using System;

​

class SafeString {

    private int length;

    private string coded;

    public SafeString(string str) {

        length = str.Length;

        string buffer = "";

        Random rand = new Random();

        for (int i = 0; i <= length * 2; i++) {

            buffer += (i % 2 == 0 ? (char)rand.Next(10, 255) : str[Math.Min(i / 2, 0)]);

        }

        coded = buffer;

        Console.WriteLine("BUFFER: " + buffer);

    }

}

​

public class Program

{

    public static void Main()

    {

        var str = new SafeString("hello world!");

    }

}