/// <summary>
        /// 3DES加密方法
        /// </summary>
        /// <param name="strPlain">明文</param>
        /// <param name="strDESKey">密钥</param>
        /// <param name="strDESIV">向量</param>
        /// <param name="ReturnBytes">标志位，如果返回数组则填写标志位</param>
        /// <returns>密文</returns>
        public static byte[] TripleDESEncrypt(string strPlain, string strDESKey, string strDESIV, bool ReturnBytes)
        {
            //把密钥转换成字节数组
            byte[] bytesDESKey = ASCIIEncoding.ASCII.GetBytes(strDESKey);
            //把向量转换成字节数组
            byte[] bytesDESIV = ASCIIEncoding.ASCII.GetBytes(strDESIV);
            //声明1个新的3DES对象
            TripleDESCryptoServiceProvider tripledesEncrypt = new TripleDESCryptoServiceProvider();
            //开辟一块内存流
            MemoryStream msEncrypt = new MemoryStream();
            //把内存流对象包装成加密流对象
            CryptoStream csEncrypt = new CryptoStream(msEncrypt, tripledesEncrypt.CreateEncryptor(bytesDESKey, bytesDESIV), CryptoStreamMode.Write);
            //把加密流对象包装成写入流对象
            StreamWriter swEncrypt = new StreamWriter(csEncrypt);
            //写入流对象写入明文
            swEncrypt.WriteLine(strPlain);
            //写入流关闭
            swEncrypt.Close();
            //加密流关闭
            csEncrypt.Close();
            //把内存流转换成字节数组，内存流现在已经是密文了
            byte[] bytesCipher = msEncrypt.ToArray();
            //内存流关闭
            msEncrypt.Close();
            tripledesEncrypt.Clear();
            return bytesCipher;
        }

        /// <summary>
        /// 3DES解密方法
        /// </summary>
        /// <param name="bytes">包含密文的字节数组</param>
        /// <param name="lenght">字节数组中需要加密的字节长度</param>
        /// <param name="strDESKey">密钥</param>
        /// <param name="strDESIV">向量</param>
        /// <returns>明文</returns>
        public static string TripleDESDecrypt(byte[] bytes, int lenght, string strDESKey, string strDESIV)
        {
            //把密钥转换成字节数组
            byte[] bytesDESKey = ASCIIEncoding.ASCII.GetBytes(strDESKey);
            //把向量转换成字节数组
            byte[] bytesDESIV = ASCIIEncoding.ASCII.GetBytes(strDESIV);
            byte[] bytesCipher = new byte[lenght];
            Array.Copy(bytes, bytesCipher, lenght);
            //声明1个新的3DES对象
            TripleDESCryptoServiceProvider tripledesDecrypt = new TripleDESCryptoServiceProvider();
            //开辟一块内存流，并存放密文字节数组
            MemoryStream msDecrypt = new MemoryStream(bytesCipher);
            //把内存流对象包装成解密流对象
            CryptoStream csDecrypt = new CryptoStream(msDecrypt, tripledesDecrypt.CreateDecryptor(bytesDESKey, bytesDESIV), CryptoStreamMode.Read);
            //把解密流对象包装成读出流对象
            StreamReader srDecrypt = new StreamReader(csDecrypt);
            //明文=读出流的读出内容
            string strPlainText = srDecrypt.ReadLine();
            //读出流关闭
            srDecrypt.Close();
            //解密流关闭
            csDecrypt.Close();
            //内存流关闭
            msDecrypt.Close();
            //返回明文
            tripledesDecrypt.Clear();
            return strPlainText;
        }

//然后用这两个方法对字符串加密：
sMsg = "{\rtf1\ansi\ansicpg936\deff0\deflang1033\deflangfe2052{\fonttbl{\f0\fnil\fcharset134 \'cb\'ce\'cc\'e5;}}
\viewkind4\uc1\pard\lang2052\f0\fs18 1
}";
byte[] ByteData = Security.TripleDESEncrypt(sMsg, strKey,strIV, true);
//进行解密：
string s = TripleDESDecrypt(ByteData, ByteData.Length,strKey,strIV);
//解密后字符串为：{\rtf1\ansi\ansicpg936\deff0\deflang1033\deflangfe2052{\font