Certification, decided by a machine

Specification v0.1 (Working Draft) Steward: Concert Foundation Tier: Normative Licence: Apache-2.0 (suite) · CC0-1.0 (this document)

This document defines what it means for a document or an implementation to conform to the SIGNET standard, the conformance levels, and the neutrality rules that govern certification. It is the companion to the SIGNET Canonical Data Model specification (CDM §13 Conformance) and the Concert IP & Licensing Policy.

The accompanying machine-runnable suite (conformance/) tests every requirement below. A claim of conformance is only meaningful when accompanied by a passing report from that suite (report-schema.json).

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1. Conformance targets

Two things can conform:

• A document — a single CDM instance (an Invoice, a Decision, …). Document conformance is purely structural (CDM §13.1).
• An implementation — a system that reads, writes, and changes CDM documents. Implementation conformance additionally covers behaviour: round-trip fidelity, mapping fidelity, and event/provenance integrity (CDM §13.2).

Only implementations are certified. Document conformance is a building block of implementation conformance.

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2. Conformance levels

2.1 SIGNET Core v0.1

The floor. An implementation is Core-conformant if it satisfies every MUST in:

• C-DOC — Document conformance. Every document it emits validates against the published JSON Schema for its declared version, and it rejects documents that do not (CDM §13.1). Tested by: positive fixtures must validate; negative fixtures must be rejected.
• C-EVT — Event & audit integrity (Layer 3). Every material change produces an append-only Event carrying Provenance; Events hash-chain via previousEventHash so tampering is evident (CDM §1.7, §7.1, §7.2). Tested by: a valid chain verifies; a tampered chain is detected.
• C-PROV — Provenance presence. Every Decision and every Event carries a provenance object identifying what generated the assertion and when (CDM §6.4, §7.2). Tested by: provenance presence and shape checks.

Core corresponds to Layer 1 (Wire Contract) + Layer 3 (Event & Audit) of the SIGNET architecture.

2.2 SIGNET Full v1.0

Core, plus:

• F-MAP — Interoperability mapping fidelity (Layer 4). The implementation performs the normative §8 standards mappings without loss of mapped fields. For v0.1 the tested mapping is Invoice → Peppol BIS Billing 3.0 (EN 16931): the projection must preserve every mapped Business Term and the monetary totals must reconcile (CDM §8, §13.2(b)). Tested by: the mapping-conformance cases.
• F-SEM — Behavioural semantics (Layer 2). Policy objects carry both an executable expression and a humanReadable statement; Mandates bound agent actions; Decisions reference the inputs and policies they applied (CDM §6.3–6.5, §13.2). Tested by: the semantics cases.

Full corresponds to Core + Layer 2 (Behavioural Semantics) + Layer 4 (Interoperability).

2.3 Reporting

The suite reports, per requirement, pass | fail | not-applicable, and computes the highest level fully satisfied: Full, Core, or none. A partial result (e.g. Core met, Full partially met) is reported honestly as Core with the failing Full requirements listed. There is no rounding up.

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3. Certification neutrality rules (CN)

These rules are the operational expression of the governance firewall in the IP & Licensing Policy. They bind Concert as the certifier.

• CN-1 — Machine-runnable. Conformance is determined solely by the machine-runnable suite. No subjective assessment, interview, or discretionary judgement contributes to a pass/fail. If the suite cannot decide a requirement, that requirement is not part of certification.
• CN-2 — Identical suite. Every implementer is assessed against the byte-for- byte identical suite at a given version. There is no bespoke, relaxed, or extended suite for any party.
• CN-3 — No preferential path. No implementer — including Score Networks — receives early access to the suite, pre-graded fixtures, a privileged certification route, or any advantage in the process. The suite is public.
• CN-4 — Reproducible & publishable. A conformance result is reproducible by any third party from the published suite and the implementation's adapter, and the result report is publishable. Certification records which suite version and which CDM version were used.

A certification that cannot cite a passing, reproducible suite report under these rules is invalid.

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4. Versioning

The suite is versioned with the CDM. A certification is always qualified by both versions, e.g. "SIGNET Full — CDM v0.1, suite v0.1". A new CDM major version requires re-certification; minor/patch suite updates that only add or clarify tests do not invalidate existing certifications but may be required at renewal.