Make emergency revocation reach cached consumers
An operator revokes a synthetic compromised key, but a worker's indefinite cache continues signing requests with it. Another worker refreshes and succeeds, hiding the inconsistent state.
- Focused work estimate
- 5h + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Revocation consistency · Cache lifetimes · Failure modes · Security operations
Estimated field mix
- Security60%
- Distributed systems40%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
A fictional supplier integration signs incoming webhooks and uses an outbound API credential. Operators currently replace environment values by hand. Build with a deterministic secret-store adapter and fabricated keys only; no live provider account or production credential is part of the exercise.
Setup prerequisites
- Cryptographic hash APIs
- HTTP webhook handling
- Access control
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
- VAULT-101 · Inventory credential consumers without exporting their values
- VAULT-102 · Move secret lookup behind a version-aware provider
- VAULT-103 · Redact credentials from failed supplier requests
- VAULT-104 · Model credential activation and retirement as explicit transitions
- VAULT-105 · Verify signed webhooks against raw bytes before parsing
- VAULT-106 · Accept old and new webhook signatures only during a bounded overlap
- VAULT-107 · Keep duplicate signed callbacks from creating duplicate supplier events
- VAULT-108 · Rotate outbound credentials without retrying an ambiguous write twice
Acceptance criteria
- Bound cache lifetime and propagate credential authority revisions to all consumers.
- Prevent use after the declared revocation deadline, including during provider outage.
- Audit revocation convergence using version references and consumer acknowledgements only.
Implementation constraints
- Cached availability cannot override explicit revocation; define the exercise's maximum revocation delay.
Verification to include
- Revoke a cached fixture key across two consumers and measure convergence.
- Drop one invalidation notification and disable lookup; verify use stops at the deadline.
Deliverables
- Revocation propagation design and failure-interleaving tests
Rollout and recovery
Enforce bounded caching before testing emergency revoke; pause outbound work when authority cannot be refreshed safely.
Value of the work
For the engineer: Practice credential lifecycle design, overlap windows, authenticated webhooks, and failure recovery without handling real secrets.
For the team: Review whether an engineer can make rotation auditable and fail closed while preserving availability and replay safety.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.