/scalar.h b/src/scalar.h index fb3fb187cec3f..aaaa3d88277ad 100644 --- a/src/scalar.h +++ b/src/scalar.h @@ -1,13 +1,12 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SCALAR_H #define SECP256K1_SCALAR_H -#include "num.h" #include "util.h" #if defined HAVE_CONFIG_H @@ -63,9 +62,6 @@ static void secp256k1_scalar_mul(secp256k1_scalar *r, const secp256k1_scalar *a, * the low bits that were shifted off */ static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n); -/** Compute the square of a scalar (modulo the group order). */ -static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a); - /** Compute the inverse of a scalar (modulo the group order). */ static void secp256k1_scalar_inverse(secp256k1_scalar *r, const secp256k1_scalar *a); @@ -91,14 +87,6 @@ static int secp256k1_scalar_is_high(const secp256k1_scalar *a); * Returns -1 if the number was negated, 1 otherwise */ static int secp256k1_scalar_cond_negate(secp256k1_scalar *a, int flag); -#ifndef USE_NUM_NONE -/** Convert a scalar to a number. */ -static void secp256k1_scalar_get_num(secp256k1_num *r, const secp256k1_scalar *a); - -/** Get the order of the group as a number. */ -static void secp256k1_scalar_order_get_num(secp256k1_num *r); -#endif - /** Compare two scalars. */ static int secp256k1_scalar_eq(const secp256k1_scalar *a, const secp256k1_scalar *b); diff --git a/src/scalar_4x64.h b/src/scalar_4x64.h index 19c7495d1c8e3..700964291ee28 100644 --- a/src/scalar_4x64.h +++ b/src/scalar_4x64.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SCALAR_REPR_H #define SECP256K1_SCALAR_REPR_H diff --git a/src/scalar_4x64_impl.h b/src/scalar_4x64_impl.h index 73cbd5e18a4d6..a1def26fca7af 100644 --- a/src/scalar_4x64_impl.h +++ b/src/scalar_4x64_impl.h @@ -1,12 +1,14 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SCALAR_REPR_IMPL_H #define SECP256K1_SCALAR_REPR_IMPL_H +#include "modinv64_impl.h" + /* Limbs of the secp256k1 order. */ #define SECP256K1_N_0 ((uint64_t)0xBFD25E8CD0364141ULL) #define SECP256K1_N_1 ((uint64_t)0xBAAEDCE6AF48A03BULL) @@ -212,28 +214,6 @@ static int secp256k1_scalar_cond_negate(secp256k1_scalar *r, int flag) { VERIFY_CHECK(c1 >= th); \ } -/** Add 2*a*b to the number defined by (c0,c1,c2). c2 must never overflow. */ -#define muladd2(a,b) { \ - uint64_t tl, th, th2, tl2; \ - { \ - uint128_t t = (uint128_t)a * b; \ - th = t >> 64; /* at most 0xFFFFFFFFFFFFFFFE */ \ - tl = t; \ - } \ - th2 = th + th; /* at most 0xFFFFFFFFFFFFFFFE (in case th was 0x7FFFFFFFFFFFFFFF) */ \ - c2 += (th2 < th); /* never overflows by contract (verified the next line) */ \ - VERIFY_CHECK((th2 >= th) || (c2 != 0)); \ - tl2 = tl + tl; /* at most 0xFFFFFFFFFFFFFFFE (in case the lowest 63 bits of tl were 0x7FFFFFFFFFFFFFFF) */ \ - th2 += (tl2 < tl); /* at most 0xFFFFFFFFFFFFFFFF */ \ - c0 += tl2; /* overflow is handled on the next line */ \ - th2 += (c0 < tl2); /* second overflow is handled on the next line */ \ - c2 += (c0 < tl2) & (th2 == 0); /* never overflows by contract (verified the next line) */ \ - VERIFY_CHECK((c0 >= tl2) || (th2 != 0) || (c2 != 0)); \ - c1 += th2; /* overflow is handled on the next line */ \ - c2 += (c1 < th2); /* never overflows by contract (verified the next line) */ \ - VERIFY_CHECK((c1 >= th2) || (c2 != 0)); \ -} - /** Add a to the number defined by (c0,c1,c2). c2 must never overflow. */ #define sumadd(a) { \ unsigned int over; \ @@ -743,148 +723,10 @@ static void secp256k1_scalar_mul_512(uint64_t l[8], const secp256k1_scalar *a, c #endif } -static void secp256k1_scalar_sqr_512(uint64_t l[8], const secp256k1_scalar *a) { -#ifdef USE_ASM_X86_64 - __asm__ __volatile__( - /* Preload */ - "movq 0(%%rdi), %%r11\n" - "movq 8(%%rdi), %%r12\n" - "movq 16(%%rdi), %%r13\n" - "movq 24(%%rdi), %%r14\n" - /* (rax,rdx) = a0 * a0 */ - "movq %%r11, %%rax\n" - "mulq %%r11\n" - /* Extract l0 */ - "movq %%rax, 0(%%rsi)\n" - /* (r8,r9,r10) = (rdx,0) */ - "movq %%rdx, %%r8\n" - "xorq %%r9, %%r9\n" - "xorq %%r10, %%r10\n" - /* (r8,r9,r10) += 2 * a0 * a1 */ - "movq %%r11, %%rax\n" - "mulq %%r12\n" - "addq %%rax, %%r8\n" - "adcq %%rdx, %%r9\n" - "adcq $0, %%r10\n" - "addq %%rax, %%r8\n" - "adcq %%rdx, %%r9\n" - "adcq $0, %%r10\n" - /* Extract l1 */ - "movq %%r8, 8(%%rsi)\n" - "xorq %%r8, %%r8\n" - /* (r9,r10,r8) += 2 * a0 * a2 */ - "movq %%r11, %%rax\n" - "mulq %%r13\n" - "addq %%rax, %%r9\n" - "adcq %%rdx, %%r10\n" - "adcq $0, %%r8\n" - "addq %%rax, %%r9\n" - "adcq %%rdx, %%r10\n" - "adcq $0, %%r8\n" - /* (r9,r10,r8) += a1 * a1 */ - "movq %%r12, %%rax\n" - "mulq %%r12\n" - "addq %%rax, %%r9\n" - "adcq %%rdx, %%r10\n" - "adcq $0, %%r8\n" - /* Extract l2 */ - "movq %%r9, 16(%%rsi)\n" - "xorq %%r9, %%r9\n" - /* (r10,r8,r9) += 2 * a0 * a3 */ - "movq %%r11, %%rax\n" - "mulq %%r14\n" - "addq %%rax, %%r10\n" - "adcq %%rdx, %%r8\n" - "adcq $0, %%r9\n" - "addq %%rax, %%r10\n" - "adcq %%rdx, %%r8\n" - "adcq $0, %%r9\n" - /* (r10,r8,r9) += 2 * a1 * a2 */ - "movq %%r12, %%rax\n" - "mulq %%r13\n" - "addq %%rax, %%r10\n" - "adcq %%rdx, %%r8\n" - "adcq $0, %%r9\n" - "addq %%rax, %%r10\n" - "adcq %%rdx, %%r8\n" - "adcq $0, %%r9\n" - /* Extract l3 */ - "movq %%r10, 24(%%rsi)\n" - "xorq %%r10, %%r10\n" - /* (r8,r9,r10) += 2 * a1 * a3 */ - "movq %%r12, %%rax\n" - "mulq %%r14\n" - "addq %%rax, %%r8\n" - "adcq %%rdx, %%r9\n" - "adcq $0, %%r10\n" - "addq %%rax, %%r8\n" - "adcq %%rdx, %%r9\n" - "adcq $0, %%r10\n" - /* (r8,r9,r10) += a2 * a2 */ - "movq %%r13, %%rax\n" - "mulq %%r13\n" - "addq %%rax, %%r8\n" - "adcq %%rdx, %%r9\n" - "adcq $0, %%r10\n" - /* Extract l4 */ - "movq %%r8, 32(%%rsi)\n" - "xorq %%r8, %%r8\n" - /* (r9,r10,r8) += 2 * a2 * a3 */ - "movq %%r13, %%rax\n" - "mulq %%r14\n" - "addq %%rax, %%r9\n" - "adcq %%rdx, %%r10\n" - "adcq $0, %%r8\n" - "addq %%rax, %%r9\n" - "adcq %%rdx, %%r10\n" - "adcq $0, %%r8\n" - /* Extract l5 */ - "movq %%r9, 40(%%rsi)\n" - /* (r10,r8) += a3 * a3 */ - "movq %%r14, %%rax\n" - "mulq %%r14\n" - "addq %%rax, %%r10\n" - "adcq %%rdx, %%r8\n" - /* Extract l6 */ - "movq %%r10, 48(%%rsi)\n" - /* Extract l7 */ - "movq %%r8, 56(%%rsi)\n" - : - : "S"(l), "D"(a->d) - : "rax", "rdx", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "cc", "memory"); -#else - /* 160 bit accumulator. */ - uint64_t c0 = 0, c1 = 0; - uint32_t c2 = 0; - - /* l[0..7] = a[0..3] * b[0..3]. */ - muladd_fast(a->d[0], a->d[0]); - extract_fast(l[0]); - muladd2(a->d[0], a->d[1]); - extract(l[1]); - muladd2(a->d[0], a->d[2]); - muladd(a->d[1], a->d[1]); - extract(l[2]); - muladd2(a->d[0], a->d[3]); - muladd2(a->d[1], a->d[2]); - extract(l[3]); - muladd2(a->d[1], a->d[3]); - muladd(a->d[2], a->d[2]); - extract(l[4]); - muladd2(a->d[2], a->d[3]); - extract(l[5]); - muladd_fast(a->d[3], a->d[3]); - extract_fast(l[6]); - VERIFY_CHECK(c1 == 0); - l[7] = c0; -#endif -} - #undef sumadd #undef sumadd_fast #undef muladd #undef muladd_fast -#undef muladd2 #undef extract #undef extract_fast @@ -906,12 +748,6 @@ static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n) { return ret; } -static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a) { - uint64_t l[8]; - secp256k1_scalar_sqr_512(l, a); - secp256k1_scalar_reduce_512(r, l); -} - static void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *k) { r1->d[0] = k->d[0]; r1->d[1] = k->d[1]; @@ -955,4 +791,78 @@ static SECP256K1_INLINE void secp256k1_scalar_cmov(secp256k1_scalar *r, const se r->d[3] = (r->d[3] & mask0) | (a->d[3] & mask1); } +static void secp256k1_scalar_from_signed62(secp256k1_scalar *r, const secp256k1_modinv64_signed62 *a) { + const uint64_t a0 = a->v[0], a1 = a->v[1], a2 = a->v[2], a3 = a->v[3], a4 = a->v[4]; + + /* The output from secp256k1_modinv64{_var} should be normalized to range [0,modulus), and + * have limbs in [0,2^62). The modulus is < 2^256, so the top limb must be below 2^(256-62*4). + */ + VERIFY_CHECK(a0 >> 62 == 0); + VERIFY_CHECK(a1 >> 62 == 0); + VERIFY_CHECK(a2 >> 62 == 0); + VERIFY_CHECK(a3 >> 62 == 0); + VERIFY_CHECK(a4 >> 8 == 0); + + r->d[0] = a0 | a1 << 62; + r->d[1] = a1 >> 2 | a2 << 60; + r->d[2] = a2 >> 4 | a3 << 58; + r->d[3] = a3 >> 6 | a4 << 56; + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_check_overflow(r) == 0); +#endif +} + +static void secp256k1_scalar_to_signed62(secp256k1_modinv64_signed62 *r, const secp256k1_scalar *a) { + const uint64_t M62 = UINT64_MAX >> 2; + const uint64_t a0 = a->d[0], a1 = a->d[1], a2 = a->d[2], a3 = a->d[3]; + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_check_overflow(a) == 0); +#endif + + r->v[0] = a0 & M62; + r->v[1] = (a0 >> 62 | a1 << 2) & M62; + r->v[2] = (a1 >> 60 | a2 << 4) & M62; + r->v[3] = (a2 >> 58 | a3 << 6) & M62; + r->v[4] = a3 >> 56; +} + +static const secp256k1_modinv64_modinfo secp256k1_const_modinfo_scalar = { + {{0x3FD25E8CD0364141LL, 0x2ABB739ABD2280EELL, -0x15LL, 0, 256}}, + 0x34F20099AA774EC1LL +}; + +static void secp256k1_scalar_inverse(secp256k1_scalar *r, const secp256k1_scalar *x) { + secp256k1_modinv64_signed62 s; +#ifdef VERIFY + int zero_in = secp256k1_scalar_is_zero(x); +#endif + secp256k1_scalar_to_signed62(&s, x); + secp256k1_modinv64(&s, &secp256k1_const_modinfo_scalar); + secp256k1_scalar_from_signed62(r, &s); + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_is_zero(r) == zero_in); +#endif +} + +static void secp256k1_scalar_inverse_var(secp256k1_scalar *r, const secp256k1_scalar *x) { + secp256k1_modinv64_signed62 s; +#ifdef VERIFY + int zero_in = secp256k1_scalar_is_zero(x); +#endif + secp256k1_scalar_to_signed62(&s, x); + secp256k1_modinv64_var(&s, &secp256k1_const_modinfo_scalar); + secp256k1_scalar_from_signed62(r, &s); + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_is_zero(r) == zero_in); +#endif +} + +SECP256K1_INLINE static int secp256k1_scalar_is_even(const secp256k1_scalar *a) { + return !(a->d[0] & 1); +} + #endif /* SECP256K1_SCALAR_REPR_IMPL_H */ diff --git a/src/scalar_8x32.h b/src/scalar_8x32.h index 2c9a348e24760..17863ef93710b 100644 --- a/src/scalar_8x32.h +++ b/src/scalar_8x32.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SCALAR_REPR_H #define SECP256K1_SCALAR_REPR_H diff --git a/src/scalar_8x32_impl.h b/src/scalar_8x32_impl.h index 6853f79eccbe1..62c7ae7156d37 100644 --- a/src/scalar_8x32_impl.h +++ b/src/scalar_8x32_impl.h @@ -1,12 +1,14 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SCALAR_REPR_IMPL_H #define SECP256K1_SCALAR_REPR_IMPL_H +#include "modinv32_impl.h" + /* Limbs of the secp256k1 order. */ #define SECP256K1_N_0 ((uint32_t)0xD0364141UL) #define SECP256K1_N_1 ((uint32_t)0xBFD25E8CUL) @@ -291,28 +293,6 @@ static int secp256k1_scalar_cond_negate(secp256k1_scalar *r, int flag) { VERIFY_CHECK(c1 >= th); \ } -/** Add 2*a*b to the number defined by (c0,c1,c2). c2 must never overflow. */ -#define muladd2(a,b) { \ - uint32_t tl, th, th2, tl2; \ - { \ - uint64_t t = (uint64_t)a * b; \ - th = t >> 32; /* at most 0xFFFFFFFE */ \ - tl = t; \ - } \ - th2 = th + th; /* at most 0xFFFFFFFE (in case th was 0x7FFFFFFF) */ \ - c2 += (th2 < th); /* never overflows by contract (verified the next line) */ \ - VERIFY_CHECK((th2 >= th) || (c2 != 0)); \ - tl2 = tl + tl; /* at most 0xFFFFFFFE (in case the lowest 63 bits of tl were 0x7FFFFFFF) */ \ - th2 += (tl2 < tl); /* at most 0xFFFFFFFF */ \ - c0 += tl2; /* overflow is handled on the next line */ \ - th2 += (c0 < tl2); /* second overflow is handled on the next line */ \ - c2 += (c0 < tl2) & (th2 == 0); /* never overflows by contract (verified the next line) */ \ - VERIFY_CHECK((c0 >= tl2) || (th2 != 0) || (c2 != 0)); \ - c1 += th2; /* overflow is handled on the next line */ \ - c2 += (c1 < th2); /* never overflows by contract (verified the next line) */ \ - VERIFY_CHECK((c1 >= th2) || (c2 != 0)); \ -} - /** Add a to the number defined by (c0,c1,c2). c2 must never overflow. */ #define sumadd(a) { \ unsigned int over; \ @@ -576,71 +556,10 @@ static void secp256k1_scalar_mul_512(uint32_t *l, const secp256k1_scalar *a, con l[15] = c0; } -static void secp256k1_scalar_sqr_512(uint32_t *l, const secp256k1_scalar *a) { - /* 96 bit accumulator. */ - uint32_t c0 = 0, c1 = 0, c2 = 0; - - /* l[0..15] = a[0..7]^2. */ - muladd_fast(a->d[0], a->d[0]); - extract_fast(l[0]); - muladd2(a->d[0], a->d[1]); - extract(l[1]); - muladd2(a->d[0], a->d[2]); - muladd(a->d[1], a->d[1]); - extract(l[2]); - muladd2(a->d[0], a->d[3]); - muladd2(a->d[1], a->d[2]); - extract(l[3]); - muladd2(a->d[0], a->d[4]); - muladd2(a->d[1], a->d[3]); - muladd(a->d[2], a->d[2]); - extract(l[4]); - muladd2(a->d[0], a->d[5]); - muladd2(a->d[1], a->d[4]); - muladd2(a->d[2], a->d[3]); - extract(l[5]); - muladd2(a->d[0], a->d[6]); - muladd2(a->d[1], a->d[5]); - muladd2(a->d[2], a->d[4]); - muladd(a->d[3], a->d[3]); - extract(l[6]); - muladd2(a->d[0], a->d[7]); - muladd2(a->d[1], a->d[6]); - muladd2(a->d[2], a->d[5]); - muladd2(a->d[3], a->d[4]); - extract(l[7]); - muladd2(a->d[1], a->d[7]); - muladd2(a->d[2], a->d[6]); - muladd2(a->d[3], a->d[5]); - muladd(a->d[4], a->d[4]); - extract(l[8]); - muladd2(a->d[2], a->d[7]); - muladd2(a->d[3], a->d[6]); - muladd2(a->d[4], a->d[5]); - extract(l[9]); - muladd2(a->d[3], a->d[7]); - muladd2(a->d[4], a->d[6]); - muladd(a->d[5], a->d[5]); - extract(l[10]); - muladd2(a->d[4], a->d[7]); - muladd2(a->d[5], a->d[6]); - extract(l[11]); - muladd2(a->d[5], a->d[7]); - muladd(a->d[6], a->d[6]); - extract(l[12]); - muladd2(a->d[6], a->d[7]); - extract(l[13]); - muladd_fast(a->d[7], a->d[7]); - extract_fast(l[14]); - VERIFY_CHECK(c1 == 0); - l[15] = c0; -} - #undef sumadd #undef sumadd_fast #undef muladd #undef muladd_fast -#undef muladd2 #undef extract #undef extract_fast @@ -666,12 +585,6 @@ static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n) { return ret; } -static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a) { - uint32_t l[16]; - secp256k1_scalar_sqr_512(l, a); - secp256k1_scalar_reduce_512(r, l); -} - static void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *k) { r1->d[0] = k->d[0]; r1->d[1] = k->d[1]; @@ -731,4 +644,92 @@ static SECP256K1_INLINE void secp256k1_scalar_cmov(secp256k1_scalar *r, const se r->d[7] = (r->d[7] & mask0) | (a->d[7] & mask1); } +static void secp256k1_scalar_from_signed30(secp256k1_scalar *r, const secp256k1_modinv32_signed30 *a) { + const uint32_t a0 = a->v[0], a1 = a->v[1], a2 = a->v[2], a3 = a->v[3], a4 = a->v[4], + a5 = a->v[5], a6 = a->v[6], a7 = a->v[7], a8 = a->v[8]; + + /* The output from secp256k1_modinv32{_var} should be normalized to range [0,modulus), and + * have limbs in [0,2^30). The modulus is < 2^256, so the top limb must be below 2^(256-30*8). + */ + VERIFY_CHECK(a0 >> 30 == 0); + VERIFY_CHECK(a1 >> 30 == 0); + VERIFY_CHECK(a2 >> 30 == 0); + VERIFY_CHECK(a3 >> 30 == 0); + VERIFY_CHECK(a4 >> 30 == 0); + VERIFY_CHECK(a5 >> 30 == 0); + VERIFY_CHECK(a6 >> 30 == 0); + VERIFY_CHECK(a7 >> 30 == 0); + VERIFY_CHECK(a8 >> 16 == 0); + + r->d[0] = a0 | a1 << 30; + r->d[1] = a1 >> 2 | a2 << 28; + r->d[2] = a2 >> 4 | a3 << 26; + r->d[3] = a3 >> 6 | a4 << 24; + r->d[4] = a4 >> 8 | a5 << 22; + r->d[5] = a5 >> 10 | a6 << 20; + r->d[6] = a6 >> 12 | a7 << 18; + r->d[7] = a7 >> 14 | a8 << 16; + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_check_overflow(r) == 0); +#endif +} + +static void secp256k1_scalar_to_signed30(secp256k1_modinv32_signed30 *r, const secp256k1_scalar *a) { + const uint32_t M30 = UINT32_MAX >> 2; + const uint32_t a0 = a->d[0], a1 = a->d[1], a2 = a->d[2], a3 = a->d[3], + a4 = a->d[4], a5 = a->d[5], a6 = a->d[6], a7 = a->d[7]; + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_check_overflow(a) == 0); +#endif + + r->v[0] = a0 & M30; + r->v[1] = (a0 >> 30 | a1 << 2) & M30; + r->v[2] = (a1 >> 28 | a2 << 4) & M30; + r->v[3] = (a2 >> 26 | a3 << 6) & M30; + r->v[4] = (a3 >> 24 | a4 << 8) & M30; + r->v[5] = (a4 >> 22 | a5 << 10) & M30; + r->v[6] = (a5 >> 20 | a6 << 12) & M30; + r->v[7] = (a6 >> 18 | a7 << 14) & M30; + r->v[8] = a7 >> 16; +} + +static const secp256k1_modinv32_modinfo secp256k1_const_modinfo_scalar = { + {{0x10364141L, 0x3F497A33L, 0x348A03BBL, 0x2BB739ABL, -0x146L, 0, 0, 0, 65536}}, + 0x2A774EC1L +}; + +static void secp256k1_scalar_inverse(secp256k1_scalar *r, const secp256k1_scalar *x) { + secp256k1_modinv32_signed30 s; +#ifdef VERIFY + int zero_in = secp256k1_scalar_is_zero(x); +#endif + secp256k1_scalar_to_signed30(&s, x); + secp256k1_modinv32(&s, &secp256k1_const_modinfo_scalar); + secp256k1_scalar_from_signed30(r, &s); + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_is_zero(r) == zero_in); +#endif +} + +static void secp256k1_scalar_inverse_var(secp256k1_scalar *r, const secp256k1_scalar *x) { + secp256k1_modinv32_signed30 s; +#ifdef VERIFY + int zero_in = secp256k1_scalar_is_zero(x); +#endif + secp256k1_scalar_to_signed30(&s, x); + secp256k1_modinv32_var(&s, &secp256k1_const_modinfo_scalar); + secp256k1_scalar_from_signed30(r, &s); + +#ifdef VERIFY + VERIFY_CHECK(secp256k1_scalar_is_zero(r) == zero_in); +#endif +} + +SECP256K1_INLINE static int secp256k1_scalar_is_even(const secp256k1_scalar *a) { + return !