.NET DES 加密

using System;
using System.Collections.Generic;
using System.Text;
using System.Security;
using System.IO;
using System.Security.Cryptography;

namespace DLProject
{
    class EncryptAndDecrypt
    {
        /// <summary>
        /// 对字符串进行DES加密
        /// </summary>
        /// <param >将要加密的字符串</param>
        /// <param >密钥值（需为8位字符串）</param>
        /// <returns></returns>
        public string EncryptString(string sInputString, string sKey)
        {
            byte[] data = Encoding.ASCII.GetBytes(sInputString);
            DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
            DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();  //创建其支持存储区为内存的流。
            CryptoStream cs = new CryptoStream(ms, DES.CreateEncryptor(), CryptoStreamMode.Write);//将数据流连接到加密转换流
            cs.Write(data, 0, data.Length);
            cs.FlushFinalBlock();  //用缓冲区的当前状态更新基础数据源或储存库，随后清除缓
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            return ret.ToString();
        }
        // DES解密字符串
        public string DecryptString(string sInputString, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            //Put  the  input  string  into  the  byte  array  
            byte[] inputByteArray = new byte[sInputString.Length / 2];
            for (int x = 0; x < sInputString.Length; x += 2)
            {
                int i = Convert.ToInt32(sInputString.Substring(x, 2), 16);
                inputByteArray[x / 2] = (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);
            //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.UTF8.GetString(ms.ToArray());

        }

    }
}