ORIGINAL COMPANY-CONTEXT PRACTICE
Verify membership during a temporary store-network outage
Original practice scenario: A hypothetical membership retailer wants an offline fallback at checkout. Membership may expire or be revoked while a store is disconnected. Define a bounded decision policy.
Written for independent practice using company context; this is not a verified question from a company interview.
A REASONED APPROACH
Model answer.
Define what evidence an offline terminal may trust and for how long. Offline availability creates an explicit freshness tradeoff; it cannot guarantee awareness of an unseen revocation.
Work through it
- Issue a signed, minimal membership assertion containing identity, validity interval and generation, verifying its integrity locally without storing unnecessary profile information.
- Specify a maximum offline age and actions allowed under stale evidence, routing higher-risk or unsupported cases to a clear alternative process.
- Record offline decisions for later reconciliation, refresh revocation information on reconnect and test clock drift, copied credentials and duplicate terminal records.
Tradeoffs to discuss
- A generous offline window reduces checkout disruption but accepts a larger stale-authority window; strict online dependence may halt otherwise legitimate purchases.
Common pitfalls
- Do not call a cached assertion a current live membership lookup.
- Separate authentication of the presenter from validation of the signed membership state.