]> Gravit Open Network

Zurich Switzerland ietf@gravit.space

GEVP defines a minimal protocol for epistemic convergence. Renamed from VCP to avoid collision with draft-kamimura-scitt-vcp. It maps the GEVP Epistemic State Machine to the evidence taxonomy of the Gravit Verifiable Epistemic Decision Standard (VEDS). This revision corrects the Implementation Status: the threshold calibration and the cost relation reported in earlier revisions could not be reproduced and are replaced by reproducible results; no specific theta threshold is recommended any longer.

Introduction Gravit open network for verifiable knowledge transformations. Stable. Future is implementations. GEVP defines ESM RAW->VALIDATED->VERIFIED->COMMITTED, verification types, persistence MAY Ledger IPFS GSS DB Archive, bindings separate.

Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Epistemic State Machine States RAW VALIDATED VERIFIED COMMITTED explicit logged.

Protocol Data Types Artifact id hash SHA3-256 claim provenance signatures optional. Record artifact-id verifier-id theta result timestamp. Convergence h>0.7 f<0.3.

Persistence MAY not MUST. Ledger IPFS GSS DB Archive.

Security Considerations Replay hash nonce. Sybil cost model. No PII. Signatures OPTIONAL. Earlier revisions stated a cost relation C_manip > 2 * C_val as an engineering invariant. In the trace published with those revisions (pinned 7755f53), the relation holds for 1457 of 3000 records (48.6 %). It is therefore retained only as a design target; it is not a guarantee, and deployments MUST NOT rely on it for security. Convergence over unsigned Records offers no protection against a single party fabricating several "independent" Records. Deployments that use COMMITTED as the basis for a VEDS Verified Fact SHOULD require Records signed by keys of distinct, registered operators, with the keys of one operator counted as one source.

Privacy Considerations Content MAY encrypted, provenance MAY redacted.

IANA Considerations No IANA actions.

Implementation Status Reference verifier: https://github.com/gravit-open-network-foundation/verifier, release v0.5.0 (Python, with a Rust port), Apache-2.0. It implements Sections 3, 4 and 10, requires Records signed by keys of registered operators for COMMITTED, accepts the operator registry only when signed by a threshold of root keys, and produces content-addressed decision records. 40 golden test vectors are reproduced by both implementations. Reproducible evaluation: https://github.com/gravit-open-network-foundation/gravit-eval-pack reproduces every figure in this section with one command. Threshold calibration: a 3000-claim trace generated by the consensus engine at https://github.com/gravit-open-network-foundation/gravit-grover (10x Sybil amplification) gives, at theta = 0.73, a true positive rate of 91.7 % (1376/1500) and a false positive rate of 7.3 % (110/1500). The rates are identical for every theta in [0.11, 0.78]: once the network has converged, the threshold has little effect; what decides is whether honest evidence outweighs the Sybil evidence. Correction: revisions -00 to -07 reported TPR 93.4 % and FPR 0.4 % at theta 0.73 from a trace pinned at commit 7755f53 of the gravitnet repository. No generator for that trace exists and its figures could not be reproduced; it is superseded by the calibration above and kept unchanged for the record.

VEDS Conformance Mapping This section defines a normative mapping between an Artifact's position in the Epistemic State Machine () and the epistemic classification taxonomy defined in Section 4.1 of (VEDS). This mapping specifies one conformant way for a GEVP-based implementation to satisfy the VEDS admissibility and classification requirements referenced from VEDS Section 1; implementations are not required to use GEVP, but if they do, this section applies.

RAW and VALIDATED A RAW Artifact MUST NOT be treated as admissible evidence under VEDS Section 4.2; it has not yet been checked against any admissibility element. A GEVP implementation MUST transition an Artifact from RAW to VALIDATED only after confirming all four elements required by VEDS Section 4.2.1:

• Provenance: the Artifact's provenance field resolves to an identifiable, nameable origin.
• Integrity: the Artifact's SHA3-256 hash verifies against its content.
• Freshness Bound: the Artifact's timestamp falls within the deployment-defined validity interval.
• Interpretability: the Artifact's claim conforms to a documented, unambiguous schema.

A VALIDATED Artifact is admissible under VEDS Section 4.2 but MUST NOT be assigned an epistemic classification under VEDS Section 4.1.1 higher than Speculative Claim; admissibility alone does not establish truth.

VERIFIED An Artifact transitions to VERIFIED when at least one Record () is produced for it by a verifier, with a theta value and a result. A VERIFIED Artifact backed by exactly one Record corresponds to a VEDS Probabilistic Assessment (VEDS Section 4.1.1): the verifier's theta-scoring method is the documented, reproducible method, and the recorded theta is the confidence value. Where the Artifact is to serve as part of the basis for a definitive VEDS decision, the deployment MUST document the theta threshold it applies and how that threshold was calibrated, consistent with the Impact-Based Evidence Strength requirement in VEDS Section 4.2.3. This document does not recommend a specific value (see ). A GEVP implementation MUST NOT treat a single Record, regardless of its theta value, as satisfying the VEDS Verified Fact definition; a single verifier does not constitute independent cross-corroboration.

COMMITTED An Artifact transitions to COMMITTED when Records from multiple verifiers achieve Convergence, h>0.7 and f<0.3 (). A COMMITTED Artifact corresponds to a VEDS Verified Fact (VEDS Section 4.1.1): the Convergence condition is the mechanism by which the Artifact has been "independently confirmed accurate ... through reproduction, cross-corroboration, or equivalent means," as required by the VEDS Verified Fact definition. This document does not define criteria for treating two verifiers as independent for the purpose of Convergence. Implementations MUST apply criteria at least as strict as the Independent Corroboration Threshold mechanism in VEDS Section 4.6.2, and MUST document their specific criteria in their VEDS Conformance Statement (VEDS Section 5.2).

Aggregation Restriction A set of RAW or VALIDATED Artifacts, however large, MUST NOT be treated as equivalent to a COMMITTED Artifact. Only Convergence over independently produced Records, per , MUST be used to reach COMMITTED. This reflects the No Aggregation Laundering requirement of VEDS Section 4.1.2: aggregating multiple Speculative Claims does not, by itself, produce a Verified Fact.

Normative References Gravit Open Network

Changes from draft-gravit-gevp-07

• Implementation Status replaced with the reference verifier and a reproducible threshold calibration; the unreproducible figures of earlier revisions are corrected, not deleted.
• Theta 0.73 is no longer RECOMMENDED; deployments document their threshold and its calibration (Section 10.2).
• The cost relation C_manip > 2 * C_val is reclassified from invariant to design target (Security Considerations).
• Security Considerations: signed Records from distinct registered operators recommended for COMMITTED.
• Repository references updated to the gravit-open-network-foundation organisation.

Acknowledgments Contributors Canon Final v1.1