using System;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        string senha = GerarPasswordRandom().Result;

        Console.WriteLine(senha);

    }

    public static async Task<string> GerarPasswordRandom() {

            string pass = await Task<string>.Run(() => {

                var rnd = new Random();

                return string.Format("{0}{1}{2}{3}{4}",

                        GetRandomChar(rnd),

                        GetRandomChar(rnd),

                        Guid.NewGuid().ToString().Substring(0, 8),

                        GetRandomChar(rnd),

                        GetRandomChar(rnd)

                    );

            });

            return pass;

        }

​

        public static string GetRandomChar(Random rnd) {

            // 35 - 43 ASCII => #$%&'()*+

            return ((char)rnd.Next(35, 43)).ToString();

        }

}