{ "schema": "varexis-index-free-publication-preview/1", "catalogue_version": "pub-9-tranche-59-v1", "route_id": "agentic_reviewed_http_signature_content_digest_recheck", "record_id": "VXI-EXT-PROCUREMENT-HTTP-SIGNATURE-CONTENT-DIGEST-RECHECK-01-v1", "question": "Does verifying a signature over Content-Digest alone establish the integrity of the received body?", "answer": "RFC 9421 does not directly sign message content. A digest field can bind it indirectly, but the verifier must both verify the signature and recompute the digest against the received content. Otherwise substituted content can leave the signed digest field unchanged. Content-encoding changes can also change the digest and invalidate the existing signature.", "records": [ { "record_id": "VXI-EXT-PROCUREMENT-HTTP-SIGNATURE-CONTENT-DIGEST-RECHECK-01-v1", "url": "/varexis-index/records/http-signature-content-digest-recheck.json", "content_sha256": "330ab4ecdbea23d2e5d92a8b32b9f8bfde09e4bae8670f4d989d24254375b0ec", "evidence": { "schema": "varexis-public-evidence-record/0.3", "generated_at_utc": "2026-10-25T20:55:19.974986+00:00", "record_id": "VXI-EXT-PROCUREMENT-HTTP-SIGNATURE-CONTENT-DIGEST-RECHECK-01-v1", "record_kind": "external_reference", "title": "HTTP signed digest and actual content", "system": "IETF RFC 9421", "evidence_family": "vendor_evidence_review", "index_status": "PUBLIC_SAFE_SOURCE_REVIEW", "evidence_state": "PRIMARY_DOCUMENTATION_REVIEW_ONLY", "canonical_question": "Does verifying a signature over Content-Digest alone establish the integrity of the received body?", "near_questions": [ "Must a signed Content-Digest be checked against the body?", "Can a signature pass while the HTTP payload was substituted?", "Does covering a digest field automatically validate content bytes?", "Can content re-encoding invalidate an HTTP signature?" ], "supported_claims": [ { "claim": "RFC 9421 does not directly sign message content. A digest field can bind it indirectly, but the verifier must both verify the signature and recompute the digest against the received content. Otherwise substituted content can leave the signed digest field unchanged. Content-encoding changes can also change the digest and invalidate the existing signature.", "reliance": "DOCUMENTED_CAPABILITY_ONLY" } ], "not_demonstrated_claims": [ "Signature verification covers the digest field value, not automatic recomputation of the actual content; content encoding changes matter.", "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 does not directly sign message content. A digest field can bind it indirectly, but the verifier must both verify the signature and recompute the digest against the received content. Otherwise substituted content can leave the signed digest field unchanged. Content-encoding changes can also change the digest and invalidate the existing signature.", "related_record_ids": [], "source_review": { "source_type": "official_external_documentation", "source_title": "IETF RFC 9421", "source_url": "https://www.rfc-editor.org/rfc/rfc9421.txt", "checked_on": "2026-10-25", "candidate_record_id": "VXI-EXT-PROCUREMENT-HTTP-SIGNATURE-CONTENT-DIGEST-RECHECK-01-v1", "candidate_record_sha256": "c2f9e6f5e686a036a2c6e3544863f592c67bab5b8b849a056a26f6b0fce4efa0", "method": "Primary documentation reviewed for the published bounded statement.", "deployment_tested_by_varexis": false, "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." }, "answer_policy": { "classification": "DOCUMENTED_WITH_DEPLOYMENT_BOUNDARY", "bounded_answer": "RFC 9421 does not directly sign message content. A digest field can bind it indirectly, but the verifier must both verify the signature and recompute the digest against the received content. Otherwise substituted content can leave the signed digest field unchanged. Content-encoding changes can also change the digest and invalidate the existing signature.", "required_buyer_context": "Received content bytes and encoding; Digest field and hash algorithm; Signature coverage and recomputed digest. 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": { "schema": "varexis-vendor-evidence-review/1", "review_status": "documentation_review_only", "checked_on": "2026-10-25", "claim_to_check": "Does verifying a signature over Content-Digest alone establish the integrity of the received body?", "documented_statement": { "status": "documented", "statement": "RFC 9421 does not directly sign message content. A digest field can bind it indirectly, but the verifier must both verify the signature and recompute the digest against the received content. Otherwise substituted content can leave the signed digest field unchanged. Content-encoding changes can also change the digest and invalidate the existing signature.", "source_ids": [ "rfc9421" ] }, "review_inference": { "status": "review_inference", "statement": "Verify the received body against the signed digest before treating HTTP content as integrity checked. This is a documentation-review judgment, not an observed deployment outcome.", "source_ids": [ "rfc9421" ] }, "buyer_evidence_required": [ "Received content bytes and encoding", "Digest field and hash algorithm", "Signature coverage and recomputed digest" ], "review_condition": { "status": "varexis_review_policy", "statement": "Refuse buyer-specific assurance from documentation alone. Signature verification covers the digest field value, not automatic recomputation of the actual content; content encoding changes matter." }, "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": "Verify the received body against the signed digest before treating HTTP content as integrity checked.", "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 7.2.8 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": "Verify the received body against the signed digest before treating HTTP content as integrity checked.", "refusal_conditions": [ "Refuse buyer-specific assurance from documentation alone. Signature verification covers the digest field value, not automatic recomputation of the actual content; content encoding changes matter." ] }, "niche": { "niche_id": "agent-authority-action-evidence", "label": "Agent Authority & Action Evidence", "classification_id": "audit", "classification_label": "Audit, Provenance & Evidence Accountability", "topic_id": "audit", "buyer_intent": "Verify the received body against the signed digest before treating HTTP content as integrity checked.", "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.", "service_route": { "request_guide": "/varexis-index/request.html", "request_workflow": "/varexis-index/request-workflow.json", "service_id": "single_request", "service_routes_url": "/varexis-index/service-routes.json", "payment_required": true, "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-content-digest-recheck", "machine_readable_record": "/varexis-index/records/http-signature-content-digest-recheck.json" } } ], "access": { "mode": "exact_http_only", "payment_required": false, "purchase_url": null, "mcp_preview_available": false, "paid_saved_retrieval_available": false, "natural_language_search_qualified": false }, "boundary": "Catalogue additions are available free through the exact HTTP JSON links below. Enhanced natural-language discovery is not yet qualified for these records. They are outside MCP search, MCP preview and paid saved retrieval. No search qualification, executable capability or entitlement is added.", "content_sha256": "f281cd60e20531b38815f3f5527a1c32e2f3fe41a9a0ef29a372760b89629158" }