Re: Where is EVP_aes_256_gcm?

[Matt Caswell (fr...@baggins.org)]

On 22/05/12 17:35, Li, David wrote:

Hi All,

I can't find this function in the source tree? It seems pointing to FIPS_aes_256_gcm. All I see is:

grep -r FIPS_evp_aes_256_gcm .

./crypto/evp/evp_fips.c:const EVP_CIPHER *EVP_aes_256_gcm(void) { return FIPS_evp_aes_256_gcm(); }

Anyone know where it is?

David

Its defined in ./crypto/evp/e_aes.c

Its cunningly hidden. See this line:

BLOCK_CIPHER_custom(NID_aes,256,1,12,gcm,GCM,
        EVP_CIPH_FLAG_FIPS|EVP_CIPH_FLAG_AEAD_CIPHER|CUSTOM_FLAGS)

With BLOCK_CIPHER_custom defined as:

#define BLOCK_CIPHER_custom(nid,keylen,blocksize,ivlen,mode,MODE,flags) \
static const EVP_CIPHER aesni_##keylen##_##mode = { \
    nid##_##keylen##_##mode,blocksize, \
    (EVP_CIPH_##MODE##_MODE==EVP_CIPH_XTS_MODE?2:1)*keylen/8, ivlen, \
    flags|EVP_CIPH_##MODE##_MODE,    \
    aesni_##mode##_init_key,    \
    aesni_##mode##_cipher,        \
    aes_##mode##_cleanup,        \
    sizeof(EVP_AES_##MODE##_CTX),    \
    NULL,NULL,aes_##mode##_ctrl,NULL }; \
static const EVP_CIPHER aes_##keylen##_##mode = { \
    nid##_##keylen##_##mode,blocksize, \
    (EVP_CIPH_##MODE##_MODE==EVP_CIPH_XTS_MODE?2:1)*keylen/8, ivlen, \
    flags|EVP_CIPH_##MODE##_MODE,    \
    aes_##mode##_init_key,        \
    aes_##mode##_cipher,        \
    aes_##mode##_cleanup,        \
    sizeof(EVP_AES_##MODE##_CTX),    \
    NULL,NULL,aes_##mode##_ctrl,NULL }; \
const EVP_CIPHER *EVP_aes_##keylen##_##mode(void) \
{ return AESNI_CAPABLE?&aesni_##keylen##_##mode:&aes_##keylen##_##mode; }


Matt