public String xor(String toChifre, String schlüssel) {
        String verschlüsselt = "";
        if(!schlüssel.equals(toChifre)) {
            System.out.println("Error.Schlüssel zu kurz.");
        } else {
            try {
                verschlüsselt  = toChifre^schlüssel;
            } catch(Exception e) {
            System.out.println("Error. Failded to XOR");
        }
        }
        return verschlüsselt;
    }