Stream Kryptering

Hej

Jeg er ved at prøve at lave en Client/Server hvor stream bliver krypteret. Jeg kan godt sende / modtage ukrypteret men lige så snart jeg prøver at kryptere kan jeg ikke sende, modtage eller begge dele.

Kode til at Sende/Modtage:
private Stream Net()
{
  if(Encrypted)
  {
    CryptoStream SecStream = new CryptoStream(NetStream,TDes.CreateDecryptor(),CryptoStreamMode.Read);
    return SecStream;
  }
  else
    return NetStream;
}

public void GetStreamData(IAsyncResult ar)
{
  int intCount;
  try
  {
    lock(Net())
    {
      intCount = Net().EndRead(ar);
    }
    if(intCount<1)
    {
      Client.Close();
   
      if(Disconnected!=null)
      {   
        EventArgs e = new EventArgs();
        Disconnected(this, e);
      }
    }
               
    BuildData(recByte,0,intCount);
       
    AsyncCallback GetStreamDataCallback = new AsyncCallback(GetStreamData);
    Net().BeginRead(recByte,0,1024,GetStreamDataCallback,null);       
  }
  catch
  {
    Client.Close();

    if(Disconnected!=null)
    {
      EventArgs e = new EventArgs();
      Disconnected(this, e);
    }
  }
}

private void BuildData(byte[] Databyte, int offset, int count)
{
  string Data = Encoding.UTF8.GetString(Databyte, offset, count);
  string[] DataCmd = Data.Split(':');

  if(!Encrypted)
  {
    switch(DataCmd[0])
    {
      case "HELO":
      {
        Send("Welcome");

        break;
      }
      case "DesKey":
      {
        TDes.GenerateKey();
        DesKey = TDes.Key;
                                       
        Send("DesKey:" + Convert.ToBase64String(DesKey));

        break;
      }
      case "DesIV":
      {
        TDes.GenerateIV();
        DesIV = TDes.IV;

        Send("DesIV:" + Convert.ToBase64String(DesIV));

        Encrypted = true;

        break;
      }
    }
  }
  else
  {
    Send(Data);
  }
}

public void Send(string Data)
{
  StreamWriter Writer;

  if(Encrypted)
  {
    CryptoStream SecStream = new CryptoStream(NetStream,TDes.CreateEncryptor(),CryptoStreamMode.Write);
    Writer = new StreamWriter(SecStream);
  }
  else
    Writer = new StreamWriter(NetStream);

  Writer.Write(Data);
  Writer.Flush();       
}