Demonstrates how to serialize and encrypt any object in C#

crypttest.cs

/*
 * crypttest.cs: Demonstrates how to serialize and encrypt any object
 *
 * Gaute Hope <[email protected]>
 *
 * To deserialize it you need to know the unencrypted serialized length.
 * So to store or send also pass the length, e.g. create a struct like this:
 *
 * public struct EncryptedObject {
 *  public int length;
 *  public byte[] encrypteddata;
 * }
 *
 * Serialize it and send it, e.g. over a NetworkStream (Deserializing directly
 * on the NetworkStream works with this since the CryptStream would work
 * on a MemoryStream where it knows when the end is reached.)
 *
 */

using System;
using System.IO;

using System.Security.Cryptography;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;


namespace crypttest
{
	class MainClass
	{
		[Serializable]
		public struct Data {
			public string d;
		}

		public static void Main (string[] args)
		{
			Console.WriteLine ("Hello World!");

			IFormatter form = new BinaryFormatter ();


			Console.WriteLine ("Serialization test");
			Data sd = new Data ();
			sd.d = "testing";

			MemoryStream ser = new MemoryStream ();
			form.Serialize (ser, (object) sd);

			Console.WriteLine ("Size: " + ser.Length);

			Console.WriteLine ("Deserializing..");
			ser.Position = 0; // Rewind stream
			Data restoredd = (Data) form.Deserialize (ser);
			Console.WriteLine ("Got: " + restoredd.d);


			Console.WriteLine ("Setup crypto..");
			Rijndael alg = Rijndael.Create ();
			alg.GenerateIV ();
			alg.GenerateKey ();

			Console.WriteLine ("Encrypt test..");
			ser.Position = 0;

			MemoryStream enc = new MemoryStream ();
			CryptoStream cw = new CryptoStream (enc, alg.CreateEncryptor (), CryptoStreamMode.Write);
			cw.Write (ser.ToArray(), 0, (int) ser.Length);
			Console.WriteLine ("Encrypted: " + enc.Length);
			cw.FlushFinalBlock (); // Also .Close()'s
			Console.WriteLine ("Final Encrypted: " + enc.Length);

			enc.Position = 0; // rewind
			byte [] benc = enc.ToArray ();

			Console.WriteLine ("Decrypt test..");
			MemoryStream bencr = new MemoryStream (benc);

			CryptoStream cr = new CryptoStream (bencr, alg.CreateDecryptor (), CryptoStreamMode.Read);

			byte[] buf = new byte [(int) ser.Length];
			cr.Read (buf, 0, (int) ser.Length);

			MemoryStream unenc = new MemoryStream (buf);
			unenc.Position = 0;

			Console.WriteLine ("Deserialize test..");
			Data resd = (Data) form.Deserialize (unenc);
			Console.WriteLine ("Got: " + resd.d);

		}
	}
}