@deftypefun {const char *} {gnutls_digest_get_oid} (gnutls_digest_algorithm_t @var{algorithm}) @var{algorithm}: is a digest algorithm Convert a @code{gnutls_digest_algorithm_t} value to its object identifier. @strong{Returns:} a string that contains the object identifier of the specified digest algorithm, or @code{NULL} . @strong{Since:} 3.4.3 @end deftypefun