/**  * 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>';