# AirGap Time Anchor Scaffold (prep for AIRGAP-TIME-57-001)

## Scope for prep
- Provide a deterministic parsing surface for signed time tokens (Roughtime, RFC3161) so staleness calculations and telemetry wiring can start without full crypto yet.

## What landed (2025-11-20)
- New project: `src/AirGap/StellaOps.AirGap.Time/StellaOps.AirGap.Time.csproj` (net10.0), BCL-only.
- Model: `TimeAnchor` canonical record (anchor time, source, format, signature fingerprint placeholder, token digest).
- Parser: `TimeTokenParser` with deterministic SHA-256 digest derivation and structured success/failure reasons.
- Result envelope: `TimeAnchorValidationResult` and `TimeTokenFormat` enum.
- Tests: `tests/AirGap/StellaOps.AirGap.Time.Tests` cover empty-token failure and digest production for Roughtime tokens.

## Updates (2025-11-20)
- Added staleness calculator (`StalenessCalculator`) and budgets/evaluation models to derive warning/breach states deterministically.
- Added `TimeAnchorLoader` to ingest hex-encoded tokens from fixtures; sample tokens placed under `src/AirGap/StellaOps.AirGap.Time/fixtures/`.
- Added `TimeStatusService` + `InMemoryTimeAnchorStore` for per-tenant anchor/budget status + staleness; tests in `TimeStatusServiceTests`.
- Added verification pipeline (`TimeVerificationService`) with stub Roughtime/RFC3161 verifiers requiring trust roots; loader now verifies using trust roots.
- Added API surface `/api/v1/time/status` (plus POST `/api/v1/time/anchor`) via `TimeStatusController` and web host wiring.
- Added sealed startup hook (`StartupValidationExtensions`) to block app start when anchor missing/stale; uses budgets and returns structured reasons.
- Upgraded Roughtime verifier to real Ed25519 signature check + RFC3161 verifier using SignedCms; failures now return `roughtime-*` / `rfc3161-*` reasons.
- Added config binding (`AirGap:*`) for tenant and staleness budgets; startup validation pulls from config.
- Added config sample at `docs/airgap/time-config-sample.json` for sealed-mode deployments.
- Documented endpoints and payloads at `docs/airgap/time-api.md`.
- Health check: `/healthz/ready` reports degraded/healthy based on staleness; consumers should scrape for sealed-mode readiness.

## Next implementation hooks
- Plug real Roughtime and RFC3161 decoders, verifying against trust roots supplied via sealed-mode config.
- Persist `TimeAnchor` rows under controller/importer once schema is final; emit telemetry counters/alerts.
- Replace placeholder signature fingerprint with actual signer fingerprint post-verification.

## Determinism/air-gap posture
- Parser avoids wall-clock; anchor time derived deterministically from token digest until real parser is wired.
- No network calls; uses cached NuGet (`local-nugets/`) for tests.

## How to consume
```bash
DOTNET_NOLOGO=1 dotnet test tests/AirGap/StellaOps.AirGap.Time.Tests/StellaOps.AirGap.Time.Tests.csproj --no-build
```

## Owners
- AirGap Time Guild (per sprint 0510).