Minimize secp256k1 precomputed table

The size is reduced from more than 1M to 128 bytes only The verification cycles is increased from 1.4M to 1.7M.
XuJiandong · Feb 5, 2024 · 8d20c61 · 8d20c61
1 parent f7988ed
commit 8d20c61
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Showing 6 changed files with 24 additions and 52 deletions.
diff --git a/Makefile b/Makefile
@@ -38,6 +38,9 @@ build/always_success: c/always_success.c
 build/secp256k1_data_info_20210801.h: build/dump_secp256k1_data_20210801
 	$<
 
+c/secp256k1_data_20210801.h: build/secp256k1_data_20210801
+	xxd -i -name ckb_secp256k1_data $< > $@
+
 build/dump_secp256k1_data_20210801: c/dump_secp256k1_data_20210801.c $(SECP256K1_SRC_20210801)
 	mkdir -p build
 	gcc -I deps/secp256k1-20210801/src -I deps/secp256k1-20210801 -o $@ $<
@@ -46,13 +49,9 @@ build/dump_secp256k1_data_20210801: c/dump_secp256k1_data_20210801.c $(SECP256K1
 $(SECP256K1_SRC_20210801):
 	cd deps/secp256k1-20210801 && \
 		./autogen.sh && \
-		CC=$(CC) LD=$(LD) ./configure --with-bignum=no --enable-ecmult-static-precomputation --enable-endomorphism --enable-module-recovery --host=$(TARGET) && \
+		CC=$(CC) LD=$(LD) ./configure --enable-ecmult-static-precomputation --with-ecmult-window=2 --enable-module-recovery --host=$(TARGET) && \
 		make src/ecmult_static_pre_context.h src/ecmult_static_context.h
 
-
-build/impl.o: deps/ckb-c-std-lib/libc/src/impl.c
-	$(CC) -c $(filter-out -DCKB_DECLARATION_ONLY, $(CFLAGS_MBEDTLS)) $(LDFLAGS_MBEDTLS) -o $@ $^
-
 ${PROTOCOL_SCHEMA}:
 	curl -L -o $@ ${PROTOCOL_URL}
 

diff --git a/c/ckb_identity.h b/c/ckb_identity.h
@@ -163,8 +163,7 @@ static int _ckb_recover_secp256k1_pubkey(const uint8_t *sig, size_t sig_len,
 
   /* Load signature */
   secp256k1_context context;
-  uint8_t secp_data[CKB_SECP256K1_DATA_SIZE];
-  ret = ckb_secp256k1_custom_verify_only_initialize(&context, secp_data);
+  ret = ckb_secp256k1_custom_verify_only_initialize(&context, NULL);
   if (ret != 0) {
     return ret;
   }
@@ -285,8 +284,7 @@ static int _recover_secp256k1_pubkey_btc(const uint8_t *sig, size_t sig_len,
   }
 
   secp256k1_context context;
-  uint8_t secp_data[CKB_SECP256K1_DATA_SIZE];
-  ret = ckb_secp256k1_custom_verify_only_initialize(&context, secp_data);
+  ret = ckb_secp256k1_custom_verify_only_initialize(&context, NULL);
   if (ret != 0) {
     return ret;
   }
@@ -823,8 +821,7 @@ int verify_multisig(const uint8_t *lock_bytes, size_t lock_bytes_len,
   // contract, you don't have to wait for the foundation to ship a new
   // cryptographic algorithm. You can just build and ship your own.
   secp256k1_context context;
-  uint8_t secp_data[CKB_SECP256K1_DATA_SIZE];
-  ret = ckb_secp256k1_custom_verify_only_initialize(&context, secp_data);
+  ret = ckb_secp256k1_custom_verify_only_initialize(&context, NULL);
   if (ret != 0) return ret;
 
   // We will perform *threshold* number of signature verifications here.

diff --git a/c/dump_secp256k1_data_20210801.c b/c/dump_secp256k1_data_20210801.c
@@ -42,14 +42,6 @@ int main(int argc, char* argv[]) {
                  pre128_size);
   blake2b_final(&blake2b_ctx, hash, 32);
 
-  fprintf(fp, "static uint8_t ckb_secp256k1_data_hash[32] = {\n  ");
-  for (int i = 0; i < 32; i++) {
-    fprintf(fp, "%u", hash[i]);
-    if (i != 31) {
-      fprintf(fp, ", ");
-    }
-  }
-  fprintf(fp, "\n};\n");
   fprintf(fp, "#endif\n");
   fclose(fp);
 

