algovoi-substrate-pqc

AlgoVoi substrate-author layer for JCS+PQC integration.

This package implements the AlgoVoi-authored substrate convention for binding canonical-JSON-serialised payloads to post-quantum signature primitives, with a fail-closed verifier discipline over an open-enum signature_algorithm registry.

The underlying cryptographic primitives are not AlgoVoi-authored. This package is a thin substrate-author layer over audited upstream libraries. See the upstream-attribution table below for the full credit chain.

pip install algovoi-substrate-pqc

What this package provides

Upstream primitives

This package wraps existing audited primitives. Authorship of those primitives belongs to the parties listed below, not to AlgoVoi:

The Falcon algorithm itself is the work of Fouque, Hoffstein, Kirchner, Lyubashevsky, Pornin, Prest, Ricosset, Seiler, Whyte, and Zhang (NIST PQC competition; standardised as NIST FIPS 206). The ML-DSA algorithm (Dilithium / CRYSTALS-Dilithium) is the work of Bai, Ducas, Kiltz, Lepoint, Lyubashevsky, Schwabe, Seiler, and Stehlé (standardised as NIST FIPS 204).

PQC cross-implementor contribution

The ML-DSA-65 cross-implementor fixture this package verifies against was contributed by PQSafe (@rayc0) per the AP2 #250 joint conformance fixture. The contribution scope is the pqsafe-side/ ML-DSA-65 signature over the same canonical bytes the AlgoVoi-side fixture signs (FIPS 204 / NIST Level 3). PQSafe is named co-maintainer of chopmob-cloud/ap2-pq-conformance (the joint conformance repo) per the published policy. Credit is scoped to that ML-DSA-65 contribution only; substrate-author work for this package (signature_algorithm convention, JCS+PQC binding pattern, fail-closed verifier discipline, byte-anchor proof methodology) is AlgoVoi's.

Position relative to the substrate-author work

This package sits above the audited PQC primitives and alongside the AlgoVoi-authored canonicalisation discipline. It emits receipts under urn:x402:canonicalisation:jcs-rfc8785-v2 (PQC-aware), the strictly-additive successor to urn:x402:canonicalisation:jcs-rfc8785-v1. The canonicalisation core (RFC 8785 JCS plus schema-normalisation rules) is unchanged between v1 and v2; v2 adds the signature_algorithm open-enum registry and the fail-closed verifier discipline this package implements.

IETF Internet-Draft status. An IETF Internet-Draft formalising urn:x402:canonicalisation:jcs-rfc8785-v2 under the Independent Submissions stream is pending an active IETF list thread (May 2026) on the appropriate scope and use of the Independent Submissions stream for x402-related substrate documentation. The v2 discipline is published on docs.algovoi.co.uk/canonicalisation-substrate-v2, in this reference implementation, and in the Substrate Adopters Registry independently of that process.

AlgoVoi's substrate-author contribution is the convention, the binding, and the proof methodology, not the primitives.

Cross-implementor byte-anchor convergence

The AlgoVoi substrate-author position rests on byte-anchor convergence: multiple independent signature schemes verifying against the identical canonical-byte representation of a single payload. The reference exemplar is the AP2 PaymentMandate joint conformance fixture at chopmob-cloud/ap2-pq-conformance:

Four signature schemes, one canonical payload, byte-identical SHA-256 across implementations. This package is the reference implementation of that convergence-proof methodology.

Verifier rule (fail-closed)

Verifiers MUST treat unknown signature_algorithm values as opaque and refuse to verify.

This rule is the fail-closed normative discipline that allows the signature_algorithm registry to evolve without breaking schema changes. Implementors MAY declare any value. Verifiers MUST reject unknown values or escalate to a registered extension, rather than guessing.

The Python implementation surfaces this rule as UnknownSignatureAlgorithm raised from lookup_signature_algorithm().

License

Apache 2.0.

This package is Apache-2.0 licensed, consistent with all upstream dependencies (pqcrypto, cryptography, rfc8785).

Contact

• Author: AlgoVoi (chopmob-cloud) — chopmob@gmail.com
• Source: https://github.com/chopmob-cloud/algovoi-substrate-pqc
• Cross-implementor reference fixture: https://github.com/chopmob-cloud/ap2-pq-conformance
• Canonicalisation discipline v1: https://docs.algovoi.co.uk/canonicalisation-substrate (also at IETF datatracker as draft-hopley-x402-canonicalisation-jcs-v1)
• Canonicalisation discipline v2 (PQC-aware): https://docs.algovoi.co.uk/canonicalisation-substrate-v2 (IETF I-D filing pending IETF list thread on Independent Submissions stream scope)

Adopters

Parties pinning canon_version: jcs-rfc8785-v2 in publicly-citable artefacts are recorded in the Substrate Adopters Registry alongside v1 adopters. Current v2 adopters:

• AlgoVoi -- this reference implementation (Python + npm packages published 2026-05-26). Cross-validated byte-for-byte across three audit-grade PQC implementations (PQClean via pqcrypto, @noble/post-quantum, Bouncy Castle 1.84 with MLDSASigner).

To request listing as a v2 adopter, follow the submission process. AlgoVoi validates submissions against the artefact's canonical bytes and adds qualifying entries.

v1 adopters retain their registry position. Adopting v2 adds a separate row pinned to jcs-rfc8785-v2 rather than replacing the v1 row.

Acknowledgments

The v2 discipline is solely AlgoVoi-authored. AlgoVoi acknowledges with thanks the post-quantum contribution and reference-implementation work that makes the cross-implementor convergence proof empirically possible:

Post-quantum contribution (v2-specific):

• PQSafe (@rayc0) -- ML-DSA-65 (FIPS 204) signature contribution over the AP2 PaymentMandate canonical bytes (chopmob-cloud/ap2-pq-conformance#1, merged 2026-05-26). Credit is scoped to this ML-DSA-65 contribution only.

Audit-grade PQC implementations cross-validated in the matrix:

• PQClean (via pqcrypto) -- PQClean community + Backbone Authors
• @noble/post-quantum -- Paul Miller
• Bouncy Castle 1.84 (MLDSASigner for FIPS 204 final; experimental FalconSigner) -- Bouncy Castle community

The three audit-grade PQC implementations agree byte-for-byte across the 24-cell producer × verifier matrix. The substrate-author position rests on this independent multi-author cross-validation, not on AlgoVoi self-claim.

Classical primitives and JCS library wrapped:

• cryptography (Python) -- Python Cryptographic Authority
• rfc8785 (Python) -- Anders Rundgren et al. (RFC 8785 reference implementation)
• @noble/curves and @noble/hashes (TypeScript) -- Paul Miller
• canonicalize (TypeScript) -- Samuel Erdtman

v1 validator and contributor acknowledgments (the broader cross-impl validation matrix v2 builds on) are recorded at docs.algovoi.co.uk/canonicalisation-substrate#acknowledgments-and-external-contributions and in the chopmob-cloud/algovoi-substrate README.

Co-maintainer policy

Contributors who land a substrate-aligned signature scheme (new family in the registry, or a new cross-implementor convergence-proof against the same canonical-bytes discipline) MAY be invited as co-maintainers of this repository for the duration of their contribution. Attribution is per-component; each contributor is named for the specific scheme or proof they contribute.

This policy mirrors the chopmob-cloud/ap2-pq-conformance policy under which PQSafe (rayc0) joined as co-maintainer with the ML-DSA-65 contribution.