(a->d[0] & 1); +} + #endif /* SECP256K1_SCALAR_REPR_IMPL_H */ diff --git a/src/scalar_impl.h b/src/scalar_impl.h index fc758918180b6..e124474773c3e 100644 --- a/src/scalar_impl.h +++ b/src/scalar_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SCALAR_IMPL_H #define SECP256K1_SCALAR_IMPL_H @@ -31,231 +31,12 @@ static const secp256k1_scalar secp256k1_scalar_one = SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 1); static const secp256k1_scalar secp256k1_scalar_zero = SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 0); -#ifndef USE_NUM_NONE -static void secp256k1_scalar_get_num(secp256k1_num *r, const secp256k1_scalar *a) { - unsigned char c[32]; - secp256k1_scalar_get_b32(c, a); - secp256k1_num_set_bin(r, c, 32); -} - -/** secp256k1 curve order, see secp256k1_ecdsa_const_order_as_fe in ecdsa_impl.h */ -static void secp256k1_scalar_order_get_num(secp256k1_num *r) { -#if defined(EXHAUSTIVE_TEST_ORDER) - static const unsigned char order[32] = { - 0,0,0,0,0,0,0,0, - 0,0,0,0,0,0,0,0, - 0,0,0,0,0,0,0,0, - 0,0,0,0,0,0,0,EXHAUSTIVE_TEST_ORDER - }; -#else - static const unsigned char order[32] = { - 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, - 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFE, - 0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B, - 0xBF,0xD2,0x5E,0x8C,0xD0,0x36,0x41,0x41 - }; -#endif - secp256k1_num_set_bin(r, order, 32); -} -#endif - static int secp256k1_scalar_set_b32_seckey(secp256k1_scalar *r, const unsigned char *bin) { int overflow; secp256k1_scalar_set_b32(r, bin, &overflow); return (!overflow) & (!secp256k1_scalar_is_zero(r)); } -static void secp256k1_scalar_inverse(secp256k1_scalar *r, const secp256k1_scalar *x) { -#if defined(EXHAUSTIVE_TEST_ORDER) - int i; - *r = 0; - for (i = 0; i < EXHAUSTIVE_TEST_ORDER; i++) - if ((i * *x) % EXHAUSTIVE_TEST_ORDER == 1) - *r = i; - /* If this VERIFY_CHECK triggers we were given a noninvertible scalar (and thus - * have a composite group order; fix it in exhaustive_tests.c). */ - VERIFY_CHECK(*r != 0); -} -#else - secp256k1_scalar *t; - int i; - /* First compute xN as x ^ (2^N - 1) for some values of N, - * and uM as x ^ M for some values of M. */ - secp256k1_scalar x2, x3, x6, x8, x14, x28, x56, x112, x126; - secp256k1_scalar u2, u5, u9, u11, u13; - - secp256k1_scalar_sqr(&u2, x); - secp256k1_scalar_mul(&x2, &u2, x); - secp256k1_scalar_mul(&u5, &u2, &x2); - secp256k1_scalar_mul(&x3, &u5, &u2); - secp256k1_scalar_mul(&u9, &x3, &u2); - secp256k1_scalar_mul(&u11, &u9, &u2); - secp256k1_scalar_mul(&u13, &u11, &u2); - - secp256k1_scalar_sqr(&x6, &u13); - secp256k1_scalar_sqr(&x6, &x6); - secp256k1_scalar_mul(&x6, &x6, &u11); - - secp256k1_scalar_sqr(&x8, &x6); - secp256k1_scalar_sqr(&x8, &x8); - secp256k1_scalar_mul(&x8, &x8, &x2); - - secp256k1_scalar_sqr(&x14, &x8); - for (i = 0; i < 5; i++) { - secp256k1_scalar_sqr(&x14, &x14); - } - secp256k1_scalar_mul(&x14, &x14, &x6); - - secp256k1_scalar_sqr(&x28, &x14); - for (i = 0; i < 13; i++) { - secp256k1_scalar_sqr(&x28, &x28); - } - secp256k1_scalar_mul(&x28, &x28, &x14); - - secp256k1_scalar_sqr(&x56, &x28); - for (i = 0; i < 27; i++) { - secp256k1_scalar_sqr(&x56, &x56); - } - secp256k1_scalar_mul(&x56, &x56, &x28); - - secp256k1_scalar_sqr(&x112, &x56); - for (i = 0; i < 55; i++) { - secp256k1_scalar_sqr(&x112, &x112); - } - secp256k1_scalar_mul(&x112, &x112, &x56); - - secp256k1_scalar_sqr(&x126, &x112); - for (i = 0; i < 13; i++) { - secp256k1_scalar_sqr(&x126, &x126); - } - secp256k1_scalar_mul(&x126, &x126, &x14); - - /* Then accumulate the final result (t starts at x126). */ - t = &x126; - for (i = 0; i < 3; i++) { - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u5); /* 101 */ - for (i = 0; i < 4; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &x3); /* 111 */ - for (i = 0; i < 4; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u5); /* 101 */ - for (i = 0; i < 5; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u11); /* 1011 */ - for (i = 0; i < 4; i++) { - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u11); /* 1011 */ - for (i = 0; i < 4; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &x3); /* 111 */ - for (i = 0; i < 5; i++) { /* 00 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &x3); /* 111 */ - for (i = 0; i < 6; i++) { /* 00 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u13); /* 1101 */ - for (i = 0; i < 4; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u5); /* 101 */ - for (i = 0; i < 3; i++) { - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &x3); /* 111 */ - for (i = 0; i < 5; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u9); /* 1001 */ - for (i = 0; i < 6; i++) { /* 000 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u5); /* 101 */ - for (i = 0; i < 10; i++) { /* 0000000 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &x3); /* 111 */ - for (i = 0; i < 4; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &x3); /* 111 */ - for (i = 0; i < 9; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &x8); /* 11111111 */ - for (i = 0; i < 5; i++) { /* 0 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u9); /* 1001 */ - for (i = 0; i < 6; i++) { /* 00 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u11); /* 1011 */ - for (i = 0; i < 4; i++) { - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u13); /* 1101 */ - for (i = 0; i < 5; i++) { - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &x2); /* 11 */ - for (i = 0; i < 6; i++) { /* 00 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u13); /* 1101 */ - for (i = 0; i < 10; i++) { /* 000000 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u13); /* 1101 */ - for (i = 0; i < 4; i++) { - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, &u9); /* 1001 */ - for (i = 0; i < 6; i++) { /* 00000 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(t, t, x); /* 1 */ - for (i = 0; i < 8; i++) { /* 00 */ - secp256k1_scalar_sqr(t, t); - } - secp256k1_scalar_mul(r, t, &x6); /* 111111 */ -} - -SECP256K1_INLINE static int secp256k1_scalar_is_even(const secp256k1_scalar *a) { - return !(a->d[0] & 1); -} -#endif - -static void secp256k1_scalar_inverse_var(secp256k1_scalar *r, const secp256k1_scalar *x) { -#if defined(USE_SCALAR_INV_BUILTIN) - secp256k1_scalar_inverse(r, x); -#elif defined(USE_SCALAR_INV_NUM) - unsigned char b[32]; - secp256k1_num n, m; - secp256k1_scalar t = *x; - secp256k1_scalar_get_b32(b, &t); - secp256k1_num_set_bin(&n, b, 32); - secp256k1_scalar_order_get_num(&m); - secp256k1_num_mod_inverse(&n, &n, &m); - secp256k1_num_get_bin(b, 32, &n); - secp256k1_scalar_set_b32(r, b, NULL); - /* Verify that the inverse was computed correctly, without GMP code. */ - secp256k1_scalar_mul(&t, &t, r); - CHECK(secp256k1_scalar_is_one(&t)); -#else -#error "Please select scalar inverse implementation" -#endif -} - /* These parameters are generated using sage/gen_exhaustive_groups.sage. */ #if defined(EXHAUSTIVE_TEST_ORDER) # if EXHAUSTIVE_TEST_ORDER == 13 diff --git a/src/scalar_low.h b/src/scalar_low.h index 2794a7f171fa3..67051bd30b788 100644 --- a/src/scalar_low.h +++ b/src/scalar_low.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SCALAR_REPR_H #define SECP256K1_SCALAR_REPR_H diff --git a/src/scalar_low_impl.h b/src/scalar_low_impl.h index a615ec074b2b4..7176f0b2caeab 100644 --- a/src/scalar_low_impl.h +++ b/src/scalar_low_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2015 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2015 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SCALAR_REPR_IMPL_H #define SECP256K1_SCALAR_REPR_IMPL_H @@ -104,10 +104,6 @@ static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n) { return ret; } -static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a) { - *r = (*a * *a) % EXHAUSTIVE_TEST_ORDER; -} - static void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *a) { *r1 = *a; *r2 = 0; @@ -125,4 +121,19 @@ static SECP256K1_INLINE void secp256k1_scalar_cmov(secp256k1_scalar *r, const se *r = (*r & mask0) | (*a & mask1); } +static void secp256k1_scalar_inverse(secp256k1_scalar *r, const secp256k1_scalar *x) { + int i; + *r = 0; + for (i = 0; i < EXHAUSTIVE_TEST_ORDER; i++) + if ((i * *x) % EXHAUSTIVE_TEST_ORDER == 1) + *r = i; + /* If this VERIFY_CHECK triggers we were given a noninvertible scalar (and thus + * have a composite group order; fix it in exhaustive_tests.c). */ + VERIFY_CHECK(*r != 0); +} + +static void secp256k1_scalar_inverse_var(secp256k1_scalar *r, const secp256k1_scalar *x) { + secp256k1_scalar_inverse(r, x); +} + #endif /* SECP256K1_SCALAR_REPR_IMPL_H */ diff --git a/src/scratch.h b/src/scratch.h index 77b35d126bbe6..9dcb7581f6fc4 100644 --- a/src/scratch.h +++ b/src/scratch.h @@ -1,11 +1,11 @@ -/********************************************************************** - * Copyright (c) 2017 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ - -#ifndef _SECP256K1_SCRATCH_ -#define _SECP256K1_SCRATCH_ +/*********************************************************************** + * Copyright (c) 2017 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ + +#ifndef SECP256K1_SCRATCH_H +#define SECP256K1_SCRATCH_H /* The typedef is used internally; the struct name is used in the public API * (where it is exposed as a different typedef) */ diff --git a/src/scratch_impl.h b/src/scratch_impl.h index f381e2e322744..688e18eb66208 100644 --- a/src/scratch_impl.h +++ b/src/scratch_impl.h @@ -1,11 +1,11 @@ -/********************************************************************** - * Copyright (c) 2017 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2017 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ -#ifndef _SECP256K1_SCRATCH_IMPL_H_ -#define _SECP256K1_SCRATCH_IMPL_H_ +#ifndef SECP256K1_SCRATCH_IMPL_H +#define SECP256K1_SCRATCH_IMPL_H #include "util.h" #include "scratch.h" diff --git a/src/secp256k1.c b/src/secp256k1.c index dae506d08c946..aef3f99ac3b39 100644 --- a/src/secp256k1.c +++ b/src/secp256k1.c @@ -1,15 +1,14 @@ -/********************************************************************** - * Copyright (c) 2013-2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013-2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include "include/secp256k1.h" #include "include/secp256k1_preallocated.h" #include "assumptions.h" #include "util.h" -#include "num_impl.h" #include "field_impl.h" #include "scalar_impl.h" #include "group_impl.h" @@ -86,6 +85,8 @@ const secp256k1_context *secp256k1_context_no_precomp = &secp256k1_context_no_pr size_t secp256k1_context_preallocated_size(unsigned int flags) { size_t ret = ROUND_TO_ALIGN(sizeof(secp256k1_context)); + /* A return value of 0 is reserved as an indicator for errors when we call this function internally. */ + VERIFY_CHECK(ret != 0); if (EXPECT((flags & SECP256K1_FLAGS_TYPE_MASK) != SECP256K1_FLAGS_TYPE_CONTEXT, 0)) { secp256k1_callback_call(&default_illegal_callback, @@ -122,21 +123,21 @@ secp256k1_context* secp256k1_context_preallocated_create(void* prealloc, unsigne if (!secp256k1_selftest()) { secp256k1_callback_call(&default_error_callback, "self test failed"); } - VERIFY_CHECK(prealloc != NULL); + prealloc_size = secp256k1_context_preallocated_size(flags); + if (prealloc_size == 0) { + return NULL; + } + VERIFY_CHECK(prealloc != NULL); ret = (secp256k1_context*)manual_alloc(&prealloc, sizeof(secp256k1_context), base, prealloc_size); ret->illegal_callback = default_illegal_callback; ret->error_callback = default_error_callback; - if (EXPECT((flags & SECP256K1_FLAGS_TYPE_MASK) != SECP256K1_FLAGS_TYPE_CONTEXT, 0)) { - secp256k1_callback_call(&ret->illegal_callback, - "Invalid flags"); - return NULL; - } - secp256k1_ecmult_context_init(&ret->ecmult_ctx); secp256k1_ecmult_gen_context_init(&ret->ecmult_gen_ctx); + /* Flags have been checked by secp256k1_context_preallocated_size. */ + VERIFY_CHECK((flags & SECP256K1_FLAGS_TYPE_MASK) == SECP256K1_FLAGS_TYPE_CONTEXT); if (flags & SECP256K1_FLAGS_BIT_CONTEXT_SIGN) { secp256k1_ecmult_gen_context_build(&ret->ecmult_gen_ctx, &prealloc); } @@ -420,17 +421,17 @@ int secp256k1_ecdsa_signature_normalize(const secp256k1_context* ctx, secp256k1_ return ret; } -int secp256k1_ecdsa_verify(const secp256k1_context* ctx, const secp256k1_ecdsa_signature *sig, const unsigned char *msg32, const secp256k1_pubkey *pubkey) { +int secp256k1_ecdsa_verify(const secp256k1_context* ctx, const secp256k1_ecdsa_signature *sig, const unsigned char *msghash32, const secp256k1_pubkey *pubkey) { secp256k1_ge q; secp256k1_scalar r, s; secp256k1_scalar m; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); - ARG_CHECK(msg32 != NULL); + ARG_CHECK(msghash32 != NULL); ARG_CHECK(sig != NULL); ARG_CHECK(pubkey != NULL); - secp256k1_scalar_set_b32(&m, msg32, NULL); + secp256k1_scalar_set_b32(&m, msghash32, NULL); secp256k1_ecdsa_signature_load(ctx, &r, &s, sig); return (!secp256k1_scalar_is_high(&s) && secp256k1_pubkey_load(ctx, &q, pubkey) && @@ -531,16 +532,16 @@ static int secp256k1_ecdsa_sign_inner(const secp256k1_context* ctx, secp256k1_sc return ret; } -int secp256k1_ecdsa_sign(const secp256k1_context* ctx, secp256k1_ecdsa_signature *signature, const unsigned char *msg32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) { +int secp256k1_ecdsa_sign(const secp256k1_context* ctx, secp256k1_ecdsa_signature *signature, const unsigned char *msghash32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) { secp256k1_scalar r, s; int ret; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)); - ARG_CHECK(msg32 != NULL); + ARG_CHECK(msghash32 != NULL); ARG_CHECK(signature != NULL); ARG_CHECK(seckey != NULL); - ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, NULL, msg32, seckey, noncefp, noncedata); + ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, NULL, msghash32, seckey, noncefp, noncedata); secp256k1_ecdsa_signature_save(signature, &r, &s); return ret; } @@ -580,7 +581,7 @@ int secp256k1_ec_pubkey_create(const secp256k1_context* ctx, secp256k1_pubkey *p ret = secp256k1_ec_pubkey_create_helper(&ctx->ecmult_gen_ctx, &seckey_scalar, &p, seckey); secp256k1_pubkey_save(pubkey, &p); - memczero(pubkey, sizeof(*pubkey), !ret); + secp256k1_memczero(pubkey, sizeof(*pubkey), !ret); secp256k1_scalar_clear(&seckey_scalar); return ret; @@ -621,26 +622,26 @@ int secp256k1_ec_pubkey_negate(const secp256k1_context* ctx, secp256k1_pubkey *p } -static int secp256k1_ec_seckey_tweak_add_helper(secp256k1_scalar *sec, const unsigned char *tweak) { +static int secp256k1_ec_seckey_tweak_add_helper(secp256k1_scalar *sec, const unsigned char *tweak32) { secp256k1_scalar term; int overflow = 0; int ret = 0; - secp256k1_scalar_set_b32(&term, tweak, &overflow); + secp256k1_scalar_set_b32(&term, tweak32, &overflow); ret = (!overflow) & secp256k1_eckey_privkey_tweak_add(sec, &term); secp256k1_scalar_clear(&term); return ret; } -int secp256k1_ec_seckey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { +int secp256k1_ec_seckey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak32) { secp256k1_scalar sec; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(seckey != NULL); - ARG_CHECK(tweak != NULL); + ARG_CHECK(tweak32 != NULL); ret = secp256k1_scalar_set_b32_seckey(&sec, seckey); - ret &= secp256k1_ec_seckey_tweak_add_helper(&sec, tweak); + ret &= secp256k1_ec_seckey_tweak_add_helper(&sec, tweak32); secp256k1_scalar_cmov(&sec, &secp256k1_scalar_zero, !ret); secp256k1_scalar_get_b32(seckey, &sec); @@ -648,28 +649,28 @@ int secp256k1_ec_seckey_tweak_add(const secp256k1_context* ctx, unsigned char *s return ret; } -int secp256k1_ec_privkey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { - return secp256k1_ec_seckey_tweak_add(ctx, seckey, tweak); +int secp256k1_ec_privkey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak32) { + return secp256k1_ec_seckey_tweak_add(ctx, seckey, tweak32); } -static int secp256k1_ec_pubkey_tweak_add_helper(const secp256k1_ecmult_context* ecmult_ctx, secp256k1_ge *p, const unsigned char *tweak) { +static int secp256k1_ec_pubkey_tweak_add_helper(const secp256k1_ecmult_context* ecmult_ctx, secp256k1_ge *p, const unsigned char *tweak32) { secp256k1_scalar term; int overflow = 0; - secp256k1_scalar_set_b32(&term, tweak, &overflow); + secp256k1_scalar_set_b32(&term, tweak32, &overflow); return !overflow && secp256k1_eckey_pubkey_tweak_add(ecmult_ctx, p, &term); } -int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) { +int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak32) { secp256k1_ge p; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); ARG_CHECK(pubkey != NULL); - ARG_CHECK(tweak != NULL); + ARG_CHECK(tweak32 != NULL); ret = secp256k1_pubkey_load(ctx, &p, pubkey); memset(pubkey, 0, sizeof(*pubkey)); - ret = ret && secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &p, tweak); + ret = ret && secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &p, tweak32); if (ret) { secp256k1_pubkey_save(pubkey, &p); } @@ -677,16 +678,16 @@ int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey return ret; } -int secp256k1_ec_seckey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { +int secp256k1_ec_seckey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak32) { secp256k1_scalar factor; secp256k1_scalar sec; int ret = 0; int overflow = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(seckey != NULL); - ARG_CHECK(tweak != NULL); + ARG_CHECK(tweak32 != NULL); - secp256k1_scalar_set_b32(&factor, tweak, &overflow); + secp256k1_scalar_set_b32(&factor, tweak32, &overflow); ret = secp256k1_scalar_set_b32_seckey(&sec, seckey); ret &= (!overflow) & secp256k1_eckey_privkey_tweak_mul(&sec, &factor); secp256k1_scalar_cmov(&sec, &secp256k1_scalar_zero, !ret); @@ -697,11 +698,11 @@ int secp256k1_ec_seckey_tweak_mul(const secp256k1_context* ctx, unsigned char *s return ret; } -int secp256k1_ec_privkey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { - return secp256k1_ec_seckey_tweak_mul(ctx, seckey, tweak); +int secp256k1_ec_privkey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak32) { + return secp256k1_ec_seckey_tweak_mul(ctx, seckey, tweak32); } -int secp256k1_ec_pubkey_tweak_mul(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) { +int secp256k1_ec_pubkey_tweak_mul(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak32) { secp256k1_ge p; secp256k1_scalar factor; int ret = 0; @@ -709,9 +710,9 @@ int secp256k1_ec_pubkey_tweak_mul(const secp256k1_context* ctx, secp256k1_pubkey VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); ARG_CHECK(pubkey != NULL); - ARG_CHECK(tweak != NULL); + ARG_CHECK(tweak32 != NULL); - secp256k1_scalar_set_b32(&factor, tweak, &overflow); + secp256k1_scalar_set_b32(&factor, tweak32, &overflow); ret = !overflow && secp256k1_pubkey_load(ctx, &p, pubkey); memset(pubkey, 0, sizeof(*pubkey)); if (ret) { diff --git a/src/selftest.h b/src/selftest.h index 0e37510c1e95a..52f1b8442e712 100644 --- a/src/selftest.h +++ b/src/selftest.