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

public class Test
{
	public static void Main()
	{
		var tempData = "This is the text to encrypt. It's not much, but it's all there is.";
		byte[] iv;
		byte[] key;
		byte[] encryptedData;
		using (var rijCrypto = new RijndaelManaged())
		{
		    rijCrypto.Padding = System.Security.Cryptography.PaddingMode.ISO10126;
		    rijCrypto.KeySize = 256;
		    rijCrypto.GenerateIV();
		    rijCrypto.GenerateKey();
		    iv = new byte[rijCrypto.IV.Length];
		    rijCrypto.IV.CopyTo(iv, 0);
		    key = new byte[rijCrypto.Key.Length];
		    rijCrypto.Key.CopyTo(key, 0);

		    using (var input = new MemoryStream(Encoding.Unicode.GetBytes(tempData)))
		    using (var output = new MemoryStream())
		    {
		        var encryptor = rijCrypto.CreateEncryptor();
		
		        using (var cryptStream = new CryptoStream(output, encryptor, CryptoStreamMode.Write))
		        {
		            var buffer = new byte[1024];
		            var read = input.Read(buffer, 0, buffer.Length);
		            while (read > 0)
		            {
		                cryptStream.Write(buffer, 0, read);
		                read = input.Read(buffer, 0, buffer.Length);
		            }
		            cryptStream.FlushFinalBlock();
		            encryptedData = output.ToArray();
		        }
		    }
		}

		using (var rijCrypto = new RijndaelManaged())
		{
		    rijCrypto.Padding = System.Security.Cryptography.PaddingMode.ISO10126;
		    rijCrypto.KeySize = 256;
		    rijCrypto.IV = iv;
		    rijCrypto.Key = key;
		
		    using (var input = new MemoryStream(encryptedData))
		    using (var output = new MemoryStream())
		    {
		        var decryptor = rijCrypto.CreateDecryptor();
		        using (var cryptStream = new CryptoStream(input, decryptor, CryptoStreamMode.Read))
		        {
		            var buffer = new byte[1024];
		            var read = cryptStream.Read(buffer, 0, buffer.Length);
		            while (read > 0)
		            {
		                output.Write(buffer, 0, read);
		                read = cryptStream.Read(buffer, 0, buffer.Length);
		            }
		            cryptStream.Flush();
		            var result = Encoding.Unicode.GetString(output.ToArray());
		            Console.WriteLine(result);
		        }
		    }
		}
	}
}