pass key 
noun
1A key to the door of a restricted area, given only to those who are officially allowed access: I was able to use my pass key to get into the storage room...
- Earp was employed by Johnson Security Services and was entrusted with a pass key which allowed him access to all parts of the school.
- Two of these she recognised as the type of key used by patients on their lockers and a large key was similar to the pass key that Michael had.
- And, if we don't get the pass key to the Treasury, we're outa’ here and all of America will suffer.’
2A master key: the night porter used a pass key for those rooms that were empty...
- January roared at them now, pretending - they assumed - to berate them while she created a pass key to open the door.
- I am quite certain that there will be more issues with the security of these systems due to the use of standard pass keys,’ Trifinite notes.
- Armed with the pass keys January had created for them, they split up, each unlocking and reprogramming three fighters.