using System;

using System.Collections.Generic;

using System.Security.Cryptography;

using System.Text;

​

public class Program

{

    private static readonly Random Random = new Random();

​

    public static string GenerateTemporaryPassword(int lowerCount = 10, int upperCount = 2, int numberCount = 2, int symbolCount = 2)

    {

        // Possible Characters o,O,l,0,(,),{,},[,],@ omitted

        char[] upper = "ABCDEFGHIJKLMNPQRSTUVWXYZ".ToCharArray();

        char[] lower = "abcdefghijkmnpqrstuvwxyz".ToCharArray();

        char[] number = "123456789".ToCharArray();

        char[] symbol = "!#$%^&*_-+=;:<>./?".ToCharArray();

        // Ensure valid counts

        upperCount = Math.Max(upperCount, 1);

        lowerCount = Math.Max(lowerCount, 1);

        symbolCount = Math.Max(symbolCount, 1);

        numberCount = Math.Max(numberCount, 1);

        var totalChar = upperCount + lowerCount + numberCount + symbolCount;

        if (totalChar < 10)

        {

            lowerCount += 10 - totalChar;

        }

        // Get random bytes for picking characters

        RandomNumberGenerator rngCrypt = RandomNumberGenerator.Create();        

        byte[] bytes = new byte[totalChar * 8];

        rngCrypt.GetBytes(bytes);

        // Convert byte values to characters for each of the character types & counts

        var result = new char[totalChar];

​

        for (int i = 0; i < totalChar; i++)

        {

            ulong value = BitConverter.ToUInt64(bytes, i * 8);

            if (upperCount > 0){

                result[i] = upper[value % (uint)upper.Length];

                upperCount--;

            } else if (numberCount > 0) {

                result[i] = number[value % (uint)number.Length];

                numberCount--;

            } else if (symbolCount > 0) {

                result[i] = symbol[value % (uint)symbol.Length];

                symbolCount--;

            } else {

                result[i] = lower[value % (uint)lower.Length];

                lowerCount--;

            }

        }

        //Shuffle the array;

        var n = result.Length;

        while (n > 1)

        {

            n--;

            var k = Random.Next(n + 1);

            var value = result[k];

            result[k] = result[n];

            result[n] = value;

        }

​

        var password = new string(result);

        // Ensure password length fits the maximum bound

        if (password.Length > 128)

        {

            return password.Substring(0, 128);

        } else

        {

            return password;

        }

    }

    public static void Main()

    {

        string password = GenerateTemporaryPassword();

        Console.WriteLine(password);

    }

}

​