.net MD5

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.Text;
using System.Collections;
using System.Security.Cryptography;

public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {

        if (!IsPostBack)
        {

            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            byte[] mdstr = System.Text.Encoding.UTF8.GetBytes("666666");
            byte[] mdresult = md5.ComputeHash(mdstr);

            Response.Write(Convert.ToBase64String(mdresult));
        }

    }
}