<?php
//可用于加密解密，如cookie，账号，手机号 as so on

class DES

{

	var $key;

	var $iv; //偏移量

	function __construct( $key, $iv=0 ) {

	//key长度8例如:1234abcd

		$this->key = $key;

		if( $iv == 0 ) {

			$this->iv = $key; //默认以$key 作为 iv

		} else {

			$this->iv = $iv; //mcrypt_create_iv ( mcrypt_get_block_size (MCRYPT_DES, MCRYPT_MODE_CBC), MCRYPT_DEV_RANDOM );

		}

	}

	function encrypt($str) {

	//加密，返回大写十六进制字符串

		$size = mcrypt_get_block_size ( MCRYPT_DES, MCRYPT_MODE_CBC );

		$str = $this->pkcs5Pad ( $str, $size );

		return strtoupper( bin2hex( mcrypt_cbc(MCRYPT_DES, $this->key, $str, MCRYPT_ENCRYPT, $this->iv ) ) );

	}

	function decrypt($str) {

	//解密

		$strBin = $this->hex2bin( strtolower( $str ) );

		$str = mcrypt_cbc( MCRYPT_DES, $this->key, $strBin, MCRYPT_DECRYPT, $this->iv );

		$str = $this->pkcs5Unpad( $str );

		return $str;

	}

	function hex2bin($hexData) {

		$binData = "";

		for($i = 0; $i < strlen ( $hexData ); $i += 2) {

			$binData .= chr ( hexdec ( substr ( $hexData, $i, 2 ) ) );

		}

		return $binData;

	}

	function pkcs5Pad($text, $blocksize) {

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

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

	}

	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;

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

	}

}

// 实例化，并传入两个参数，都为8位,即 KEY, VI的值

$des = new DES('abcd1234', '87654321');

//加密结果 $aa 为 7A3C7BBA8B42ADC4

$str = '123456';

$aa = $des->encrypt($str);

echo $aa;

// 解密结果 $bb 为 123456

$bb = $des->decrypt($aa);

echo $bb;

?>