using System;

//using System.Security.Cryptography;

using System.Collections.Generic;

​

public class Program

{

    static List<string> hashDB = new List<string>()

    {"9EDEEFBDC696E79C1AE5F1468F55F9499599C3A18E924BF36DEB8B417DE69667", "0866A6EAEA5CB085E4CF6EF19296BF19647552DD5F96F1E530DB3AE61837EFE7"};

    public static void Main()

    {

        Console.WriteLine(PerformPermiterCheck("4246315133159999"));

    }

​

    private static bool PerformPermiterCheck(string cardNum)

    {

        var hash = ComputeHash(cardNum);

        return hashDB.Contains(hash);

    }

​

    private static string ComputeHash(string text)

    {

        if (String.IsNullOrEmpty(text))

            return String.Empty;

        using (var sha = new System.Security.Cryptography.SHA256Managed())

        {

            byte[] textData = System.Text.Encoding.UTF8.GetBytes(text);

            byte[] hash = sha.ComputeHash(textData);

            return BitConverter.ToString(hash).Replace("-", String.Empty);

        }

    }

}