[PetrefiedThunder]

Linear: SEL-334
Fixes #124

Coding engine: codex, dispatched by Grok Bot for C.Lee.

What changed

At HEAD 1861d6e, genuine P-256 receipts still became malformed or unknown_key before reaching unsupported. The Python and TypeScript SDKs now retain the published per-key algorithm, verify P-256 DER signatures against DER SPKI public keys, and classify a genuine P-256 receipt as unsupported under the current Ed25519 receipt policy. Altered signed bytes remain invalid. The independent failure-lab verifier now checks P-256 signatures too. Ed25519 raw-key callers and local permit verification remain Ed25519-only. Updated the wire-format docs and shared vectors.

How verified

• ~/metacode/fleet/heavy env PYTHONPATH=sdk/python/src:spec/test-vectors:gateway /Users/sellers/Projects/agent-middleware-api/.venv/bin/python -m pytest sdk/python/tests/test_receipt_verifier.py sdk/python/tests/test_receipt_verifier_signed.py sdk/python/tests/test_receipt_vectors.py sdk/python/tests/test_local_permit_validator.py spec/test-vectors/test_contract.py spec/test-vectors/test_generate.py gateway/tests/test_failure_lab_verifier.py gateway/tests/test_spec_conformance.py -q --no-cov , 246 passed; two unknown-mark warnings from gateway test setup.
• From sdk/typescript: ~/metacode/fleet/heavy npm test , 121 passed, one pre-existing skip; build passed as the test pre-step. ~/metacode/fleet/heavy npm run lint , passed.
• ~/metacode/fleet/heavy env PYTHONPATH=sdk/python/src /Users/sellers/Projects/agent-middleware-api/.venv/bin/python verifier/check_vectors.py , 54/54 vectors passed.
• ~/metacode/fleet/heavy env PYTHONPATH=sdk/python/src:gateway /Users/sellers/Projects/agent-middleware-api/.venv/bin/python -m pytest gateway/tests/test_public_mcp_endpoint.py -k 'verify_receipt or unverified_algorithm_claim' -q --no-cov , 6 passed, 32 deselected.
• ruff check on the changed Python files, ruff format --line-length 100 --check on the changed Python SDK files, and git diff --check , passed.

Not done / follow-ups

The gateway signing plane remains Ed25519-only. Enabling P-256 issuance or accepting P-256 receipts as verified needs a separate KMS and receipt-policy change. No live KMS or production service was called. No commit, push, or deployment was made.

---

Note

Medium Risk
Touches cross-language cryptographic verification and status semantics; behavior change is intentional but affects how non-Ed25519 receipts are classified at the trust boundary.

Overview
Receipt verification now understands dormant ECDSA-P256-SHA256 keys without accepting them as receipt v0.1. Python and TypeScript verifiers load P-256 public keys from trust-keys.json (DER SPKI), check signatures using the published per-key alg, then return unsupported for a cryptographically valid P-256 receipt; tampered bytes stay invalid instead of being mislabeled malformed or unknown_key.

The Python SDK adds a VerificationKey type; the failure-lab verifier and gateway public MCP key-set typing follow the same model. Ed25519-only paths (local permit verification, issuance) are unchanged. Specs, key-management docs, and shared test vectors include new P-256 cases (p256.valid → unsupported, tampered → invalid).

^{Reviewed by Cursor Bugbot for commit 240bbdf. Bugbot is set up for automated code reviews on this repo. Configure here.}

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-20T10:27:42.944306Z	688f038	PR opened

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.