LobbyServer/LobbyClient/PasswordHash.cs

using System.Security.Cryptography;

namespace Lobbies
{
    internal class PasswordHash
    {
        const int keySize = 64;
        const int saltSize = 16;
        const int iterations = 350000;
        static HashAlgorithmName hashAlgorithm = HashAlgorithmName.SHA512;

        static internal (byte[] hash, byte[] salt) Hash(string text)
        {
            using (var pbkdf2 = new Rfc2898DeriveBytes(
                text,
                saltSize,
                iterations,
                hashAlgorithm))
            {
                return (pbkdf2.GetBytes(keySize), pbkdf2.Salt);
            }
        }

        static internal byte[] Hash(string text, byte[] salt)
        {
            using (var pbkdf2 = new Rfc2898DeriveBytes(
                text,
                salt,
                iterations,
                hashAlgorithm))
            {
                return pbkdf2.GetBytes(keySize);                
            }
        }
    }
}