为什么小弟我用TDES(3重DES加密算法)加密解密字符串后，该字符串少了一截

请教大家为什么我用TDES(3重DES加密算法)加密解密字符串后，该字符串少了一截？
我用TripleDES加密一个字符串，且设置该算法的KEY和IV设置为固定值。
但是用这个加密一个字符串后生成字节数组。
然后对该字节数组用同样用TripleDES解密，却发现少了一截数据，不知道为什么，请大家帮忙看看。

代码如下：

C# code

        /// <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{\fonttbl{\f0\fnil\fcharset134 \'cb\'ce\'cc\'e5;}}

up
[解决办法]
//明文=读出流的读出内容
string strPlainText = srDecrypt.ReadToEnd();
 
[解决办法]
几个建议，
一是不要对每行代码进行注释，善来注释用来解释你的意图。
二是对IDisposable要善于利用using模式 - 它更健壮而且可以省掉很多麻烦。

C# code

/// <summary>///  你的注释.../// </summary>public static string TripleDESDecrypt(byte[] bytes, int lenght, string DESKey, string DESIv){    byte[] bytesDESKey = ASCIIEncoding.ASCII.GetBytes(DESKey);    byte[] bytesDESIV = ASCIIEncoding.ASCII.GetBytes(DESIv);        // 为什么要拷贝...    byte[] bytesCipher = new byte[ Length ];    Array.Copy(bytes, bytesCipher, lenght);    using( TripleDESCryptoServiceProvider tripledes = new TripleDESCryptoServiceProvider())    using( MemoryStream ms = new MemoryStream(bytesCipher) )    using( CryptoStream cs = new CryptoStream(ms, tripledes.CreateDecryptor(bytesDESKey, bytesDESIV), CryptoStreamMode.Read) )    using (StreamReader sr = new StreamReader(cs))    {        return sr.ReadToEnd();    }}