void hmac_sha512(const void *key_p, const uint32_t keylen, const void *msg_p, const uint32_t msglen, uint8_t *hmac)
{
const uint8_t *key = key_p;
const uint8_t *msg = msg_p;
int i;
uint8_t buf[SHA512_BLOCK_LENGTH], o_key_pad[SHA512_BLOCK_LENGTH], i_key_pad[SHA512_BLOCK_LENGTH];
SHA512_CTX ctx;
memset(buf, 0, SHA512_BLOCK_LENGTH);
if (keylen > SHA512_BLOCK_LENGTH) {
sha512_Raw(key, keylen, buf);
} else {
memcpy(buf, key, keylen);
}
for (i = 0; i < SHA512_BLOCK_LENGTH; i++) {
o_key_pad[i] = buf[i] ^ 0x5c;
i_key_pad[i] = buf[i] ^ 0x36;
}
sha512_Init(&ctx);
sha512_Update(&ctx, i_key_pad, SHA512_BLOCK_LENGTH);
sha512_Update(&ctx, msg, msglen);
sha512_Final(buf, &ctx);
sha512_Init(&ctx);
sha512_Update(&ctx, o_key_pad, SHA512_BLOCK_LENGTH);
sha512_Update(&ctx, buf, SHA512_DIGEST_LENGTH);
sha512_Final(hmac, &ctx);
MEMSET_BZERO(buf, sizeof(buf));
MEMSET_BZERO(o_key_pad, sizeof(o_key_pad));
MEMSET_BZERO(i_key_pad, sizeof(i_key_pad));
}
void hmac_sha512_prepare(const uint8_t *key, const uint32_t keylen,
uint64_t *opad_digest, uint64_t *ipad_digest) {
static CONFIDENTIAL uint64_t key_pad[SHA512_BLOCK_LENGTH / sizeof(uint64_t)];
memzero(key_pad, sizeof(key_pad));
if (keylen > SHA512_BLOCK_LENGTH) {
static CONFIDENTIAL SHA512_CTX context;
sha512_Init(&context);
sha512_Update(&context, key, keylen);
sha512_Final(&context, (uint8_t *)key_pad);
} else {
memcpy(key_pad, key, keylen);
}
/* compute o_key_pad and its digest */
for (int i = 0; i < SHA512_BLOCK_LENGTH / (int)sizeof(uint64_t); i++) {
uint64_t data;
#if BYTE_ORDER == LITTLE_ENDIAN
REVERSE64(key_pad[i], data);
#else
data = key_pad[i];
#endif
key_pad[i] = data ^ 0x5c5c5c5c5c5c5c5c;
}
sha512_Transform(sha512_initial_hash_value, key_pad, opad_digest);
/* convert o_key_pad to i_key_pad and compute its digest */
for (int i = 0; i < SHA512_BLOCK_LENGTH / (int)sizeof(uint64_t); i++) {
key_pad[i] = key_pad[i] ^ 0x5c5c5c5c5c5c5c5c ^ 0x3636363636363636;
}
sha512_Transform(sha512_initial_hash_value, key_pad, ipad_digest);
memzero(key_pad, sizeof(key_pad));
}
void hmac_sha512_Final(HMAC_SHA512_CTX *hctx, uint8_t *hmac) {
sha512_Final(&(hctx->ctx), hmac);
sha512_Init(&(hctx->ctx));
sha512_Update(&(hctx->ctx), hctx->o_key_pad, SHA512_BLOCK_LENGTH);
sha512_Update(&(hctx->ctx), hmac, SHA512_DIGEST_LENGTH);
sha512_Final(&(hctx->ctx), hmac);
memzero(hctx, sizeof(HMAC_SHA512_CTX));
}
void hmac_sha512_Init(HMAC_SHA512_CTX *hctx, const uint8_t *key,
const uint32_t keylen) {
static CONFIDENTIAL uint8_t i_key_pad[SHA512_BLOCK_LENGTH];
memzero(i_key_pad, SHA512_BLOCK_LENGTH);
if (keylen > SHA512_BLOCK_LENGTH) {
sha512_Raw(key, keylen, i_key_pad);
} else {
memcpy(i_key_pad, key, keylen);
}
for (int i = 0; i < SHA512_BLOCK_LENGTH; i++) {
hctx->o_key_pad[i] = i_key_pad[i] ^ 0x5c;
i_key_pad[i] ^= 0x36;
}
sha512_Init(&(hctx->ctx));
sha512_Update(&(hctx->ctx), i_key_pad, SHA512_BLOCK_LENGTH);
memzero(i_key_pad, sizeof(i_key_pad));
}
