php实现和c#一致的DES加密解密，可以从网上搜到一大堆，但是测试后发现都没法用。以下正确代码是我经过苦苦才找到的。希望大家在系统整合时能用的上。
注意：key的长度为8位以内。

//C# 版DES 加解密算法
using System;   
using System.Data;   
using System.Configuration;   
using System.Web;   
using System.Web.Security;   
using System.Web.UI;   
using System.Web.UI.WebControls;   
using System.Web.UI.WebControls.WebParts;   
using System.Web.UI.HtmlControls;   
using System.Data.SqlClient;   
using System.Security.Cryptography;   
using System.IO;   
using System.Text;   
public class Des{   
    //加解密密钥
    private static  string skey = "12345678";
    //初始化向量
    private static byte[] DESIV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF }; 
  
                #region DESEnCode DES加密   
                public static string DESEnCode(string pToEncrypt, string sKey)   
                {   
                    pToEncrypt = HttpContext.Current.Server.UrlEncode(pToEncrypt);   
                    DESCryptoServiceProvider des = new DESCryptoServiceProvider();   
                    byte[] inputByteArray = Encoding.GetEncoding("UTF-8").GetBytes(pToEncrypt);   
               
                    //建立加密对象的密钥和偏移量    
                    //原文使用ASCIIEncoding.ASCII方法的GetBytes方法    
                    //使得输入密码必须输入英文文本    
                    des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);   
                    des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);   
                    MemoryStream ms = new MemoryStream();   
                    CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);   
               
                    cs.Write(inputByteArray, 0, inputByteArray.Length);   
                    cs.FlushFinalBlock();   
               
                    StringBuilder ret = new StringBuilder();   
                    foreach (byte b in ms.ToArray())   
                    {   
                        ret.AppendFormat("{0:X2}", b);   
                    }   
                    ret.ToString();   
                    return ret.ToString();   
                }  
                #endregion  
                /// <summary>
                /// 
                /// </summary>
                /// <param name="pToDecrypt"> 待解密的字符串</param>
                /// <param name="sKey"> 解密密钥,要求为8字节,和加密密钥相同</param>
                /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
                #region DESDeCode DES解密
                public static string DESDeCode(string pToDecrypt, string sKey)
                {
                    //    HttpContext.Current.Response.Write(pToDecrypt + "<br>" + sKey);   
                    //    HttpContext.Current.Response.End();   
                    DESCryptoServiceProvider des = new DESCryptoServiceProvider();
             
                    byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
                    for (int x = 0; x < pToDecrypt.Length / 2; x++)
                    {
                        int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                        inputByteArray[x] = (byte)i;
                    }
             
                    des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
                    des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
                    MemoryStream ms = new MemoryStream();
                    CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
                    cs.Write(inputByteArray, 0, inputByteArray.Length);
                    cs.FlushFinalBlock();
             
                    StringBuilder ret = new StringBuilder();
             
                    return HttpContext.Current.Server.UrlDecode(System.Text.Encoding.Default.GetString(ms.ToArray()));
                }
    #endregion 
}     

<?php
class DES
{
	var $key;
	var $iv; //偏移量
	
	function DES( $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 = http://www.mamicode.com/"";>


原文出处：http://blog.csdn.net/e421083458/article/details/39373815
php实现和c#一致的DES加密解密