C#加密文件后怎样解密

Question

             try
            {
                byte[] Key = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 
0x09, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16 };                byte[] IV = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 
0x09, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16 };                RijndaelManaged RMCrypto = new RijndaelManaged();                FileStream file = new FileStream(@"f:\a.txt",FileMode.Open);                CryptoStream crypto = new CryptoStream(file,RMCrypto.CreateEncryptor(Key, IV), CryptoStreamMode.Read);                StreamReader SReader = new StreamReader(crypto);                SReader.Close();                file.Close();            }
            catch 
            {
                Console.WriteLine("The Listener Failed.");
            }
用CryptoStream和RijndaelManaged算法把txt加密成功了，打开乱码。 但是我想解密，把文件复原。都按照msdn的做了没效果，也没异常。搞不懂 

Answer 1

看眼花了吧，加密时用CreateEncryptor，解密时用CreateDecryptor。你代码中是要解密但是使用的是CreateEncryptor。

Answer 2

那就要看文件的编码格式了。中间使用错误的编码将导致乱码，最后的结果当然也就不可能对了。看看下面的代码，可以正常工作的：
用法：
  a. 调用TestEnDencrypt.Encrypt(@"f:\a.xml") 加密获得"f:\a.xml_"文件，我测试用的xml是Unicode编码的，所以代码中用Encoding.Unicode.GetString获取的，你要对照文件更改对应的编码格式，这个是一个关键点；
  b. 调用TestEnDencrypt.Dencrypt(@"f:\a.xml_")文件就可以成功得到解密后的字符串内容了。
    class TestEnDencrypt
    {        static byte[] Key = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 
0x09, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16 };        static byte[] IV = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 
0x09, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16 };
        static void Encrypt(string fileName)
        {            try
            {
                RijndaelManaged RMCrypto = new RijndaelManaged();                FileStream file = new FileStream(fileName, FileMode.Open);
                byte[] data = new byte[file.Length];                file.Read(data, 0, (int)file.Length);                file.Close();                MemoryStream ms = new MemoryStream();                CryptoStream crypto = new CryptoStream(ms, RMCrypto.CreateEncryptor(Key, IV), CryptoStreamMode.Write);                using (StreamWriter sw = new StreamWriter(crypto))
                {
                    string text = Encoding.Unicode.GetString(data);
                    sw.Write(text);
                }                File.WriteAllBytes(fileName + "_", ms.ToArray());
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }        static string Dencrypt(string fileName)
        {
            string ret = null;            try
            {
                RijndaelManaged RMCrypto = new RijndaelManaged();
                FileStream file = new FileStream(fileName, FileMode.Open);                CryptoStream crypto = new CryptoStream(file, RMCrypto.CreateDecryptor(Key, IV), CryptoStreamMode.Read);                StreamReader SReader = new StreamReader(crypto);                ret = SReader.ReadToEnd();                SReader.Close();                file.Close();            }
            catch
            {
                Console.WriteLine("The Listener Failed.");
            }            return ret;
        }
    }