Caroline is worried about security for her server room. She wants the most secure lock she can find for the server room door. Which of the following would be the optimal choice for her?

Of the locks listed here, deadbolts are the most secure. The locking bolt goes into the door frame, making it more secure. Whether a lock uses a key or combination, it does not change how secure it is. Key-in-knob is very common, and generally provides less resistance to bypass than a deadbolt-based solution. Finally, padlocks can be cut off with common bolt cutters.