CBAM Supplier Attestation
Chain the country, origin, and carbon-intensity attributes required by EU CBAM as cryptographic attestations without exposing supplier raw data, so importers can verify CBAM compliance against cryptographic facts while each supplier's production data stays inside its own perimeter.
For CBAM compliance teams
Attest CBAM conformance without making suppliers expose raw data to auditors — resolving the bind between disclosure and confidentiality.
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Regulatory-affairs leads at manufacturers exporting steel, aluminum, cement, or fertilizer to the EU
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Procurement leads gathering CBAM evidence from upstream suppliers, including multi-tier suppliers they don't directly contract with
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Risk and trade-compliance owners balancing supplier confidentiality against EU regulatory exposure
Hand over the source, or just the facts?
Nothing changes on the floor. Everything changes for the receiver.
① Your team just saves, as always.
- The usual step
- Fill in the record and save
- On save
- A proof is attached (API, behind the scenes)
- The document itself
- never sent
② They just open a link.
- Proven fact
- meets CBAM-required country, origin and carbon-intensity attributes
- production data, cost and supplier-internal dealings
- not shown
- Login / keys
- not needed
- The document stays private — the record itself is never sent or disclosed.
- Independent verification — the receiver just opens a link. No account, no keys.
- Edits are detected — even a one-character edit fails verification.
Each tier of the chain — the smelter, the rolling mill, the trader, the importer — issues attestations for the attributes CBAM actually checks: country of production, carbon intensity, the regulatory regime the attribute was measured against. The attributes are signed against each supplier's reference data (production logs, energy mix, monitoring system output), but the proof reveals only the attribute, never the underlying source.
Downstream parties verify the attestation directly. A trader chaining steel from a smelter to an EU importer doesn't need the smelter's production data — it needs proof that the smelter's reported carbon intensity holds under CBAM's measurement scheme. When that proof is a ZK attestation rather than a PDF, the trader can compose it with their own attestation and pass a single chained proof to the importer.
The result is that CBAM evidence becomes a cryptographic chain instead of a document-discovery exercise — and each link controls exactly what flows downstream.
Why the usual methods fall short.
Only work that needs all three at once — pass without exposing, independent verification, tamper-evidence — is Lemma's domain.
| Method | Pass without exposing | Independent verification | Tamper-evident | What happens |
|---|---|---|---|---|
| Access control / permissions | △ | ✗ | ✗ | “Someone inside could have edited it” remains possible |
| Masking / redacted copies | △ | ✗ | ✗ | Redaction work grows; the original is still unproven |
| Encrypt and store / send | ✓ | ✗ | ✗ | To verify, the receiver needs it disclosed after all |
| Lemma (ZK proof)the only one with all 3 | ✓ | ✓ | ✓ | The receiver just opens a link |
How it works — and how to start.
We help design disclosure scope and retention, run the PoC, and support production.
Start with a 30-minute call.
Tell us one path where CBAM evidence collection has stalled, in the first 30 minutes. No supplier data or production methodology required.
Find the case that matches your industry and problem
Browse all 36 use cases →TRY LEMMA
Run it yourself.
No sales call needed — start hands-on with Lemma's products.