Remove the sample program aescrypt2

The sample program aescrypt2 shows bad practice: hand-rolled CBC implementation, CBC+HMAC for AEAD, hand-rolled iterated SHA-2 for key stretching, no algorithm agility. The new sample program pbcrypt does the same thing, but better. So remove aescrypt2. Fix Mbed-TLS#1906 Signed-off-by: Gilles Peskine <[email protected]>
gilles-peskine-arm · Apr 28, 2021 · 98b3cd6 · 98b3cd6
1 parent b5939e8
commit 98b3cd6
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diff --git a/ChangeLog.d/aescrypt2.txt b/ChangeLog.d/aescrypt2.txt
@@ -0,0 +1,3 @@
+Changes
+   * Remove the AES sample application programs/aes/aescrypt2 which shows
+     bad cryptographic practice. Fix #1906.
diff --git a/programs/.gitignore b/programs/.gitignore
@@ -8,7 +8,6 @@
 *.o
 *.exe
 
-aes/aescrypt2
 aes/crypt_and_hash
 hash/generic_sum
 hash/hello

diff --git a/programs/Makefile b/programs/Makefile
@@ -56,7 +56,6 @@ LOCAL_LDFLAGS += -lz
 endif
 
 APPS = \
-	aes/aescrypt2$(EXEXT) \
 	aes/crypt_and_hash$(EXEXT) \
 	hash/generic_sum$(EXEXT) \
 	hash/hello$(EXEXT) \
@@ -139,10 +138,6 @@ $(MBEDLIBS):
 ${MBEDTLS_TEST_OBJS}:
 	$(MAKE) -C ../tests mbedtls_test
 
-aes/aescrypt2$(EXEXT): aes/aescrypt2.c $(DEP)
-	echo "  CC    aes/aescrypt2.c"
-	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) aes/aescrypt2.c    $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
-
 aes/crypt_and_hash$(EXEXT): aes/crypt_and_hash.c $(DEP)
 	echo "  CC    aes/crypt_and_hash.c"
 	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) aes/crypt_and_hash.c $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@

diff --git a/programs/README.md b/programs/README.md
@@ -5,9 +5,6 @@ This subdirectory mostly contains sample programs that illustrate specific featu
 
 ## Symmetric cryptography (AES) examples
 
-* [`aes/aescrypt2.c`](aes/aescrypt2.c): file encryption and authentication with a key derived from a low-entropy secret, demonstrating the low-level AES interface, the digest interface and HMAC.  
-  Warning: this program illustrates how to use low-level functions in the library. It should not be taken as an example of how to build a secure encryption mechanism. To derive a key from a low-entropy secret such as a password, use a standard key stretching mechanism such as PBKDF2 (provided by the `pkcs5` module). To encrypt and authenticate data, use a standard mode such as GCM or CCM (both available as library module).
-
 * [`aes/crypt_and_hash.c`](aes/crypt_and_hash.c): file encryption and authentication, demonstrating the generic cipher interface and the generic hash interface.
 
 ## Hash (digest) examples

diff --git a/programs/aes/CMakeLists.txt b/programs/aes/CMakeLists.txt
@@ -1,5 +1,4 @@
 set(executables
-    aescrypt2
     crypt_and_hash
 )