int
hmac_sha256 (const void *key, size_t keylen,
const void *in, size_t inlen, void *resbuf)
{
struct sha256_ctx inner;
struct sha256_ctx outer;
char optkeybuf[32];
char block[64];
char innerhash[32];
/* Reduce the key's size, so that it becomes <= 64 bytes large. */
if (keylen > 64)
{
struct sha256_ctx keyhash;
sha256_init_ctx (&keyhash);
sha256_process_bytes (key, keylen, &keyhash);
sha256_finish_ctx (&keyhash, optkeybuf);
key = optkeybuf;
keylen = 32;
}
/* Compute INNERHASH from KEY and IN. */
sha256_init_ctx (&inner);
memset (block, IPAD, sizeof (block));
memxor (block, key, keylen);
sha256_process_block (block, 64, &inner);
sha256_process_bytes (in, inlen, &inner);
sha256_finish_ctx (&inner, innerhash);
/* Compute result from KEY and INNERHASH. */
sha256_init_ctx (&outer);
memset (block, OPAD, sizeof (block));
memxor (block, key, keylen);
sha256_process_block (block, 64, &outer);
sha256_process_bytes (innerhash, 32, &outer);
sha256_finish_ctx (&outer, resbuf);
return 0;
}
//-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------//
// update hash
void sha256_t::update(const void * const p, uint64_t size)
{
if (this->psha256_item == NULL) return;
sha256_process_bytes(p, size, &this->ctx);
}
