Unclear what happens if client_id_scheme appears twice

[Oliver Terbu]

Clarify why client_id_scheme is needed in the request and in the Verifier Metadata. If this is by design, we need to clarify what happens in case both are present and potentially different.

[Kristina Yasuda]

my understanding has been that client_id_scheme in the verifier metadata is supposed to be the schemes supported by the verifier vs client_id_scheme in the request is supposed to be which one verifier is using in that specific transaction. so i am pretty surprised to see the below definition in the verifier metadata:

client_id_scheme: OPTIONAL. JSON String identifying the Client Identifier scheme. The value range defined by this specification is pre-registered, redirect_uri, entity_id, did. If omitted, the default value is pre-registered.

I would have imagined it is client_id_schemes and is an array.

cc:@Torsten Lodderstedt

[Mark Haine]

Migrated to GitHub

https://github.com/openid/OpenID4VP