Stage352: Hybrid Signature Manifest Verification Layer

Stage352 extends Stage351 by verifying the hybrid signature manifest.

What Stage352 Verifies

• docs/signatures/stage351_signature_manifest.json exists
• docs/enforcement/enforcement_session.json exists
• Stage351 required fields are present
• Stage351 session_sha256 matches Stage350 session_sha256
• canonical_payload_sha256 is recomputed and checked
• signature_manifest_sha256 is recomputed and checked
• CI / local context is consistent
• Sigstore OIDC requirement is consistent
• PQC ML-DSA intent_only state is not falsely treated as a real signature
• Missing signatures are not claimed as verified
• Private keys and raw secrets are not referenced

Public Evidence

• docs/signatures/stage352_signature_manifest_verification.json

Decision Model

• accept_metadata_only: local metadata-only manifest is structurally valid and hash-bound
• accept: CI context and required signature conditions are satisfied
• warn: non-critical inconsistency
• reject: hash mismatch, structure mismatch, or fake PQC/signature claim
• block: CI requires Sigstore OIDC but it is missing

Safety Boundary

Stage352 does not publish private keys, raw secrets, fake signatures, or unverified PQC claims.