flowchart TD
A[Append-Only File] --> B[Open-Source Verifier]
A --> C{Webhook / API}
C --> D[ERP System]
C --> E[DPP Portal]
C --> F[Consumer App]
C --> G[Regulator Dashboard]
B --> H[Hash continuity ✓]
B --> I[Signature validity ✓]
B --> J[Temporal anchors ✓]
7 Open Verification, Helios Implementation
Digital Product Passport regulations require that product records remain verifiable beyond the existence of any single manufacturer, platform, or vendor, and that verification stays light enough for broad participation (European Parliament and Council 2024). A proprietary proof format fails both requirements: it ties long-lived products to short-lived companies and forces every verifier to license tooling. EventChain is designed with DPP mandates in mind. It builds on public standards and ships an open-source verifier, so no proprietary dependency stands between data and proof.
Every component is a published standard with multiple independent implementations: JSONL, SHA-256, WebAuthn/FIDO2, HTTP webhooks. Nothing requires a custom codec, binary envelope, or vendor SDK to parse or validate. A verifier built from the specification can confirm any AOF — past, present, or produced by a different Hub implementation.
The open-source reference verifier performs three checks: hash continuity across the chain, signature validity against registered public keys, and temporal anchor confirmation against OpenTimestamps receipts (Section 6.9). Any party holding a copy of the file can run verification independently, offline, without contacting the originating hub or any third-party service. Regulators, insurers, and downstream holders verify the same artifact with the same tool.
Integration uses standard HTTP webhooks and REST endpoints. Subscribing systems (ERP platforms, DPP portals, consumer-facing applications, regulator dashboards) receive events as they occur and store their own verifiable copy. Helios business logic determines which lifecycle actions become evidence; role-based access control determines what each subscriber sees. The underlying proof artifact remains self-verifying regardless of presentation layer (Section 3.4).
The consequence is a layered ecosystem. Portals, registries, QR-code interfaces, and analytics tools can consume EventChain artifacts through standard protocols and verify them with open tooling. Open verification does not make Helios trivial to reproduce: the hard operating work is deciding which document changes, comments, approvals, objections, supplier responses, and MRB decisions become signed evidence, how they inherit business context, and who receives which view.
7.1 Adoption Sequence
Helios deployments can start without a consortium ledger, vendor alignment, or blockchain infrastructure procurement, but production deployment requires integration, governance, and operational discipline. The path below is a reference sequence; organisations adapt the ordering to their context.
Pilot — scope a bounded proof-of-value on one of three entry points:
- End-to-end project tracking: follow a single fabrication or OPEX project from RFQ through material certificate, MRB decision, delivery, and installation, capturing material changes and handoffs as signed evidence.
- Historical enrolment: enrol existing assets during scheduled maintenance by signing inspection, certification, and document-revision records into a new AOF.
- Low-value items: prove provenance for components where distributed-ledger costs made tracking infeasible, demonstrating coverage at low marginal proof cost.
Production — deepen integration into procurement, quality control, and logistics workflows. The transition is not a gate but a widening: more event types, more signers, more recipients, tighter ERP/API coupling.
| Dependency | Owner | Why it matters | Risk if ignored |
|---|---|---|---|
| Hub instance (SaaS or self-hosted) | Operator | Processes events, distributes AOF, enforces RBAC | No chain creation or distribution |
| Identity provider integration | IT / Security | Maps passkeys to verified personnel | Unsigned or unattributable events |
| Helios business logic and event schema definition | Domain / Engineering | Determines which lifecycle actions become evidence and what each entry records | Inconsistent, noisy, or unverifiable payloads |
| Signer onboarding | HR / IT | Registers passkeys against identity | Adoption stalls at first signing step |
| RBAC policy | Governance / Legal | Controls who sees what | Over-sharing or under-sharing halts rollout |
| Recipient verifier access | Recipient IT | Enables independent verification | Proof exists but is never checked |
| ERP/API webhook integration | Engineering | Connects EventChain to existing workflows | Manual data entry, adoption friction |
| Contractual verification clause | Legal / Procurement | Defines consequences of failed verification | Proof has no business teeth |
The table makes explicit what the protocol leaves to Helios and its operators. EventChain defines the proof artifact and verification logic; Helios turns business activity into meaningful evidence. Governance, integration, onboarding, legal standing, and recipient adoption remain deployment work that production programmes must address.