[Openid-specs-ab] Issue #1793: OID4VP - determining which VCs are required (openid/connect)

[David W Chadwick]

New issue 1793: OID4VP - determining which VCs are required
https://bitbucket.org/openid/connect/issues/1793/oid4vp-determining-which-vcs-are-required

David W Chadwick:

The first version of the OpenID4VPs spec referred to DIF PEv1 as the only allowed way for the RP to request a set of VCs from the wallet. This was subsequently changed to mandate DIF PEv2. Now DIF are working on PEv3. Furthermore W3C has its own draft Presentation Request specification \(see [https://w3c-ccg.github.io/vp-request-spec/](https://w3c-ccg.github.io/vp-request-spec/)\), but this specification cannot be used with the current OpenID4VPs spec.

It is not tenable for the OpenID4VPs spec to mandate one particular way of requesting a set of VCs, especially when that one way is neither long lived nor stable, and when competing methods are being standardised.

The proposal is that we replace the `presentation_definition` parameter with a type and a value, where the type is a URI that indicates the presentation request syntax and the value is the presentation request in that syntax. We give example URIs for PEv1, PEv2, PEv3 and W3C PR and provide a couple of request examples in different syntaxes.