A system can be secure as long as nobody outside its implementation group is told anything about its internal mechanisms. This belief is called

Group of answer choices

security by obscurity and it is an ineffective countermeasure to hacker attack

security by unknown and it is an effective countermeasure to hacker attack

security by transparency and it is an ineffective countermeasure to hacker attack

security by anonymity and it is an effective countermeasure to hacker attack