gistfile1.txt

using System;

namespace MACPlay
{
    class Program
    {
        static void Main(string[] args)
        {
            int id = 200;
            DateTime expiry = DateTime.UtcNow.AddMinutes(15);

            var idbytes = BitConverter.GetBytes(id);
            var datebytes = BitConverter.GetBytes(expiry.Ticks);

            byte[] allstuff = new byte[12];
            System.Array.Copy(idbytes, allstuff,4);
            System.Array.Copy(datebytes, 0, allstuff, 4, 8);
// protect here!!

//unprotect
            var newid = BitConverter.ToInt32(idbytes);
            var dateticks = BitConverter.ToInt64(datebytes);
            var newexpiry = new DateTime(dateticks, DateTimeKind.Utc);

            Console.WriteLine("Hello World!");
        }
    }
}