Key control log
Who has which key right now, and who had it before.
Add the keys that get signed in and out, then issue and return them. Each move is added to that key’s history, never written over the last one — which is the whole point of a key register. Two keys stamped with the same label stay two separate keys with two separate histories. No door codes, no access-control integration, and nothing stored beyond a name and whatever note you type.