<?php

/**

*

* PHP版3DES加解密类

*

* 可与java的3DES(DESede)加密方式兼容

*

* @Author:蓝凤(ilanfeng.com)

*

* @version: V0.1 2011.02.18

*

*/

class Cc3des{

    //加密的时候只用替换key就行了，ecb模式不需要提供iv值

    public $key    = "0123456789QWEQWEEWQQ1234";

    public $iv    = "33889955"; //like java: private static byte[] myIV = { 50, 51, 52, 53, 54, 55, 56, 57 };

    //解密

    public function decrypt($string) {

        $td = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_ECB, '');

        srand();

        $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);

        $key = substr($this->key, 0, mcrypt_enc_get_key_size($td));

        mcrypt_generic_init($td, $key, $iv);

        $value = @pack("H*", $string);

        $ret = trim(mdecrypt_generic($td, $value));

        // 去掉多余的补位

        $ret = $this->pkcs5_unpad($ret);

        mcrypt_generic_deinit($td);

        mcrypt_module_close($td);

        return $ret;

    }

    //加密

    public function encrypt($value) {

        $td = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_ECB, '');

        srand();

        $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);

        $key = substr($this->key, 0, mcrypt_enc_get_key_size($td));

        mcrypt_generic_init($td, $key, $iv);

        $value = $this->pkcs5_pad($value, mcrypt_get_block_size(MCRYPT_3DES, 'ecb'));

        $ret = mcrypt_generic($td, $value);

        mcrypt_generic_deinit($td);

        mcrypt_module_close($td);

        return strtoupper(bin2hex($ret));

    }

    /*

     * 位数补齐

     */

    private function pkcs5_pad($text, $blocksize) {

        $pad = $blocksize - (strlen($text) % $blocksize);

        return $text . str_repeat(chr($pad), $pad);

    }

    /*

     * 去除补位

     */

    private function pkcs5_unpad($text) {

        $pad = ord($text{strlen($text) - 1});

        if($pad > strlen($text)) {

            return false;

        }

        if(strspn($text, chr($pad), strlen($text) - $pad) != $pad) {

            return false;

        }

        return substr($text, 0, -1 * $pad);

    }

}

?>