receipt

Verifiable custody of agent-produced records.

Status

Shipped so far: the release-chain verifier, the append gate, ECMAScript-compatible canonical JSON, standalone Ed25519 signing with consumer-pinned threshold keyrings, RFC 3161 dual-witness verification, and workflow-provenance verification. The machinery arrives by extraction from three production systems that each built it independently (pre-registered forecast records, an observation-ledger release chain, a signed statute corpus), behind a byte-equivalence gate: the extracted verifier must reproduce the source verifier's verdict, pass and fail alike, on the live production chain at a pinned commit before any system consumes the package. That gate has held end to end — the observation ledger consumes the package in production, with the differential harnesses re-proving equivalence on every package change.

What it provides (shipped rows) and what is still arriving

• receipt.chain — append-only hash-chained manifests over record sets: enumerated genesis, content-addressed links, immutable-prefix verification
• receipt.tsa — RFC 3161 dual-witness verification against consumer-committed trust bundles and signer identities, with explicit unavailable-witness outcomes
• receipt.sign — Ed25519 producer signatures verified against fingerprints pinned in the consumer's own committed code (shipped: ported ledger primitives, sign-side helpers, N-of-M keyrings with legacy verification generations — retired keys verify immutable history only; rotation by reviewed spec change)
• receipt.attest — workflow-provenance verification with self-anchoring enforcement epochs and a full-history sweep over every protected-tree commit
• receipt.ratchet — shrink-only exception registries recomputed from live state; an excused failure that starts passing is an error until removed
• receipt.chronology — record-vs-event ordering tiers: does witnessed time prove the record existed ante quem — before the event it predicts or observes?
• receipt verify — the outside auditor's command: a clone, commodity tools, one offline fail-closed verdict

Design principle

Trust anchors live in the consumer's committed code, never in runtime configuration a producer could swap. The package ships machinery; consumers pin roots.

The name

A receipt is the record you keep so anyone can check it later. Software already uses the word in exactly this sense: an app-store receipt is a signed proof validated offline, without trusting the store that issued it. This package writes receipts for agent-produced records; receipt verify is what happens when someone asks to see them.

Releases through 0.1.2 shipped as vidimus; those remain on PyPI under the old name.

License

Apache-2.0.