Mynt.cs

using System;
using System.IO;

namespace Translator
{
    class Program
    {
        static void Main(string[] args)
        {
            if(args.Length == 0)
            {
                Console.WriteLine("Please drop the cyphertext onto this application.");
                Console.ReadKey();
                Environment.Exit(0);
            }
            var CypherText = File.ReadAllText(args[0]);
            foreach(char c in CypherText)
            {
                switch (c)
                {
                    //Uppercase
                    case 'A':
                        Console.Write("F");
                        break;
                    case 'B':
                        Console.Write("P");
                        break;
                    case 'C':
                        Console.Write("W");
                        break;
                    case 'D':
                        Console.Write("G");
                        break;
                    case 'E':
                        Console.Write("Y");
                        break;
                    case 'F':
                        Console.Write("J");
                        break;
                    case 'G':
                        Console.Write("N");
                        break;
                    case 'I':
                        Console.Write("C");
                        break;
                    case 'J':
                        Console.Write("M");
                        break;
                    case 'L':
                        Console.Write("S");
                        break;
                    case 'M':
                        Console.Write("H");
                        break;
                    case 'N':
                        Console.Write("R");
                        break;
                    case 'O':
                        Console.Write("U");
                        break;
                    case 'Q':
                        Console.Write("A");
                        break;
                    case 'R':
                        Console.Write("X");
                        break;
                    case 'S':
                        Console.Write("L");
                        break;
                    case 'T':
                        Console.Write("K");
                        break;
                    case 'U':
                        Console.Write("O");
                        break;
                    case 'P':
                        Console.Write("B");
                        break;
                    case 'V':
                        Console.Write("D");
                        break;
                    case 'W':
                        Console.Write("V");
                        break;
                    case 'X':
                        Console.Write("T");
                        break;
                    case 'Y':
                        Console.Write("I");
                        break;
                    case 'Z':
                        Console.Write("E");
                        break;
                    //Lowercase
                    case 'a':
                        Console.Write("f");
                        break;
                    case 'b':
                        Console.Write("p");
                        break;
                    case 'c':
                        Console.Write("w");
                        break;
                    case 'd':
                        Console.Write("g");
                        break;
                    case 'e':
                        Console.Write("y");
                        break;
                    case 'f':
                        Console.Write("j");
                        break;
                    case 'g':
                        Console.Write("n");
                        break;
                    case 'i':
                        Console.Write("c");
                        break;
                    case 'j':
                        Console.Write("m");
                        break;
                    case 'l':
                        Console.Write("s");
                        break;
                    case 'm':
                        Console.Write("h");
                        break;
                    case 'n':
                        Console.Write("r");
                        break;
                    case 'o':
                        Console.Write("u");
                        break;
                    case 'q':
                        Console.Write("a");
                        break;
                    case 'r':
                        Console.Write("x");
                        break;
                    case 'p':
                        Console.Write("b");
                        break;
                    case 's':
                        Console.Write("l");
                        break;
                    case 't':
                        Console.Write("k");
                        break;
                    case 'u':
                        Console.Write("o");
                        break;
                    case 'v':
                        Console.Write("d");
                        break;
                    case 'w':
                        Console.Write("v");
                        break;
                    case 'x':
                        Console.Write("t");
                        break;
                    case 'y':
                        Console.Write("i");
                        break;
                    case 'z':
                        Console.Write("e");
                        break;
                    default:
                        Console.Write(c);
                        break;
                }
            }
            Console.WriteLine(Environment.NewLine);
            Console.WriteLine("Done");
            Console.ReadKey();
        }
    }
}