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2020 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2020 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_SELFTEST_H #define SECP256K1_SELFTEST_H diff --git a/src/testrand.h b/src/testrand.h index a76003d5b8e17..667d1867bd615 100644 --- a/src/testrand.h +++ b/src/testrand.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_TESTRAND_H #define SECP256K1_TESTRAND_H diff --git a/src/testrand_impl.h b/src/testrand_impl.h index 3392566329818..e643778f36b1e 100644 --- a/src/testrand_impl.h +++ b/src/testrand_impl.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013-2015 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013-2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_TESTRAND_IMPL_H #define SECP256K1_TESTRAND_IMPL_H diff --git a/src/tests.c b/src/tests.c index bb4b5b4c077e8..a146394305cb6 100644 --- a/src/tests.c +++ b/src/tests.c @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014, 2015 Pieter Wuille, Gregory Maxwell * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014, 2015 Pieter Wuille, Gregory Maxwell * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #if defined HAVE_CONFIG_H #include "libsecp256k1-config.h" @@ -18,12 +18,13 @@ #include "include/secp256k1.h" #include "include/secp256k1_preallocated.h" #include "testrand_impl.h" +#include "util.h" #ifdef ENABLE_OPENSSL_TESTS -#include "openssl/bn.h" -#include "openssl/ec.h" -#include "openssl/ecdsa.h" -#include "openssl/obj_mac.h" +#include +#include +#include +#include # if OPENSSL_VERSION_NUMBER < 0x10100000L void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps) {*pr = sig->r; *ps = sig->s;} # endif @@ -32,6 +33,11 @@ void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps) #include "contrib/lax_der_parsing.c" #include "contrib/lax_der_privatekey_parsing.c" +#include "modinv32_impl.h" +#ifdef SECP256K1_WIDEMUL_INT128 +#include "modinv64_impl.h" +#endif + static int count = 64; static secp256k1_context *ctx = NULL; @@ -416,6 +422,25 @@ void run_scratch_tests(void) { secp256k1_context_destroy(none); } +void run_ctz_tests(void) { + static const uint32_t b32[] = {1, 0xffffffff, 0x5e56968f, 0xe0d63129}; + static const uint64_t b64[] = {1, 0xffffffffffffffff, 0xbcd02462139b3fc3, 0x98b5f80c769693ef}; + int shift; + unsigned i; + for (i = 0; i < sizeof(b32) / sizeof(b32[0]); ++i) { + for (shift = 0; shift < 32; ++shift) { + CHECK(secp256k1_ctz32_var_debruijn(b32[i] << shift) == shift); + CHECK(secp256k1_ctz32_var(b32[i] << shift) == shift); + } + } + for (i = 0; i < sizeof(b64) / sizeof(b64[0]); ++i) { + for (shift = 0; shift < 64; ++shift) { + CHECK(secp256k1_ctz64_var_debruijn(b64[i] << shift) == shift); + CHECK(secp256k1_ctz64_var(b64[i] << shift) == shift); + } + } +} + /***** HASH TESTS *****/ void run_sha256_tests(void) { @@ -611,202 +636,924 @@ void run_rand_int(void) { } } -/***** NUM TESTS *****/ +/***** MODINV TESTS *****/ + +/* Compute the modular inverse of (odd) x mod 2^64. */ +uint64_t modinv2p64(uint64_t x) { + /* If w = 1/x mod 2^(2^L), then w*(2 - w*x) = 1/x mod 2^(2^(L+1)). See + * Hacker's Delight second edition, Henry S. Warren, Jr., pages 245-247 for + * why. Start with L=0, for which it is true for every odd x that + * 1/x=1 mod 2. Iterating 6 times gives us 1/x mod 2^64. */ + int l; + uint64_t w = 1; + CHECK(x & 1); + for (l = 0; l < 6; ++l) w *= (2 - w*x); + return w; +} -#ifndef USE_NUM_NONE -void random_num_negate(secp256k1_num *num) { - if (secp256k1_testrand_bits(1)) { - secp256k1_num_negate(num); +/* compute out = (a*b) mod m; if b=NULL, treat b=1. + * + * Out is a 512-bit number (represented as 32 uint16_t's in LE order). The other + * arguments are 256-bit numbers (represented as 16 uint16_t's in LE order). */ +void mulmod256(uint16_t* out, const uint16_t* a, const uint16_t* b, const uint16_t* m) { + uint16_t mul[32]; + uint64_t c = 0; + int i, j; + int m_bitlen = 0; + int mul_bitlen = 0; + + if (b != NULL) { + /* Compute the product of a and b, and put it in mul. */ + for (i = 0; i < 32; ++i) { + for (j = i <= 15 ? 0 : i - 15; j <= i && j <= 15; j++) { + c += (uint64_t)a[j] * b[i - j]; + } + mul[i] = c & 0xFFFF; + c >>= 16; + } + CHECK(c == 0); + + /* compute the highest set bit in mul */ + for (i = 511; i >= 0; --i) { + if ((mul[i >> 4] >> (i & 15)) & 1) { + mul_bitlen = i; + break; + } + } + } else { + /* if b==NULL, set mul=a. */ + memcpy(mul, a, 32); + memset(mul + 16, 0, 32); + /* compute the highest set bit in mul */ + for (i = 255; i >= 0; --i) { + if ((mul[i >> 4] >> (i & 15)) & 1) { + mul_bitlen = i; + break; + } + } } -} -void random_num_order_test(secp256k1_num *num) { - secp256k1_scalar sc; - random_scalar_order_test(&sc); - secp256k1_scalar_get_num(num, &sc); + /* Compute the highest set bit in m. */ + for (i = 255; i >= 0; --i) { + if ((m[i >> 4] >> (i & 15)) & 1) { + m_bitlen = i; + break; + } + } + + /* Try do mul -= m<= 0; --i) { + uint16_t mul2[32]; + int64_t cs; + + /* Compute mul2 = mul - m<= 0 && bitpos < 256) { + sub |= ((m[bitpos >> 4] >> (bitpos & 15)) & 1) << p; + } + } + /* Add mul[j]-sub to accumulator, and shift bottom 16 bits out to mul2[j]. */ + cs += mul[j]; + cs -= sub; + mul2[j] = (cs & 0xFFFF); + cs >>= 16; + } + /* If remainder of subtraction is 0, set mul = mul2. */ + if (cs == 0) { + memcpy(mul, mul2, sizeof(mul)); + } + } + /* Sanity check: test that all limbs higher than m's highest are zero */ + for (i = (m_bitlen >> 4) + 1; i < 32; ++i) { + CHECK(mul[i] == 0); + } + memcpy(out, mul, 32); } -void random_num_order(secp256k1_num *num) { - secp256k1_scalar sc; - random_scalar_order(&sc); - secp256k1_scalar_get_num(num, &sc); +/* Convert a 256-bit number represented as 16 uint16_t's to signed30 notation. */ +void uint16_to_signed30(secp256k1_modinv32_signed30* out, const uint16_t* in) { + int i; + memset(out->v, 0, sizeof(out->v)); + for (i = 0; i < 256; ++i) { + out->v[i / 30] |= (int32_t)(((in[i >> 4]) >> (i & 15)) & 1) << (i % 30); + } } -void test_num_negate(void) { - secp256k1_num n1; - secp256k1_num n2; - random_num_order_test(&n1); /* n1 = R */ - random_num_negate(&n1); - secp256k1_num_copy(&n2, &n1); /* n2 = R */ - secp256k1_num_sub(&n1, &n2, &n1); /* n1 = n2-n1 = 0 */ - CHECK(secp256k1_num_is_zero(&n1)); - secp256k1_num_copy(&n1, &n2); /* n1 = R */ - secp256k1_num_negate(&n1); /* n1 = -R */ - CHECK(!secp256k1_num_is_zero(&n1)); - secp256k1_num_add(&n1, &n2, &n1); /* n1 = n2+n1 = 0 */ - CHECK(secp256k1_num_is_zero(&n1)); - secp256k1_num_copy(&n1, &n2); /* n1 = R */ - secp256k1_num_negate(&n1); /* n1 = -R */ - CHECK(secp256k1_num_is_neg(&n1) != secp256k1_num_is_neg(&n2)); - secp256k1_num_negate(&n1); /* n1 = R */ - CHECK(secp256k1_num_eq(&n1, &n2)); +/* Convert a 256-bit number in signed30 notation to a representation as 16 uint16_t's. */ +void signed30_to_uint16(uint16_t* out, const secp256k1_modinv32_signed30* in) { + int i; + memset(out, 0, 32); + for (i = 0; i < 256; ++i) { + out[i >> 4] |= (((in->v[i / 30]) >> (i % 30)) & 1) << (i & 15); + } } -void test_num_add_sub(void) { +/* Randomly mutate the sign of limbs in signed30 representation, without changing the value. */ +void mutate_sign_signed30(secp256k1_modinv32_signed30* x) { int i; - secp256k1_scalar s; - secp256k1_num n1; - secp256k1_num n2; - secp256k1_num n1p2, n2p1, n1m2, n2m1; - random_num_order_test(&n1); /* n1 = R1 */ - if (secp256k1_testrand_bits(1)) { - random_num_negate(&n1); + for (i = 0; i < 16; ++i) { + int pos = secp256k1_testrand_int(8); + if (x->v[pos] > 0 && x->v[pos + 1] <= 0x3fffffff) { + x->v[pos] -= 0x40000000; + x->v[pos + 1] += 1; + } else if (x->v[pos] < 0 && x->v[pos + 1] >= 0x3fffffff) { + x->v[pos] += 0x40000000; + x->v[pos + 1] -= 1; + } } - random_num_order_test(&n2); /* n2 = R2 */ - if (secp256k1_testrand_bits(1)) { - random_num_negate(&n2); - } - secp256k1_num_add(&n1p2, &n1, &n2); /* n1p2 = R1 + R2 */ - secp256k1_num_add(&n2p1, &n2, &n1); /* n2p1 = R2 + R1 */ - secp256k1_num_sub(&n1m2, &n1, &n2); /* n1m2 = R1 - R2 */ - secp256k1_num_sub(&n2m1, &n2, &n1); /* n2m1 = R2 - R1 */ - CHECK(secp256k1_num_eq(&n1p2, &n2p1)); - CHECK(!secp256k1_num_eq(&n1p2, &n1m2)); - secp256k1_num_negate(&n2m1); /* n2m1 = -R2 + R1 */ - CHECK(secp256k1_num_eq(&n2m1, &n1m2)); - CHECK(!secp256k1_num_eq(&n2m1, &n1)); - secp256k1_num_add(&n2m1, &n2m1, &n2); /* n2m1 = -R2 + R1 + R2 = R1 */ - CHECK(secp256k1_num_eq(&n2m1, &n1)); - CHECK(!secp256k1_num_eq(&n2p1, &n1)); - secp256k1_num_sub(&n2p1, &n2p1, &n2); /* n2p1 = R2 + R1 - R2 = R1 */ - CHECK(secp256k1_num_eq(&n2p1, &n1)); - - /* check is_one */ - secp256k1_scalar_set_int(&s, 1); - secp256k1_scalar_get_num(&n1, &s); - CHECK(secp256k1_num_is_one(&n1)); - /* check that 2^n + 1 is never 1 */ - secp256k1_scalar_get_num(&n2, &s); - for (i = 0; i < 250; ++i) { - secp256k1_num_add(&n1, &n1, &n1); /* n1 *= 2 */ - secp256k1_num_add(&n1p2, &n1, &n2); /* n1p2 = n1 + 1 */ - CHECK(!secp256k1_num_is_one(&n1p2)); +} + +/* Test secp256k1_modinv32{_var}, using inputs in 16-bit limb format, and returning inverse. */ +void test_modinv32_uint16(uint16_t* out, const uint16_t* in, const uint16_t* mod) { + uint16_t tmp[16]; + secp256k1_modinv32_signed30 x; + secp256k1_modinv32_modinfo m; + int i, vartime, nonzero; + + uint16_to_signed30(&x, in); + nonzero = (x.v[0] | x.v[1] | x.v[2] | x.v[3] | x.v[4] | x.v[5] | x.v[6] | x.v[7] | x.v[8]) != 0; + uint16_to_signed30(&m.modulus, mod); + mutate_sign_signed30(&m.modulus); + + /* compute 1/modulus mod 2^30 */ + m.modulus_inv30 = modinv2p64(m.modulus.v[0]) & 0x3fffffff; + CHECK(((m.modulus_inv30 * m.modulus.v[0]) & 0x3fffffff) == 1); + + for (vartime = 0; vartime < 2; ++vartime) { + /* compute inverse */ + (vartime ? secp256k1_modinv32_var : secp256k1_modinv32)(&x, &m); + + /* produce output */ + signed30_to_uint16(out, &x); + + /* check if the inverse times the input is 1 (mod m), unless x is 0. */ + mulmod256(tmp, out, in, mod); + CHECK(tmp[0] == nonzero); + for (i = 1; i < 16; ++i) CHECK(tmp[i] == 0); + + /* invert again */ + (vartime ? secp256k1_modinv32_var : secp256k1_modinv32)(&x, &m); + + /* check if the result is equal to the input */ + signed30_to_uint16(tmp, &x); + for (i = 0; i < 16; ++i) CHECK(tmp[i] == in[i]); } } -void test_num_mod(void) { +#ifdef SECP256K1_WIDEMUL_INT128 +/* Convert a 256-bit number represented as 16 uint16_t's to signed62 notation. */ +void uint16_to_signed62(secp256k1_modinv64_signed62* out, const uint16_t* in) { int i; - secp256k1_scalar s; - secp256k1_num order, n; - - /* check that 0 mod anything is 0 */ - random_scalar_order_test(&s); - secp256k1_scalar_get_num(&order, &s); - secp256k1_scalar_set_int(&s, 0); - secp256k1_scalar_get_num(&n, &s); - secp256k1_num_mod(&n, &order); - CHECK(secp256k1_num_is_zero(&n)); - - /* check that anything mod 1 is 0 */ - secp256k1_scalar_set_int(&s, 1); - secp256k1_scalar_get_num(&order, &s); - secp256k1_scalar_get_num(&n, &s); - secp256k1_num_mod(&n, &order); - CHECK(secp256k1_num_is_zero(&n)); - - /* check that increasing the number past 2^256 does not break this */ - random_scalar_order_test(&s); - secp256k1_scalar_get_num(&n, &s); - /* multiply by 2^8, which'll test this case with high probability */ - for (i = 0; i < 8; ++i) { - secp256k1_num_add(&n, &n, &n); + memset(out->v, 0, sizeof(out->v)); + for (i = 0; i < 256; ++i) { + out->v[i / 62] |= (int64_t)(((in[i >> 4]) >> (i & 15)) & 1) << (i % 62); } - secp256k1_num_mod(&n, &order); - CHECK(secp256k1_num_is_zero(&n)); } -void test_num_jacobi(void) { - secp256k1_scalar sqr; - secp256k1_scalar small; - secp256k1_scalar five; /* five is not a quadratic residue */ - secp256k1_num order, n; +/* Convert a 256-bit number in signed62 notation to a representation as 16 uint16_t's. */ +void signed62_to_uint16(uint16_t* out, const secp256k1_modinv64_signed62* in) { int i; - /* squares mod 5 are 1, 4 */ - const int jacobi5[10] = { 0, 1, -1, -1, 1, 0, 1, -1, -1, 1 }; + memset(out, 0, 32); + for (i = 0; i < 256; ++i) { + out[i >> 4] |= (((in->v[i / 62]) >> (i % 62)) & 1) << (i & 15); + } +} - /* check some small values with 5 as the order */ - secp256k1_scalar_set_int(&five, 5); - secp256k1_scalar_get_num(&order, &five); - for (i = 0; i < 10; ++i) { - secp256k1_scalar_set_int(&small, i); - secp256k1_scalar_get_num(&n, &small); - CHECK(secp256k1_num_jacobi(&n, &order) == jacobi5[i]); +/* Randomly mutate the sign of limbs in signed62 representation, without changing the value. */ +void mutate_sign_signed62(secp256k1_modinv64_signed62* x) { + static const int64_t M62 = (int64_t)(UINT64_MAX >> 2); + int i; + for (i = 0; i < 8; ++i) { + int pos = secp256k1_testrand_int(4); + if (x->v[pos] > 0 && x->v[pos + 1] <= M62) { + x->v[pos] -= (M62 + 1); + x->v[pos + 1] += 1; + } else if (x->v[pos] < 0 && x->v[pos + 1] >= -M62) { + x->v[pos] += (M62 + 1); + x->v[pos + 1] -= 1; + } } +} - /** test large values with 5 as group order */ - secp256k1_scalar_get_num(&order, &five); - /* we first need a scalar which is not a multiple of 5 */ - do { - secp256k1_num fiven; - random_scalar_order_test(&sqr); - secp256k1_scalar_get_num(&fiven, &five); - secp256k1_scalar_get_num(&n, &sqr); - secp256k1_num_mod(&n, &fiven); - } while (secp256k1_num_is_zero(&n)); - /* next force it to be a residue. 2 is a nonresidue mod 5 so we can - * just multiply by two, i.e. add the number to itself */ - if (secp256k1_num_jacobi(&n, &order) == -1) { - secp256k1_num_add(&n, &n, &n); - } - - /* test residue */ - CHECK(secp256k1_num_jacobi(&n, &order) == 1); - /* test nonresidue */ - secp256k1_num_add(&n, &n, &n); - CHECK(secp256k1_num_jacobi(&n, &order) == -1); - - /** test with secp group order as order */ - secp256k1_scalar_order_get_num(&order); - random_scalar_order_test(&sqr); - secp256k1_scalar_sqr(&sqr, &sqr); - /* test residue */ - secp256k1_scalar_get_num(&n, &sqr); - CHECK(secp256k1_num_jacobi(&n, &order) == 1); - /* test nonresidue */ - secp256k1_scalar_mul(&sqr, &sqr, &five); - secp256k1_scalar_get_num(&n, &sqr); - CHECK(secp256k1_num_jacobi(&n, &order) == -1); - /* test multiple of the order*/ - CHECK(secp256k1_num_jacobi(&order, &order) == 0); - - /* check one less than the order */ - secp256k1_scalar_set_int(&small, 1); - secp256k1_scalar_get_num(&n, &small); - secp256k1_num_sub(&n, &order, &n); - CHECK(secp256k1_num_jacobi(&n, &order) == 1); /* sage confirms this is 1 */ +/* Test secp256k1_modinv64{_var}, using inputs in 16-bit limb format, and returning inverse. */ +void test_modinv64_uint16(uint16_t* out, const uint16_t* in, const uint16_t* mod) { + static const int64_t M62 = (int64_t)(UINT64_MAX >> 2); + uint16_t tmp[16]; + secp256k1_modinv64_signed62 x; + secp256k1_modinv64_modinfo m; + int i, vartime, nonzero; + + uint16_to_signed62(&x, in); + nonzero = (x.v[0] | x.v[1] | x.v[2] | x.v[3] | x.v[4]) != 0; + uint16_to_signed62(&m.modulus, mod); + mutate_sign_signed62(&m.modulus); + + /* compute 1/modulus mod 2^62 */ + m.modulus_inv62 = modinv2p64(m.modulus.v[0]) & M62; + CHECK(((m.modulus_inv62 * m.modulus.v[0]) & M62) == 1); + + for (vartime = 0; vartime < 2; ++vartime) { + /* compute inverse */ + (vartime ? secp256k1_modinv64_var : secp256k1_modinv64)(&x, &m); + + /* produce output */ + signed62_to_uint16(out, &x); + + /* check if the inverse times the input is 1 (mod m), unless x is 0. */ + mulmod256(tmp, out, in, mod); + CHECK(tmp[0] == nonzero); + for (i = 1; i < 16; ++i) CHECK(tmp[i] == 0); + + /* invert again */ + (vartime ? secp256k1_modinv64_var : secp256k1_modinv64)(&x, &m); + + /* check if the result is equal to the input */ + signed62_to_uint16(tmp, &x); + for (i = 0; i < 16; ++i) CHECK(tmp[i] == in[i]); + } } +#endif -void run_num_smalltests(void) { +/* test if a and b are coprime */ +int coprime(const uint16_t* a, const uint16_t* b) { + uint16_t x[16], y[16], t[16]; int i; - for (i = 0; i < 100*count; i++) { - test_num_negate(); - test_num_add_sub(); - test_num_mod(); - test_num_jacobi(); + int iszero; + memcpy(x, a, 32); + memcpy(y, b, 32); + + /* simple gcd loop: while x!