Assay records and verifies security-relevant evidence. Please disclose suspected vulnerabilities privately so users can rotate keys and preserve affected ledgers before details become public.

• Do not open a public issue containing live ledger data, secrets, customer identifiers or an exploitable reproduction against a production deployment.
• Use the private security advisory flow of the repository that hosts this project.
• Include the version, a minimal reproduction built from synthetic events, the expected result and the observed result.
• If a signing key may have been exposed, rotate it first and state that rotation in the report.

We aim to acknowledge a report within two business days and to agree a disclosure timeline with the reporter. Good-faith research on your own deployment is welcome; do not test against systems you do not own or have permission to assess.

In scope:

• hash-chain construction and verification;
• HMAC signing and key handling;
• canonical JSON and event validation;
• policy matching, first-match order and fail-closed amount checks;
• evidence-pack integrity and the CLI exit-code contract;
• path handling, atomic writes and denial of service through malformed input.

Out of scope:

• the truthfulness of a producer that records false or incomplete events;
• compromise of the host, the Python interpreter or the storage account;
• social engineering and physical access;
• third-party services that a deployment chooses to connect.

The full threat model, including the tail-truncation limitation and key-custody guidance, is in docs/SECURITY.md.