using System;

using System.IO;

public class Program

{

    internal static class Utilities {

    static Random randomGenerator = new Random();

    internal static string GenerateRandomString(int length) {

        byte[] randomBytes = new byte[randomGenerator.Next(length)];

        randomGenerator.NextBytes(randomBytes);

        var data = Convert.ToBase64String(randomBytes);

        data = data.Replace("+", string.Empty);

        data = data.Replace("=", string.Empty);

        if(data.Length > length)

        {

            data = data.Substring(0, length);

        }

        if(data.Length != length)

        {

            data = data + GenerateRandomString(length);

        }

​

        if(data.Length > length)

        {

            data = data.Substring(0, length);

        }

        return data;

    }

}

​

    public static void Main()

    {

        var randomLength = 6;

        var data = Utilities.GenerateRandomString(randomLength);

        Console.WriteLine(data);

        Console.WriteLine(data.Length);

        //Console.WriteLine(Path.GetRandomFileName());      

        for (int x = 0; x < 10; x++)

        {

            string output = GetRandomString(randomLength);

            Console.WriteLine(output);

        }

    }

    static string GetRandomString(int lenOfTheNewStr)

    {

        string output = string.Empty;

        while (true)

        {

            output = output + Path.GetRandomFileName().Replace(".", string.Empty);

​

            if (output.Length > lenOfTheNewStr)

            {

                output = output.Substring(0, lenOfTheNewStr);

                break;

            }

        }

        return output;

    }

}