What presents identity?
A phone, wearable, fob, or staff member must carry or establish authorized evidence. A working network cannot invent a missing credential.
Can the door verify you without your phone?
Predict first. Change the carrier, verifier, and token age. Then trace the exact rule that opens or locks the gym entrance.
Credential designKeys 1-4
DependenciesChange one variable
Credential ageExpires at 30 min
Your predictionPredict before testing
Choose a prediction, then run the authorization path.
Observed rule0 trials
The reader has not evaluated a credential yet.
Loading Three.js r168...
The app is only one part of the key.
Where is trust checked?
A cloud service may approve each entry, while a local reader can verify a signed pass without internet. Those architectures fail differently.
Can old evidence replay?
Short-lived credentials limit copied-code reuse. A screenshot can look correct yet fail because its signed time window has passed.
What works when digital fails?
A staffed desk can verify identity through a separate process. It is a real fallback, not a universal bypass for an unstaffed door.
Four architectures. Four different failure boundaries.
Transfer the rule beyond this door.
Parking garage
A mobile pass may be cloud-authorized, locally signed, or copied into a vehicle wallet. Ask which carrier and verifier are required before assuming “the app” means “the internet.”
Office turnstile
A badge can verify locally while revocation updates arrive later. Convenience and rapid revocation pull the architecture in different directions.
Hotel room
A phone key can be provisioned for a time window, then verified at the lock. Expiry is not a bug: it is the control that prevents yesterday's credential from opening today's room.
Your phone is home. The saved pass expired.
Choose the truthful same-day recovery path. This is the transfer test: apply carrier, verifier, and freshness reasoning to a scenario the first challenges did not solve for you.
Choose one recovery path and explain it by observing the feedback.