using System;

　　using System.Text;

　　using System.Security.Cryptography;

　　using System.IO;

　　//默认密钥向量

　　private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

　　/// <summary>

　　/// DES加密字符串

　　/// </summary>

　　/// <param name="encryptString">待加密的字符串</param>

　　/// <param name="encryptKey">加密密钥,要求为8位</param>

　　/// <returns>加密成功返回加密后的字符串，失败返回源串</returns>

　　public static string EncryptDES(string encryptString, string encryptKey)

　　{

　　try

　　{

　　byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));

　　byte[] rgbIV = Keys;

　　byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);

　　DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();

　　MemoryStream mStream = new MemoryStream();

　　CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

　　cStream.Write(inputByteArray, 0, inputByteArray.Length);

　　cStream.FlushFinalBlock();

　　return Convert.ToBase64String(mStream.ToArray());

　　}

　　catch

　　{

　　return encryptString;

　　}

　　}

　　/// <summary>

　　/// DES解密字符串

　　/// </summary>

　　/// <param name="decryptString">待解密的字符串</param>

　　/// <param name="decryptKey">解密密钥,要求为8位,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>

　　public static string DecryptDES(string decryptString, string decryptKey)

　　{

　　try

　　{

　　byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);

　　byte[] rgbIV = Keys;

　　byte[] inputByteArray = Convert.FromBase64String(decryptString);

　　DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();

　　MemoryStream mStream = new MemoryStream();

　　CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

　　cStream.Write(inputByteArray, 0, inputByteArray.Length);

　　cStream.FlushFinalBlock();

　　return Encoding.UTF8.GetString(mStream.ToArray());

　　}

　　catch

　　{

　　return decryptString;

　　}

　　}