using System;

using System.Security.Cryptography;

using System.Text;

public class Program

{

    public static void Main()

    {

        string guid1, guid2;

        byte[] hash1, hash2;

        using (var md5 = MD5.Create())

        {

            hash1 = md5.ComputeHash(Encoding.UTF8.GetBytes("hello;world"));

            guid1 = new Guid(hash1).ToString();

        }

        using (var md5 = MD5.Create())

        {

            hash2 = md5.ComputeHash(Encoding.Default.GetBytes("hello;world"));

            guid2 = new Guid(hash2).ToString();

        }

        Console.WriteLine("guid1: " + guid1 + "\nguid2: " + guid2);

    }

}