I moved into an apartment complex where the key is both unique to each apartment door, but every key can open the front door, how are both possible?

Question

I moved into an apartment complex where the key is both unique to each apartment door, but every key can open the front door, how are both possible?

In: 986

Answer 1

Every key has a few sections of the cut similar. The front door key core in the lock is only looking for those to line up.

My work has the opposite scenario. The core on each lock is stamped with a code, lets say C3AB. If you had a key stamped C3AB you can open it. But if you had a key stamped C3BB you could not. But lets step back a level, a key stamped C3A could open it, as well as a lock stamped with C3AA, C3A1, etc. It goes all the way back to our “Master Key” which is just labeled C. That key will open any door, padlock, etc that begins with a C.

That is the key I have. We actually use key cards for all the doors but some people have normal keys for emergency purposes. My position is responsible for the entire building (Data center) and if the key card server ever goes down, I am the guy who needs to be able to get in to fix it.