using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(Descriptografar("5651525846404A02"));

    }

     public static string Criptografar(string Strg)

        {

            var str1 = "";

            var str2 = "";

            var str4 = "";

            var Start1 = 1;

            var str3 = "2E6R8G4B7Z9S7TU8JMD09432MLKK950DK204MACJFO54602JPDAP3240IKFSAD349K94782JHSKJDISI";

            var num1 = str3.Length;

            var Start2 = 1;

            while (Start2 <= num1)

            {

                str2 += Convert.ToString(Asc(Mid(str3, Start2, 1)));

                checked

                {

                    ++Start2;

                }

            }

​

            var num2 = Strg.Length;

            var Start3 = 1;

            while (Start3 <= num2)

            {

                var num3 = Asc(Mid(str2, Start1, 1));

                checked

                {

                    ++Start1;

                }

​

                if (Start1 > str2.Length)

                    Start1 = 1;

                var num4 = Asc(Mid(Strg, Start3, 1));

​

                var Expression = ToHex(num3 ^ num4);

​

                if (Expression.Length < 2)

                    Expression = "0" + Expression;

                str1 += Expression;

                checked

                {

                    ++Start3;

                }

            }

​

            return str1;

        }

     public static string Descriptografar(string Strg)

        {

            var str1 = "";

            try

            {

                var str2 = "";

                var str3 = "";

                var Start1 = 1;

                var str4 = "2E6R8G4B7Z9S7TU8JMD09432MLKK950DK204MACJFO54602JPDAP3240IKFSAD349K94782JHSKJDISI";

                var num1 = str4.Length;

                var Start2 = 1;

                while (Start2 <= num1)

                {

                    str3 += Convert.ToString(Asc(Mid(str4, Start2, 1)));

                    checked

                    {

                        ++Start2;

                    }

                }

​

                var num2 = Strg.Length;

                var Start3 = 1;

                while (Start3 <= num2)

                {

                    var num3 = Asc(Mid(str3, Start1, 1));

                    checked

                    {

                        ++Start1;

                    }

​

                    if (Start1 > str3.Length)

                        Start1 = 1;

                    var integer = int.Parse(Mid(Strg, Start3, 2), System.Globalization.NumberStyles.HexNumber);

                    var CharCode = num3 ^ integer;

                    str2 += Convert.ToString(Chr(CharCode));

                    checked

                    {

                        Start3 += 2;

                    }

                }

​

                str1 = str2;

            }

            catch (Exception ex)

            {

                if (Strg.Length > 0)

                    str1 = Strg;

            }

​

            return str1;

        }

        /// <summary>  

        /// This is equivalent to Mid Function in VB6  

        /// </summary>  

        /// <param name="s"> String to Check.</param>  

        /// <param name="a">Position of Character</param>  

        /// <param name="b">Length </param>  

        /// <returns></returns>  

        public static string Mid(string s, int a, int b)

        {

            var temp = s.Substring(a - 1, b);

            return temp;

        }

​

        public static char Chr(int codigo)

        {

            return (char)codigo;

        }

​

        public static int Asc(string letra)

        {

            return (int)Convert.ToChar(letra);

        }

​

        public static string ToHex(int value)

        {

            return string.Format("{0:X}", value);

        }

}