@deftypefun {int} {gnutls_fingerprint} (gnutls_digest_algorithm_t @var{algo}, const gnutls_datum_t * @var{data}, void * @var{result}, size_t * @var{result_size}) @var{algo}: is a digest algorithm @var{data}: is the data @var{result}: is the place where the result will be copied (may be null). @var{result_size}: should hold the size of the result. The actual size of the returned result will also be copied there. This function will calculate a fingerprint (actually a hash), of the given data. The result is not printable data. You should convert it to hex, or to something else printable. This is the usual way to calculate a fingerprint of an X.509 DER encoded certificate. Note however that the fingerprint of an OpenPGP certificate is not just a hash and cannot be calculated with this function. @strong{Returns:} On success, @code{GNUTLS_E_SUCCESS} (0) is returned, otherwise an error code is returned. @end deftypefun