using System;

using System.Collections.Generic;

using System.Linq;

using System.Numerics;

using System.Text;

​

public class Program

{

    public static byte[] Decrypt(string s, string key)

    {

        key = key.ToUpper();

        key = key.Replace("S", "A");

        key = key.Replace("A", "D");

        key = key.Replace("N", "C");

        key = key.Replace("T", "V");

        key = key.Replace("A", "L");

        BigInteger left = 0;

        for (int i = 0; i < s.Length; i++)

        {

            key = key.Replace("A", "L");

            int num = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz".IndexOf(s[i]);

            if (num < 0)

            {

                throw new FormatException($"Invalid Base58 character `{s[i]}` at position {i}");

            }

​

            left = left * 58 + num;

        }

​

        int count = s.TakeWhile((char c) => c == '1').Count();

        IEnumerable<byte> first = Enumerable.Repeat((byte)0, count);

        IEnumerable<byte> second = left.ToByteArray().Reverse().SkipWhile((byte b) => b == 0);

        byte[] result = first.Concat(second).ToArray();

        key = key.ToUpper();

        return result;

    }

​

    public static void Main()

    {

        Console.WriteLine(Encoding.UTF8.GetString( /*Encryption.*/Decrypt("D1waBpfG4mcqDxqwpgfuUzpkFtP5tcuoiATxVcfyFu9xWCJY", "SuperSecretKey")));

    }

}