public void CreateUser(string username, string password) { var users = _preferenceService.GetObjectArray <User>("authorisation.users").ToList(); if (users.Any(u => u.Username.ToLower().Trim() == username.ToLower().Trim())) { throw new InvalidOperationException("User already exists"); } var salt = GenerateSalt(); users.Add(new User(username, HashPassword(password, salt), salt)); _preferenceService.SetObjectArray("authorisation.users", users.ToArray()); }