using System;

using System.Collections.Generic;

using System.Linq;

using System.Runtime.InteropServices;

using System.Security.Cryptography;

public class Program

{

    public static void Main()

    {

        for(int i = 0; i <= 50; i++)

        {

            Console.WriteLine(SequentialGuid.NewGuid());

        }

    }

    public enum SequentialGuidType

    {

      SequentialAsString,

      SequentialAsBinary,

      SequentialAtEnd

    } 

​

    public static class SequentialGuid

    {

      private static readonly RNGCryptoServiceProvider _rng = new RNGCryptoServiceProvider();

      public static Guid NewGuid()

      {

          byte[] randomBytes = new byte[10];

        _rng.GetBytes(randomBytes);

        long timestamp = DateTime.UtcNow.Ticks / 10000L;

        byte[] timestampBytes = BitConverter.GetBytes(timestamp);

        if (BitConverter.IsLittleEndian)

        {

          Array.Reverse(timestampBytes);

        }

        byte[] guidBytes = new byte[16];

        Buffer.BlockCopy(timestampBytes, 2, guidBytes, 0, 6);

        Buffer.BlockCopy(randomBytes, 0, guidBytes, 6, 10);

        // If formatting as a string, we have to reverse the order

        // of the Data1 and Data2 blocks on little-endian systems.

        Array.Reverse(guidBytes, 0, 4);

        Array.Reverse(guidBytes, 4, 2);

​

        return new Guid(guidBytes);

      }

    }   

}