int silc_message_signed_verify(SilcMessageSignedPayload sig,
                                   SilcMessagePayload message,
                                   SilcPublicKey remote_public_key,
                                   SilcHash hash);

    This routine can be used to verify the signature found in
    SilcMessageSignedPayload Payload.  This returns SILC_AUTH_OK if the
    signature verification was successful.