常用对称加密算法（DES/AES）类（PHP）

    /**      * 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);                  $ret = trim($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;          }                        }  

Demo:

    <?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>';  

转自：

http://blog.csdn.net/linvo/article/details/8497056

参考：

1.http://php.net/manual/en/function.mcrypt-encrypt.php