diff --git a/c/secp256k1_data_20210801.h b/c/secp256k1_data_20210801.h
@@ -0,0 +1,14 @@
+unsigned char ckb_secp256k1_data[] = {
+  0x98, 0x17, 0xf8, 0x16, 0x5b, 0x81, 0xf2, 0x59, 0xd9, 0x28, 0xce, 0x2d,
+  0xdb, 0xfc, 0x9b, 0x02, 0x07, 0x0b, 0x87, 0xce, 0x95, 0x62, 0xa0, 0x55,
+  0xac, 0xbb, 0xdc, 0xf9, 0x7e, 0x66, 0xbe, 0x79, 0xb8, 0xd4, 0x10, 0xfb,
+  0x8f, 0xd0, 0x47, 0x9c, 0x19, 0x54, 0x85, 0xa6, 0x48, 0xb4, 0x17, 0xfd,
+  0xa8, 0x08, 0x11, 0x0e, 0xfc, 0xfb, 0xa4, 0x5d, 0x65, 0xc4, 0xa3, 0x26,
+  0x77, 0xda, 0x3a, 0x48, 0xda, 0xc0, 0xc4, 0x9e, 0x4c, 0x44, 0x7b, 0x1b,
+  0x35, 0xa3, 0x3e, 0x72, 0x78, 0x56, 0x8c, 0xe8, 0x2e, 0x16, 0x1f, 0x98,
+  0xad, 0xc1, 0x39, 0x92, 0x33, 0x5f, 0x3b, 0xf6, 0xd2, 0xb9, 0x68, 0x8f,
+  0x82, 0xff, 0x1f, 0x50, 0x79, 0xbf, 0x3c, 0xf2, 0xfd, 0x0b, 0x51, 0x95,
+  0xfe, 0x2c, 0xea, 0xbb, 0x5d, 0x21, 0xbe, 0xb6, 0xc2, 0x90, 0x1d, 0xde,
+  0x86, 0x39, 0x06, 0xba, 0x2d, 0x9f, 0x2a, 0x66
+};
+unsigned int ckb_secp256k1_data_len = 128;
diff --git a/c/secp256k1_helper_20210801.h b/c/secp256k1_helper_20210801.h
@@ -16,6 +16,7 @@
 #define HAVE_CONFIG_H 1
 #define USE_EXTERNAL_DEFAULT_CALLBACKS
 #include <secp256k1.c>
+#include "secp256k1_data_20210801.h"
 
 void secp256k1_default_illegal_callback_fn(const char* str, void* data) {
   (void)str;
@@ -35,38 +36,6 @@ void secp256k1_default_error_callback_fn(const char* str, void* data) {
  */
 int ckb_secp256k1_custom_verify_only_initialize(secp256k1_context* context,
                                                 void* data) {
-  size_t index = 0;
-  int running = 1;
-  while (running && index < SIZE_MAX) {
-    uint64_t len = 32;
-    uint8_t hash[32];
-
-    int ret = ckb_load_cell_by_field(hash, &len, 0, index, CKB_SOURCE_CELL_DEP,
-                                     CKB_CELL_FIELD_DATA_HASH);
-    switch (ret) {
-      case CKB_ITEM_MISSING:
-        break;
-      case CKB_SUCCESS:
-        if (memcmp(ckb_secp256k1_data_hash, hash, 32) == 0) {
-          /* Found a match, load data here */
-          len = CKB_SECP256K1_DATA_SIZE;
-          ret = ckb_load_cell_data(data, &len, 0, index, CKB_SOURCE_CELL_DEP);
-          if (ret != CKB_SUCCESS || len != CKB_SECP256K1_DATA_SIZE) {
-            return CKB_SECP256K1_HELPER_ERROR_LOADING_DATA;
-          }
-          running = 0;
-        }
-        break;
-      default:
-        return CKB_SECP256K1_HELPER_ERROR_LOADING_DATA;
-    }
-    if (running) {
-      index++;
-    }
-  }
-  if (index == SIZE_MAX) {
-    return CKB_SECP256K1_HELPER_ERROR_LOADING_DATA;
-  }
 
   context->illegal_callback = default_illegal_callback;
   context->error_callback = default_error_callback;
@@ -75,7 +44,7 @@ int ckb_secp256k1_custom_verify_only_initialize(secp256k1_context* context,
   secp256k1_ecmult_gen_context_init(&context->ecmult_gen_ctx);
 
   /* Recasting data to (uint8_t*) for pointer math */
-  uint8_t* p = data;
+  uint8_t* p = ckb_secp256k1_data;
   secp256k1_ge_storage(*pre_g)[] = (secp256k1_ge_storage(*)[])p;
   secp256k1_ge_storage(*pre_g_128)[] =
       (secp256k1_ge_storage(*)[])(&p[CKB_SECP256K1_DATA_PRE_SIZE]);

diff --git a/tests/omni_lock_rust/tests/test_secp256k1_compatibility.rs b/tests/omni_lock_rust/tests/test_secp256k1_compatibility.rs
@@ -39,6 +39,7 @@ fn test_sighash_all_unlock() {
     let mut verifier = verify_tx(resolved_tx, data_loader.clone());
     verifier.set_debug_printer(debug_printer);
     let verify_result = verifier.verify(MAX_CYCLES);
+    print!("cycles = {}", verify_result.clone().unwrap());
     verify_result.expect("pass verification");
 }