PHP实现加密解密算法

PHP实现加密解密的算法，如下代码：

class Mcrypt   
{   
    /**  
     * 解密  
     *   
     * @param string $encryptedText 已加密字符串  
     * @param string $key  密钥  
     * @return string  
     */   
    public static function _decrypt($encryptedText,$key = null)   
    {   
        $key = $key === null ? Config::get('secret_key') : $key;   
        $cryptText = base64_decode($encryptedText);   
        $ivSize = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);   
        $iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);   
        $decryptText = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $cryptText, MCRYPT_MODE_ECB, $iv);   
        return trim($decryptText);   
    }   
   
    /**  
     * 加密  
     *  
     * @param string $plainText 未加密字符串   
     * @param string $key        密钥  
     */   
    public static function _encrypt($plainText,$key = null)   
    {   
        $key = $key === null ? Config::get('secret_key') : $key;   
        $ivSize = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);   
        $iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);   
        $encryptText = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $plainText, MCRYPT_MODE_ECB, $iv);   
        return trim(base64_encode($encryptText));   
    }   
}   
 
//调用 
class Cookie extends Mcrypt   
{   
    /**  
     * 删除cookie  
     *   
     * @param array $args  
     * @return boolean  
     */   
    public static function del($args)   
    {   
        $name = $args['name'];   
        $domain = isset($args['domain']) ? $args['domain'] : null;   
        return isset($_COOKIE[$name]) ? setcookie($name, '', time() - 86400, '/', $domain) : true;   
    }   
       
    /**  
     * 得到指定cookie的值  
     *   
     * @param string $name  
     */   
    public static function get($name)   
    {   
        return isset($_COOKIE[$name]) ? parent::_decrypt($_COOKIE[$name]) : null;   
    }   
       
    /**  
     * 设置cookie  
     *  
     * @param array $args  
     * @return boolean  
     */   
    public static function set($args)   
    {   
        $name = $args['name'];   
        $value= parent::_encrypt($args['value']);   
        $expire = isset($args['expire']) ? $args['expire'] : null;   
        $path = isset($args['path']) ? $args['path'] : '/';   
        $domain = isset($args['domain']) ? $args['domain'] : null;   
        $secure = isset($args['secure']) ? $args['secure'] : 0;   
        return setcookie($name, $value, $expire, $path, $domain, $secure);   
    }   
}