KEY 是之前定义的常量
Mcrypt::encrypt();
Mcrypt::decrypt();

   defined('ROOT') or exit('Access Denied');    class Mcrypt{             public static function encrypt($code){          return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5(KEY), $code, MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND)));      }             public static function decrypt($code){          return mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5(KEY), base64_decode($code), MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND));      }    }