DES加解密

using System;
using System.Data;
using System.Data.SqlClient;
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.IO;
using System.Security.Cryptography;
using System.Text;

/// <summary>
/// myDes 的摘要说明
/// </summary>
///
    public class myDes
    {//
        public myDes()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }
        //加密方法
       public string Encrypt(string pToEncrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            //把字符串放到byte数组中 
            //原来使用的UTF8编码，我改成Unicode编码了，不行 
            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            //byte[]  inputByteArray=Encoding.Unicode.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);
            //Write  the  byte  array  into  the  crypto  stream 
            //(It  will  end  up  in  the  memory  stream) 
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            //Get  the  data  back  from  the  memory  stream,  and  into  a  string 
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                //Format  as  hex 
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();
        }

        //解密方法 
       public string Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            //Put  the  input  string  into  the  byte  array 
            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;
            }
            //建立加密对象的密钥和偏移量，此值重要，不能修改 
            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);
            //Flush  the  data  through  the  crypto  stream  into  the  memory  stream 
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            //Get  the  decrypted  data  back  from  the  memory  stream 
            //建立StringBuild对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象 
            StringBuilder ret = new StringBuilder();
            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }
    }