=0, (x,y)=(y%x,x) */ + while (1) { + iszero = 1; + for (i = 0; i < 16; ++i) { + if (x[i] != 0) { + iszero = 0; + break; + } + } + if (iszero) break; + mulmod256(t, y, NULL, x); + memcpy(y, x, 32); + memcpy(x, t, 32); } + + /* return whether y=1 */ + if (y[0] != 1) return 0; + for (i = 1; i < 16; ++i) { + if (y[i] != 0) return 0; + } + return 1; } + +void run_modinv_tests(void) { + /* Fixed test cases. Each tuple is (input, modulus, output), each as 16x16 bits in LE order. */ + static const uint16_t CASES[][3][16] = { + /* Test cases triggering edge cases in divsteps */ + + /* Test case known to need 713 divsteps */ + {{0x1513, 0x5389, 0x54e9, 0x2798, 0x1957, 0x66a0, 0x8057, 0x3477, + 0x7784, 0x1052, 0x326a, 0x9331, 0x6506, 0xa95c, 0x91f3, 0xfb5e}, + {0x2bdd, 0x8df4, 0xcc61, 0x481f, 0xdae5, 0x5ca7, 0xf43b, 0x7d54, + 0x13d6, 0x469b, 0x2294, 0x20f4, 0xb2a4, 0xa2d1, 0x3ff1, 0xfd4b}, + {0xffd8, 0xd9a0, 0x456e, 0x81bb, 0xbabd, 0x6cea, 0x6dbd, 0x73ab, + 0xbb94, 0x3d3c, 0xdf08, 0x31c4, 0x3e32, 0xc179, 0x2486, 0xb86b}}, + /* Test case known to need 589 divsteps, reaching delta=-140 and + delta=141. */ + {{0x3fb1, 0x903b, 0x4eb7, 0x4813, 0xd863, 0x26bf, 0xd89f, 0xa8a9, + 0x02fe, 0x57c6, 0x554a, 0x4eab, 0x165e, 0x3d61, 0xee1e, 0x456c}, + {0x9295, 0x823b, 0x5c1f, 0x5386, 0x48e0, 0x02ff, 0x4c2a, 0xa2da, + 0xe58f, 0x967c, 0xc97e, 0x3f5a, 0x69fb, 0x52d9, 0x0a86, 0xb4a3}, + {0x3d30, 0xb893, 0xa809, 0xa7a8, 0x26f5, 0x5b42, 0x55be, 0xf4d0, + 0x12c2, 0x7e6a, 0xe41a, 0x90c7, 0xebfa, 0xf920, 0x304e, 0x1419}}, + /* Test case known to need 650 divsteps, and doing 65 consecutive (f,g/2) steps. */ + {{0x8583, 0x5058, 0xbeae, 0xeb69, 0x48bc, 0x52bb, 0x6a9d, 0xcc94, + 0x2a21, 0x87d5, 0x5b0d, 0x42f6, 0x5b8a, 0x2214, 0xe9d6, 0xa040}, + {0x7531, 0x27cb, 0x7e53, 0xb739, 0x6a5f, 0x83f5, 0xa45c, 0xcb1d, + 0x8a87, 0x1c9c, 0x51d7, 0x851c, 0xb9d8, 0x1fbe, 0xc241, 0xd4a3}, + {0xcdb4, 0x275c, 0x7d22, 0xa906, 0x0173, 0xc054, 0x7fdf, 0x5005, + 0x7fb8, 0x9059, 0xdf51, 0x99df, 0x2654, 0x8f6e, 0x070f, 0xb347}}, + /* example needing 713 divsteps; delta=-2..3 */ + {{0xe2e9, 0xee91, 0x4345, 0xe5ad, 0xf3ec, 0x8f42, 0x0364, 0xd5c9, + 0xff49, 0xbef5, 0x4544, 0x4c7c, 0xae4b, 0xfd9d, 0xb35b, 0xda9d}, + {0x36e7, 0x8cca, 0x2ed0, 0x47b3, 0xaca4, 0xb374, 0x7d2a, 0x0772, + 0x6bdb, 0xe0a7, 0x900b, 0xfe10, 0x788c, 0x6f22, 0xd909, 0xf298}, + {0xd8c6, 0xba39, 0x13ed, 0x198c, 0x16c8, 0xb837, 0xa5f2, 0x9797, + 0x0113, 0x882a, 0x15b5, 0x324c, 0xabee, 0xe465, 0x8170, 0x85ac}}, + /* example needing 713 divsteps; delta=-2..3 */ + {{0xd5b7, 0x2966, 0x040e, 0xf59a, 0x0387, 0xd96d, 0xbfbc, 0xd850, + 0x2d96, 0x872a, 0xad81, 0xc03c, 0xbb39, 0xb7fa, 0xd904, 0xef78}, + {0x6279, 0x4314, 0xfdd3, 0x1568, 0x0982, 0x4d13, 0x625f, 0x010c, + 0x22b1, 0x0cc3, 0xf22d, 0x5710, 0x1109, 0x5751, 0x7714, 0xfcf2}, + {0xdb13, 0x5817, 0x232e, 0xe456, 0xbbbc, 0x6fbe, 0x4572, 0xa358, + 0xc76d, 0x928e, 0x0162, 0x5314, 0x8325, 0x5683, 0xe21b, 0xda88}}, + /* example needing 713 divsteps; delta=-2..3 */ + {{0xa06f, 0x71ee, 0x3bac, 0x9ebb, 0xdeaa, 0x09ed, 0x1cf7, 0x9ec9, + 0x7158, 0x8b72, 0x5d53, 0x5479, 0x5c75, 0xbb66, 0x9125, 0xeccc}, + {0x2941, 0xd46c, 0x3cd4, 0x4a9d, 0x5c4a, 0x256b, 0xbd6c, 0x9b8e, + 0x8fe0, 0x8a14, 0xffe8, 0x2496, 0x618d, 0xa9d7, 0x5018, 0xfb29}, + {0x437c, 0xbd60, 0x7590, 0x94bb, 0x0095, 0xd35e, 0xd4fe, 0xd6da, + 0x0d4e, 0x5342, 0x4cd2, 0x169b, 0x661c, 0x1380, 0xed2d, 0x85c1}}, + /* example reaching delta=-64..65; 661 divsteps */ + {{0xfde4, 0x68d6, 0x6c48, 0x7f77, 0x1c78, 0x96de, 0x2fd9, 0xa6c2, + 0xbbb5, 0xd319, 0x69cf, 0xd4b3, 0xa321, 0xcda0, 0x172e, 0xe530}, + {0xd9e3, 0x0f60, 0x3d86, 0xeeab, 0x25ee, 0x9582, 0x2d50, 0xfe16, + 0xd4e2, 0xe3ba, 0x94e2, 0x9833, 0x6c5e, 0x8982, 0x13b6, 0xe598}, + {0xe675, 0xf55a, 0x10f6, 0xabde, 0x5113, 0xecaa, 0x61ae, 0xad9f, + 0x0c27, 0xef33, 0x62e5, 0x211d, 0x08fa, 0xa78d, 0xc675, 0x8bae}}, + /* example reaching delta=-64..65; 661 divsteps */ + {{0x21bf, 0x52d5, 0x8fd4, 0xaa18, 0x156a, 0x7247, 0xebb8, 0x5717, + 0x4eb5, 0x1421, 0xb58f, 0x3b0b, 0x5dff, 0xe533, 0xb369, 0xd28a}, + {0x9f6b, 0xe463, 0x2563, 0xc74d, 0x6d81, 0x636a, 0x8fc8, 0x7a94, + 0x9429, 0x1585, 0xf35e, 0x7ff5, 0xb64f, 0x9720, 0xba74, 0xe108}, + {0xa5ab, 0xea7b, 0xfe5e, 0x8a85, 0x13be, 0x7934, 0xe8a0, 0xa187, + 0x86b5, 0xe477, 0xb9a4, 0x75d7, 0x538f, 0xdd70, 0xc781, 0xb67d}}, + /* example reaching delta=-64..65; 661 divsteps */ + {{0xa41a, 0x3e8d, 0xf1f5, 0x9493, 0x868c, 0x5103, 0x2725, 0x3ceb, + 0x6032, 0x3624, 0xdc6b, 0x9120, 0xbf4c, 0x8821, 0x91ad, 0xb31a}, + {0x5c0b, 0xdda5, 0x20f8, 0x32a1, 0xaf73, 0x6ec5, 0x4779, 0x43d6, + 0xd454, 0x9573, 0xbf84, 0x5a58, 0xe04e, 0x307e, 0xd1d5, 0xe230}, + {0xda15, 0xbcd6, 0x7180, 0xabd3, 0x04e6, 0x6986, 0xc0d7, 0x90bb, + 0x3a4d, 0x7c95, 0xaaab, 0x9ab3, 0xda34, 0xa7f6, 0x9636, 0x6273}}, + /* example doing 123 consecutive (f,g/2) steps; 615 divsteps */ + {{0xb4d6, 0xb38f, 0x00aa, 0xebda, 0xd4c2, 0x70b8, 0x9dad, 0x58ee, + 0x68f8, 0x48d3, 0xb5ff, 0xf422, 0x9e46, 0x2437, 0x18d0, 0xd9cc}, + {0x5c83, 0xfed7, 0x97f5, 0x3f07, 0xcaad, 0x95b1, 0xb4a4, 0xb005, + 0x23af, 0xdd27, 0x6c0d, 0x932c, 0xe2b2, 0xe3ae, 0xfb96, 0xdf67}, + {0x3105, 0x0127, 0xfd48, 0x039b, 0x35f1, 0xbc6f, 0x6c0a, 0xb572, + 0xe4df, 0xebad, 0x8edc, 0xb89d, 0x9555, 0x4c26, 0x1fef, 0x997c}}, + /* example doing 123 consecutive (f,g/2) steps; 614 divsteps */ + {{0x5138, 0xd474, 0x385f, 0xc964, 0x00f2, 0x6df7, 0x862d, 0xb185, + 0xb264, 0xe9e1, 0x466c, 0xf39e, 0xafaf, 0x5f41, 0x47e2, 0xc89d}, + {0x8607, 0x9c81, 0x46a2, 0x7dcc, 0xcb0c, 0x9325, 0xe149, 0x2bde, + 0x6632, 0x2869, 0xa261, 0xb163, 0xccee, 0x22ae, 0x91e0, 0xcfd5}, + {0x831c, 0xda22, 0xb080, 0xba7a, 0x26e2, 0x54b0, 0x073b, 0x5ea0, + 0xed4b, 0xcb3d, 0xbba1, 0xbec8, 0xf2ad, 0xae0d, 0x349b, 0x17d1}}, + /* example doing 123 consecutive (f,g/2) steps; 614 divsteps */ + {{0xe9a5, 0xb4ad, 0xd995, 0x9953, 0xcdff, 0x50d7, 0xf715, 0x9dc7, + 0x3e28, 0x15a9, 0x95a3, 0x8554, 0x5b5e, 0xad1d, 0x6d57, 0x3d50}, + {0x3ad9, 0xbd60, 0x5cc7, 0x6b91, 0xadeb, 0x71f6, 0x7cc4, 0xa58a, + 0x2cce, 0xf17c, 0x38c9, 0x97ed, 0x65fb, 0x3fa6, 0xa6bc, 0xeb24}, + {0xf96c, 0x1963, 0x8151, 0xa0cc, 0x299b, 0xf277, 0x001a, 0x16bb, + 0xfd2e, 0x532d, 0x0410, 0xe117, 0x6b00, 0x44ec, 0xca6a, 0x1745}}, + /* example doing 446 (f,g/2) steps; 523 divsteps */ + {{0x3758, 0xa56c, 0xe41e, 0x4e47, 0x0975, 0xa82b, 0x107c, 0x89cf, + 0x2093, 0x5a0c, 0xda37, 0xe007, 0x6074, 0x4f68, 0x2f5a, 0xbb8a}, + {0x4beb, 0xa40f, 0x2c42, 0xd9d6, 0x97e8, 0xca7c, 0xd395, 0x894f, + 0x1f50, 0x8067, 0xa233, 0xb850, 0x1746, 0x1706, 0xbcda, 0xdf32}, + {0x762a, 0xceda, 0x4c45, 0x1ca0, 0x8c37, 0xd8c5, 0xef57, 0x7a2c, + 0x6e98, 0xe38a, 0xc50e, 0x2ca9, 0xcb85, 0x24d5, 0xc29c, 0x61f6}}, + /* example doing 446 (f,g/2) steps; 523 divsteps */ + {{0x6f38, 0x74ad, 0x7332, 0x4073, 0x6521, 0xb876, 0xa370, 0xa6bd, + 0xcea5, 0xbd06, 0x969f, 0x77c6, 0x1e69, 0x7c49, 0x7d51, 0xb6e7}, + {0x3f27, 0x4be4, 0xd81e, 0x1396, 0xb21f, 0x92aa, 0x6dc3, 0x6283, + 0x6ada, 0x3ca2, 0xc1e5, 0x8b9b, 0xd705, 0x5598, 0x8ba1, 0xe087}, + {0x6a22, 0xe834, 0xbc8d, 0xcee9, 0x42fc, 0xfc77, 0x9c45, 0x1ca8, + 0xeb66, 0xed74, 0xaaf9, 0xe75f, 0xfe77, 0x46d2, 0x179b, 0xbf3e}}, + /* example doing 336 (f,(f+g)/2) steps; 693 divsteps */ + {{0x7ea7, 0x444e, 0x84ea, 0xc447, 0x7c1f, 0xab97, 0x3de6, 0x5878, + 0x4e8b, 0xc017, 0x03e0, 0xdc40, 0xbbd0, 0x74ce, 0x0169, 0x7ab5}, + {0x4023, 0x154f, 0xfbe4, 0x8195, 0xfda0, 0xef54, 0x9e9a, 0xc703, + 0x2803, 0xf760, 0x6302, 0xed5b, 0x7157, 0x6456, 0xdd7d, 0xf14b}, + {0xb6fb, 0xe3b3, 0x0733, 0xa77e, 0x44c5, 0x3003, 0xc937, 0xdd4d, + 0x5355, 0x14e9, 0x184e, 0xcefe, 0xe6b5, 0xf2e0, 0x0a28, 0x5b74}}, + /* example doing 336 (f,(f+g)/2) steps; 687 divsteps */ + {{0xa893, 0xb5f4, 0x1ede, 0xa316, 0x242c, 0xbdcc, 0xb017, 0x0836, + 0x3a37, 0x27fb, 0xfb85, 0x251e, 0xa189, 0xb15d, 0xa4b8, 0xc24c}, + {0xb0b7, 0x57ba, 0xbb6d, 0x9177, 0xc896, 0xc7f2, 0x43b4, 0x85a6, + 0xe6c4, 0xe50e, 0x3109, 0x7ca5, 0xd73d, 0x13ff, 0x0c3d, 0xcd62}, + {0x48ca, 0xdb34, 0xe347, 0x2cef, 0x4466, 0x10fb, 0x7ee1, 0x6344, + 0x4308, 0x966d, 0xd4d1, 0xb099, 0x994f, 0xd025, 0x2187, 0x5866}}, + /* example doing 267 (g,(g-f)/2) steps; 678 divsteps */ + {{0x0775, 0x1754, 0x01f6, 0xdf37, 0xc0be, 0x8197, 0x072f, 0x6cf5, + 0x8b36, 0x8069, 0x5590, 0xb92d, 0x6084, 0x47a4, 0x23fe, 0xddd5}, + {0x8e1b, 0xda37, 0x27d9, 0x312e, 0x3a2f, 0xef6d, 0xd9eb, 0x8153, + 0xdcba, 0x9fa3, 0x9f80, 0xead5, 0x134d, 0x2ebb, 0x5ec0, 0xe032}, + {0x1cb6, 0x5a61, 0x1bed, 0x77d6, 0xd5d1, 0x7498, 0xef33, 0x2dd2, + 0x1089, 0xedbd, 0x6958, 0x16ae, 0x336c, 0x45e6, 0x4361, 0xbadc}}, + /* example doing 267 (g,(g-f)/2) steps; 676 divsteps */ + {{0x0207, 0xf948, 0xc430, 0xf36b, 0xf0a7, 0x5d36, 0x751f, 0x132c, + 0x6f25, 0xa630, 0xca1f, 0xc967, 0xaf9c, 0x34e7, 0xa38f, 0xbe9f}, + {0x5fb9, 0x7321, 0x6561, 0x5fed, 0x54ec, 0x9c3a, 0xee0e, 0x6717, + 0x49af, 0xb896, 0xf4f5, 0x451c, 0x722a, 0xf116, 0x64a9, 0xcf0b}, + {0xf4d7, 0xdb47, 0xfef2, 0x4806, 0x4cb8, 0x18c7, 0xd9a7, 0x4951, + 0x14d8, 0x5c3a, 0xd22d, 0xd7b2, 0x750c, 0x3de7, 0x8b4a, 0x19aa}}, + + /* Test cases triggering edge cases in divsteps variant starting with delta=1/2 */ + + /* example needing 590 divsteps; delta=-5/2..7/2 */ + {{0x9118, 0xb640, 0x53d7, 0x30ab, 0x2a23, 0xd907, 0x9323, 0x5b3a, + 0xb6d4, 0x538a, 0x7637, 0xfe97, 0xfd05, 0x3cc0, 0x453a, 0xfb7e}, + {0x6983, 0x4f75, 0x4ad1, 0x48ad, 0xb2d9, 0x521d, 0x3dbc, 0x9cc0, + 0x4b60, 0x0ac6, 0xd3be, 0x0fb6, 0xd305, 0x3895, 0x2da5, 0xfdf8}, + {0xcec1, 0x33ac, 0xa801, 0x8194, 0xe36c, 0x65ef, 0x103b, 0xca54, + 0xfa9b, 0xb41d, 0x9b52, 0xb6f7, 0xa611, 0x84aa, 0x3493, 0xbf54}}, + /* example needing 590 divsteps; delta=-3/2..5/2 */ + {{0xb5f2, 0x42d0, 0x35e8, 0x8ca0, 0x4b62, 0x6e1d, 0xbdf3, 0x890e, + 0x8c82, 0x23d8, 0xc79a, 0xc8e8, 0x789e, 0x353d, 0x9766, 0xea9d}, + {0x6fa1, 0xacba, 0x4b7a, 0x5de1, 0x95d0, 0xc845, 0xebbf, 0x6f5a, + 0x30cf, 0x52db, 0x69b7, 0xe278, 0x4b15, 0x8411, 0x2ab2, 0xf3e7}, + {0xf12c, 0x9d6d, 0x95fa, 0x1878, 0x9f13, 0x4fb5, 0x3c8b, 0xa451, + 0x7182, 0xc4b6, 0x7e2a, 0x7bb7, 0x6e0e, 0x5b68, 0xde55, 0x9927}}, + /* example needing 590 divsteps; delta=-3/2..5/2 */ + {{0x229c, 0x4ef8, 0x1e93, 0xe5dc, 0xcde5, 0x6d62, 0x263b, 0xad11, + 0xced0, 0x88ff, 0xae8e, 0x3183, 0x11d2, 0xa50b, 0x350d, 0xeb40}, + {0x3157, 0xe2ea, 0x8a02, 0x0aa3, 0x5ae1, 0xb26c, 0xea27, 0x6805, + 0x87e2, 0x9461, 0x37c1, 0x2f8d, 0x85d2, 0x77a8, 0xf805, 0xeec9}, + {0x6f4e, 0x2748, 0xf7e5, 0xd8d3, 0xabe2, 0x7270, 0xc4e0, 0xedc7, + 0xf196, 0x78ca, 0x9139, 0xd8af, 0x72c6, 0xaf2f, 0x85d2, 0x6cd3}}, + /* example needing 590 divsteps; delta=-5/2..7/2 */ + {{0xdce8, 0xf1fe, 0x6708, 0x021e, 0xf1ca, 0xd609, 0x5443, 0x85ce, + 0x7a05, 0x8f9c, 0x90c3, 0x52e7, 0x8e1d, 0x97b8, 0xc0bf, 0xf2a1}, + {0xbd3d, 0xed11, 0x1625, 0xb4c5, 0x844c, 0xa413, 0x2569, 0xb9ba, + 0xcd35, 0xff84, 0xcd6e, 0x7f0b, 0x7d5d, 0x10df, 0x3efe, 0xfbe5}, + {0xa9dd, 0xafef, 0xb1b7, 0x4c8d, 0x50e4, 0xafbf, 0x2d5a, 0xb27c, + 0x0653, 0x66b6, 0x5d36, 0x4694, 0x7e35, 0xc47c, 0x857f, 0x32c5}}, + /* example needing 590 divsteps; delta=-3/2..5/2 */ + {{0x7902, 0xc9f8, 0x926b, 0xaaeb, 0x90f8, 0x1c89, 0xcce3, 0x96b7, + 0x28b2, 0x87a2, 0x136d, 0x695a, 0xa8df, 0x9061, 0x9e31, 0xee82}, + {0xd3a9, 0x3c02, 0x818c, 0x6b81, 0x34b3, 0xebbb, 0xe2c8, 0x7712, + 0xbfd6, 0x8248, 0xa6f4, 0xba6f, 0x03bb, 0xfb54, 0x7575, 0xfe89}, + {0x8246, 0x0d63, 0x478e, 0xf946, 0xf393, 0x0451, 0x08c2, 0x5919, + 0x5fd6, 0x4c61, 0xbeb7, 0x9a15, 0x30e1, 0x55fc, 0x6a01, 0x3724}}, + /* example reaching delta=-127/2..129/2; 571 divsteps */ + {{0x3eff, 0x926a, 0x77f5, 0x1fff, 0x1a5b, 0xf3ef, 0xf64b, 0x8681, + 0xf800, 0xf9bc, 0x761d, 0xe268, 0x62b0, 0xa032, 0xba9c, 0xbe56}, + {0xb8f9, 0x00e7, 0x47b7, 0xdffc, 0xfd9d, 0x5abb, 0xa19b, 0x1868, + 0x31fd, 0x3b29, 0x3674, 0x5449, 0xf54d, 0x1d19, 0x6ac7, 0xff6f}, + {0xf1d7, 0x3551, 0x5682, 0x9adf, 0xe8aa, 0x19a5, 0x8340, 0x71db, + 0xb7ab, 0x4cfd, 0xf661, 0x632c, 0xc27e, 0xd3c6, 0xdf42, 0xd306}}, + /* example reaching delta=-127/2..129/2; 571 divsteps */ + {{0x0000, 0x0000, 0x0000, 0x0000, 0x3aff, 0x2ed7, 0xf2e0, 0xabc7, + 0x8aee, 0x166e, 0x7ed0, 0x9ac7, 0x714a, 0xb9c5, 0x4d58, 0xad6c}, + {0x9cf9, 0x47e2, 0xa421, 0xb277, 0xffc2, 0x2747, 0x6486, 0x94c1, + 0x1d99, 0xd49b, 0x1096, 0x991a, 0xe986, 0xae02, 0xe89b, 0xea36}, + {0x1fb4, 0x98d8, 0x19b7, 0x80e9, 0xcdac, 0xaa5a, 0xf1e6, 0x0074, + 0xe393, 0xed8b, 0x8d5c, 0xe17d, 0x81b3, 0xc16d, 0x54d3, 0x9be3}}, + /* example reaching delta=-127/2..129/2; 571 divsteps */ + {{0xd047, 0x7e36, 0x3157, 0x7ab6, 0xb4d9, 0x8dae, 0x7534, 0x4f5d, + 0x489e, 0xa8ab, 0x8a3d, 0xd52c, 0x62af, 0xa032, 0xba9c, 0xbe56}, + {0xb1f1, 0x737f, 0x5964, 0x5afb, 0x3712, 0x8ef9, 0x19f7, 0x9669, + 0x664d, 0x03ad, 0xc352, 0xf7a5, 0xf545, 0x1d19, 0x6ac7, 0xff6f}, + {0xa834, 0x5256, 0x27bc, 0x33bd, 0xba11, 0x5a7b, 0x791e, 0xe6c0, + 0x9ac4, 0x9370, 0x1130, 0x28b4, 0x2b2e, 0x231b, 0x082a, 0x796e}}, + /* example doing 123 consecutive (f,g/2) steps; 554 divsteps */ + {{0x6ab1, 0x6ea0, 0x1a99, 0xe0c2, 0xdd45, 0x645d, 0x8dbc, 0x466a, + 0xfa64, 0x4289, 0xd3f7, 0xfc8f, 0x2894, 0xe3c5, 0xa008, 0xcc14}, + {0xc75f, 0xc083, 0x4cc2, 0x64f2, 0x2aff, 0x4c12, 0x8461, 0xc4ae, + 0xbbfa, 0xb336, 0xe4b2, 0x3ac5, 0x2c22, 0xf56c, 0x5381, 0xe943}, + {0xcd80, 0x760d, 0x4395, 0xb3a6, 0xd497, 0xf583, 0x82bd, 0x1daa, + 0xbe92, 0x2613, 0xfdfb, 0x869b, 0x0425, 0xa333, 0x7056, 0xc9c5}}, + /* example doing 123 consecutive (f,g/2) steps; 554 divsteps */ + {{0x71d4, 0x64df, 0xec4f, 0x74d8, 0x7e0c, 0x40d3, 0x7073, 0x4cc8, + 0x2a2a, 0xb1ff, 0x8518, 0x6513, 0xb0ea, 0x640a, 0x62d9, 0xd5f4}, + {0xdc75, 0xd937, 0x3b13, 0x1d36, 0xdf83, 0xd034, 0x1c1c, 0x4332, + 0x4cc3, 0xeeec, 0x7d94, 0x6771, 0x3384, 0x74b0, 0x947d, 0xf2c4}, + {0x0a82, 0x37a4, 0x12d5, 0xec97, 0x972c, 0xe6bf, 0xc348, 0xa0a9, + 0xc50c, 0xdc7c, 0xae30, 0x19d1, 0x0fca, 0x35e1, 0xd6f6, 0x81ee}}, + /* example doing 123 consecutive (f,g/2) steps; 554 divsteps */ + {{0xa6b1, 0xabc5, 0x5bbc, 0x7f65, 0xdd32, 0xaa73, 0xf5a3, 0x1982, + 0xced4, 0xe949, 0x0fd6, 0x2bc4, 0x2bd7, 0xe3c5, 0xa008, 0xcc14}, + {0x4b5f, 0x8f96, 0xa375, 0xfbcf, 0x1c7d, 0xf1ec, 0x03f5, 0xb35d, + 0xb999, 0xdb1f, 0xc9a1, 0xb4c7, 0x1dd5, 0xf56c, 0x5381, 0xe943}, + {0xaa3d, 0x38b9, 0xf17d, 0xeed9, 0x9988, 0x69ee, 0xeb88, 0x1495, + 0x203f, 0x18c8, 0x82b7, 0xdcb2, 0x34a7, 0x6b00, 0x6998, 0x589a}}, + /* example doing 453 (f,g/2) steps; 514 divsteps */ + {{0xa478, 0xe60d, 0x3244, 0x60e6, 0xada3, 0xfe50, 0xb6b1, 0x2eae, + 0xd0ef, 0xa7b1, 0xef63, 0x05c0, 0xe213, 0x443e, 0x4427, 0x2448}, + {0x258f, 0xf9ef, 0xe02b, 0x92dd, 0xd7f3, 0x252b, 0xa503, 0x9089, + 0xedff, 0x96c1, 0xfe3a, 0x3a39, 0x198a, 0x981d, 0x0627, 0xedb7}, + {0x595a, 0x45be, 0x8fb0, 0x2265, 0xc210, 0x02b8, 0xdce9, 0xe241, + 0xcab6, 0xbf0d, 0x0049, 0x8d9a, 0x2f51, 0xae54, 0x5785, 0xb411}}, + /* example doing 453 (f,g/2) steps; 514 divsteps */ + {{0x48f0, 0x7db3, 0xdafe, 0x1c92, 0x5912, 0xe11a, 0xab52, 0xede1, + 0x3182, 0x8980, 0x5d2b, 0x9b5b, 0x8718, 0xda27, 0x1683, 0x1de2}, + {0x168f, 0x6f36, 0xce7a, 0xf435, 0x19d4, 0xda5e, 0x2351, 0x9af5, + 0xb003, 0x0ef5, 0x3b4c, 0xecec, 0xa9f0, 0x78e1, 0xdfef, 0xe823}, + {0x5f55, 0xfdcc, 0xb233, 0x2914, 0x84f0, 0x97d1, 0x9cf4, 0x2159, + 0xbf56, 0xb79c, 0x17a3, 0x7cef, 0xd5de, 0x34f0, 0x5311, 0x4c54}}, + /* example doing 510 (f,(f+g)/2) steps; 512 divsteps */ + {{0x2789, 0x2e04, 0x6e0e, 0xb6cd, 0xe4de, 0x4dbf, 0x228d, 0x7877, + 0xc335, 0x806b, 0x38cd, 0x8049, 0xa73b, 0xcfa2, 0x82f7, 0x9e19}, + {0xc08d, 0xb99d, 0xb8f3, 0x663d, 0xbbb3, 0x1284, 0x1485, 0x1d49, + 0xc98f, 0x9e78, 0x1588, 0x11e3, 0xd91a, 0xa2c7, 0xfff1, 0xc7b9}, + {0x1e1f, 0x411d, 0x7c49, 0x0d03, 0xe789, 0x2f8e, 0x5d55, 0xa95e, + 0x826e, 0x8de5, 0x52a0, 0x1abc, 0x4cd7, 0xd13a, 0x4395, 0x63e1}}, + /* example doing 510 (f,(f+g)/2) steps; 512 divsteps */ + {{0xd5a1, 0xf786, 0x555c, 0xb14b, 0x44ae, 0x535f, 0x4a49, 0xffc3, + 0xf497, 0x70d1, 0x57c8, 0xa933, 0xc85a, 0x1910, 0x75bf, 0x960b}, + {0xfe53, 0x5058, 0x496d, 0xfdff, 0x6fb8, 0x4100, 0x92bd, 0xe0c4, + 0xda89, 0xe0a4, 0x841b, 0x43d4, 0xa388, 0x957f, 0x99ca, 0x9abf}, + {0xe530, 0x05bc, 0xfeec, 0xfc7e, 0xbcd3, 0x1239, 0x54cb, 0x7042, + 0xbccb, 0x139e, 0x9076, 0x0203, 0x6068, 0x90c7, 0x1ddf, 0x488d}}, + /* example doing 228 (g,(g-f)/2) steps; 538 divsteps */ + {{0x9488, 0xe54b, 0x0e43, 0x81d2, 0x06e7, 0x4b66, 0x36d0, 0x53d6, + 0x2b68, 0x22ec, 0x3fa9, 0xc1a7, 0x9ad2, 0xa596, 0xb3ac, 0xdf42}, + {0xe31f, 0x0b28, 0x5f3b, 0xc1ff, 0x344c, 0xbf5f, 0xd2ec, 0x2936, + 0x9995, 0xdeb2, 0xae6c, 0x2852, 0xa2c6, 0xb306, 0x8120, 0xe305}, + {0xa56e, 0xfb98, 0x1537, 0x4d85, 0x619e, 0x866c, 0x3cd4, 0x779a, + 0xdd66, 0xa80d, 0xdc2f, 0xcae4, 0xc74c, 0x5175, 0xa65d, 0x605e}}, + /* example doing 228 (g,(g-f)/2) steps; 537 divsteps */ + {{0x8cd5, 0x376d, 0xd01b, 0x7176, 0x19ef, 0xcf09, 0x8403, 0x5e52, + 0x83c1, 0x44de, 0xb91e, 0xb33d, 0xe15c, 0x51e7, 0xbad8, 0x6359}, + {0x3b75, 0xf812, 0x5f9e, 0xa04e, 0x92d3, 0x226e, 0x540e, 0x7c9a, + 0x31c6, 0x46d2, 0x0b7b, 0xdb4a, 0xe662, 0x4950, 0x0265, 0xf76f}, + {0x09ed, 0x692f, 0xe8f1, 0x3482, 0xab54, 0x36b4, 0x8442, 0x6ae9, + 0x4329, 0x6505, 0x183b, 0x1c1d, 0x482d, 0x7d63, 0xb44f, 0xcc09}}, + + /* Test cases with the group order as modulus. */ + + /* Test case with the group order as modulus, needing 635 divsteps. */ + {{0x95ed, 0x6c01, 0xd113, 0x5ff1, 0xd7d0, 0x29cc, 0x5817, 0x6120, + 0xca8e, 0xaad1, 0x25ae, 0x8e84, 