using System;

public class Program

{

    public static void Main()

    {

        var cardData = "76803210e000030e858e0ff8d38b8a4d7b47da113629ab28770dd243a694538da43c4bc9de0e227aa408a57f19068521ec3e6abf72b72dc61ee0bd3d0b3d50ca51a7fa44832b748f8639abdba68ff868e4eb93dc150a665aea93b9f3d180f82a0ea659a2e059d80c5c98462b254477d4e455932d3d82de4a8192604cef2246de30303030";

        Console.WriteLine(cardData.Substring(0, 12) + "00"); //el ksn con los ceros

        Console.WriteLine(cardData.Substring(0, 14)); //el ksn sin los ceros

    }

}