Cross-Tenant Receipt Federation for Human-AI Governance Substrates: Public Verification of Signed Governance Artifacts Without Substrate Trust | APR-Lite Phase 18 — Technical Note

This record documents Phase 18 of APR‑Lite, a cryptographic governance layer designed to preserve human decision authority over AI‑influenced outputs in regulated environments. Phase 18 extends prior work by making governance proofs externally verifiable without reliance on internal substrate access, so that parties holding signed artifacts can confirm their authenticity and provenance using only public material. The phase adopts a transparency model analogous to those used for public cryptographic infrastructures: governance artifacts produced by the system can be checked by any observer without prior trust in the underlying platform, and without requiring authentication, traversal of internal history, or knowledge of internal data structures. Verification remains specific to the kind of artifact presented, while sharing a common proof regime. A dedicated public interface now accepts signed governance artifacts, applies type‑appropriate validation, and returns structured verification results. A companion interface exposes the evolution of verification material for governed entities over time, with provenance anchored in prior governance acts, so that verification keys are themselves subject to the same institutional controls as other high‑authority behavior. The externally visible payloads available through this surface are confined to governance‑oriented constraints and status signals rather than operational business data or substrate internals, maintaining a separation between institutional assurances and application content. Phase 18 achieved full success on its smoke‑test suite for the extended federation and verification pipeline in worker version 8.2.0‑p18.1. A more detailed treatment of the transparency model, key‑lifecycle handling, and constraint exposure is available under restricted access to qualified requesters.