php 接口中常用的aes加密

<?php
/**
 * Aes  对称加密
 */
class Aes {

    public $key;

    public function __construct($key){
        $this->key = $key;
        $this->iv  = $key;
    }

    /**
     * 加密   ECB - 128 - addPkcs7Padding
     */
    public function encrypts($data)
    {
        $encrypted = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $this->key, $this->addPkcs7Padding($data), MCRYPT_MODE_ECB,$this->iv);
        return base64_encode($encrypted);
    }

    /**
     * 解密
     */
    public function decrypts($data)
    {
        $data =base64_decode($data);
        return $this->stripPkcs7Padding(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $this->key, $data, MCRYPT_MODE_ECB, $this->iv));

    }


    public function addPkcs7Padding($string, $blocksize = 16) 
    {
        $len = strlen($string); //取得字符串长度
        $pad = $blocksize - ($len % $blocksize); //取得补码的长度
        $string .= str_repeat(chr($pad), $pad); //用ASCII码为补码长度的字符， 补足最后一段
        return $string;
    }


    public function stripPkcs7Padding($string){
        $slast = ord(substr($string, -1));
        $slastc = chr($slast);
        $pcheck = substr($string, -$slast);

        if(preg_match("/$slastc{".$slast."}/", $string)){
            $string = substr($string, 0, strlen($string)-$slast);
            return $string;
        } else {
            return false;
        }
    }
}

$sir   = 'zimakaimen';

$key  = md5($_POST['key'].$sir); 

$aes  = new Aes($key);

$data = $aes->decrypts($params);