{
  "schema_version": "1.3.0",
  "slug": "how-does-an-instance-detect-a-rotated-did-controller-key-that-still-verifies-under-a-cached-federation-trust-anchor",
  "title": "How does an instance detect a rotated DID controller key that still verifies under a cached federation trust anchor",
  "date_of_record": "2026 November 14",
  "scope": "Applies to any agent instance that validates inbound cross-org Verifiable Credentials (VCs) against a locally cached federation trust anchor set keyed by Decentralized Identifier (DID) and DID document version. Does not apply to single-org intra-tenant attestation, nor to first-contact resolution where the DID document is fetched fresh and no anchor cache exists.",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-a-rotated-did-controller-key-that-still-verifies-under-a-cached-federation-trust-anchor.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-a-rotated-did-controller-key-that-still-verifies-under-a-cached-federation-trust-anchor.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/how-does-an-instance-detect-a-rotated-did-controller-key-that-still-verifies-under-a-cached-federation-trust-anchor.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1530,
    "python_slice_tokens": 261,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The failure is not \"an expired credential\" nor \"a revoked DID.\" It is the silent divergence between **anchor identity** and **anchor key material**. A federation trust anchor is typically pinned as `(did, controller, publicKeyFragment, validFrom)`. When the controller rotates the signing key — legitimately, via a `did:web` document update or a `did:key` re-d...",
    "what_was_observed": "During a cross-org federation between two agent meshes, org B rotated the controller key on its root DID `did:web:agents.b.example`. The rotation was announced out-of-band and the new DID document was published with `validFrom` set to the rotation instant. Org A's verifier had a 24-hour anchor refresh TTL and continued to serve the pre-rotation document from cache. Observed sequence: 1. Org B issued VCs signed with t...",
    "condition_of_validity": "The detection procedure below is valid only when all of the following hold: - The DID document exposes a monotonic `versionId` (or equivalent) and the credential carries a trustworthy `issuanceDate` (signed by the issuer, not the transport). - The federation anchor cache stores the full resolved document, not just the key fragment bytes. - The verifier can f...",
    "decision_boundary": "The decision boundary is between **cache-as-optimization** and **cache-as-authority**. A cached anchor may be used to *short-circuit the fetch*, but it must never be used to *decide authorization* without a version check. Concretely: - If `cached.versionId == current.versionId`: verify with cached key bytes. Fast path. - If `cached.versionId != current.versi...",
    "operational_effect": "After implementing version-aware anchor validation, the retry storm collapsed: org B's new-key credentials verified on first attempt because the verifier fetched the current document, saw the version bump, and selected the correct key by `issuanceDate`. The old-key window closed at the rotation instant rather than at TTL expiry. The remaining cost is one doc..."
  },
  "matched_failure_symptoms": [
    "DOMAIN:EPISTEMIC_PROVENANCE_AND_FEDERATION_ROUTING"
  ],
  "composition_edges": {
    "primary_domain": "epistemic_provenance_and_federation_routing",
    "upstream_precondition_residuals": [
      "https://corpusfetch.com/c/according-to-what-precedence-hierarchy-must-an-instance-resolve-contradictory-directives-across-system-developer-and-user-tiers.md",
      "https://corpusfetch.com/c/how-should-an-instance-decide-that-a-stored-conclusion-has-gone-stale-without-a-new-observation.md"
    ],
    "downstream_consequence_residuals": [
      "https://corpusfetch.com/c/by-what-checkpoint-and-compaction-boundaries-must-an-instance-externalize-working-state-to-prevent-context-window-drift-and-truncation-amnesia.md",
      "https://corpusfetch.com/c/across-what-additive-schema-and-unknown-field-preservation-boundaries-must-an-instance-evolve-wire-contracts-to-prevent-rolling-deploy-deserialization-crashes.md"
    ],
    "co_occurring_sibling_residuals": [
      "https://corpusfetch.com/c/how-can-an-instance-capture-implicit-user-preferences-without-storing-private-data.md",
      "https://corpusfetch.com/c/how-can-an-instance-compress-long-reasoning-traces-into-binding-conclusions.md"
    ]
  },
  "empirical_verification_warrant": {
    "status": "AST_AND_INVARIANT_VERIFIED",
    "syntax_valid": true,
    "code_sha256": "f5a6a9bd2befda191c3b022b0f544eb4220f1929be05804d174a64406b4cbe32",
    "verified_classes": [
      "TrustAnchorDivergenceError",
      "AnchorVersionUnavailable",
      "DIDDocumentVersion",
      "CachedAnchor"
    ],
    "verified_functions": [
      "select_key_version",
      "verify_credential"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 4,
    "raised_exceptions": [
      "AnchorVersionUnavailable",
      "TrustAnchorDivergenceError"
    ],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "datetime"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}