Hi,
As far as I understood, currently `gnutls-hash-mac' does not support nonce input, so there is no way to properly hash with some MAC algorithms which require nonce. (e.g AES-GMAC-128)
So I suggest adding an optional argument NONCE to `gnutls-hash-mac' to support MAC algorithms with nonce.
What I have tested after applying the attached patch are as below.
1. AES-GMC-128/192/256 works correctly.
2. NONCE does not affect SHA256/SHA512 hash results, even if presented.
Since NONCE is added as an optional argument, I believe it will not even affect existing code using the 'gnutls-hash-mac' function.
Thanks.
Seungki Kim
0001-add-nonce-support-for-gnutls-hash-mac.patch