Why trust an issuer?

Imagine running a repair workshop. A training school and a hobby club each issue a credential for completing a mechanics course. Both pass their cryptographic checks. That does not make them equivalent qualifications for operating workshop equipment.

The VC data model does not choose trusted issuers for a verifier. Which issuers to trust, for which claims and purposes, remains the verifier’s decision. Source: VC Data Model 2.0 §5.1.

First inspect the claim: course attendance, an examination result, or permission to operate a machine? Then consider the issuer: why accept that organization’s judgment on this subject? Finally consider the purpose: visiting the workshop may require different evidence from operating machinery independently.

Read “verifiable” as an invitation to make checks explicit. The reason for accepting a claim still needs to be established.

Who decides after verification?

In this hypothetical workshop, a system can check the school’s statement and then apply its own eligibility rules. It also needs an appropriate binding between the credential subject and the applicant, plus validity and applicable status checks. Uploading a credential file does not itself grant access.

One workshop may accept a course credential while another rejects it because they recognize different issuers or require different qualifications. That difference need not indicate broken cryptographic verification. Credentials make statements and their origin inspectable; application rules determine how the evidence is used.

Book and sources

This lesson develops the questions in Chapter 4 of 《区块链实战》 with later standards. It is not an excerpt.