Adv2016/D05.2/Program.cs

using System;
using System.Security.Cryptography;
using System.Text;

namespace D05._2
{
    class Program
    {
        static byte[] ToB(string str) => Encoding.ASCII.GetBytes(str);
        static string ToS(byte[] b) => BitConverter.ToString(b).Replace("-", "");

        static void Main(string[] args)
        {
            if (args.Length < 1) throw new ArgumentException();
            string input = args[0];

            var password = new char[8];
            int found = 0;

            using (var md5 = MD5.Create())
            {
                int i = 0;
                while (found < 8)
                {
                    var h = md5.ComputeHash(ToB($"{input}{i}"));
                    var sh = ToS(h);

                    if (sh.StartsWith("00000") && sh[5] < '8')
                    {
                        int p = sh[5] - '0';
                        if (password[p] == '\0')
                        {
                            found++;
                            password[p] = sh[6];
                        }
                    }

                    i++;
                }
            }

            Console.WriteLine($"Password is : {string.Join("", password)}");
        }
    }
}