0x9af6, 0x30bf, 0xf0ed, 0x1686}, + {0x4141, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x1631, 0xbf4a, 0x286a, 0x2716, 0x469f, 0x2ac8, 0x1312, 0xe9bc, + 0x04f4, 0x304b, 0x9931, 0x113b, 0xd932, 0xc8f4, 0x0d0d, 0x01a1}}, + /* example with group size as modulus needing 631 divsteps */ + {{0x85ed, 0xc284, 0x9608, 0x3c56, 0x19b6, 0xbb5b, 0x2850, 0xdab7, + 0xa7f5, 0xe9ab, 0x06a4, 0x5bbb, 0x1135, 0xa186, 0xc424, 0xc68b}, + {0x4141, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x8479, 0x450a, 0x8fa3, 0xde05, 0xb2f5, 0x7793, 0x7269, 0xbabb, + 0xc3b3, 0xd49b, 0x3377, 0x03c6, 0xe694, 0xc760, 0xd3cb, 0x2811}}, + /* example with group size as modulus needing 565 divsteps starting at delta=1/2 */ + {{0x8432, 0x5ceb, 0xa847, 0x6f1e, 0x51dd, 0x535a, 0x6ddc, 0x70ce, + 0x6e70, 0xc1f6, 0x18f2, 0x2a7e, 0xc8e7, 0x39f8, 0x7e96, 0xebbf}, + {0x4141, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x257e, 0x449f, 0x689f, 0x89aa, 0x3989, 0xb661, 0x376c, 0x1e32, + 0x654c, 0xee2e, 0xf4e2, 0x33c8, 0x3f2f, 0x9716, 0x6046, 0xcaa3}}, + /* Test case with the group size as modulus, needing 981 divsteps with + broken eta handling. */ + {{0xfeb9, 0xb877, 0xee41, 0x7fa3, 0x87da, 0x94c4, 0x9d04, 0xc5ae, + 0x5708, 0x0994, 0xfc79, 0x0916, 0xbf32, 0x3ad8, 0xe11c, 0x5ca2}, + {0x4141, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x0f12, 0x075e, 0xce1c, 0x6f92, 0xc80f, 0xca92, 0x9a04, 0x6126, + 0x4b6c, 0x57d6, 0xca31, 0x97f3, 0x1f99, 0xf4fd, 0xda4d, 0x42ce}}, + /* Test case with the group size as modulus, input = 0. */ + {{0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}, + {0x4141, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}}, + /* Test case with the group size as modulus, input = 1. */ + {{0x0001, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}, + {0x4141, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x0001, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}}, + /* Test case with the group size as modulus, input = 2. */ + {{0x0002, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}, + {0x4141, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x20a1, 0x681b, 0x2f46, 0xdfe9, 0x501d, 0x57a4, 0x6e73, 0x5d57, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x7fff}}, + /* Test case with the group size as modulus, input = group - 1. */ + {{0x4140, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x4141, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x4140, 0xd036, 0x5e8c, 0xbfd2, 0xa03b, 0xaf48, 0xdce6, 0xbaae, + 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}}, + + /* Test cases with the field size as modulus. */ + + /* Test case with the field size as modulus, needing 637 divsteps. */ + {{0x9ec3, 0x1919, 0xca84, 0x7c11, 0xf996, 0x06f3, 0x5408, 0x6688, + 0x1320, 0xdb8a, 0x632a, 0x0dcb, 0x8a84, 0x6bee, 0x9c95, 0xe34e}, + {0xfc2f, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x18e5, 0x19b6, 0xdf92, 0x1aaa, 0x09fb, 0x8a3f, 0x52b0, 0x8701, + 0xac0c, 0x2582, 0xda44, 0x9bcc, 0x6828, 0x1c53, 0xbd8f, 0xbd2c}}, + /* example with field size as modulus needing 637 divsteps */ + {{0xaec3, 0xa7cf, 0x2f2d, 0x0693, 0x5ad5, 0xa8ff, 0x7ec7, 0x30ff, + 0x0c8b, 0xc242, 0xcab2, 0x063a, 0xf86e, 0x6057, 0x9cbd, 0xf6d8}, + {0xfc2f, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x0310, 0x579d, 0xcb38, 0x9030, 0x3ded, 0x9bb9, 0x1234, 0x63ce, + 0x0c63, 0x8e3d, 0xacfe, 0x3c20, 0xdc85, 0xf859, 0x919e, 0x1d45}}, + /* example with field size as modulus needing 564 divsteps starting at delta=1/2 */ + {{0x63ae, 0x8d10, 0x0071, 0xdb5c, 0xb454, 0x78d1, 0x744a, 0x5f8e, + 0xe4d8, 0x87b1, 0x8e62, 0x9590, 0xcede, 0xa070, 0x36b4, 0x7f6f}, + {0xfc2f, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0xfdc8, 0xe8d5, 0xbe15, 0x9f86, 0xa5fe, 0xf18e, 0xa7ff, 0xd291, + 0xf4c2, 0x9c87, 0xf150, 0x073e, 0x69b8, 0xf7c4, 0xee4b, 0xc7e6}}, + /* Test case with the field size as modulus, needing 935 divsteps with + broken eta handling. */ + {{0x1b37, 0xbdc3, 0x8bcd, 0x25e3, 0x1eae, 0x567d, 0x30b6, 0xf0d8, + 0x9277, 0x0cf8, 0x9c2e, 0xecd7, 0x631d, 0xe38f, 0xd4f8, 0x5c93}, + {0xfc2f, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x1622, 0xe05b, 0xe880, 0x7de9, 0x3e45, 0xb682, 0xee6c, 0x67ed, + 0xa179, 0x15db, 0x6b0d, 0xa656, 0x7ccb, 0x8ef7, 0xa2ff, 0xe279}}, + /* Test case with the field size as modulus, input = 0. */ + {{0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}, + {0xfc2f, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}}, + /* Test case with the field size as modulus, input = 1. */ + {{0x0001, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}, + {0xfc2f, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0x0001, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}}, + /* Test case with the field size as modulus, input = 2. */ + {{0x0002, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000}, + {0xfc2f, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0xfe18, 0x7fff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x7fff}}, + /* Test case with the field size as modulus, input = field - 1. */ + {{0xfc2e, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0xfc2f, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, + {0xfc2e, 0xffff, 0xfffe, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, + 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}}, + + /* Selected from a large number of random inputs to reach small/large + * d/e values in various configurations. */ + {{0x3a08, 0x23e1, 0x4d8c, 0xe606, 0x3263, 0x67af, 0x9bf1, 0x9d70, + 0xf5fd, 0x12e4, 0x03c8, 0xb9ca, 0xe847, 0x8c5d, 0x6322, 0xbd30}, + {0x8359, 0x59dd, 0x1831, 0x7c1a, 0x1e83, 0xaee1, 0x770d, 0xcea8, + 0xfbb1, 0xeed6, 0x10b5, 0xe2c6, 0x36ea, 0xee17, 0xe32c, 0xffff}, + {0x1727, 0x0f36, 0x6f85, 0x5d0c, 0xca6c, 0x3072, 0x9628, 0x5842, + 0xcb44, 0x7c2b, 0xca4f, 0x62e5, 0x29b1, 0x6ffd, 0x9055, 0xc196}}, + {{0x905d, 0x41c8, 0xa2ff, 0x295b, 0x72bb, 0x4679, 0x6d01, 0x2c98, + 0xb3e0, 0xc537, 0xa310, 0xe07e, 0xe72f, 0x4999, 0x1148, 0xf65e}, + {0x5b41, 0x4239, 0x3c37, 0x5130, 0x30e3, 0xff35, 0xc51f, 0x1a43, + 0xdb23, 0x13cf, 0x9f49, 0xf70c, 0x5e70, 0xd411, 0x3005, 0xf8c6}, + {0xc30e, 0x68f0, 0x201a, 0xe10c, 0x864a, 0x6243, 0xe946, 0x43ae, + 0xf3f1, 0x52dc, 0x1f7f, 0x50d4, 0x2797, 0x064c, 0x5ca4, 0x90e3}}, + {{0xf1b5, 0xc6e5, 0xd2c4, 0xff95, 0x27c5, 0x0c92, 0x5d19, 0x7ae5, + 0x4fbe, 0x5438, 0x99e1, 0x880d, 0xd892, 0xa05c, 0x6ffd, 0x7eac}, + {0x2153, 0xcc9d, 0xfc6c, 0x8358, 0x49a1, 0x01e2, 0xcef0, 0x4969, + 0xd69a, 0x8cef, 0xf5b2, 0xfd95, 0xdcc2, 0x71f4, 0x6ae2, 0xceeb}, + {0x9b2e, 0xcdc6, 0x0a5c, 0x7317, 0x9084, 0xe228, 0x56cf, 0xd512, + 0x628a, 0xce21, 0x3473, 0x4e13, 0x8823, 0x1ed0, 0x34d0, 0xbfa3}}, + {{0x5bae, 0x53e5, 0x5f4d, 0x21ca, 0xb875, 0x8ecf, 0x9aa6, 0xbe3c, + 0x9f96, 0x7b82, 0x375d, 0x4d3e, 0x491c, 0xb1eb, 0x04c9, 0xb6c8}, + {0xfcfd, 0x10b7, 0x73b2, 0xd23b, 0xa357, 0x67da, 0x0d9f, 0x8702, + 0xa037, 0xff8e, 0x0e8b, 0x1801, 0x2c5c, 0x4e6e, 0x4558, 0xfff2}, + {0xc50f, 0x5654, 0x6713, 0x5ef5, 0xa7ce, 0xa647, 0xc832, 0x69ce, + 0x1d5c, 0x4310, 0x0746, 0x5a01, 0x96ea, 0xde4b, 0xa88b, 0x5543}}, + {{0xdc7f, 0x5e8c, 0x89d1, 0xb077, 0xd521, 0xcf90, 0x32fa, 0x5737, + 0x839e, 0x1464, 0x007c, 0x09c6, 0x9371, 0xe8ea, 0xc1cb, 0x75c4}, + {0xe3a3, 0x107f, 0xa82a, 0xa375, 0x4578, 0x60f4, 0x75c9, 0x5ee4, + 0x3fd7, 0x2736, 0x2871, 0xd3d2, 0x5f1d, 0x1abb, 0xa764, 0xffff}, + {0x45c6, 0x1f2e, 0xb14c, 0x84d7, 0x7bb7, 0x5a04, 0x0504, 0x3f33, + 0x5cc1, 0xb07a, 0x6a6c, 0x786f, 0x647f, 0xe1d7, 0x78a2, 0x4cf4}}, + {{0xc006, 0x356f, 0x8cd2, 0x967b, 0xb49e, 0x2d4e, 0x14bf, 0x4bcb, + 0xddab, 0xd3f9, 0xa068, 0x2c1c, 0xd242, 0xa56d, 0xf2c7, 0x5f97}, + {0x465b, 0xb745, 0x0e0d, 0x69a9, 0x987d, 0xcb37, 0xf637, 0xb311, + 0xc4d6, 0x2ddb, 0xf68f, 0x2af9, 0x959d, 0x3f53, 0x98f2, 0xf640}, + {0xc0f2, 0x6bfb, 0xf5c3, 0x91c1, 0x6b05, 0x0825, 0x5ca0, 0x7df7, + 0x9d55, 0x6d9e, 0xfe94, 0x2ad9, 0xd9f0, 0xe68b, 0xa72b, 0xd1b2}}, + {{0x2279, 0x61ba, 0x5bc6, 0x136b, 0xf544, 0x717c, 0xafda, 0x02bd, + 0x79af, 0x1fad, 0xea09, 0x81bb, 0x932b, 0x32c9, 0xdf1d, 0xe576}, + {0x8215, 0x7817, 0xca82, 0x43b0, 0x9b06, 0xea65, 0x1291, 0x0621, + 0x0089, 0x46fe, 0xc5a6, 0xddd7, 0x8065, 0xc6a0, 0x214b, 0xfc64}, + {0x04bf, 0x6f2a, 0x86b2, 0x841a, 0x4a95, 0xc632, 0x97b7, 0x5821, + 0x2b18, 0x1bb0, 0x3e97, 0x935e, 0xcc7d, 0x066b, 0xd513, 0xc251}}, + {{0x76e8, 0x5bc2, 0x3eaa, 0x04fc, 0x9974, 0x92c1, 0x7c15, 0xfa89, + 0x1151, 0x36ee, 0x48b2, 0x049c, 0x5f16, 0xcee4, 0x925b, 0xe98e}, + {0x913f, 0x0a2d, 0xa185, 0x9fea, 0xda5a, 0x4025, 0x40d7, 0x7cfa, + 0x88ca, 0xbbe8, 0xb265, 0xb7e4, 0x6cb1, 0xed64, 0xc6f9, 0xffb5}, + {0x6ab1, 0x1a86, 0x5009, 0x152b, 0x1cc4, 0xe2c8, 0x960b, 0x19d0, + 0x3554, 0xc562, 0xd013, 0xcf91, 0x10e1, 0x7933, 0xe195, 0xcf49}}, + {{0x9cb5, 0xd2d7, 0xc6ed, 0xa818, 0xb495, 0x06ee, 0x0f4a, 0x06e3, + 0x4c5a, 0x80ce, 0xd49a, 0x4cd7, 0x7487, 0x92af, 0xe516, 0x676c}, + {0xd6e9, 0x6b85, 0x619a, 0xb52c, 0x20a0, 0x2f79, 0x3545, 0x1edd, + 0x5a6f, 0x8082, 0x9b80, 0xf8f8, 0xc78a, 0xd0a3, 0xadf4, 0xffff}, + {0x01c2, 0x2118, 0xef5e, 0xa877, 0x046a, 0xd2c2, 0x2ad5, 0x951c, + 0x8900, 0xa5c9, 0x8d0f, 0x6b61, 0x55d3, 0xd572, 0x48de, 0x9219}}, + {{0x5114, 0x0644, 0x23dd, 0x01d3, 0xc101, 0xa659, 0xea17, 0x640f, + 0xf767, 0x2644, 0x9cec, 0xd8ba, 0xd6da, 0x9156, 0x8aeb, 0x875a}, + {0xc1bf, 0xdae9, 0xe96b, 0xce77, 0xf7a1, 0x3e99, 0x5c2e, 0x973b, + 0xd048, 0x5bd0, 0x4e8a, 0xcb85, 0xce39, 0x37f5, 0x815d, 0xffff}, + {0x48cc, 0x35b6, 0x26d4, 0x2ea6, 0x50d6, 0xa2f9, 0x64b6, 0x03bf, + 0xd00c, 0xe057, 0x3343, 0xfb79, 0x3ce5, 0xf717, 0xc5af, 0xe185}}, + {{0x13ff, 0x6c76, 0x2077, 0x16e0, 0xd5ca, 0xf2ad, 0x8dba, 0x8f49, + 0x7887, 0x16f9, 0xb646, 0xfc87, 0xfa31, 0x5096, 0xf08c, 0x3fbe}, + {0x8139, 0x6fd7, 0xf6df, 0xa7bf, 0x6699, 0x5361, 0x6f65, 0x13c8, + 0xf4d1, 0xe28f, 0xc545, 0x0a8c, 0x5274, 0xb0a6, 0xffff, 0xffff}, + {0x22ca, 0x0cd6, 0xc1b5, 0xb064, 0x44a7, 0x297b, 0x495f, 0x34ac, + 0xfa95, 0xec62, 0xf08d, 0x621c, 0x66a6, 0xba94, 0x84c6, 0x8ee0}}, + {{0xaa30, 0x312e, 0x439c, 0x4e88, 0x2e2f, 0x32dc, 0xb880, 0xa28e, + 0xf795, 0xc910, 0xb406, 0x8dd7, 0xb187, 0xa5a5, 0x38f1, 0xe49e}, + {0xfb19, 0xf64a, 0xba6a, 0x8ec2, 0x7255, 0xce89, 0x2cf9, 0x9cba, + 0xe1fe, 0x50da, 0x1705, 0xac52, 0xe3d4, 0x4269, 0x0648, 0xfd77}, + {0xb4c8, 0x6e8a, 0x2b5f, 0x4c2d, 0x5a67, 0xa7bb, 0x7d6d, 0x5569, + 0xa0ea, 0x244a, 0xc0f2, 0xf73d, 0x58cf, 0xac7f, 0xd32b, 0x3018}}, + {{0xc953, 0x1ae1, 0xae46, 0x8709, 0x19c2, 0xa986, 0x9abe, 0x1611, + 0x0395, 0xd5ab, 0xf0f6, 0xb5b0, 0x5b2b, 0x0317, 0x80ba, 0x376d}, + {0xfe77, 0xbc03, 0xac2f, 0x9d00, 0xa175, 0x293d, 0x3b56, 0x0e3a, + 0x0a9c, 0xf40c, 0x690e, 0x1508, 0x95d4, 0xddc4, 0xe805, 0xffff}, + {0xb1ce, 0x0929, 0xa5fe, 0x4b50, 0x9d5d, 0x8187, 0x2557, 0x4376, + 0x11ba, 0xdcef, 0xc1f3, 0xd531, 0x1824, 0x93f6, 0xd81f, 0x8f83}}, + {{0xb8d2, 0xb900, 0x4a0c, 0x7188, 0xa5bf, 0x1b0b, 0x2ae5, 0xa35b, + 0x98e0, 0x610c, 0x86db, 0x2487, 0xa267, 0x002c, 0xebb6, 0xc5f4}, + {0x9cdd, 0x1c1b, 0x2f06, 0x43d1, 0xce47, 0xc334, 0x6e60, 0xc016, + 0x989e, 0x0ab2, 0x0cac, 0x1196, 0xe2d9, 0x2e04, 0xc62b, 0xffff}, + {0xdc36, 0x1f05, 0x6aa9, 0x7a20, 0x944f, 0x2fd3, 0xa553, 0xdb4f, + 0xbd5c, 0x3a75, 0x25d4, 0xe20e, 0xa387, 0x1410, 0xdbb1, 0x1b60}}, + {{0x76b3, 0x2207, 0x4930, 0x5dd7, 0x65a0, 0xd55c, 0xb443, 0x53b7, + 0x5c22, 0x818a, 0xb2e7, 0x9de8, 0x9985, 0xed45, 0x33b1, 0x53e8}, + {0x7913, 0x44e1, 0xf15b, 0x5edd, 0x34f3, 0x4eba, 0x0758, 0x7104, + 0x32d9, 0x28f3, 0x4401, 0x85c5, 0xb695, 0xb899, 0xc0f2, 0xffff}, + {0x7f43, 0xd202, 0x24c9, 0x69f3, 0x74dc, 0x1a69, 0xeaee, 0x5405, + 0x1755, 0x4bb8, 0x04e3, 0x2fd2, 0xada8, 0x39eb, 0x5b4d, 0x96ca}}, + {{0x807b, 0x7112, 0xc088, 0xdafd, 0x02fa, 0x9d95, 0x5e42, 0xc033, + 0xde0a, 0xeecf, 0x8e90, 0x8da1, 0xb17e, 0x9a5b, 0x4c6d, 0x1914}, + {0x4871, 0xd1cb, 0x47d7, 0x327f, 0x09ec, 0x97bb, 0x2fae, 0xd346, + 0x6b78, 0x3707, 0xfeb2, 0xa6ab, 0x13df, 0x76b0, 0x8fb9, 0xffb3}, + {0x179e, 0xb63b, 0x4784, 0x231e, 0x9f42, 0x7f1a, 0xa3fb, 0xdd8c, + 0xd1eb, 0xb4c9, 0x8ca7, 0x018c, 0xf691, 0x576c, 0xa7d6, 0xce27}}, + {{0x5f45, 0x7c64, 0x083d, 0xedd5, 0x08a0, 0x0c64, 0x6c6f, 0xec3c, + 0xe2fb, 0x352c, 0x9303, 0x75e4, 0xb4e0, 0x8b09, 0xaca4, 0x7025}, + {0x1025, 0xb482, 0xfed5, 0xa678, 0x8966, 0x9359, 0x5329, 0x98bb, + 0x85b2, 0x73ba, 0x9982, 0x6fdc, 0xf190, 0xbe8c, 0xdc5c, 0xfd93}, + {0x83a2, 0x87a4, 0xa680, 0x52a1, 0x1ba1, 0x8848, 0x5db7, 0x9744, + 0x409c, 0x0745, 0x0e1e, 0x1cfc, 0x00cd, 0xf573, 0x2071, 0xccaa}}, + {{0xf61f, 0x63d4, 0x536c, 0x9eb9, 0x5ddd, 0xbb11, 0x9014, 0xe904, + 0xfe01, 0x6b45, 0x1858, 0xcb5b, 0x4c38, 0x43e1, 0x381d, 0x7f94}, + {0xf61f, 0x63d4, 0xd810, 0x7ca3, 0x8a04, 0x4b83, 0x11fc, 0xdf94, + 0x4169, 0xbd05, 0x608e, 0x7151, 0x4fbf, 0xb31a, 0x38a7, 0xa29b}, + {0xe621, 0xdfa5, 0x3d06, 0x1d03, 0x81e6, 0x00da, 0x53a6, 0x965e, + 0x93e5, 0x2164, 0x5b61, 0x59b8, 0xa629, 0x8d73, 0x699a, 0x6111}}, + {{0x4cc3, 0xd29e, 0xf4a3, 0x3428, 0x2048, 0xeec9, 0x5f50, 0x99a4, + 0x6de9, 0x05f2, 0x5aa9, 0x5fd2, 0x98b4, 0x1adc, 0x225f, 0x777f}, + {0xe649, 0x37da, 0x5ba6, 0x5765, 0x3f4a, 0x8a1c, 0x2e79, 0xf550, + 0x1a54, 0xcd1e, 0x7218, 0x3c3c, 0x6311, 0xfe28, 0x95fb, 0xed97}, + {0xe9b6, 0x0c47, 0x3f0e, 0x849b, 0x11f8, 0xe599, 0x5e4d, 0xd618, + 0xa06d, 0x33a0, 0x9a3e, 0x44db, 0xded8, 0x10f0, 0x94d2, 0x81fb}}, + {{0x2e59, 0x7025, 0xd413, 0x455a, 0x1ce3, 0xbd45, 0x7263, 0x27f7, + 0x23e3, 0x518e, 0xbe06, 0xc8c4, 0xe332, 0x4276, 0x68b4, 0xb166}, + {0x596f, 0x0cf6, 0xc8ec, 0x787b, 0x04c1, 0x473c, 0xd2b8, 0x8d54, + 0x9cdf, 0x77f2, 0xd3f3, 0x6735, 0x0638, 0xf80e, 0x9467, 0xc6aa}, + {0xc7e7, 0x1822, 0xb62a, 0xec0d, 0x89cd, 0x7846, 0xbfa2, 0x35d5, + 0xfa38, 0x870f, 0x494b, 0x1697, 0x8b17, 0xf904, 0x10b6, 0x9822}}, + {{0x6d5b, 0x1d4f, 0x0aaf, 0x807b, 0x35fb, 0x7ee8, 0x00c6, 0x059a, + 0xddf0, 0x1fb1, 0xc38a, 0xd78e, 0x2aa4, 0x79e7, 0xad28, 0xc3f1}, + {0xe3bb, 0x174e, 0xe0a8, 0x74b6, 0xbd5b, 0x35f6, 0x6d23, 0x6328, + 0xc11f, 0x83e1, 0xf928, 0xa918, 0x838e, 0xbf43, 0xe243, 0xfffb}, + {0x9cf2, 0x6b8b, 0x3476, 0x9d06, 0xdcf2, 0xdb8a, 0x89cd, 0x4857, + 0x75c2, 0xabb8, 0x490b, 0xc9bd, 0x890e, 0xe36e, 0xd552, 0xfffa}}, + {{0x2f09, 0x9d62, 0xa9fc, 0xf090, 0xd6d1, 0x9d1d, 0x1828, 0xe413, + 0xc92b, 0x3d5a, 0x1373, 0x368c, 0xbaf2, 0x2158, 0x71eb, 0x08a3}, + {0x2f09, 0x1d62, 0x4630, 0x0de1, 0x06dc, 0xf7f1, 0xc161, 0x1e92, + 0x7495, 0x97e4, 0x94b6, 0xa39e, 0x4f1b, 0x18f8, 0x7bd4, 0x0c4c}, + {0xeb3d, 0x723d, 0x0907, 0x525b, 0x463a, 0x49a8, 0xc6b8, 0xce7f, + 0x740c, 0x0d7d, 0xa83b, 0x457f, 0xae8e, 0xc6af, 0xd331, 0x0475}}, + {{0x6abd, 0xc7af, 0x3e4e, 0x95fd, 0x8fc4, 0xee25, 0x1f9c, 0x0afe, + 0x291d, 0xcde0, 0x48f4, 0xb2e8, 0xf7af, 0x8f8d, 0x0bd6, 0x078d}, + {0x4037, 0xbf0e, 0x2081, 0xf363, 0x13b2, 0x381e, 0xfb6e, 0x818e, + 0x27e4, 0x5662, 0x18b0, 0x0cd2, 0x81f5, 0x9415, 0x0d6c, 0xf9fb}, + {0xd205, 0x0981, 0x0498, 0x1f08, 0xdb93, 0x1732, 0x0579, 0x1424, + 0xad95, 0x642f, 0x050c, 0x1d6d, 0xfc95, 0xfc4a, 0xd41b, 0x3521}}, + {{0xf23a, 0x4633, 0xaef4, 0x1a92, 0x3c8b, 0x1f09, 0x30f3, 0x4c56, + 0x2a2f, 0x4f62, 0xf5e4, 0x8329, 0x63cc, 0xb593, 0xec6a, 0xc428}, + {0x93a7, 0xfcf6, 0x606d, 0xd4b2, 0x2aad, 0x28b4, 0xc65b, 0x8998, + 0x4e08, 0xd178, 0x0900, 0xc82b, 0x7470, 0xa342, 0x7c0f, 0xffff}, + {0x315f, 0xf304, 0xeb7b, 0xe5c3, 0x1451, 0x6311, 0x8f37, 0x93a8, + 0x4a38, 0xa6c6, 0xe393, 0x1087, 0x6301, 0xd673, 0x4ec4, 0xffff}}, + {{0x892e, 0xeed0, 0x1165, 0xcbc1, 0x5545, 0xa280, 0x7243, 0x10c9, + 0x9536, 0x36af, 0xb3fc, 0x2d7c, 0xe8a5, 0x09d6, 0xe1d4, 0xe85d}, + {0xae09, 0xc28a, 0xd777, 0xbd80, 0x23d6, 0xf980, 0xeb7c, 0x4e0e, + 0xf7dc, 0x6475, 0xf10a, 0x2d33, 0x5dfd, 0x797a, 0x7f1c, 0xf71a}, + {0x4064, 0x8717, 0xd091, 0x80b0, 0x4527, 0x8442, 0xac8b, 0x9614, + 0xc633, 0x35f5, 0x7714, 0x2e83, 0x4aaa, 0xd2e4, 0x1acd, 0x0562}}, + {{0xdb64, 0x0937, 0x308b, 0x53b0, 0x00e8, 0xc77f, 0x2f30, 0x37f7, + 0x79ce, 0xeb7f, 0xde81, 0x9286, 0xafda, 0x0e62, 0xae00, 0x0067}, + {0x2cc7, 0xd362, 0xb161, 0x0557, 0x4ff2, 0xb9c8, 0x06fe, 0x5f2b, + 0xde33, 0x0190, 0x28c6, 0xb886, 0xee2b, 0x5a4e, 0x3289, 0x0185}, + {0x4215, 0x923e, 0xf34f, 0xb362, 0x88f8, 0xceec, 0xafdd, 0x7f42, + 0x0c57, 0x56b2, 0xa366, 0x6a08, 0x0826, 0xfb8f, 0x1b03, 0x0163}}, + {{0xa4ba, 0x8408, 0x810a, 0xdeba, 0x47a3, 0x853a, 0xeb64, 0x2f74, + 0x3039, 0x038c, 0x7fbb, 0x498e, 0xd1e9, 0x46fb, 0x5691, 0x32a4}, + {0xd749, 0xb49d, 0x20b7, 0x2af6, 0xd34a, 0xd2da, 0x0a10, 0xf781, + 0x58c9, 0x171f, 0x3cb6, 0x6337, 0x88cd, 0xcf1e, 0xb246, 0x7351}, + {0xf729, 0xcf0a, 0x96ea, 0x032c, 0x4a8f, 0x42fe, 0xbac8, 0xec65, + 0x1510, 0x0d75, 0x4c17, 0x8d29, 0xa03f, 0x8b7e, 0x2c49, 0x0000}}, + {{0x0fa4, 0x8e1c, 0x3788, 0xba3c, 0x8d52, 0xd89d, 0x12c8, 0xeced, + 0x9fe6, 0x9b88, 0xecf3, 0xe3c8, 0xac48, 0x76ed, 0xf23e, 0xda79}, + {0x1103, 0x227c, 0x5b00, 0x3fcf, 0xc5d0, 0x2d28, 0x8020, 0x4d1c, + 0xc6b9, 0x67f9, 0x6f39, 0x989a, 0xda53, 0x3847, 0xd416, 0xe0d0}, + {0xdd8e, 0xcf31, 0x3710, 0x7e44, 0xa511, 0x933c, 0x0cc3, 0x5145, + 0xf632, 0x5e1d, 0x038f, 0x5ce7, 0x7265, 0xda9d, 0xded6, 0x08f8}}, + {{0xe2c8, 0x91d5, 0xa5f5, 0x735f, 0x6b58, 0x56dc, 0xb39d, 0x5c4a, + 0x57d0, 0xa1c2, 0xd92f, 0x9ad4, 0xf7c4, 0x51dd, 0xaf5c, 0x0096}, + {0x1739, 0x7207, 0x7505, 0xbf35, 0x42de, 0x0a29, 0xa962, 0xdedf, + 0x53e8, 0x12bf, 0xcde7, 0xd8e2, 0x8d4d, 0x2c4b, 0xb1b1, 0x0628}, + {0x992d, 0xe3a7, 0xb422, 0xc198, 0x23ab, 0xa6ef, 0xb45d, 0x50da, + 0xa738, 0x014a, 0x2310, 0x85fb, 0x5fe8, 0x1b18, 0x1774, 0x03a7}}, + {{0x1f16, 0x2b09, 0x0236, 0xee90, 0xccf9, 0x9775, 0x8130, 0x4c91, + 0x9091, 0x310b, 0x6dc4, 