diff options
Diffstat (limited to '')
| -rw-r--r-- | hmac_init.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/hmac_init.c b/hmac_init.c new file mode 100644 index 0000000..4aee2c2 --- /dev/null +++ b/hmac_init.c @@ -0,0 +1,45 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" + + +/** + * Initialise an HMAC state + * + * @param state The state that should be initialised + * @param algorithm The hashing algorithm + * @param key The key + * @param key_length The length of key, in bits + * @return Zero on success, -1 on error + */ +int +libsha2_hmac_init(struct libsha2_hmac_state *restrict state, enum libsha2_algorithm algorithm, + const void *restrict key_, size_t keylen) +{ + const unsigned char *restrict key = key_; + size_t i; + + state->sha2_state.algorithm = algorithm; + state->outsize = libsha2_algorithm_output_size(algorithm) * 8; + state->inited = 0; + + if (keylen <= state->sha2_state.chunk_size * 8) { + memset(state->ipad, 0x36, sizeof(state->ipad)); + memset(state->opad, 0x5C, sizeof(state->opad)); + for (i = 0, keylen /= 8; i < keylen; i++) { + state->ipad[i] ^= key[i]; + state->opad[i] ^= key[i]; + } + } else { + memset(state->ipad, 0, sizeof(state->ipad)); + if (libsha2_init(&state->sha2_state, algorithm)) + return -1; + libsha2_digest(&state->sha2_state, key, keylen, state->ipad); + memcpy(state->opad, state->ipad, sizeof(state->ipad)); + for (i = 0; i < sizeof(state->ipad); i++) { + state->ipad[i] ^= 0x36; + state->opad[i] ^= 0x5C; + } + } + + return 0; +} |