37 lines
1.7 KiB
Markdown
37 lines
1.7 KiB
Markdown
# Trust and Signing (DOCS-AIRGAP-58-002)
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Guidance on DSSE/TUF roots, rotation, and signed time tokens.
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## Trust roots
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- Maintain offline root keys for DSSE/TUF; store in HSM or sealed vault.
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- Distribute intermediate/leaf keys via bootstrap packs with fingerprints.
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- Keep trust roots versioned; record `rootVersion` and validity period.
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## DSSE
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- Use DSSE for bundle manifests (mirror/bootstrap) and evidence timelines when possible.
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- Verification in sealed mode uses bundled roots; no online Rekor needed.
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- Rotate signing keys with overlapping validity; publish new root in next bundle.
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## TUF (planned enhancement)
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- **Current**: TUF metadata can be shipped with bundles (`root.json`, `snapshot.json`, `timestamp.json`).
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- **Planned**: Full TUF client integration for dynamic trust metadata distribution.
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- See: `SPRINT_20260125_001_Attestor_tuf_trust_foundation.md`
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- See: `SPRINT_20260125_002_Attestor_trust_automation.md`
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- In sealed mode, trust only bundled metadata; no remote refresh.
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## Signed time tokens
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- Export signed time anchors (see `docs/modules/airgap/guides/staleness-and-time.md`):
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- Token fields: `issuedAt`, `notAfter`, `timeSource`, `signature`, `rootVersion`.
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- Validate offline against trust roots; expire strictly at `notAfter`.
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## Rotation procedure
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1. Prepare new root and leaf keys; sign new root with current root.
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2. Include new `root.json` and fingerprints in next mirror/bootstrap bundle.
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3. During import, verify both current and new root; switch default after verification.
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4. Re-sign manifests/time tokens with new leaf.
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## Security notes
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- Never fetch keys online in sealed mode.
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- Keep audit log of rotations (who, when, rootVersion, fingerprints).
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- Enforce least privilege for signing service accounts.
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