{
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  "record_id": "VXI-EXT-PROCUREMENT-HTTP-SIGNATURE-MULTIPLE-SIGNER-POLICY-01-v1",
  "record_kind": "external_reference",
  "title": "HTTP multiple-signature acceptance policy",
  "system": "IETF RFC 9421",
  "evidence_family": "vendor_evidence_review",
  "index_status": "PUBLIC_SAFE_SOURCE_REVIEW",
  "evidence_state": "PRIMARY_DOCUMENTATION_REVIEW_ONLY",
  "canonical_question": "Can a verifier accept an HTTP message because any one attached signature is valid?",
  "near_questions": [
    "Is one valid signature enough when an HTTP message carries several?",
    "Can an unexpected signer add a valid signature to another message?",
    "Could rejecting every message with one bad signature enable denial of service?",
    "Which keys are authorized by a multi-signature verification policy?"
  ],
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    {
      "claim": "RFC 9421 requires a verifier to account for the expected signers, rather than accepting any cryptographically valid signature attached to a message. Applications must also decide how invalid additional signatures affect acceptance: rejecting a message for any invalid signature can permit denial of service by injection. Key, algorithm and acceptance policy must be assessed together.",
      "reliance": "DOCUMENTED_CAPABILITY_ONLY"
    }
  ],
  "not_demonstrated_claims": [
    "A valid attacker signature is insufficient; any-valid versus all-valid policy and invalid-signature denial of service require explicit handling.",
    "Buyer implementation, live runtime enforcement, settled payment, physical outcome, certification or permission to act are not established.",
    "No expanded capabilities or licences for existing INDEX executables."
  ],
  "public_summary": "RFC 9421 requires a verifier to account for the expected signers, rather than accepting any cryptographically valid signature attached to a message. Applications must also decide how invalid additional signatures affect acceptance: rejecting a message for any invalid signature can permit denial of service by injection. Key, algorithm and acceptance policy must be assessed together.",
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    "source_title": "IETF RFC 9421",
    "source_url": "https://www.rfc-editor.org/rfc/rfc9421.txt",
    "checked_on": "2026-10-25",
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    "revalidation": "The delivered snapshot preserves the review date shown. Recheck current primary documentation and deployment context before relying on present applicability; payment does not trigger fresh research."
  },
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    "required_buyer_context": "Expected signer/key set; All signature validation results; Any-valid or required-signature acceptance policy. Buyer deployment not inspected.",
    "missing_evidence": "A broader claim needs evidence matching the intended use. Payment does not upgrade the evidence state."
  },
  "private_boundary": "Raw logs, thresholds, private paths, source code, protected mechanisms and reconstruction-level details are excluded from public and paid delivery.",
  "decision_profile": {
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      "statement": "RFC 9421 requires a verifier to account for the expected signers, rather than accepting any cryptographically valid signature attached to a message. Applications must also decide how invalid additional signatures affect acceptance: rejecting a message for any invalid signature can permit denial of service by injection. Key, algorithm and acceptance policy must be assessed together.",
      "source_ids": [
        "rfc9421"
      ]
    },
    "review_inference": {
      "status": "review_inference",
      "statement": "Decide which HTTP signatures satisfy an expected-signer policy when a message carries several signatures. This is a documentation-review judgment, not an observed deployment outcome.",
      "source_ids": [
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    },
    "buyer_evidence_required": [
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      "All signature validation results",
      "Any-valid or required-signature acceptance policy"
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    "review_condition": {
      "status": "varexis_review_policy",
      "statement": "Refuse buyer-specific assurance from documentation alone. A valid attacker signature is insufficient; any-valid versus all-valid policy and invalid-signature denial of service require explicit handling."
    },
    "unknowns": "The buyer implementation, effective configuration, complete evidence inventory and actual business outcome were not inspected.",
    "unknown_finding": {
      "status": "unknown",
      "statement": "The buyer implementation, effective configuration, complete evidence inventory and actual business outcome were not inspected."
