Proof of Qualified Assignment & Safety Training
Prove that qualified, safety-trained personnel performed a task without exposing their record. Primes and auditors can verify only that the worker is qualified, and the records cannot be tampered with afterward.
For safety and site-management teams
Show a prime or auditor that a qualification was valid at the time — without disclosing the worker's sensitive record — resolving the dilemma.
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Safety / construction managers in manufacturing, critical infrastructure, construction
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Primes and clients verifying many workers' and subcontractors' qualifications
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Teams required to evidence qualified assignment on public works
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
- holds the required qualification, valid
- personal history and training records
- 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.
Present only a proof that a worker "validly holds the required qualification and safety training." The worker's record, scores, and attendance history are not disclosed. Because revocation (expiry, withdrawal) is trackable, "valid at assignment but now lapsed" is detectable.
Attributes are issued with issuer signatures (certifiers, training bodies, primes); the site and auditor verify them as ZK proofs.
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 the one task where qualified-assignment evidence matters most, in the first 30 minutes. No disclosure of sensitive data 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.