using System;

using System.Collections.Generic;

​

public class Program

{

    static string alpha = "abcdefghijklmnopqrstuvwxyz";

    static string cipher = "RYIBPCARRRWERYBRMPEERXXIOMWTNFZRRYBMZCHNDPXHDZTPDVVHWUTLTTENUCGY".ToLower();

    static string crib = "lincoln";

    public static void Main()

    {

        var length = cipher.Length - crib.Length;

        var poly = GetPolyDict();

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

        {

            var c = cipher[i];

            var key = String.Empty;

            Console.WriteLine("---------------------------------");

            for (int j = 0; j < crib.Length; j++)

            {

                var a = cipher[i + j];

                var b = crib[j];

                string ap = null;

                poly.TryGetValue(b, out ap);

                var z = ap.IndexOf(a);

                var d = alpha[z];

                key += d;

                Console.WriteLine(String.Format("Cipher: {0} Crib: {1} E: {2}", a, b, d));

            }

​

            Console.WriteLine("Key: " + key);

        }

​

        Console.WriteLine();

    }

​

    public static Dictionary<char, string> GetPolyDict()

    {

        var poly = new Dictionary<char, string>();

        poly.Add('l', "LMNOPQRSTUVWXYZABCDEFGHIJK".ToLower());

        poly.Add('i', "IJKLMNOPQRSTUVWXYZABCDEFGH".ToLower());

        poly.Add('c', "CDEFGHIJKLMNOPQRSTUVWXYZAB".ToLower());

        poly.Add('o', "OPQRSTUVWXYZABCDEFGHIJKLMN".ToLower());

        poly.Add('n', "NOPQRSTUVWXYZABCDEFGHIJKLM".ToLower());

        return poly;

    }

}