



@deftypefun {int} {gnutls_openpgp_crt_get_auth_subkey} (gnutls_openpgp_crt_t @var{crt}, gnutls_openpgp_keyid_t @var{keyid}, unsigned int @var{flag})
@var{crt}: the structure that contains the OpenPGP public key.

@var{keyid}: the struct to save the keyid.

@var{flag}: Non-zero indicates that a valid subkey is always returned.

Returns the 64-bit keyID of the first valid OpenPGP subkey marked
for authentication.  If flag is non-zero and no authentication
subkey exists, then a valid subkey will be returned even if it is
not marked for authentication.

@strong{Returns:} @code{GNUTLS_E_SUCCESS}  on success, or an error code.
@end deftypefun
