Password Hasher

using System.Collections.Generic;
using System.Security.Cryptography;

namespace PlexRequests.Helpers
{
    public static class PasswordHasher
    {
        // 24 = 192 bits
        private const int SaltByteSize = 24;
        private const int HashByteSize = 24;
        private const int HasingIterationsCount = 10101;

        public static byte[] ComputeHash(string password, byte[] salt, int iterations = HasingIterationsCount, int hashByteSize = HashByteSize)
        {
            var hashGenerator = new Rfc2898DeriveBytes(password, salt) { IterationCount = iterations };
            return hashGenerator.GetBytes(hashByteSize);
        }

        public static byte[] GenerateSalt(int saltByteSize = SaltByteSize)
        {
            var saltGenerator = new RNGCryptoServiceProvider();
            var salt = new byte[saltByteSize];
            saltGenerator.GetBytes(salt);
            return salt;
        }

        public static bool VerifyPassword(string password, byte[] passwordSalt, byte[] passwordHash)
        {
            var computedHash = ComputeHash(password, passwordSalt);
            return AreHashesEqual(computedHash, passwordHash);
        }

        //Length constant verification - prevents timing attack
        private static bool AreHashesEqual(IReadOnlyList<byte> firstHash, IReadOnlyList<byte> secondHash)
        {
            var minHashLength = firstHash.Count <= secondHash.Count ? firstHash.Count : secondHash.Count;
            var xor = firstHash.Count ^ secondHash.Count;
            for (var i = 0; i < minHashLength; i++)
                xor |= firstHash[i] ^ secondHash[i];
            return 0 == xor;
        }
    }
}