final String challenge) throws NTLMEngineException {
        Type2Message type2Message;
        try {
            type2Message = new Type2Message(Base64.getDecoder().decode(challenge));
        } catch (final IOException exception) {
            throw new NTLMEngineException("Invalid NTLM type 2 message", exception);
        }
        final int type2Flags = type2Message.getFlags();