[System.Serializable]
public class Login : MonoBehaviour {

    public ArrayList PlayerNames;
    public ArrayList PlayerPass;
    public GameObject LoginName;
    public GameObject Password;
    public string Playname;
    public string Playerpass;


    // Use this for initialization
    void Start () {
        Load();
        PlayerNames = new ArrayList();
        PlayerPass = new ArrayList();


    }

    // Update is called once per frame
    void Update () {


    }

    public  void Save()
    {

        BinaryFormatter bf = new BinaryFormatter();
        FileStream username = File.Create(Application.persistentDataPath + "/username.gd");
        FileStream password = File.Create(Application.persistentDataPath + "/password.gd");
        bf.Serialize(username, PlayerNames);
        bf.Serialize(password, PlayerPass);
        username.Close();
        password.Close();
        Debug.Log("Saved");
        Debug.Log(PlayerNames);

    }

    public void Load()
    {

        if (File.Exists(Application.persistentDataPath + "/username.gd") && File.Exists(Application.persistentDataPath + "/password.gd"))
        {
            Debug.LogError("Loaded");

            BinaryFormatter bf = new BinaryFormatter();
            FileStream username = File.Open(Application.persistentDataPath + "/username.gd", FileMode.Open);
            FileStream password = File.Open(Application.persistentDataPath + "/password.gd", FileMode.Open);
            PlayerNames = (ArrayList)bf.Deserialize(username);
            PlayerPass = (ArrayList)bf.Deserialize(password);
            username.Close();
            password.Close();

        }
    }

    int i;
    string Playerpasz;
    public void CheckRegister()
    {
        Playname = LoginName.GetComponent<InputField>().text;
        Playerpass = Password.GetComponent<InputField>().text;
        if (PlayerNames.Contains(Playname))
        {
            int indexItem = PlayerNames.IndexOf(Playname);
            string pass = PlayerPass.IndexOf(indexItem).ToString();

            foreach(var Passworz in PlayerPass)
            {
                if (i == indexItem) {

                    Playerpasz = Passworz.ToString();
                    Debug.Log(Playerpasz);
                    i = 0;
                }
                indexItem++;
            }
            Debug.Log("Username found: " + PlayerNames.IndexOf(Playname));
           // Debug.Log("Pass1:" + Playerpasz);
           // Debug.Log("Pass2:" + Playerpass);

            if (Playerpasz == Playerpass)
            {
                Debug.LogError("Pasword found");
                LoginSucess();
            }
            else
            {
                Debug.LogError("Falsches Passwort");
            }

        }
        else
        {
            Register();

        }
    }

    public void Register() {
        Debug.Log("Reg");
        PlayerNames.Add(Playname);
        PlayerPass.Add(Playerpass);
        Save();
        LoginSucess();
    }
    void LoginSucess()
    {
        Debug.LogError("Eingeloggt");

    }
}
`