PHP对称加密算法（DES/AES）类的实现代码

/**  * 常用对称加密算法类  * 支持密钥：64/128/256 bit（字节长度8/16/32）  * 支持算法：DES/AES（根据密钥长度自动匹配使用：DES:64bit AES:128/256bit）  * 支持模式：CBC/ECB/OFB/CFB  * 密文编码：base64字符串/十六进制字符串/二进制字符串流  * 填充方式: PKCS5Padding（DES）  *  * @author: linvo  * @version: 1.0.0  * @date: 2013/1/10  */  class Xcrypt{      private $mcrypt;    private $key;    private $mode;    private $iv;    private $blocksize;      /**    * 构造函数    *    * @param string 密钥    * @param string 模式    * @param string 向量（"off":不使用 / "auto":自动 / 其他:指定值，长度同密钥）    */    public function __construct($key, $mode = 'cbc', $iv = "off"){      switch (strlen($key)){      case 8:        $this->mcrypt = MCRYPT_DES;        break;      case 16:        $this->mcrypt = MCRYPT_RIJNDAEL_128;        break;      case 32:        $this->mcrypt = MCRYPT_RIJNDAEL_256;        break;      default:        die("Key size must be 8/16/32");      }        $this->key = $key;        switch (strtolower($mode)){      case 'ofb':        $this->mode = MCRYPT_MODE_OFB;        if ($iv == 'off') die('OFB must give a IV'); //OFB必须有向量        break;      case 'cfb':        $this->mode = MCRYPT_MODE_CFB;        if ($iv == 'off') die('CFB must give a IV'); //CFB必须有向量        break;      case 'ecb':        $this->mode = MCRYPT_MODE_ECB;        $iv = 'off'; //ECB不需要向量        break;      case 'cbc':      default:        $this->mode = MCRYPT_MODE_CBC;      }        switch (strtolower($iv)){      case "off":        $this->iv = null;        break;      case "auto":        $source = PHP_OS=='WINNT' ? MCRYPT_RAND : MCRYPT_DEV_RANDOM;        $this->iv = mcrypt_create_iv(mcrypt_get_block_size($this->mcrypt, $this->mode), $source);        break;      default:        $this->iv = $iv;      }      }      /**    * 获取向量值    * @param string 向量值编码（base64/hex/bin）    * @return string 向量值    */    public function getIV($code = 'base64'){      switch ($code){      case 'base64':        $ret = base64_encode($this->iv);        break;      case 'hex':        $ret = bin2hex($this->iv);        break;      case 'bin':      default:        $ret = $this->iv;      }      return $ret;    }      /**    * 加密    * @param string 明文    * @param string 密文编码（base64/hex/bin）    * @return string 密文    */    public function encrypt($str, $code = 'base64'){      if ($this->mcrypt == MCRYPT_DES) $str = $this->_pkcs5Pad($str);        if (isset($this->iv)) {        $result = mcrypt_encrypt($this->mcrypt, $this->key, $str, $this->mode, $this->iv);       } else {        @$result = mcrypt_encrypt($this->mcrypt, $this->key, $str, $this->mode);       }        switch ($code){      case 'base64':        $ret = base64_encode($result);        break;      case 'hex':        $ret = bin2hex($result);        break;      case 'bin':      default:        $ret = $result;      }        return $ret;      }      /**    * 解密     * @param string 密文    * @param string 密文编码（base64/hex/bin）    * @return string 明文    */    public function decrypt($str, $code = "base64"){        $ret = false;        switch ($code){      case 'base64':        $str = base64_decode($str);        break;      case 'hex':        $str = $this->_hex2bin($str);        break;      case 'bin':      default:      }        if ($str !== false){        if (isset($this->iv)) {          $ret = mcrypt_decrypt($this->mcrypt, $this->key, $str, $this->mode, $this->iv);         } else {          @$ret = mcrypt_decrypt($this->mcrypt, $this->key, $str, $this->mode);         }        if ($this->mcrypt == MCRYPT_DES) $ret = $this->_pkcs5Unpad($ret);      }        return $ret;     }       private function _pkcs5Pad($text){      $this->blocksize = mcrypt_get_block_size($this->mcrypt, $this->mode);       $pad = $this->blocksize - (strlen($text) % $this->blocksize);      return $text . str_repeat(chr($pad), $pad);    }      private function _pkcs5Unpad($text){      $pad = ord($text{strlen($text) - 1});      if ($pad > strlen($text)) return false;      if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) return false;      $ret = substr($text, 0, -1 * $pad);      return $ret;    }      private function _hex2bin($hex = false){      $ret = $hex !== false && preg_match('/^[0-9a-fA-F]+$/i', $hex) ? pack("H*", $hex) : false;        return $ret;    }    }  

<?php  header('Content-Type:text/html;Charset=utf-8;');    include "xcrypt.php";    echo '<pre>';  //////////////////////////////////////  $a = isset($_GET['a']) ? $_GET['a'] : '测试123';    //密钥  $key = '12345678123456781234567812345678'; //256 bit  $key = '1234567812345678'; //128 bit  $key = '12345678'; //64 bit    //设置模式和IV  $m = new Xcrypt($key, 'cbc', 'auto');    //获取向量值  echo '向量：';  var_dump($m->getIV());    //加密  $b = $m->encrypt($a, 'base64');  //解密  $c = $m->decrypt($b, 'base64');    echo '加密后：';  var_dump($b);  echo '解密后：';  var_dump($c);    /////////////////////////////////////////  echo '</pre>';