using System;

using System.Security.Cryptography;

public class Program

{

    public const int SaltByteSize = 24;

    public const int HashByteSize = 20; // to match the size of the PBKDF2-HMAC-SHA-1 hash 

    public const int Pbkdf2Iterations = 1000;

    public const int IterationIndex = 0;

    public const int SaltIndex = 1;

    public const int Pbkdf2Index = 2;

​

     public static string HashPassword(string password)

    {

        var cryptoProvider = new RNGCryptoServiceProvider();

        byte[] salt = new byte[SaltByteSize];

        cryptoProvider.GetBytes(salt);

​

        var hash = GetPbkdf2Bytes(password, salt, Pbkdf2Iterations, HashByteSize);

        return Pbkdf2Iterations + ":" + Convert.ToBase64String(salt) + ":" + Convert.ToBase64String(hash);

    }

​

    public static bool ValidatePassword(string password, string correctHash)

    {

        char[] delimiter = { ':' };

        var split = correctHash.Split(delimiter);

        var iterations = Int32.Parse(split[IterationIndex]);

        var salt = Convert.FromBase64String(split[SaltIndex]);

        var hash = Convert.FromBase64String(split[Pbkdf2Index]);

​

        var testHash = GetPbkdf2Bytes(password, salt, iterations, hash.Length);

        return CryptographicOperations.FixedTimeEquals(hash, testHash);

        //return SlowEquals(hash, testHash);

    }

​

    private static bool SlowEquals(byte[] a, byte[] b)

    {

        var diff = (uint)a.Length ^ (uint)b.Length;

        for (int i = 0; i < a.Length && i < b.Length; i++)

        {

            diff |= (uint)(a[i] ^ b[i]);

        }

        return diff == 0;

    }

     private static byte[] GetPbkdf2Bytes(string password, byte[] salt, int iterations, int outputBytes)

    {

        var pbkdf2 = new Rfc2898DeriveBytes(password, salt, iterations);

        return pbkdf2.GetBytes(outputBytes);

    }

    public static void Main()

    {

        var def = HashPassword("test");

        Console.WriteLine(def);

        var res = ValidatePassword("test", def);

        Console.WriteLine(res);

    }

}