PassportModel::jiemi PHP Method

    private function jiemi($txt, $key = null)
    {
        empty($key) && ($key = C('SECURE_CODE'));
        //有mcrypt扩展时
        if (function_exists('mcrypt_module_open')) {
            return desdecrypt($txt, $key);
        }
        //无mcrypt扩展时
        return tsauthcode($text, 'DECODE', $key);
    }