代码如下：

using System;
using System.Security.Cryptography;  
using System.Text;
namespace Maticsoft.Common.DEncrypt
{
 /// 
 /// DES加密/解密类。
    /// Copyright (C) Maticsoft
 /// 
 public class DESEncrypt
 {
  public DESEncrypt()
  {   
  }

#region ========加密======== 
/// 
/// 加密
/// 
/// 
/// 
  public static string Encrypt(string Text) 
  {
   return Encrypt(Text,"MATICSOFT");
  }
  ///  
  /// 加密数据 
  ///  
  ///  
  ///  
  ///  
  public static string Encrypt(string Text,string sKey) 
  { 
   DESCryptoServiceProvider des = new DESCryptoServiceProvider(); 
   byte[] inputByteArray; 
   inputByteArray=Encoding.Default.GetBytes(Text); 
   des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8)); 
   des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8)); 
   System.IO.MemoryStream ms=new System.IO.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); 
   } 
   return ret.ToString(); 
  }
#endregion
  
#region ========解密======== 
/// 
/// 解密
/// 
/// 
/// 
public static string Decrypt(string Text) 
{
   return Decrypt(Text,"MATICSOFT");
}
  ///  
  /// 解密数据 
  ///  
  ///  
  ///  
  ///  
  public static string Decrypt(string Text,string sKey) 
  { 
   DESCryptoServiceProvider des = new DESCryptoServiceProvider(); 
   int len; 
   len=Text.Length/2; 
   byte[] inputByteArray = new byte[len]; 
   int x,i; 
   for(x=0;x