



@deftypefun {int} {gnutls_hmac_init} (gnutls_hmac_hd_t * @var{dig}, gnutls_mac_algorithm_t @var{algorithm}, const void * @var{key}, size_t @var{keylen})
@var{dig}: is a @code{gnutls_hmac_hd_t}  structure.

@var{algorithm}: the HMAC algorithm to use

@var{key}: The key to be used for encryption

@var{keylen}: The length of the key

This function will initialize an context that can be used to
produce a Message Authentication Code (MAC) of data.  This will
effectively use the current crypto backend in use by gnutls or the
cryptographic accelerator in use.

@strong{Returns:} Zero or a negative error code on error.

@strong{Since:} 2.10.0
@end deftypefun