0x86f6, 0xc2e8, 0xef60, 0xfc0e, 0xf3a4}, + {0x9f49, 0xac15, 0x02af, 0x110f, 0xc59d, 0x5677, 0xa1a9, 0x38d5, + 0x914f, 0xa909, 0x3a3a, 0x4a39, 0x3703, 0xea30, 0x73da, 0xffad}, + {0x15ed, 0xdd16, 0x83c7, 0x270a, 0x862f, 0xd8ad, 0xcaa1, 0x5f41, + 0x99a9, 0x3fc8, 0x7bb2, 0x360a, 0xb06d, 0xfadc, 0x1b36, 0xffa8}}, + {{0xc4e0, 0xb8fd, 0x5106, 0xe169, 0x754c, 0xa58c, 0xc413, 0x8224, + 0x5483, 0x63ec, 0xd477, 0x8473, 0x4778, 0x9281, 0x0000, 0x0000}, + {0x85e1, 0xff54, 0xb200, 0xe413, 0xf4f4, 0x4c0f, 0xfcec, 0xc183, + 0x60d3, 0x1b0c, 0x3834, 0x601c, 0x943c, 0xbe6e, 0x0002, 0x0000}, + {0xf4f8, 0xfd5e, 0x61ef, 0xece8, 0x9199, 0xe5c4, 0x05a6, 0xe6c3, + 0xc4ae, 0x8b28, 0x66b1, 0x8a95, 0x9ece, 0x8f4a, 0x0001, 0x0000}}, + {{0xeae9, 0xa1b4, 0xc6d8, 0x2411, 0x2b5a, 0x1dd0, 0x2dc9, 0xb57b, + 0x5ccd, 0x4957, 0xaf59, 0xa04b, 0x5f42, 0xab7c, 0x2826, 0x526f}, + {0xf407, 0x165a, 0xb724, 0x2f12, 0x2ea1, 0x470b, 0x4464, 0xbd35, + 0x606f, 0xd73e, 0x50d3, 0x8a7f, 0x8029, 0x7ffc, 0xbe31, 0x6cfb}, + {0x8171, 0x1f4c, 0xced2, 0x9c99, 0x6d7e, 0x5a0f, 0xfefb, 0x59e3, + 0xa0c8, 0xabd9, 0xc4c5, 0x57d3, 0xbfa3, 0x4f11, 0x96a2, 0x5a7d}}, + {{0xe068, 0x4cc0, 0x8bcd, 0xc903, 0x9e52, 0xb3e1, 0xd745, 0x0995, + 0xdd8f, 0xf14b, 0xd2ac, 0xd65a, 0xda1d, 0xa742, 0xbac5, 0x474c}, + {0x7481, 0xf2ad, 0x9757, 0x2d82, 0xb683, 0xb16b, 0x0002, 0x7b60, + 0x8f0c, 0x2594, 0x8f64, 0x3b7a, 0x3552, 0x8d9d, 0xb9d7, 0x67eb}, + {0xcaab, 0xb9a1, 0xf966, 0xe311, 0x5b34, 0x0fa0, 0x6abc, 0x8134, + 0xab3d, 0x90f6, 0x1984, 0x9232, 0xec17, 0x74e5, 0x2ceb, 0x434e}}, + {{0x0fb1, 0x7a55, 0x1a5c, 0x53eb, 0xd7b3, 0x7a01, 0xca32, 0x31f6, + 0x3b74, 0x679e, 0x1501, 0x6c57, 0xdb20, 0x8b7c, 0xd7d0, 0x8097}, + {0xb127, 0xb20c, 0xe3a2, 0x96f3, 0xe0d8, 0xd50c, 0x14b4, 0x0b40, + 0x6eeb, 0xa258, 0x99db, 0x3c8c, 0x0f51, 0x4198, 0x3887, 0xffd0}, + {0x0273, 0x9f8c, 0x9669, 0xbbba, 0x1c49, 0x767c, 0xc2af, 0x59f0, + 0x1366, 0xd397, 0x63ac, 0x6fe8, 0x1a9a, 0x1259, 0x01d0, 0x0016}}, + {{0x7876, 0x2a35, 0xa24a, 0x433e, 0x5501, 0x573c, 0xd76d, 0xcb82, + 0x1334, 0xb4a6, 0xf290, 0xc797, 0xeae9, 0x2b83, 0x1e2b, 0x8b14}, + {0x3885, 0x8aef, 0x9dea, 0x2b8c, 0xdd7c, 0xd7cd, 0xb0cc, 0x05ee, + 0x361b, 0x3800, 0xb0d4, 0x4c23, 0xbd3f, 0x5180, 0x9783, 0xff80}, + {0xab36, 0x3104, 0xdae8, 0x0704, 0x4a28, 0x6714, 0x824b, 0x0051, + 0x8134, 0x1f6a, 0x712d, 0x1f03, 0x03b2, 0xecac, 0x377d, 0xfef9}} + }; + + int i, j, ok; + + /* Test known inputs/outputs */ + for (i = 0; (size_t)i < sizeof(CASES) / sizeof(CASES[0]); ++i) { + uint16_t out[16]; + test_modinv32_uint16(out, CASES[i][0], CASES[i][1]); + for (j = 0; j < 16; ++j) CHECK(out[j] == CASES[i][2][j]); +#ifdef SECP256K1_WIDEMUL_INT128 + test_modinv64_uint16(out, CASES[i][0], CASES[i][1]); + for (j = 0; j < 16; ++j) CHECK(out[j] == CASES[i][2][j]); #endif + } + + for (i = 0; i < 100 * count; ++i) { + /* 256-bit numbers in 16-uint16_t's notation */ + static const uint16_t ZERO[16] = {0}; + uint16_t xd[16]; /* the number (in range [0,2^256)) to be inverted */ + uint16_t md[16]; /* the modulus (odd, in range [3,2^256)) */ + uint16_t id[16]; /* the inverse of xd mod md */ + + /* generate random xd and md, so that md is odd, md>1, xd 0)); - secp256k1_scalar_negate(&neg, &s); - secp256k1_num_sub(&negnum, &order, &snum); - secp256k1_num_mod(&negnum, &order); - /* Check that comparison with the half order is equal to testing for high scalar after negation. */ - CHECK(secp256k1_scalar_is_high(&neg) == (secp256k1_num_cmp(&negnum, &half_order) > 0)); - /* Negating should change the high property, unless the value was already zero. */ - CHECK((secp256k1_scalar_is_high(&s) == secp256k1_scalar_is_high(&neg)) == secp256k1_scalar_is_zero(&s)); - secp256k1_scalar_get_num(&negnum2, &neg); - /* Negating a scalar should be equal to (order - n) mod order on the number. */ - CHECK(secp256k1_num_eq(&negnum, &negnum2)); - secp256k1_scalar_add(&neg, &neg, &s); - /* Adding a number to its negation should result in zero. */ - CHECK(secp256k1_scalar_is_zero(&neg)); - secp256k1_scalar_negate(&neg, &neg); - /* Negating zero should still result in zero. */ - CHECK(secp256k1_scalar_is_zero(&neg)); - } - - { - /* Test secp256k1_scalar_mul_shift_var. */ - secp256k1_scalar r; - secp256k1_num one; - secp256k1_num rnum; - secp256k1_num rnum2; - unsigned char cone[1] = {0x01}; - unsigned int shift = 256 + secp256k1_testrand_int(257); - secp256k1_scalar_mul_shift_var(&r, &s1, &s2, shift); - secp256k1_num_mul(&rnum, &s1num, &s2num); - secp256k1_num_shift(&rnum, shift - 1); - secp256k1_num_set_bin(&one, cone, 1); - secp256k1_num_add(&rnum, &rnum, &one); - secp256k1_num_shift(&rnum, 1); - secp256k1_scalar_get_num(&rnum2, &r); - CHECK(secp256k1_num_eq(&rnum, &rnum2)); - } - { /* test secp256k1_scalar_shr_int */ secp256k1_scalar r; @@ -955,34 +1618,6 @@ void scalar_test(void) { CHECK(expected == low); } } -#endif - - { - /* Test that scalar inverses are equal to the inverse of their number modulo the order. */ - if (!secp256k1_scalar_is_zero(&s)) { - secp256k1_scalar inv; -#ifndef USE_NUM_NONE - secp256k1_num invnum; - secp256k1_num invnum2; -#endif - secp256k1_scalar_inverse(&inv, &s); -#ifndef USE_NUM_NONE - secp256k1_num_mod_inverse(&invnum, &snum, &order); - secp256k1_scalar_get_num(&invnum2, &inv); - CHECK(secp256k1_num_eq(&invnum, &invnum2)); -#endif - secp256k1_scalar_mul(&inv, &inv, &s); - /* Multiplying a scalar with its inverse must result in one. */ - CHECK(secp256k1_scalar_is_one(&inv)); - secp256k1_scalar_inverse(&inv, &inv); - /* Inverting one must result in one. */ - CHECK(secp256k1_scalar_is_one(&inv)); -#ifndef USE_NUM_NONE - secp256k1_scalar_get_num(&invnum, &inv); - CHECK(secp256k1_num_is_one(&invnum)); -#endif - } - } { /* Test commutativity of add. */ @@ -1054,14 +1689,6 @@ void scalar_test(void) { CHECK(secp256k1_scalar_eq(&r1, &r2)); } - { - /* Test square. */ - secp256k1_scalar r1, r2; - secp256k1_scalar_sqr(&r1, &s1); - secp256k1_scalar_mul(&r2, &s1, &s1); - CHECK(secp256k1_scalar_eq(&r1, &r2)); - } - { /* Test multiplicative identity. */ secp256k1_scalar r1, v1; @@ -1126,48 +1753,6 @@ void run_scalar_tests(void) { CHECK(secp256k1_scalar_is_zero(&o)); } -#ifndef USE_NUM_NONE - { - /* Test secp256k1_scalar_set_b32 boundary conditions */ - secp256k1_num order; - secp256k1_scalar scalar; - unsigned char bin[32]; - unsigned char bin_tmp[32]; - int overflow = 0; - /* 2^256-1 - order */ - static const secp256k1_scalar all_ones_minus_order = SECP256K1_SCALAR_CONST( - 0x00000000UL, 0x00000000UL, 0x00000000UL, 0x00000001UL, - 0x45512319UL, 0x50B75FC4UL, 0x402DA173UL, 0x2FC9BEBEUL - ); - - /* A scalar set to 0s should be 0. */ - memset(bin, 0, 32); - secp256k1_scalar_set_b32(&scalar, bin, &overflow); - CHECK(overflow == 0); - CHECK(secp256k1_scalar_is_zero(&scalar)); - - /* A scalar with value of the curve order should be 0. */ - secp256k1_scalar_order_get_num(&order); - secp256k1_num_get_bin(bin, 32, &order); - secp256k1_scalar_set_b32(&scalar, bin, &overflow); - CHECK(overflow == 1); - CHECK(secp256k1_scalar_is_zero(&scalar)); - - /* A scalar with value of the curve order minus one should not overflow. */ - bin[31] -= 1; - secp256k1_scalar_set_b32(&scalar, bin, &overflow); - CHECK(overflow == 0); - secp256k1_scalar_get_b32(bin_tmp, &scalar); - CHECK(secp256k1_memcmp_var(bin, bin_tmp, 32) == 0); - - /* A scalar set to all 1s should overflow. */ - memset(bin, 0xFF, 32); - secp256k1_scalar_set_b32(&scalar, bin, &overflow); - CHECK(overflow == 1); - CHECK(secp256k1_scalar_eq(&scalar, &all_ones_minus_order)); - } -#endif - { /* Does check_overflow check catch all ones? */ static const secp256k1_scalar overflowed = SECP256K1_SCALAR_CONST( @@ -1190,9 +1775,7 @@ void run_scalar_tests(void) { secp256k1_scalar one; secp256k1_scalar r1; secp256k1_scalar r2; -#if defined(USE_SCALAR_INV_NUM) secp256k1_scalar zzv; -#endif int overflow; unsigned char chal[33][2][32] = { {{0xff, 0xff, 0x03, 0x07, 0x00, 0x00, 0x00, 0x00, @@ -1742,10 +2325,8 @@ void run_scalar_tests(void) { if (!secp256k1_scalar_is_zero(&y)) { secp256k1_scalar_inverse(&zz, &y); CHECK(!secp256k1_scalar_check_overflow(&zz)); -#if defined(USE_SCALAR_INV_NUM) secp256k1_scalar_inverse_var(&zzv, &y); CHECK(secp256k1_scalar_eq(&zzv, &zz)); -#endif secp256k1_scalar_mul(&z, &z, &zz); CHECK(!secp256k1_scalar_check_overflow(&z)); CHECK(secp256k1_scalar_eq(&x, &z)); @@ -1753,12 +2334,6 @@ void run_scalar_tests(void) { CHECK(!secp256k1_scalar_check_overflow(&zz)); CHECK(secp256k1_scalar_eq(&one, &zz)); } - secp256k1_scalar_mul(&z, &x, &x); - CHECK(!secp256k1_scalar_check_overflow(&z)); - secp256k1_scalar_sqr(&zz, &x); - CHECK(!secp256k1_scalar_check_overflow(&zz)); - CHECK(secp256k1_scalar_eq(&zz, &z)); - CHECK(secp256k1_scalar_eq(&r2, &zz)); } } } @@ -1814,13 +2389,6 @@ int check_fe_equal(const secp256k1_fe *a, const secp256k1_fe *b) { return secp256k1_fe_equal_var(&an, &bn); } -int check_fe_inverse(const secp256k1_fe *a, const secp256k1_fe *ai) { - secp256k1_fe x; - secp256k1_fe one = SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1); - secp256k1_fe_mul(&x, a, ai); - return check_fe_equal(&x, &one); -} - void run_field_convert(void) { static const unsigned char b32[32] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, @@ -1940,52 +2508,6 @@ void run_field_misc(void) { } } -void run_field_inv(void) { - secp256k1_fe x, xi, xii; - int i; - for (i = 0; i < 10*count; i++) { - random_fe_non_zero(&x); - secp256k1_fe_inv(&xi, &x); - CHECK(check_fe_inverse(&x, &xi)); - secp256k1_fe_inv(&xii, &xi); - CHECK(check_fe_equal(&x, &xii)); - } -} - -void run_field_inv_var(void) { - secp256k1_fe x, xi, xii; - int i; - for (i = 0; i < 10*count; i++) { - random_fe_non_zero(&x); - secp256k1_fe_inv_var(&xi, &x); - CHECK(check_fe_inverse(&x, &xi)); - secp256k1_fe_inv_var(&xii, &xi); - CHECK(check_fe_equal(&x, &xii)); - } -} - -void run_field_inv_all_var(void) { - secp256k1_fe x[16], xi[16], xii[16]; - int i; - /* Check it's safe to call for 0 elements */ - secp256k1_fe_inv_all_var(xi, x, 0); - for (i = 0; i < count; i++) { - size_t j; - size_t len = secp256k1_testrand_int(15) + 1; - for (j = 0; j < len; j++) { - random_fe_non_zero(&x[j]); - } - secp256k1_fe_inv_all_var(xi, x, len); - for (j = 0; j < len; j++) { - CHECK(check_fe_inverse(&x[j], &xi[j])); - } - secp256k1_fe_inv_all_var(xii, xi, len); - for (j = 0; j < len; j++) { - CHECK(check_fe_equal(&x[j], &xii[j])); - } - } -} - void run_sqr(void) { secp256k1_fe x, s; @@ -2050,6 +2572,318 @@ void run_sqrt(void) { } } +/***** FIELD/SCALAR INVERSE TESTS *****/ + +static const secp256k1_scalar scalar_minus_one = SECP256K1_SCALAR_CONST( + 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, + 0xBAAEDCE6, 0xAF48A03B, 0xBFD25E8C, 0xD0364140 +); + +static const secp256k1_fe fe_minus_one = SECP256K1_FE_CONST( + 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, + 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, 0xFFFFFC2E +); + +/* These tests test the following identities: + * + * for x==0: 1/x == 0 + * for x!=0: x*(1/x) == 1 + * for x!=0 and x!=1: 1/(1/x - 1) + 1 == -1/(x-1) + */ + +void test_inverse_scalar(secp256k1_scalar* out, const secp256k1_scalar* x, int var) +{ + secp256k1_scalar l, r, t; + + (var ? secp256k1_scalar_inverse_var : secp256k1_scalar_inverse_var)(&l, x); /* l = 1/x */ + if (out) *out = l; + if (secp256k1_scalar_is_zero(x)) { + CHECK(secp256k1_scalar_is_zero(&l)); + return; + } + secp256k1_scalar_mul(&t, x, &l); /* t = x*(1/x) */ + CHECK(secp256k1_scalar_is_one(&t)); /* x*(1/x) == 1 */ + secp256k1_scalar_add(&r, x, &scalar_minus_one); /* r = x-1 */ + if (secp256k1_scalar_is_zero(&r)) return; + (var ? secp256k1_scalar_inverse_var : secp256k1_scalar_inverse_var)(&r, &r); /* r = 1/(x-1) */ + secp256k1_scalar_add(&l, &scalar_minus_one, &l); /* l = 1/x-1 */ + (var ? secp256k1_scalar_inverse_var : secp256k1_scalar_inverse_var)(&l, &l); /* l = 1/(1/x-1) */ + secp256k1_scalar_add(&l, &l, &secp256k1_scalar_one); /* l = 1/(1/x-1)+1 */ + secp256k1_scalar_add(&l, &r, &l); /* l = 1/(1/x-1)+1 + 1/(x-1) */ + CHECK(secp256k1_scalar_is_zero(&l)); /* l == 0 */ +} + +void test_inverse_field(secp256k1_fe* out, const secp256k1_fe* x, int var) +{ + secp256k1_fe l, r, t; + + (var ? secp256k1_fe_inv_var : secp256k1_fe_inv)(&l, x) ; /* l = 1/x */ + if (out) *out = l; + t = *x; /* t = x */ + if (secp256k1_fe_normalizes_to_zero_var(&t)) { + CHECK(secp256k1_fe_normalizes_to_zero(&l)); + return; + } + secp256k1_fe_mul(&t, x, &l); /* t = x*(1/x) */ + secp256k1_fe_add(&t, &fe_minus_one); /* t = x*(1/x)-1 */ + CHECK(secp256k1_fe_normalizes_to_zero(&t)); /* x*(1/x)-1 == 0 */ + r = *x; /* r = x */ + secp256k1_fe_add(&r, &fe_minus_one); /* r = x-1 */ + if (secp256k1_fe_normalizes_to_zero_var(&r)) return; + (var ? secp256k1_fe_inv_var : secp256k1_fe_inv)(&r, &r); /* r = 1/(x-1) */ + secp256k1_fe_add(&l, &fe_minus_one); /* l = 1/x-1 */ + (var ? secp256k1_fe_inv_var : secp256k1_fe_inv)(&l, &l); /* l = 1/(1/x-1) */ + secp256k1_fe_add(&l, &secp256k1_fe_one); /* l = 1/(1/x-1)+1 */ + secp256k1_fe_add(&l, &r); /* l = 1/(1/x-1)+1 + 1/(x-1) */ + CHECK(secp256k1_fe_normalizes_to_zero_var(&l)); /* l == 0 */ +} + +void run_inverse_tests(void) +{ + /* Fixed test cases for field inverses: pairs of (x, 1/x) mod p. */ + static const secp256k1_fe fe_cases[][2] = { + /* 0 */ + {SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 0), + SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 0)}, + /* 1 */ + {SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1), + SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1)}, + /* -1 */ + {SECP256K1_FE_CONST(0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xfffffffe, 0xfffffc2e), + SECP256K1_FE_CONST(0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xfffffffe, 0xfffffc2e)}, + /* 2 */ + {SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 2), + SECP256K1_FE_CONST(0x7fffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x7ffffe18)}, + /* 2**128 */ + {SECP256K1_FE_CONST(0, 0, 0, 1, 0, 0, 0, 0), + SECP256K1_FE_CONST(0xbcb223fe, 0xdc24a059, 0xd838091d, 0xd2253530, 0xffffffff, 0xffffffff, 0xffffffff, 0x434dd931)}, + /* Input known to need 637 divsteps */ + {SECP256K1_FE_CONST(0xe34e9c95, 0x6bee8a84, 0x0dcb632a, 0xdb8a1320, 0x66885408, 0x06f3f996, 0x7c11ca84, 0x19199ec3), + SECP256K1_FE_CONST(0xbd2cbd8f, 0x1c536828, 0x9bccda44, 0x2582ac0c, 0x870152b0, 0x8a3f09fb, 0x1aaadf92, 0x19b618e5)}, + /* Input known to need 567 divsteps starting with delta=1/2. */ + {SECP256K1_FE_CONST(0xf6bc3ba3, 0x636451c4, 0x3e46357d, 0x2c21d619, 0x0988e234, 0x15985661, 0x6672982b, 0xa7549bfc), + SECP256K1_FE_CONST(0xb024fdc7, 0x5547451e, 0x426c585f, 0xbd481425, 0x73df6b75, 0xeef6d9d0, 0x389d87d4, 0xfbb440ba)}, + /* Input known to need 566 divsteps starting with delta=1/2. */ + {SECP256K1_FE_CONST(0xb595d81b, 0x2e3c1e2f, 0x482dbc65, 0xe4865af7, 0x9a0a50aa, 0x29f9e618, 0x6f87d7a5, 0x8d1063ae), + SECP256K1_FE_CONST(0xc983337c, 0x5d5c74e1, 0x49918330, 0x0b53afb5, 0xa0428a0b, 0xce6eef86, 0x059bd8ef, 0xe5b908de)}, + /* Set of 10 inputs accessing all 128 entries in the modinv32 divsteps_var table */ + {SECP256K1_FE_CONST(0x00000000, 0x00000000, 0xe0ff1f80, 0x1f000000, 0x00000000, 0x00000000, 0xfeff0100, 0x00000000), + SECP256K1_FE_CONST(0x9faf9316, 0x77e5049d, 0x0b5e7a1b, 0xef70b893, 0x18c9e30c, 0x045e7fd7, 0x29eddf8c, 0xd62e9e3d)}, + {SECP256K1_FE_CONST(0x621a538d, 0x511b2780, 0x35688252, 0x53f889a4, 0x6317c3ac, 0x32ba0a46, 0x6277c0d1, 0xccd31192), + SECP256K1_FE_CONST(0x38513b0c, 0x5eba856f, 0xe29e882e, 0x9b394d8c, 0x34bda011, 0xeaa66943, 0x6a841a4c, 0x6ae8bcff)}, + {SECP256K1_FE_CONST(0x00000200, 0xf0ffff1f, 0x00000000, 0x0000e0ff, 0xffffffff, 0xfffcffff, 0xffffffff, 0xffff0100), + SECP256K1_FE_CONST(0x5da42a52, 0x3640de9e, 0x13e64343, 0x0c7591b7, 0x6c1e3519, 0xf048c5b6, 0x0484217c, 0xedbf8b2f)}, + {SECP256K1_FE_CONST(0xd1343ef9, 0x4b952621, 0x7c52a2ee, 0x4ea1281b, 0x4ab46410, 0x9f26998d, 0xa686a8ff, 0x9f2103e8), + SECP256K1_FE_CONST(0x84044385, 0x9a4619bf, 0x74e35b6d, 0xa47e0c46, 0x6b7fb47d, 0x9ffab128, 0xb0775aa3, 0xcb318bd1)}, + {SECP256K1_FE_CONST(0xb27235d2, 0xc56a52be, 0x210db37a, 0xd50d23a4, 0xbe621bdd, 0x5df22c6a, 0xe926ba62, 0xd2e4e440), + SECP256K1_FE_CONST(0x67a26e54, 0x483a9d3c, 0xa568469e, 0xd258ab3d, 0xb9ec9981, 0xdca9b1bd, 0x8d2775fe, 0x53ae429b)}, + {SECP256K1_FE_CONST(0x00000000, 0x00000000, 0x00e0ffff, 0xffffff83, 0xffffffff, 0x3f00f00f, 0x000000e0, 0xffffffff), + SECP256K1_FE_CONST(0x310e10f8, 0x23bbfab0, 0xac94907d, 0x076c9a45, 0x8d357d7f, 0xc763bcee, 0x00d0e615, 0x5a6acef6)}, + {SECP256K1_FE_CONST(0xfeff0300, 0x001c0000, 0xf80700c0, 0x0ff0ffff, 0xffffffff, 0x0fffffff, 0xffff0100, 0x7f0000fe), + SECP256K1_FE_CONST(0x28e2fdb4, 0x0709168b, 0x86f598b0, 0x3453a370, 0x530cf21f, 0x32f978d5, 0x1d527a71, 0x59269b0c)}, + {SECP256K1_FE_CONST(0xc2591afa, 0x7bb98ef7, 0x090bb273, 0x85c14f87, 0xbb0b28e0, 0x54d3c453, 0x85c66753, 0xd5574d2f), + SECP256K1_FE_CONST(0xfdca70a2, 0x70ce627c, 0x95e66fae, 0x848a6dbb, 0x07ffb15c, 0x5f63a058, 0xba4140ed, 0x6113b503)}, + {SECP256K1_FE_CONST(0xf5475db3, 0xedc7b5a3, 0x411c047e, 0xeaeb452f, 0xc625828e, 0x1cf5ad27, 0x8eec1060, 0xc7d3e690), + SECP256K1_FE_CONST(0x5eb756c0, 0xf963f4b9, 0xdc6a215e, 0xec8cc2d8, 0x2e9dec01, 0xde5eb88d, 0x6aba7164, 0xaecb2c5a)}, + {SECP256K1_FE_CONST(0x00000000, 0x00f8ffff, 0xffffffff, 0x01000000, 0xe0ff1f00, 