ServerMessageBlock msg = (ServerMessageBlock) m;

        if ( ( msg.getFlags2() & SmbConstants.FLAGS2_SECURITY_SIGNATURES ) == 0 ) {
            // signature requirements need to be checked somewhere else
            log.warn("Expected signed response, but is not signed");
            return false;
        }

        update(this.macSigningKey, 0, this.macSigningKey.length);
        int index = offset;