[Help] Encryption of packets

[ernilos]

With some friends are trying to do p.server.
But we have found a problem in this:
ASCIIEncoding.GetEncoding (48). GetString (Receive)
The GetEncoding ... We don't found the value...
Someone help us? We can pay ...
[Srry for bad english, i'm Spanish xD]
----------
I found that:

public class ServerCipher : CipherBase
    {

        override public int Decrypt(byte[] data, out byte[] buf)
        {
             if (!inGameEncryption)
            {
                buf = new byte[data.Length];
                for (int i = 0; i < data.Length; i++)
                    buf[i] = (byte)(data[i] - 0x0F);
                return data.Length;
            }

            int len = data.Length;
            int offset = 0;
            char[] table = { (char)0, ' ', '-', '.', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '\n' };

            ........


            return 0;
        }
      
    }

Someone can give me the all code? ><