Clase: Rijandel

Funciones de encriptación Rijandel.

using System;
using System.Text;
using System.Security.Cryptography;
using System.IO;
 
namespace Encriptados
{
    class Rijndael
 
    {
        byte[] _key;
        byte[] _iv;
 
        public Rijndael()
        {
            _key =
            Encoding.ASCII.GetBytes("12EstaClave34es56dificil489ssswf");
            _iv =
            Encoding.ASCII.GetBytes("Devjoker7.37hAES");
        }
 
        public string Encrit(string inputText)
        {
            byte[] inputBytes = Encoding.ASCII.GetBytes(inputText);
            byte[] encripted;
            RijndaelManaged cripto = new RijndaelManaged();
            using (MemoryStream ms =
                new MemoryStream(inputBytes.Length))
            {
                using (CryptoStream objCryptoStream =
                    new CryptoStream(ms,
                           cripto.CreateEncryptor(_key, _iv),
                           CryptoStreamMode.Write))
                {
                    objCryptoStream.Write(inputBytes, 0, inputBytes.Length);
                    objCryptoStream.FlushFinalBlock();
                    objCryptoStream.Close();
                }
                encripted = ms.ToArray();
            }
            return Convert.ToBase64String(encripted);
        }
 
        public string Desencrit(string inputText)
        {
            byte[] inputBytes = Convert.FromBase64String(inputText);
            byte[] resultBytes = new byte[inputBytes.Length];
            string textoLimpio = String.Empty;
            RijndaelManaged cripto = new RijndaelManaged();
            using (MemoryStream ms = new MemoryStream(inputBytes))
            {
                using (CryptoStream objCryptoStream =
                new CryptoStream(ms, cripto.CreateDecryptor(_key, _iv),
                        CryptoStreamMode.Read))
                {
                    using (StreamReader sr =
                        new StreamReader(objCryptoStream, true))
                    {
                        textoLimpio = sr.ReadToEnd();
                    }
                }
            }
            return textoLimpio;
        }
    }
}

Fuente original: http://www.devjoker.com/