php 可逆的加密算法

代码：

 <?php

 class Test {

     private $authCodeKey = 'khUvFB9pijNyCYMGZdzqeKalyg7dh';    

     function authCode($input, $key) {

         # Input must be of even length.
         if (strlen($input) % 2) {
             //$input .= '0';
         }

         # Keys longer than the input will be truncated.
         if (strlen($key) > strlen($input)) {
             $key = substr($key, 0, strlen($input));
         }

         # Keys shorter than the input will be padded.
         if (strlen($key) < strlen($input)) {
             $key = str_pad($key, strlen($input), '0', STR_PAD_RIGHT);
         }

         # Now the key and input are the same length.
         # Zero is used for any trailing padding required.

         # Simple XOR'ing, each input byte with each key byte.
         $result = '';
         for ($i = 0; $i < strlen($input); $i++) {
             $result .= $input{$i} ^ $key{$i};
         }
         return $result;
     }

     /**
      * 加密
      */
     function encrypt($sessionId) {

         $hashKey = $this->base64url_encode($this->authCode($sessionId, $this->authCodeKey));
         $hashKey = $this->base64url_encode($sessionId);
         return $hashKey;
     }

     /**
      * 解密
      */
     function decrypt($hashKey) {

         $authCodeKey = 'khUvFB9pijNyCYMGZdzqeKalyg7dh';
         $sessionId = $this->authCode($this->base64url_decode($hashKey), $this->authCodeKey);
         $sessionId = $this->base64url_decode($hashKey);
         return $sessionId;
     }

     // url传输需要替换部分字符
     function base64url_encode($data) {
         return rtrim(strtr(base64_encode($data), '+/', '-_'), '=');
     }
     // url传输需要替换部分字符
     function base64url_decode($data) {
         return base64_decode(str_pad(strtr($data, '-_', '+/'), strlen($data) % 4, '=', STR_PAD_RIGHT));
     }
 }

测试代码：

 $uId = 'gouge';
 $signKey = 'gouge-test123';
 $timestamp = time();

 // 需要加密的值 根据实际情况添加
 $signParam = array($uId, $timestamp, $signKey);
 $sessionId = implode(',', $signParam);

 $e = new Test();
 // 加密
 $r = $e->encrypt($sessionId);
 // 解密
 $t = $e->decrypt($r);

 echo $r;
 echo "<br/>";
 echo $t;

输出结果：

1、加密   =》Z291Z2UsMTQ5ODc5NTMxNixnb3VnZS10ZXN0MTIz

2、解密   =》gouge,1498795316,gouge-test123