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P249 — AIEP — Cross-Node Replay Equivalence Verification

Applicant: Neil Grassby Classification: Patent Application — Confidential Priority: Claims priority from GB2519711.2 filed 20 November 2025 Architecture Layer: AIEP Phase 2 Federated Verification Layer

Framework Context

[0001] This specification operates within an AIEP environment as defined in GB2519711.2 and GB2519798.9. The present specification defines a mechanism for verifying that two independent AIEP nodes, given the same evidence inputs and reasoning parameters, produce identical reasoning outputs — confirming cross-node determinism and enabling federated replay verification.

Field of the Invention

[0002] The present invention relates to cross-node replay equivalence verification for federated deterministic AI reasoning systems.

Background

[0003] Federated AIEP deployments may process overlapping evidence sets on their respective nodes. For high-stakes decisions, a trust model requiring that independent nodes verify each other’s reasoning conclusions provides stronger assurance than single-node conclusions. Cross-node replay equivalence verification formalises this assurance mechanism.

Summary of the Invention

[0004] The invention provides a Cross-Node Replay Equivalence Verification (CNREV) system in which: a requesting node submits a verification request to one or more peer nodes identified as independent verifiers; each verifier node replays the reasoning session from the certified checkpoint (P245) with the supplied evidence activation set; the verifier returns a signed verification response containing the output hash; the requesting node confirms that all verifier output hashes match the local output hash; and a consensus equivalence certificate is constructed when all verifiers agree.

ASCII Architecture

Requesting Node
         |
         v
  Session Checkpoint (P245) + Evidence Activation Set
         |
         v
+-------------------------------------------+
| Cross-Node Replay Equivalence Verification|
|   Controller                              |
|                                           |
|  Select independent verifier nodes       |
|  Submit replay requests to peers         |
+-------------------+-----------------------+
                    |
     Peer Verifier Nodes (replay sessions)
                    |
     Signed output hashes returned
                    |
                    v
+------------------------------------------+
| Equivalence Consensus Evaluator          |
|  All hashes match?                       |
|  → Consensus Equivalence Certificate    |
|  Hash divergence?                        |
|  → Divergence Alert + Escalation        |
+------------------------------------------+

Detailed Description

[0005] Verifier Selection. The CNREV controller selects N peer verifier nodes from the federation with ESTABLISHED or TRUSTED trust status (P229). Verifier nodes must be independent (no shared evidence ledger state with the requesting node).

[0006] Replay Request. The replay request contains: the session checkpoint hash (P245); the evidence activation set Merkle root; the reasoning parameters; and a nonce preventing replay of previous verification responses.

[0007] Verifier Execution. Each verifier replays the session from the supplied checkpoint using the supplied evidence activation set. The output hash of the replayed session is signed with the verifier’s identity key.

[0008] Equivalence Evaluation. The requesting node collects signed verification responses and evaluates equivalence. If all output hashes match, a consensus equivalence certificate is constructed citing all verifier signatures. Hash divergence between nodes is escalated as a determinism violation.

Technical Effect

[0009] The invention provides distributed cryptographic verification that federated AIEP reasoning nodes produce deterministically equivalent outputs for identical session inputs, detecting implementation divergence or tampering that would otherwise be undetectable from single-node inspection. By requiring ESTABLISHED or TRUSTED verifier nodes independent of the requesting node’s evidence ledger, the protocol prevents collusion. The consensus equivalence certificate citing all verifier signatures provides a multi-party attestation of reasoning determinism admissible as evidence in regulatory and audit contexts.

Claims

A method of cross-node replay equivalence verification for evidence-bound artificial intelligence reasoning sessions, comprising the steps of: (a) selecting N peer verifier nodes from the federation with ESTABLISHED or TRUSTED trust status that do not share evidence ledger state with the requesting node; (b) issuing replay requests to each selected verifier, each request containing: the session checkpoint hash; the evidence activation set Merkle root; the reasoning parameters; and a nonce preventing reuse of previous verification responses; (c) each verifier replaying the session from the supplied checkpoint using the supplied evidence activation set and signing the output hash of the replayed session with the verifier’s identity key; (d) collecting signed verification responses and evaluating equivalence: if all output hashes agree, constructing a consensus equivalence certificate citing all verifier signatures; if output hashes diverge, escalating the divergence as a determinism violation; (e) admitting the consensus equivalence certificate or divergence escalation record to the evidence ledger.
The method of claim 1, wherein verifier node independence is verified by checking that no verifier shares a Merkle root history with the requesting node’s evidence ledger.
The method of claim 1, wherein replay requests include a validity window, and responses received after the window closes are discarded.
The method of claim 1, wherein a divergence violation escalation record includes the diverging output hashes attributed to each verifier, enabling post-hoc forensic analysis.
The method of claim 1, wherein the equivalence verification may be initiated by the requesting node on demand or by a governance policy schedule.
A cross-node replay equivalence verification engine for an evidence-bound artificial intelligence system, comprising: a verifier selection module choosing independent ESTABLISHED or TRUSTED peer nodes; a replay request dispatcher issuing nonce-protected requests; a response collector and equivalence evaluator; a certificate constructor; and a ledger admission module.
A computer-readable medium carrying instructions for implementing the method of any preceding method claim.

Abstract

A cross-node replay equivalence verification engine for evidence-bound artificial intelligence selects N independent federated peer nodes with established trust status to replay a target reasoning session from a certified checkpoint using a supplied evidence activation set. Each verifier signs its output hash with its identity key. A consensus equivalence certificate is produced when all verifier output hashes agree; hash divergence triggers a determinism violation escalation. All results are admitted to the evidence ledger, providing multi-party attestation of reasoning determinism.