Mismatch in definitions of Credentials and Verifiable Credential

[Roland Hedberg]

Just started to read OpenID for Verifiable Presentations and got sidetracked by the fact that the definitions of major terms in this document and in the W3c vc-data-model document does not align.

If OpenID for Verifiable Presentations, a Credential is defined to be:

‌ A set of one or more claims about a subject made by a Credential Issuer.

In vc-data-model

A set of one or more claims made by an issuer. … The claims in a credential can be about different subjects.

Quite different.

And for Verifiable Credentials in the OpenID document:

An Issuer-signed Credential whose authenticity can be cryptographically verified.

In the W3C document:

A verifiable credential is a tamper-evident credential that has authorship that can be cryptographically verified.

Not exactly equal.

Maybe it should be noted in the OpenID document that the definitions of both Credential and Verifiable Credential are different from those made in the W3C document.

[Kristina Yasuda]

the fact that there are three separate definitions present make it pretty clear that verifiable credential used as in OpenID4VP is different from w3c verifiable credential.

Credential:

A set of one or more claims about a subject made by a Credential Issuer. Note that the definition of the term "Credential" in this specification is different from that in [OpenID.Core].

Verifiable Credential (VC):

An Issuer-signed Credential whose authenticity can be cryptographically verified. Can be of any format used in the Issuer-Holder-Verifier Model, including, but not limited to those defined in [VC_DATA], [ISO.18013-5] (mdoc) and [Hyperledger.Indy] (AnonCreds).

W3C Verifiable Credential:

A Verifiable Credential compliant to the [VC_DATA] specification.

and introduction texts make it pretty clear that OpenID4VP covers variety of credential formats and not only w3c vcs.

so i am not sure what can be done to make this clearer.

[Roland Hedberg]

Sorry I wasn’t clear enough.

Yes, you state that many formats can be used and you don’t pick one of them: “Verifiable Credentials and Verifiable Presentations can be of any format, including, but not limited to …”

But that is about the format, of the on-the-wire representation, not about the thing itself.

My guess is that the definition of the thing (Credential/Presentation) influences the specification of the format.

Which makes it a bit awkward if you accept any format but have your own definition of the thing.

[Kristina Yasuda]

I don’t think it is awkward to define a “thing“, variations of which are supported. Credential formats supported by the spec need to meet the certain criteria and definition of Credential is what does it.

[Mark Haine]

Migrated to GitHub

https://github.com/openid/OpenID4VP