// (c) 2006 Richard Grimes
// www.grimes.demon.co.uk

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

class App
{
   static void Main()
   {
      Rijndael r = Rijndael.Create();
      r.Mode = CipherMode.ECB;
      r.Padding = PaddingMode.None;
      string phrase = "daisy, daisy, give me your answer to";
      PasswordDeriveBytes pdb = new PasswordDeriveBytes(phrase, new byte[0]);
      r.Key = pdb.GetBytes(r.KeySize >> 3);

      string data = "repeated.text...repeated.text...repeated.text...repeated.text...";
      byte[] input = Encoding.ASCII.GetBytes(data);

      ICryptoTransform en = r.CreateEncryptor();
      input = CryptoTransform(input, en);
      Console.WriteLine(BitConverter.ToString(input));

      ICryptoTransform de = r.CreateDecryptor();
      byte[] output = CryptoTransform(input, de);

      Console.WriteLine(Encoding.ASCII.GetString(output));
   }
   static byte[] CryptoTransform(byte[] input, ICryptoTransform en)
   {
      MemoryStream sInput = new MemoryStream(input);
      CryptoStream cs = new CryptoStream(sInput, en, CryptoStreamMode.Read);
      MemoryStream sOutput = new MemoryStream();
      byte[] buffer = new byte[1024];
      while (true)
      {
         int read = cs.Read(buffer, 0, buffer.Length);
         if (read == 0) break;
         sOutput.Write(buffer, 0, read);
      }
      cs.Clear();
      return sOutput.ToArray();
   }
}