    },
    "evidence_sources": [
      {
        "source_id": "rfc9421",
        "url": "https://www.rfc-editor.org/rfc/rfc9421.txt",
        "final_url": "https://www.rfc-editor.org/rfc/rfc9421.txt",
        "status": 200,
        "captured_at_utc": "2026-10-25T20:26:12.767Z",
        "sha256": "612655786bf4293bfc486e4177571467fbb3de6e6f0eea90cb74c346a34fdf3c",
        "bytes": 241160,
        "title": "IETF RFC 9421",
        "hash_basis": "SHA-256 of unmodified HTTP response body bytes",
        "rights_review": "Original factual paraphrase of the cited IETF RFC; IETF Trust and contributor rights remain applicable. No RFC text, code component or modified standard is redistributed.",
        "checked_on": "2026-10-25",
        "capture_status": 200,
        "claim_review_completed": true,
        "reviewed_sections": [
          "3.2.1",
          "7.2.1",
          "7.2.2",
          "2.4",
          "7.2.5",
          "7.2.6",
          "7.3.4",
          "7.2.8",
          "7.4.3"
        ],
        "version_context": "Fixed IETF RFC 9421 publication; later applicable updates and actual implementation conformance require separate review."
      }
    ],
    "observed_deployment": false,
    "commercial_reliance_boundary": "Documentation review only; the buyer must establish applicability and actual outcomes. INDEX does not inspect or control the deployment.",
    "paid_value": {
      "decision_context": "Decide which HTTP signatures satisfy an expected-signer policy when a message carries several signatures.",
      "free": "Complete review, practical questions, sources and limitations; may be saved locally.",
      "single_request": "Existing server-saved version-bound route snapshot for later authenticated retrieval.",
      "evidence_receipt": "The same snapshot plus the existing unsigned delivery receipt.",
      "excluded": [
        "Fresh vendor research",
        "Continuous monitoring or change alerts",
        "Testing the buyer configuration",
        "Private evidence or vendor certification"
      ],
      "integrity": "Hashes identify content versions; they do not prove truth or provide a signature."
    },
    "revalidation": {
      "trigger": "A saved purchase does not recheck the source or buyer configuration.",
      "specific_watch": "Recheck 7.2.6; 7.3.4 in IETF RFC 9421 when the source, applicable version, configuration or intended reliance changes. A detected change creates a review candidate, not automatic approval."
    },
    "buyer_relevance": "Decide which HTTP signatures satisfy an expected-signer policy when a message carries several signatures.",
    "refusal_conditions": [
      "Refuse buyer-specific assurance from documentation alone. A valid attacker signature is insufficient; any-valid versus all-valid policy and invalid-signature denial of service require explicit handling."
    ]
  },
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    "niche_id": "agent-authority-action-evidence",
    "label": "Agent Authority & Action Evidence",
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    "classification_label": "Audit, Provenance & Evidence Accountability",
    "topic_id": "audit",
    "buyer_intent": "Decide which HTTP signatures satisfy an expected-signer policy when a message carries several signatures.",
    "comparison_role": "supplementary_discovery"
  },
  "paid_access_note": "The full published answer and boundaries are free. Paid access saves the selected route and source versions, with an unsigned receipt when purchased. Preview coverage before paying. Fresh research, bespoke assessment and protected evidence are excluded.",
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    "request_guide": "/varexis-index/request.html",
    "request_workflow": "/varexis-index/request-workflow.json",
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    "service_routes_url": "/varexis-index/service-routes.json",
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    "availability_endpoint": "/api/index/capabilities",
    "operational_status": "AUTOMATIC_SERVICE_CAPABILITIES_GATED",
    "checkout_url": "/index-access"
  },
  "authority_boundary": "VAREXIS-INDEX informs evidence reliance. It does not provide advice, certification, deployment authority, security assurance, production approval, or guarantee.",
  "human_page": "/varexis-index/catalog.html#http-signature-multiple-signer-policy",
  "machine_readable_record": "/varexis-index/records/http-signature-multiple-signer-policy.json"
}