The crypto_auth_hmacsha512() function authenticates a message message using the secret key skey, and puts the authenticator into mac. Returns 0? on success.
This alternative API supports a key of arbitrary length
The crypto_auth_hmacsha512_verify() function verifies in constant time that h is a correct authenticator for the message in whose length is inlen under a secret key k. It returns -1 if the verification fails, and 0 on success.