if ((index = register_hash(&sha1_desc)) == -1)
return CRYPT_INVALID_HASH;
rc = hmac_memory(index, key, keylen, pt, tlen, tag, <aglen);
if ((index = register_hash(&sha1_desc)) == -1)
return CRYPT_INVALID_HASH;
rc = hmac_memory(index, key, keylen, pt, tlen, tag, <aglen);