0x00000000, 0xffffff7f, 0x00000000), + SECP256K1_FE_CONST(0xe0d2e3d8, 0x49b6157d, 0xe54e88c2, 0x1a7f02ca, 0x7dd28167, 0xf1125d81, 0x7bfa444e, 0xbe110037)}, + /* Selection of randomly generated inputs that reach high/low d/e values in various configurations. */ + {SECP256K1_FE_CONST(0x13cc08a4, 0xd8c41f0f, 0x179c3e67, 0x54c46c67, 0xc4109221, 0x09ab3b13, 0xe24d9be1, 0xffffe950), + SECP256K1_FE_CONST(0xb80c8006, 0xd16abaa7, 0xcabd71e5, 0xcf6714f4, 0x966dd3d0, 0x64767a2d, 0xe92c4441, 0x51008cd1)}, + {SECP256K1_FE_CONST(0xaa6db990, 0x95efbca1, 0x3cc6ff71, 0x0602e24a, 0xf49ff938, 0x99fffc16, 0x46f40993, 0xc6e72057), + SECP256K1_FE_CONST(0xd5d3dd69, 0xb0c195e5, 0x285f1d49, 0xe639e48c, 0x9223f8a9, 0xca1d731d, 0x9ca482f9, 0xa5b93e06)}, + {SECP256K1_FE_CONST(0x1c680eac, 0xaeabffd8, 0x9bdc4aee, 0x1781e3de, 0xa3b08108, 0x0015f2e0, 0x94449e1b, 0x2f67a058), + SECP256K1_FE_CONST(0x7f083f8d, 0x31254f29, 0x6510f475, 0x245c373d, 0xc5622590, 0x4b323393, 0x32ed1719, 0xc127444b)}, + {SECP256K1_FE_CONST(0x147d44b3, 0x012d83f8, 0xc160d386, 0x1a44a870, 0x9ba6be96, 0x8b962707, 0x267cbc1a, 0xb65b2f0a), + SECP256K1_FE_CONST(0x555554ff, 0x170aef1e, 0x50a43002, 0xe51fbd36, 0xafadb458, 0x7a8aded1, 0x0ca6cd33, 0x6ed9087c)}, + {SECP256K1_FE_CONST(0x12423796, 0x22f0fe61, 0xf9ca017c, 0x5384d107, 0xa1fbf3b2, 0x3b018013, 0x916a3c37, 0x4000b98c), + SECP256K1_FE_CONST(0x20257700, 0x08668f94, 0x1177e306, 0x136c01f5, 0x8ed1fbd2, 0x95ec4589, 0xae38edb9, 0xfd19b6d7)}, + {SECP256K1_FE_CONST(0xdcf2d030, 0x9ab42cb4, 0x93ffa181, 0xdcd23619, 0x39699b52, 0x08909a20, 0xb5a17695, 0x3a9dcf21), + SECP256K1_FE_CONST(0x1f701dea, 0xe211fb1f, 0x4f37180d, 0x63a0f51c, 0x29fe1e40, 0xa40b6142, 0x2e7b12eb, 0x982b06b6)}, + {SECP256K1_FE_CONST(0x79a851f6, 0xa6314ed3, 0xb35a55e6, 0xca1c7d7f, 0xe32369ea, 0xf902432e, 0x375308c5, 0xdfd5b600), + SECP256K1_FE_CONST(0xcaae00c5, 0xe6b43851, 0x9dabb737, 0x38cba42c, 0xa02c8549, 0x7895dcbf, 0xbd183d71, 0xafe4476a)}, + {SECP256K1_FE_CONST(0xede78fdd, 0xcfc92bf1, 0x4fec6c6c, 0xdb8d37e2, 0xfb66bc7b, 0x28701870, 0x7fa27c9a, 0x307196ec), + SECP256K1_FE_CONST(0x68193a6c, 0x9a8b87a7, 0x2a760c64, 0x13e473f6, 0x23ae7bed, 0x1de05422, 0x88865427, 0xa3418265)}, + {SECP256K1_FE_CONST(0xa40b2079, 0xb8f88e89, 0xa7617997, 0x89baf5ae, 0x174df343, 0x75138eae, 0x2711595d, 0x3fc3e66c), + SECP256K1_FE_CONST(0x9f99c6a5, 0x6d685267, 0xd4b87c37, 0x9d9c4576, 0x358c692b, 0x6bbae0ed, 0x3389c93d, 0x7fdd2655)}, + {SECP256K1_FE_CONST(0x7c74c6b6, 0xe98d9151, 0x72645cf1, 0x7f06e321, 0xcefee074, 0x15b2113a, 0x10a9be07, 0x08a45696), + SECP256K1_FE_CONST(0x8c919a88, 0x898bc1e0, 0x77f26f97, 0x12e655b7, 0x9ba0ac40, 0xe15bb19e, 0x8364cc3b, 0xe227a8ee)}, + {SECP256K1_FE_CONST(0x109ba1ce, 0xdafa6d4a, 0xa1cec2b2, 0xeb1069f4, 0xb7a79e5b, 0xec6eb99b, 0xaec5f643, 0xee0e723e), + SECP256K1_FE_CONST(0x93d13eb8, 0x4bb0bcf9, 0xe64f5a71, 0xdbe9f359, 0x7191401c, 0x6f057a4a, 0xa407fe1b, 0x7ecb65cc)}, + {SECP256K1_FE_CONST(0x3db076cd, 0xec74a5c9, 0xf61dd138, 0x90e23e06, 0xeeedd2d0, 0x74cbc4e0, 0x3dbe1e91, 0xded36a78), + SECP256K1_FE_CONST(0x3f07f966, 0x8e2a1e09, 0x706c71df, 0x02b5e9d5, 0xcb92ddbf, 0xcdd53010, 0x16545564, 0xe660b107)}, + {SECP256K1_FE_CONST(0xe31c73ed, 0xb4c4b82c, 0x02ae35f7, 0x4cdec153, 0x98b522fd, 0xf7d2460c, 0x6bf7c0f8, 0x4cf67b0d), + SECP256K1_FE_CONST(0x4b8f1faf, 0x94e8b070, 0x19af0ff6, 0xa319cd31, 0xdf0a7ffb, 0xefaba629, 0x59c50666, 0x1fe5b843)}, + {SECP256K1_FE_CONST(0x4c8b0e6e, 0x83392ab6, 0xc0e3e9f1, 0xbbd85497, 0x16698897, 0xf552d50d, 0x79652ddb, 0x12f99870), + SECP256K1_FE_CONST(0x56d5101f, 0xd23b7949, 0x17dc38d6, 0xf24022ef, 0xcf18e70a, 0x5cc34424, 0x438544c3, 0x62da4bca)}, + {SECP256K1_FE_CONST(0xb0e040e2, 0x40cc35da, 0x7dd5c611, 0x7fccb178, 0x28888137, 0xbc930358, 0xea2cbc90, 0x775417dc), + SECP256K1_FE_CONST(0xca37f0d4, 0x016dd7c8, 0xab3ae576, 0x96e08d69, 0x68ed9155, 0xa9b44270, 0x900ae35d, 0x7c7800cd)}, + {SECP256K1_FE_CONST(0x8a32ea49, 0x7fbb0bae, 0x69724a9d, 0x8e2105b2, 0xbdf69178, 0x862577ef, 0x35055590, 0x667ddaef), + SECP256K1_FE_CONST(0xd02d7ead, 0xc5e190f0, 0x559c9d72, 0xdaef1ffc, 0x64f9f425, 0xf43645ea, 0x7341e08d, 0x11768e96)}, + {SECP256K1_FE_CONST(0xa3592d98, 0x9abe289d, 0x579ebea6, 0xbb0857a8, 0xe242ab73, 0x85f9a2ce, 0xb6998f0f, 0xbfffbfc6), + SECP256K1_FE_CONST(0x093c1533, 0x32032efa, 0x6aa46070, 0x0039599e, 0x589c35f4, 0xff525430, 0x7fe3777a, 0x44b43ddc)}, + {SECP256K1_FE_CONST(0x647178a3, 0x229e607b, 0xcc98521a, 0xcce3fdd9, 0x1e1bc9c9, 0x97fb7c6a, 0x61b961e0, 0x99b10709), + SECP256K1_FE_CONST(0x98217c13, 0xd51ddf78, 0x96310e77, 0xdaebd908, 0x602ca683, 0xcb46d07a, 0xa1fcf17e, 0xc8e2feb3)}, + {SECP256K1_FE_CONST(0x7334627c, 0x73f98968, 0x99464b4b, 0xf5964958, 0x1b95870d, 0xc658227e, 0x5e3235d8, 0xdcab5787), + SECP256K1_FE_CONST(0x000006fd, 0xc7e9dd94, 0x40ae367a, 0xe51d495c, 0x07603b9b, 0x2d088418, 0x6cc5c74c, 0x98514307)}, + {SECP256K1_FE_CONST(0x82e83876, 0x96c28938, 0xa50dd1c5, 0x605c3ad1, 0xc048637d, 0x7a50825f, 0x335ed01a, 0x00005760), + SECP256K1_FE_CONST(0xb0393f9f, 0x9f2aa55e, 0xf5607e2e, 0x5287d961, 0x60b3e704, 0xf3e16e80, 0xb4f9a3ea, 0xfec7f02d)}, + {SECP256K1_FE_CONST(0xc97b6cec, 0x3ee6b8dc, 0x98d24b58, 0x3c1970a1, 0xfe06297a, 0xae813529, 0xe76bb6bd, 0x771ae51d), + SECP256K1_FE_CONST(0x0507c702, 0xd407d097, 0x47ddeb06, 0xf6625419, 0x79f48f79, 0x7bf80d0b, 0xfc34b364, 0x253a5db1)}, + {SECP256K1_FE_CONST(0xd559af63, 0x77ea9bc4, 0x3cf1ad14, 0x5c7a4bbb, 0x10e7d18b, 0x7ce0dfac, 0x380bb19d, 0x0bb99bd3), + SECP256K1_FE_CONST(0x00196119, 0xb9b00d92, 0x34edfdb5, 0xbbdc42fc, 0xd2daa33a, 0x163356ca, 0xaa8754c8, 0xb0ec8b0b)}, + {SECP256K1_FE_CONST(0x8ddfa3dc, 0x52918da0, 0x640519dc, 0x0af8512a, 0xca2d33b2, 0xbde52514, 0xda9c0afc, 0xcb29fce4), + SECP256K1_FE_CONST(0xb3e4878d, 0x5cb69148, 0xcd54388b, 0xc23acce0, 0x62518ba8, 0xf09def92, 0x7b31e6aa, 0x6ba35b02)}, + {SECP256K1_FE_CONST(0xf8207492, 0xe3049f0a, 0x65285f2b, 0x0bfff996, 0x00ca112e, 0xc05da837, 0x546d41f9, 0x5194fb91), + SECP256K1_FE_CONST(0x7b7ee50b, 0xa8ed4bbd, 0xf6469930, 0x81419a5c, 0x071441c7, 0x290d046e, 0x3b82ea41, 0x611c5f95)}, + {SECP256K1_FE_CONST(0x050f7c80, 0x5bcd3c6b, 0x823cb724, 0x5ce74db7, 0xa4e39f5c, 0xbd8828d7, 0xfd4d3e07, 0x3ec2926a), + SECP256K1_FE_CONST(0x000d6730, 0xb0171314, 0x4764053d, 0xee157117, 0x48fd61da, 0xdea0b9db, 0x1d5e91c6, 0xbdc3f59e)}, + {SECP256K1_FE_CONST(0x3e3ea8eb, 0x05d760cf, 0x23009263, 0xb3cb3ac9, 0x088f6f0d, 0x3fc182a3, 0xbd57087c, 0xe67c62f9), + SECP256K1_FE_CONST(0xbe988716, 0xa29c1bf6, 0x4456aed6, 0xab1e4720, 0x49929305, 0x51043bf4, 0xebd833dd, 0xdd511e8b)}, + {SECP256K1_FE_CONST(0x6964d2a9, 0xa7fa6501, 0xa5959249, 0x142f4029, 0xea0c1b5f, 0x2f487ef6, 0x301ac80a, 0x768be5cd), + SECP256K1_FE_CONST(0x3918ffe4, 0x07492543, 0xed24d0b7, 0x3df95f8f, 0xaffd7cb4, 0x0de2191c, 0x9ec2f2ad, 0x2c0cb3c6)}, + {SECP256K1_FE_CONST(0x37c93520, 0xf6ddca57, 0x2b42fd5e, 0xb5c7e4de, 0x11b5b81c, 0xb95e91f3, 0x95c4d156, 0x39877ccb), + SECP256K1_FE_CONST(0x9a94b9b5, 0x57eb71ee, 0x4c975b8b, 0xac5262a8, 0x077b0595, 0xe12a6b1f, 0xd728edef, 0x1a6bf956)} + }; + /* Fixed test cases for scalar inverses: pairs of (x, 1/x) mod n. */ + static const secp256k1_scalar scalar_cases[][2] = { + /* 0 */ + {SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 0), + SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 0)}, + /* 1 */ + {SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 1), + SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 1)}, + /* -1 */ + {SECP256K1_SCALAR_CONST(0xffffffff, 0xffffffff, 0xffffffff, 0xfffffffe, 0xbaaedce6, 0xaf48a03b, 0xbfd25e8c, 0xd0364140), + SECP256K1_SCALAR_CONST(0xffffffff, 0xffffffff, 0xffffffff, 0xfffffffe, 0xbaaedce6, 0xaf48a03b, 0xbfd25e8c, 0xd0364140)}, + /* 2 */ + {SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 2), + SECP256K1_SCALAR_CONST(0x7fffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0x5d576e73, 0x57a4501d, 0xdfe92f46, 0x681b20a1)}, + /* 2**128 */ + {SECP256K1_SCALAR_CONST(0, 0, 0, 1, 0, 0, 0, 0), + SECP256K1_SCALAR_CONST(0x50a51ac8, 0x34b9ec24, 0x4b0dff66, 0x5588b13e, 0x9984d5b3, 0xcf80ef0f, 0xd6a23766, 0xa3ee9f22)}, + /* Input known to need 635 divsteps */ + {SECP256K1_SCALAR_CONST(0xcb9f1d35, 0xdd4416c2, 0xcd71bf3f, 0x6365da66, 0x3c9b3376, 0x8feb7ae9, 0x32a5ef60, 0x19199ec3), + SECP256K1_SCALAR_CONST(0x1d7c7bba, 0xf1893d53, 0xb834bd09, 0x36b411dc, 0x42c2e42f, 0xec72c428, 0x5e189791, 0x8e9bc708)}, + /* Input known to need 566 divsteps starting with delta=1/2. */ + {SECP256K1_SCALAR_CONST(0x7e3c993d, 0xa4272488, 0xbc015b49, 0x2db54174, 0xd382083a, 0xebe6db35, 0x80f82eff, 0xcd132c72), + SECP256K1_SCALAR_CONST(0x086f34a0, 0x3e631f76, 0x77418f28, 0xcc84ac95, 0x6304439d, 0x365db268, 0x312c6ded, 0xd0b934f8)}, + /* Input known to need 565 divsteps starting with delta=1/2. */ + {SECP256K1_SCALAR_CONST(0xbad7e587, 0x3f307859, 0x60d93147, 0x8a18491e, 0xb38a9fd5, 0x254350d3, 0x4b1f0e4b, 0x7dd6edc4), + SECP256K1_SCALAR_CONST(0x89f2df26, 0x39e2b041, 0xf19bd876, 0xd039c8ac, 0xc2223add, 0x29c4943e, 0x6632d908, 0x515f467b)}, + /* Selection of randomly generated inputs that reach low/high d/e values in various configurations. */ + {SECP256K1_SCALAR_CONST(0x1950d757, 0xb37a5809, 0x435059bb, 0x0bb8997e, 0x07e1e3c8, 0x5e5d7d2c, 0x6a0ed8e3, 0xdbde180e), + SECP256K1_SCALAR_CONST(0xbf72af9b, 0x750309e2, 0x8dda230b, 0xfe432b93, 0x7e25e475, 0x4388251e, 0x633d894b, 0x3bcb6f8c)}, + {SECP256K1_SCALAR_CONST(0x9bccf4e7, 0xc5a515e3, 0x50637aa9, 0xbb65a13f, 0x391749a1, 0x62de7d4e, 0xf6d7eabb, 0x3cd10ce0), + SECP256K1_SCALAR_CONST(0xaf2d5623, 0xb6385a33, 0xcd0365be, 0x5e92a70d, 0x7f09179c, 0x3baaf30f, 0x8f9cc83b, 0x20092f67)}, + {SECP256K1_SCALAR_CONST(0x73a57111, 0xb242952a, 0x5c5dee59, 0xf3be2ace, 0xa30a7659, 0xa46e5f47, 0xd21267b1, 0x39e642c9), + SECP256K1_SCALAR_CONST(0xa711df07, 0xcbcf13ef, 0xd61cc6be, 0xbcd058ce, 0xb02cf157, 0x272d4a18, 0x86d0feb3, 0xcd5fa004)}, + {SECP256K1_SCALAR_CONST(0x04884963, 0xce0580b1, 0xba547030, 0x3c691db3, 0x9cd2c84f, 0x24c7cebd, 0x97ebfdba, 0x3e785ec2), + SECP256K1_SCALAR_CONST(0xaaaaaf14, 0xd7c99ba7, 0x517ce2c1, 0x78a28b4c, 0x3769a851, 0xe5c5a03d, 0x4cc28f33, 0x0ec4dc5d)}, + {SECP256K1_SCALAR_CONST(0x1679ed49, 0x21f537b1, 0x815cb8ae, 0x9efc511c, 0x5b9fa037, 0x0b0f275e, 0x6c985281, 0x6c4a9905), + SECP256K1_SCALAR_CONST(0xb14ac3d5, 0x62b52999, 0xef34ead1, 0xffca4998, 0x0294341a, 0x1f8172aa, 0xea1624f9, 0x302eea62)}, + {SECP256K1_SCALAR_CONST(0x626b37c0, 0xf0057c35, 0xee982f83, 0x452a1fd3, 0xea826506, 0x48b08a9d, 0x1d2c4799, 0x4ad5f6ec), + SECP256K1_SCALAR_CONST(0xe38643b7, 0x567bfc2f, 0x5d2f1c15, 0xe327239c, 0x07112443, 0x69509283, 0xfd98e77a, 0xdb71c1e8)}, + {SECP256K1_SCALAR_CONST(0x1850a3a7, 0x759efc56, 0x54f287b2, 0x14d1234b, 0xe263bbc9, 0xcf4d8927, 0xd5f85f27, 0x965bd816), + SECP256K1_SCALAR_CONST(0x3b071831, 0xcac9619a, 0xcceb0596, 0xf614d63b, 0x95d0db2f, 0xc6a00901, 0x8eaa2621, 0xabfa0009)}, + {SECP256K1_SCALAR_CONST(0x94ae5d06, 0xa27dc400, 0x487d72be, 0xaa51ebed, 0xe475b5c0, 0xea675ffc, 0xf4df627a, 0xdca4222f), + SECP256K1_SCALAR_CONST(0x01b412ed, 0xd7830956, 0x1532537e, 0xe5e3dc99, 0x8fd3930a, 0x54f8d067, 0x32ef5760, 0x594438a5)}, + {SECP256K1_SCALAR_CONST(0x1f24278a, 0xb5bfe374, 0xa328dbbc, 0xebe35f48, 0x6620e009, 0xd58bb1b4, 0xb5a6bf84, 0x8815f63a), + SECP256K1_SCALAR_CONST(0xfe928416, 0xca5ba2d3, 0xfde513da, 0x903a60c7, 0x9e58ad8a, 0x8783bee4, 0x083a3843, 0xa608c914)}, + {SECP256K1_SCALAR_CONST(0xdc107d58, 0x274f6330, 0x67dba8bc, 0x26093111, 0x5201dfb8, 0x968ce3f5, 0xf34d1bd4, 0xf2146504), + SECP256K1_SCALAR_CONST(0x660cfa90, 0x13c3d93e, 0x7023b1e5, 0xedd09e71, 0x6d9c9d10, 0x7a3d2cdb, 0xdd08edc3, 0xaa78fcfb)}, + {SECP256K1_SCALAR_CONST(0x7cd1e905, 0xc6f02776, 0x2f551cc7, 0x5da61cff, 0x7da05389, 0x1119d5a4, 0x631c7442, 0x894fd4f7), + SECP256K1_SCALAR_CONST(0xff20862a, 0x9d3b1a37, 0x1628803b, 0x3004ccae, 0xaa23282a, 0xa89a1109, 0xd94ece5e, 0x181bdc46)}, + {SECP256K1_SCALAR_CONST(0x5b9dade8, 0x23d26c58, 0xcd12d818, 0x25b8ae97, 0x3dea04af, 0xf482c96b, 0xa062f254, 0x9e453640), + SECP256K1_SCALAR_CONST(0x50c38800, 0x15fa53f4, 0xbe1e5392, 0x5c9b120a, 0x262c22c7, 0x18fa0816, 0x5f2baab4, 0x8cb5db46)}, + {SECP256K1_SCALAR_CONST(0x11cdaeda, 0x969c464b, 0xef1f4ab0, 0x5b01d22e, 0x656fd098, 0x882bea84, 0x65cdbe7a, 0x0c19ff03), + SECP256K1_SCALAR_CONST(0x1968d0fa, 0xac46f103, 0xb55f1f72, 0xb3820bed, 0xec6b359a, 0x4b1ae0ad, 0x7e38e1fb, 0x295ccdfb)}, + {SECP256K1_SCALAR_CONST(0x2c351aa1, 0x26e91589, 0x194f8a1e, 0x06561f66, 0x0cb97b7f, 0x10914454, 0x134d1c03, 0x157266b4), + SECP256K1_SCALAR_CONST(0xbe49ada6, 0x92bd8711, 0x41b176c4, 0xa478ba95, 0x14883434, 0x9d1cd6f3, 0xcc4b847d, 0x22af80f5)}, + {SECP256K1_SCALAR_CONST(0x6ba07c6e, 0x13a60edb, 0x6247f5c3, 0x84b5fa56, 0x76fe3ec5, 0x80426395, 0xf65ec2ae, 0x623ba730), + SECP256K1_SCALAR_CONST(0x25ac23f7, 0x418cd747, 0x98376f9d, 0x4a11c7bf, 0x24c8ebfe, 0x4c8a8655, 0x345f4f52, 0x1c515595)}, + {SECP256K1_SCALAR_CONST(0x9397a712, 0x8abb6951, 0x2d4a3d54, 0x703b1c2a, 0x0661dca8, 0xd75c9b31, 0xaed4d24b, 0xd2ab2948), + SECP256K1_SCALAR_CONST(0xc52e8bef, 0xd55ce3eb, 0x1c897739, 0xeb9fb606, 0x36b9cd57, 0x18c51cc2, 0x6a87489e, 0xffd0dcf3)}, + {SECP256K1_SCALAR_CONST(0xe6a808cc, 0xeb437888, 0xe97798df, 0x4e224e44, 0x7e3b380a, 0x207c1653, 0x889f3212, 0xc6738b6f), + SECP256K1_SCALAR_CONST(0x31f9ae13, 0xd1e08b20, 0x757a2e5e, 0x5243a0eb, 0x8ae35f73, 0x19bb6122, 0xb910f26b, 0xda70aa55)}, + {SECP256K1_SCALAR_CONST(0xd0320548, 0xab0effe7, 0xa70779e0, 0x61a347a6, 0xb8c1e010, 0x9d5281f8, 0x2ee588a6, 0x80000000), + SECP256K1_SCALAR_CONST(0x1541897e, 0x78195c90, 0x7583dd9e, 0x728b6100, 0xbce8bc6d, 0x7a53b471, 0x5dcd9e45, 0x4425fcaf)}, + {SECP256K1_SCALAR_CONST(0x93d623f1, 0xd45b50b0, 0x796e9186, 0x9eac9407, 0xd30edc20, 0xef6304cf, 0x250494e7, 0xba503de9), + SECP256K1_SCALAR_CONST(0x7026d638, 0x1178b548, 0x92043952, 0x3c7fb47c, 0xcd3ea236, 0x31d82b01, 0x612fc387, 0x80b9b957)}, + {SECP256K1_SCALAR_CONST(0xf860ab39, 0x55f5d412, 0xa4d73bcc, 0x3b48bd90, 0xc248ffd3, 0x13ca10be, 0x8fba84cc, 0xdd28d6a3), + SECP256K1_SCALAR_CONST(0x5c32fc70, 0xe0b15d67, 0x76694700, 0xfe62be4d, 0xeacdb229, 0x7a4433d9, 0x52155cd0, 0x7649ab59)}, + {SECP256K1_SCALAR_CONST(0x4e41311c, 0x0800af58, 0x7a690a8e, 0xe175c9ba, 0x6981ab73, 0xac532ea8, 0x5c1f5e63, 0x6ac1f189), + SECP256K1_SCALAR_CONST(0xfffffff9, 0xd075982c, 0x7fbd3825, 0xc05038a2, 0x4533b91f, 0x94ec5f45, 0xb280b28f, 0x842324dc)}, + {SECP256K1_SCALAR_CONST(0x48e473bf, 0x3555eade, 0xad5d7089, 0x2424c4e4, 0x0a99397c, 0x2dc796d8, 0xb7a43a69, 0xd0364141), + SECP256K1_SCALAR_CONST(0x634976b2, 0xa0e47895, 0x1ec38593, 0x266d6fd0, 0x6f602644, 0x9bb762f1, 0x7180c704, 0xe23a4daa)}, + {SECP256K1_SCALAR_CONST(0xbe83878d, 0x3292fc54, 0x26e71c62, 0x556ccedc, 0x7cbb8810, 0x4032a720, 0x34ead589, 0xe4d6bd13), + SECP256K1_SCALAR_CONST(0x6cd150ad, 0x25e59d0f, 0x74cbae3d, 0x6377534a, 0x1e6562e8, 0xb71b9d18, 0xe1e5d712, 0x8480abb3)}, + {SECP256K1_SCALAR_CONST(0xcdddf2e5, 0xefc15f88, 0xc9ee06de, 0x8a846ca9, 0x28561581, 0x68daa5fb, 0xd1cf3451, 0xeb1782d0), + SECP256K1_SCALAR_CONST(0xffffffd9, 0xed8d2af4, 0x993c865a, 0x23e9681a, 0x3ca3a3dc, 0xe6d5a46e, 0xbd86bd87, 0x61b55c70)}, + {SECP256K1_SCALAR_CONST(0xb6a18f1f, 0x04872df9, 0x08165ec4, 0x319ca19c, 0x6c0359ab, 0x1f7118fb, 0xc2ef8082, 0xca8b7785), + SECP256K1_SCALAR_CONST(0xff55b19b, 0x0f1ac78c, 0x0f0c88c2, 0x2358d5ad, 0x5f455e4e, 0x3330b72f, 0x274dc153, 0xffbf272b)}, + {SECP256K1_SCALAR_CONST(0xea4898e5, 0x30eba3e8, 0xcf0e5c3d, 0x06ec6844, 0x01e26fb6, 0x75636225, 0xc5d08f4c, 0x1decafa0), + SECP256K1_SCALAR_CONST(0xe5a014a8, 0xe3c4ec1e, 0xea4f9b32, 0xcfc7b386, 0x00630806, 0x12c08d02, 0x6407ccc2, 0xb067d90e)}, + {SECP256K1_SCALAR_CONST(0x70e9aea9, 0x7e933af0, 0x8a23bfab, 0x23e4b772, 0xff951863, 0x5ffcf47d, 0x6bebc918, 0x2ca58265), + SECP256K1_SCALAR_CONST(0xf4e00006, 0x81bc6441, 0x4eb6ec02, 0xc194a859, 0x80ad7c48, 0xba4e9afb, 0x8b6bdbe0, 0x989d8f77)}, + {SECP256K1_SCALAR_CONST(0x3c56c774, 0x46efe6f0, 0xe93618b8, 0xf9b5a846, 0xd247df61, 0x83b1e215, 0x06dc8bcc, 0xeefc1bf5), + SECP256K1_SCALAR_CONST(0xfff8937a, 0x2cd9586b, 0x43c25e57, 0xd1cefa7a, 0x9fb91ed3, 0x95b6533d, 0x8ad0de5b, 0xafb93f00)}, + {SECP256K1_SCALAR_CONST(0xfb5c2772, 0x5cb30e83, 0xe38264df, 0xe4e3ebf3, 0x392aa92e, 0xa68756a1, 0x51279ac5, 0xb50711a8), + SECP256K1_SCALAR_CONST(0x000013af, 0x1105bfe7, 0xa6bbd7fb, 0x3d638f99, 0x3b266b02, 0x072fb8bc, 0x39251130, 0x2e0fd0ea)} + }; + int i, var, testrand; + unsigned char b32[32]; + secp256k1_fe x_fe; + secp256k1_scalar x_scalar; + memset(b32, 0, sizeof(b32)); + /* Test fixed test cases through test_inverse_{scalar,field}, both ways. */ + for (i = 0; (size_t)i < sizeof(fe_cases)/sizeof(fe_cases[0]); ++i) { + for (var = 0; var <= 1; ++var) { + test_inverse_field(&x_fe, &fe_cases[i][0], var); + check_fe_equal(&x_fe, &fe_cases[i][1]); + test_inverse_field(&x_fe, &fe_cases[i][1], var); + check_fe_equal(&x_fe, &fe_cases[i][0]); + } + } + for (i = 0; (size_t)i < sizeof(scalar_cases)/sizeof(scalar_cases[0]); ++i) { + for (var = 0; var <= 1; ++var) { + test_inverse_scalar(&x_scalar, &scalar_cases[i][0], var); + CHECK(secp256k1_scalar_eq(&x_scalar, &scalar_cases[i][1])); + test_inverse_scalar(&x_scalar, &scalar_cases[i][1], var); + CHECK(secp256k1_scalar_eq(&x_scalar, &scalar_cases[i][0])); + } + } + /* Test inputs 0..999 and their respective negations. */ + for (i = 0; i < 1000; ++i) { + b32[31] = i & 0xff; + b32[30] = (i >> 8) & 0xff; + secp256k1_scalar_set_b32(&x_scalar, b32, NULL); + secp256k1_fe_set_b32(&x_fe, b32); + for (var = 0; var <= 1; ++var) { + test_inverse_scalar(NULL, &x_scalar, var); + test_inverse_field(NULL, &x_fe, var); + } + secp256k1_scalar_negate(&x_scalar, &x_scalar); + secp256k1_fe_negate(&x_fe, &x_fe, 1); + for (var = 0; var <= 1; ++var) { + test_inverse_scalar(NULL, &x_scalar, var); + test_inverse_field(NULL, &x_fe, var); + } + } + /* test 128*count random inputs; half with testrand256_test, half with testrand256 */ + for (testrand = 0; testrand <= 1; ++testrand) { + for (i = 0; i < 64 * count; ++i) { + (testrand ? secp256k1_testrand256_test : secp256k1_testrand256)(b32); + secp256k1_scalar_set_b32(&x_scalar, b32, NULL); + secp256k1_fe_set_b32(&x_fe, b32); + for (var = 0; var <= 1; ++var) { + test_inverse_scalar(NULL, &x_scalar, var); + test_inverse_field(NULL, &x_fe, var); + } + } + } +} + /***** GROUP TESTS *****/ void ge_equals_ge(const secp256k1_ge *a, const secp256k1_ge *b) { @@ -2111,7 +2945,6 @@ void test_ge(void) { */ secp256k1_ge *ge = (secp256k1_ge *)checked_malloc(&ctx->error_callback, sizeof(secp256k1_ge) * (1 + 4 * runs)); secp256k1_gej *gej = (secp256k1_gej *)checked_malloc(&ctx->error_callback, sizeof(secp256k1_gej) * (1 + 4 * runs)); - secp256k1_fe *zinv = (secp256k1_fe *)checked_malloc(&ctx->error_callback, sizeof(secp256k1_fe) * (1 + 4 * runs)); secp256k1_fe zf; secp256k1_fe zfi2, zfi3; @@ -2145,23 +2978,6 @@ void test_ge(void) { } } - /* Compute z inverses. */ - { - secp256k1_fe *zs = checked_malloc(&ctx->error_callback, sizeof(secp256k1_fe) * (1 + 4 * runs)); - for (i = 0; i < 4 * runs + 1; i++) { - if (i == 0) { - /* The point at infinity does not have a meaningful z inverse. Any should do. */ - do { - random_field_element_test(&zs[i]); - } while(secp256k1_fe_is_zero(&zs[i])); - } else { - zs[i] = gej[i].z; - } - } - secp256k1_fe_inv_all_var(zinv, zs, 4 * runs + 1); - free(zs); - } - /* Generate random zf, and zfi2 = 1/zf^2, zfi3 = 1/zf^3 */ do { random_field_element_test(&zf); @@ -2270,16 +3086,9 @@ void test_ge(void) { free(gej_shuffled); } - /* Test batch gej -> ge conversion with and without known z ratios. */ + /* Test batch gej -> ge conversion without known z ratios. */ { - secp256k1_fe *zr = (secp256k1_fe *)checked_malloc(&ctx->error_callback, (4 * runs + 1) * sizeof(secp256k1_fe)); secp256k1_ge *ge_set_all = (secp256k1_ge *)checked_malloc(&ctx->error_callback, (4 * runs + 1) * sizeof(secp256k1_ge)); - for (i = 0; i < 4 * runs + 1; i++) { - /* Compute gej[i + 1].z / gez[i].z (with gej[n].z taken to be 1). */ - if (i < 4 * runs) { - secp256k1_fe_mul(&zr[i + 1], &zinv[i], &gej[i + 1].z); - } - } secp256k1_ge_set_all_gej_var(ge_set_all, gej, 4 * runs + 1); for (i = 0; i < 4 * runs + 1; i++) { secp256k1_fe s; @@ -2288,7 +3097,6 @@ void test_ge(void) { ge_equals_gej(&ge_set_all[i], &gej[i]); } free(ge_set_all); - free(zr); } /* Test batch gej -> ge conversion with many infinities. */ @@ -2309,7 +3117,6 @@ void test_ge(void) { free(ge); free(gej); - free(zinv); } @@ -2456,64 +3263,35 @@ void run_ec_combine(void) { void test_group_decompress(const secp256k1_fe* x) { /* The input itself, normalized. */ secp256k1_fe fex = *x; - secp256k1_fe fez; - /* Results of set_xquad_var, set_xo_var(..., 0), set_xo_var(..., 1). */ - secp256k1_ge ge_quad, ge_even, ge_odd; - secp256k1_gej gej_quad; + /* Results of set_xo_var(..., 0), set_xo_var(..., 1). */ + secp256k1_ge ge_even, ge_odd; /* Return values of the above calls. */ - int res_quad, res_even, res_odd; + int res_even, res_odd; secp256k1_fe_normalize_var(&fex); - res_quad = secp256k1_ge_set_xquad(&ge_quad, &fex); res_even = secp256k1_ge_set_xo_var(&ge_even, &fex, 0); res_odd = secp256k1_ge_set_xo_var(&ge_odd, &fex, 1); - CHECK(res_quad == res_even); - CHECK(res_quad == res_odd); + CHECK(res_even == res_odd); - if (res_quad) { - secp256k1_fe_normalize_var(&ge_quad.x); + if (res_even) { secp256k1_fe_normalize_var(&ge_odd.x); secp256k1_fe_normalize_var(&ge_even.x); - secp256k1_fe_normalize_var(&ge_quad.y); secp256k1_fe_normalize_var(&ge_odd.y); secp256k1_fe_normalize_var(&ge_even.y); /* No infinity allowed. */ - CHECK(!ge_quad.infinity); CHECK(!ge_even.infinity); CHECK(!ge_odd.infinity); /* Check that the x coordinates check out. */ - CHECK(secp256k1_fe_equal_var(&ge_quad.x, x)); CHECK(secp256k1_fe_equal_var(&ge_even.x, x)); CHECK(secp256k1_fe_equal_var(&ge_odd.x, x)); - /* Check that the Y coordinate result in ge_quad is a square. */ - CHECK(secp256k1_fe_is_quad_var(&ge_quad.y)); - /* Check odd/even Y in ge_odd, ge_even. */ CHECK(secp256k1_fe_is_odd(&ge_odd.y)); CHECK(!secp256k1_fe_is_odd(&ge_even.y)); - - /* Check secp256k1_gej_has_quad_y_var. */ - secp256k1_gej_set_ge(&gej_quad, &ge_quad); - CHECK(secp256k1_gej_has_quad_y_var(&gej_quad)); - do { - random_fe_test(&fez); - } while (secp256k1_fe_is_zero(&fez)); - secp256k1_gej_rescale(&gej_quad, &fez); - CHECK(secp256k1_gej_has_quad_y_var(&gej_quad)); - secp256k1_gej_neg(&gej_quad, &gej_quad); - CHECK(!secp256k1_gej_has_quad_y_var(&gej_quad)); - do { - random_fe_test(&fez); - } while (secp256k1_fe_is_zero(&fez)); - secp256k1_gej_rescale(&gej_quad, &fez); - CHECK(!secp256k1_gej_has_quad_y_var(&gej_quad)); - secp256k1_gej_neg(&gej_quad, &gej_quad); - CHECK(secp256k1_gej_has_quad_y_var(&gej_quad)); } } @@ -4373,8 +5151,10 @@ void test_ecdsa_sign_verify(void) { secp256k1_scalar one; secp256k1_scalar msg, key; secp256k1_scalar sigr, sigs; - int recid; int getrec; + /* Initialize recid to suppress a false positive -Wconditional-uninitialized in clang. + VG_UNDEF ensures that valgrind will still treat the variable as uninitialized. */ + int recid = -1; VG_UNDEF(&recid, sizeof(recid)); random_scalar_order_test(&msg); random_scalar_order_test(&key); secp256k1_ecmult_gen(&ctx->ecmult_gen_ctx, &pubj, &key); @@ -5444,18 +6224,18 @@ void run_ecdsa_openssl(void) { # include "modules/schnorrsig/tests_impl.h" #endif -void run_memczero_test(void) { +void run_secp256k1_memczero_test(void) { unsigned char buf1[6] = {1, 2, 3, 4, 5, 6}; unsigned char buf2[sizeof(buf1)]; - /* memczero(..., ..., 0) is a noop. */ + /* secp256k1_memczero(..., ..., 0) is a noop. */ memcpy(buf2, buf1, sizeof(buf1)); - memczero(buf1, sizeof(buf1), 0); + secp256k1_memczero(buf1, sizeof(buf1), 0); CHECK(secp256k1_memcmp_var(buf1, buf2, sizeof(buf1)) == 0); - /* memczero(..., ..., 1) zeros the buffer. */ + /* secp256k1_memczero(..., ..., 1) zeros the buffer. */ memset(buf2, 0, sizeof(buf2)); - memczero(buf1, sizeof(buf1) , 1); + secp256k1_memczero(buf1, sizeof(buf1) , 1); CHECK(secp256k1_memcmp_var(buf1, buf2, sizeof(buf1)) == 0); } @@ -5626,6 +6406,15 @@ int main(int argc, char **argv) { /* find iteration count */ if (argc > 1) { count = strtol(argv[1], NULL, 0); + } else { + const char* env = getenv("SECP256K1_TEST_ITERS"); + if (env) { + count = strtol(env, NULL, 0); + } + } + if (count <= 0) { + fputs("An iteration count of 0 or less is not allowed.\n", stderr); + return EXIT_FAILURE; } printf("test count = %i\n", count); @@ -5646,22 +6435,18 @@ int main(int argc, char **argv) { run_rand_bits(); run_rand_int(); + run_ctz_tests(); + run_modinv_tests(); + run_inverse_tests(); + run_sha256_tests(); run_hmac_sha256_tests(); run_rfc6979_hmac_sha256_tests(); -#ifndef USE_NUM_NONE - /* num tests */ - run_num_smalltests(); -#endif - /* scalar tests */ run_scalar_tests(); /* field tests */ - run_field_inv(); - run_field_inv_var(); - run_field_inv_all_var(); run_field_misc(); run_field_convert(); run_sqr(); @@ -5723,7 +6508,7 @@ int main(int argc, char **argv) { #endif /* util tests */ - run_memczero_test(); + run_secp256k1_memczero_test(); run_cmov_tests(); diff --git a/src/tests_exhaustive.c b/src/tests_exhaustive.c index f4d5b8e1765b4..2bb5381446ed2 100644 --- a/src/tests_exhaustive.c +++ b/src/tests_exhaustive.c @@ -1,8 +1,8 @@ /*********************************************************************** - * Copyright (c) 2016 Andrew Poelstra * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ + * Copyright (c) 2016 Andrew Poelstra * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #if defined HAVE_CONFIG_H #include "libsecp256k1-config.h" diff --git a/src/util.h b/src/util.h index 3a88a41bc61f7..f78846836cf25 100644 --- a/src/util.h +++ b/src/util.h @@ -1,8 +1,8 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #ifndef SECP256K1_UTIL_H #define SECP256K1_UTIL_H @@ -113,7 +113,7 @@ static SECP256K1_INLINE void *checked_realloc(const secp256k1_callback* cb, void #define ALIGNMENT 16 #endif -#define ROUND_TO_ALIGN(size) (((size + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT) +#define ROUND_TO_ALIGN(size) ((((size) + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT) /* Assume there is a contiguous memory object with bounds [base, base + max_size) * of which the memory range [base, *prealloc_ptr) is already allocated for usage, @@ -141,7 +141,7 @@ static SECP256K1_INLINE void *manual_alloc(void** prealloc_ptr, size_t alloc_siz VERIFY_CHECK(((unsigned char*)*prealloc_ptr - (unsigned char*)base) % ALIGNMENT == 0); VERIFY_CHECK((unsigned char*)*prealloc_ptr - (unsigned char*)base + aligned_alloc_size <= max_size); ret = *prealloc_ptr; - *((unsigned char**)prealloc_ptr) += aligned_alloc_size; + *prealloc_ptr = (unsigned char*)*prealloc_ptr + aligned_alloc_size; return ret; } @@ -202,7 +202,7 @@ static SECP256K1_INLINE void *manual_alloc(void** prealloc_ptr, size_t alloc_siz #endif /* Zero memory if flag == 1. Flag must be 0 or 1. Constant time. */ -static SECP256K1_INLINE void memczero(void *s, size_t len, int flag) { +static SECP256K1_INLINE void secp256k1_memczero(void *s, size_t len, int flag) { unsigned char *p = (unsigned char *)s; /* Access flag with a volatile-qualified lvalue. This prevents clang from figuring out (after inlining) that flag can @@ -260,14 +260,85 @@ static SECP256K1_INLINE void secp256k1_int_cmov(int *r, const int *a, int flag) # define SECP256K1_WIDEMUL_INT128 1 #elif defined(USE_FORCE_WIDEMUL_INT64) # define SECP256K1_WIDEMUL_INT64 1 -#elif defined(__SIZEOF_INT128__) +#elif defined(UINT128_MAX) || defined(__SIZEOF_INT128__) # define SECP256K1_WIDEMUL_INT128 1 #else # define SECP256K1_WIDEMUL_INT64 1 #endif #if defined(SECP256K1_WIDEMUL_INT128) +# if !defined(UINT128_MAX) && defined(__SIZEOF_INT128__) SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t; SECP256K1_GNUC_EXT typedef __int128 int128_t; +#define UINT128_MAX ((uint128_t)(-1)) +#define INT128_MAX ((int128_t)(UINT128_MAX >> 1)) +#define INT128_MIN (-INT128_MAX - 1) +/* No (U)INT128_C macros because compilers providing __int128 do not support 128-bit literals. */ +# endif +#endif + +#ifndef __has_builtin +#define __has_builtin(x) 0 +#endif + +/* Determine the number of trailing zero bits in a (non-zero) 32-bit x. + * This function is only intended to be used as fallback for + * secp256k1_ctz32_var, but permits it to be tested separately. */ +static SECP256K1_INLINE int secp256k1_ctz32_var_debruijn(uint32_t x) { + static const uint8_t debruijn[32] = { + 0x00, 0x01, 0x02, 0x18, 0x03, 0x13, 0x06, 0x19, 0x16, 0x04, 0x14, 0x0A, + 0x10, 0x07, 0x0C, 0x1A, 0x1F, 0x17, 0x12, 0x05, 0x15, 0x09, 0x0F, 0x0B, + 0x1E, 0x11, 0x08, 0x0E, 0x1D, 0x0D, 0x1C, 0x1B + }; + return debruijn[((x & -x) * 0x04D7651F) >> 27]; +} + +/* Determine the number of trailing zero bits in a (non-zero) 64-bit x. + * This function is only intended to be used as fallback for + * secp256k1_ctz64_var, but permits it to be tested separately. */ +static SECP256K1_INLINE int secp256k1_ctz64_var_debruijn(uint64_t x) { + static const uint8_t debruijn[64] = { + 0, 1, 2, 53, 3, 7, 54, 27, 4, 38, 41, 8, 34, 55, 48, 28, + 62, 5, 39, 46, 44, 42, 22, 9, 24, 35, 59, 56, 49, 18, 29, 11, + 63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10, + 51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12 + }; + return debruijn[((x & -x) * 0x022FDD63CC95386D) >> 58]; +} + +/* Determine the number of trailing zero bits in a (non-zero) 32-bit x. */ +static SECP256K1_INLINE int secp256k1_ctz32_var(uint32_t x) { + VERIFY_CHECK(x != 0); +#if (__has_builtin(__builtin_ctz) || SECP256K1_GNUC_PREREQ(3,4)) + /* If the unsigned type is sufficient to represent the largest uint32_t, consider __builtin_ctz. */ + if (((unsigned)UINT32_MAX) == UINT32_MAX) { + return __builtin_ctz(x); + } #endif +#if (__has_builtin(__builtin_ctzl) || SECP256K1_GNUC_PREREQ(3,4)) + /* Otherwise consider __builtin_ctzl (the unsigned long type is always at least 32 bits). */ + return __builtin_ctzl(x); +#else + /* If no suitable CTZ builtin is available, use a (variable time) software emulation. */ + return secp256k1_ctz32_var_debruijn(x); +#endif +} + +/* Determine the number of trailing zero bits in a (non-zero) 64-bit x. */ +static SECP256K1_INLINE int secp256k1_ctz64_var(uint64_t x) { + VERIFY_CHECK(x != 0); +#if (__has_builtin(__builtin_ctzl) || SECP256K1_GNUC_PREREQ(3,4)) + /* If the unsigned long type is sufficient to represent the largest uint64_t, consider __builtin_ctzl. */ + if (((unsigned long)UINT64_MAX) == UINT64_MAX) { + return __builtin_ctzl(x); + } +#endif +#if (__has_builtin(__builtin_ctzll) || SECP256K1_GNUC_PREREQ(3,4)) + /* Otherwise consider __builtin_ctzll (the unsigned long long type is always at least 64 bits). */ + return __builtin_ctzll(x); +#else + /* If no suitable CTZ builtin is available, use a (variable time) software emulation. */ + return secp256k1_ctz64_var_debruijn(x); +#endif +} #endif /* SECP256K1_UTIL_H */ diff --git a/src/valgrind_ctime_test.c b/src/valgrind_ctime_test.c index 3169e3651c404..cfca5a196e0ca 100644 --- a/src/valgrind_ctime_test.c +++ b/src/valgrind_ctime_test.c @@ -1,10 +1,12 @@ -/********************************************************************** - * Copyright (c) 2020 Gregory Maxwell * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ +/*********************************************************************** + * Copyright (c) 2020 Gregory Maxwell * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ #include +#include + #include "include/secp256k1.h" #include "assumptions.h" #include "util.h" @@ -25,8 +27,42 @@ #include "include/secp256k1_schnorrsig.h" #endif +void run_tests(secp256k1_context *ctx, unsigned char *key); + int main(void) { secp256k1_context* ctx; + unsigned char key[32]; + int ret, i; + + if (!RUNNING_ON_VALGRIND) { + fprintf(stderr, "This test can only usefully be run inside valgrind.\n"); + fprintf(stderr, "Usage: libtool --mode=execute valgrind ./valgrind_ctime_test\n"); + return 1; + } + ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN + | SECP256K1_CONTEXT_VERIFY + | SECP256K1_CONTEXT_DECLASSIFY); + /** In theory, testing with a single secret input should be sufficient: + * If control flow depended on secrets the tool would generate an error. + */ + for (i = 0; i < 32; i++) { + key[i] = i + 65; + } + + run_tests(ctx, key); + + /* Test context randomisation. Do this last because it leaves the context + * tainted. */ + VALGRIND_MAKE_MEM_UNDEFINED(key, 32); + ret = secp256k1_context_randomize(ctx, key); + VALGRIND_MAKE_MEM_DEFINED(&ret, sizeof(ret)); + CHECK(ret); + + secp256k1_context_destroy(ctx); + return 0; +} + +void run_tests(secp256k1_context *ctx, unsigned char *key) { secp256k1_ecdsa_signature signature; secp256k1_pubkey pubkey; size_t siglen = 74; @@ -34,7 +70,6 @@ int main(void) { int i; int ret; unsigned char msg[32]; - unsigned char key[32]; unsigned char sig[74]; unsigned char spubkey[33]; #ifdef ENABLE_MODULE_RECOVERY @@ -45,26 +80,10 @@ int main(void) { secp256k1_keypair keypair; #endif - if (!RUNNING_ON_VALGRIND) { - fprintf(stderr, "This test can only usefully be run inside valgrind.\n"); - fprintf(stderr, "Usage: libtool --mode=execute valgrind ./valgrind_ctime_test\n"); - exit(1); - } - - /** In theory, testing with a single secret input should be sufficient: - * If control flow depended on secrets the tool would generate an error. - */ - for (i = 0; i < 32; i++) { - key[i] = i + 65; - } for (i = 0; i < 32; i++) { msg[i] = i + 1; } - ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN - | SECP256K1_CONTEXT_VERIFY - | SECP256K1_CONTEXT_DECLASSIFY); - /* Test keygen. */ VALGRIND_MAKE_MEM_UNDEFINED(key, 32); ret = secp256k1_ec_pubkey_create(ctx, &pubkey, key); @@ -122,12 +141,6 @@ int main(void) { VALGRIND_MAKE_MEM_DEFINED(&ret, sizeof(ret)); CHECK(ret == 1); - /* Test context randomisation. Do this last because it leaves the context tainted. */ - VALGRIND_MAKE_MEM_UNDEFINED(key, 32); - ret = secp256k1_context_randomize(ctx, key); - VALGRIND_MAKE_MEM_DEFINED(&ret, sizeof(ret)); - CHECK(ret); - /* Test keypair_create and keypair_xonly_tweak_add. */ #ifdef ENABLE_MODULE_EXTRAKEYS VALGRIND_MAKE_MEM_UNDEFINED(key, 32); @@ -140,6 +153,12 @@ int main(void) { ret = secp256k1_keypair_xonly_tweak_add(ctx, &keypair, msg); VALGRIND_MAKE_MEM_DEFINED(&ret, sizeof(ret)); CHECK(ret == 1); + + VALGRIND_MAKE_MEM_UNDEFINED(key, 32); + VALGRIND_MAKE_MEM_UNDEFINED(&keypair, sizeof(keypair)); + ret = secp256k1_keypair_sec(ctx, key, &keypair); + VALGRIND_MAKE_MEM_DEFINED(&ret, sizeof(ret)); + CHECK(ret == 1); #endif #ifdef ENABLE_MODULE_SCHNORRSIG @@ -151,7 +170,4 @@ int main(void) { VALGRIND_MAKE_MEM_DEFINED(&ret, sizeof(ret)); CHECK(ret == 1); #endif - - secp256k1_context_destroy(ctx); - return 0; }