private static List<byte[]> generatePossiblePasswordBytes(
            String passwordString) {

        final List<byte[]> possibilties = new ArrayList<byte[]>();
        for (final PasswordByteGenerator generator : PASSWORD_BYTE_GENERATORS) {
            byte[] generated = generator.generateBytes(passwordString);
            // avoid duplicates
            boolean alreadyGenerated = false;
            for (int i = 0; !alreadyGenerated && i < possibilties.size(); ++i) {
                if (Arrays.equals(possibilties.get(i), generated)) {
                    alreadyGenerated = true;
                }
            }
            if (!alreadyGenerated) {
                possibilties.add(generated);
            }
        }
        return possibilties;
    }