Privacy-preserving verification begins with a narrow question. A recipient may need to know that a requirement is satisfied without receiving every detail of the underlying document. That goal is useful, but different technical approaches provide different guarantees.
Separate the concepts
Selective disclosure means revealing selected information rather than an entire credential. Zero-knowledge techniques can establish a defined statement without revealing the private information used to prove it. Neither phrase describes one universal format that every issuer and verifier automatically supports. The Ethereum documentation’s introduction to zero-knowledge proofs explains the general concept.
This article is a design guide, not a claim that every zero-knowledge construction or selective-disclosure format is available in Truthlocks. Confirm supported formats, proof generation, verification, and operational limits before depending on a particular design.
Write the statement precisely
“The holder meets this course requirement” is different from “this document has a valid signature.” Identify the claim to prove, the party trusted to establish the underlying fact, and the information the verifier will learn. Also consider identifiers and metadata that could connect repeated presentations.
For a training workflow, an issuer might provide a minimal signed completion record instead of sharing a longer internal learner file. That can reduce unnecessary disclosure without claiming to use a zero-knowledge proof.
Evaluate the whole lifecycle
- Which issuer creates the evidence, and why does the verifier trust it?
- What exact statement does the proof establish?
- Which fields remain visible to the recipient and connected services?
- How are expiry, revocation, and changes handled?
- Can the recipient verify the supported format with the tools available to them?
- How are keys and historical proof material retained?
A successful mathematical proof still depends on the meaning of its inputs and the trust placed in the source. It does not independently investigate whether an issuer correctly assessed the original real-world fact.
Choose the simplest supported record
Start with the minimum information your workflow needs. Review verification, access controls, and the candidate credential example. Use the current documentation to establish which proof formats are actually supported in your integration.