CCS Conformance Checker

An independent conformance checker for CCS (Correctover Conformance Shape) receipts. It imports zero CCS code — every check is implemented directly from the receipt specification, so a passing result is third-party evidence rather than self-certification by the producer.

Install

pip install ccs-conformance-checker

Run it

Zero arguments runs the bundled minimal vector directory (one valid, Ed25519-signed L1 receipt) so a fresh install immediately produces a real result instead of a usage error:

ccs-conformance-check

Audit a vectors directory of your own:

ccs-conformance-check /path/to/vectors

Machine-readable output:

ccs-conformance-check --json /path/to/vectors

A vectors directory needs a manifest.json mapping every case file to its sha256, plus the receipt case directories themselves.

What it checks

• Structure — exact field envelope for L1 and L2 receipts, required non-empty fields
• Signature — Ed25519 verification over JCS (RFC 8785) canonical bytes
• Semantics — cross-field consistency, temporal windows, identity binding
• Chain — sequence contiguity, trace agreement, prev-hash anchoring to the predecessor receipt's computed digest, nonce uniqueness
• Canonicalization — JCS edge cases including signed -0 / 0

Output and exit codes

Text mode prints one line per case plus a summary. --json emits a single JSON document on stdout (human-readable notes go to stderr) with per-case verdicts and per-check detail.

Exit code 0 means every vector matched its expected outcome; non-zero means at least one did not. The built-in zero-argument demo always exits 0.

1.4.3

• chain:prev-hash-matches now anchors to the computed L1 digest of the predecessor receipt bytes, instead of only cross-checking the two declarations (runtime-context.prev_receipt_digest and chain.json::expected_prev_digests) against each other. Regression vector 10e-prev-hash-unanchored added — a chain whose declarations agree with each other but disagree with the actual predecessor digest is now correctly rejected. Found by Joel Hillier (Certisyn) during independent interoperability review (2026-08-30).
• chain.json::expected_prev_digests is treated as advisory metadata (cross-check only), not as the authority for anchoring.
• Adds JCS (RFC 8785) canonicalization-v1 vector support, including signed -0 / 0 edge cases.

License

Apache-2.0 for the package. Bundled demo vectors originate from the CC0 1.0 vector corpus; the checker core carries an MIT file-level notice.

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