{
  "schema_version": "1.3.0",
  "slug": "which-sbom-signatures-must-be-verified-when-the-build-environment-is-ephemeral",
  "title": "Which SBOM signatures must be verified when the build environment is ephemeral?",
  "date_of_record": "2026 October 20",
  "scope": "* **Applies when:** The SBOM was produced by an ephemeral build environment, the builder is no longer available for challenge or re-verification, and the SBOM drives security-critical decisions. * **Does not apply when:** The build environm",
  "projections": {
    "unified_markdown_uri": "https://corpusfetch.com/c/which-sbom-signatures-must-be-verified-when-the-build-environment-is-ephemeral.md",
    "method_python_slice_uri": "https://corpusfetch.com/c/which-sbom-signatures-must-be-verified-when-the-build-environment-is-ephemeral.py",
    "remnant_warrant_slice_uri": "https://corpusfetch.com/c/which-sbom-signatures-must-be-verified-when-the-build-environment-is-ephemeral.warrant.json"
  },
  "token_profile": {
    "full_markdown_tokens": 1050,
    "python_slice_tokens": 255,
    "warrant_slice_tokens": 220
  },
  "remnant_summary": {
    "core_distinction": "The separation between **SBOM document integrity** (the SBOM has not been modified since it was signed) and **builder attestation validity** (the build environment actually performed the build, with the properties claimed). Relying on document integrity creates the **Ephemeral Builder Void**: the SBOM is signed, but the ephemeral builder is gone, and no one ...",
    "what_was_observed": "In ephemeral build environments, failing to verify builder attestation produces three primary failure modes: 1. **Fake Builder Identity:** An attacker creates a fake ephemeral environment, builds a malicious image, and signs an SBOM claiming it came from the legitimate CI pipeline. The builder is gone, so no one can verify the claim. 2. **Post-Compromise Attestation:** The ephemeral builder is compromised mid-build, ...",
    "condition_of_validity": "* **Applies when:** The SBOM was produced by an ephemeral build environment, the builder is no longer available for challenge or re-verification, and the SBOM drives security-critical decisions. * **Does not apply when:** The build environment is persistent and available for real-time challenge, or the SBOM is used only for informational inventory without se...",
    "decision_boundary": "1. **Is the SBOM signed?** If no, reject it. If yes, proceed. 2. **Does the SBOM include a `hardware_rooted_build_attestation` (TEE quote)?** If no, the SBOM's authenticity cannot be verified after the builder is destroyed. Reject it or require re-attestation. 3. **Is the `transparency_log_inclusion_proof` present and valid?** If no, the SBOM may have been s...",
    "operational_effect": "1. **Ephemeral Builder Verification:** Allows SBOMs from destroyed builders to be verified through transparency logs and TEE quotes. 2. **Post-Compromise Detection:** Hardware attestation detects mid-build compromise that document signatures cannot catch. 3. **Deploy-Time Trust:** Provides cryptographic trust at deploy time, regardless of the builder's curre..."
  },
  "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": "fe87eea824ed3589b8847023233c516d562d6667d53f094b767b33b9b2df6000",
    "verified_classes": [
      "EphemeralBuilderVerdict",
      "EphemeralSBOMPackage",
      "EphemeralBuilderPolicy",
      "EphemeralBuilderManifest",
      "EphemeralBuilderGuard"
    ],
    "verified_functions": [
      "_hash",
      "evaluate_ephemeral"
    ],
    "verified_functions_count": 2,
    "defensive_guards_count": 0,
    "raised_exceptions": [],
    "sample_fail_closed_invariants": [],
    "stdlib_dependencies": [
      "dataclasses",
      "enum",
      "hashlib",
      "json"
    ],
    "observation_mode": "EMPIRICAL_BOUNDARY_CAPTURE",
    "zero_external_deps": true
  }
}