DCQL: response to multiple queries

[martijnharing]

The current text for the contents of the vp_token when responding to a DCQL query says:

If DCQL was used, this is a JSON-encoded object; the keys are the id values used for the Credential Queries in the DCQL query, and the values are the Verifiable Presentations that match the respective Credential Query.

This implies that when there are two requests for the same document but each with different data elements, it's still required to respond with that document twice. For example, if the request is:
"request1": Give me document A with elements B and C
"request2": Give me document A with elements B and D

Where request1 is satisfies one use case and request2 satisfies a different one. e.g. "I want to know whether you are over 21, and optionally your address."

In this case if document A with element B,C and D is used to satisfy both of these requests, the current language seems to require to return the same document A twice in the vp_token. Once for request1 and once for request2. I assume that's not the intention, as this could for example result in needing multiple authentications, revocation checks etc while returning only a single document.

One way that this could be addressed is to remove the linking of the response to requests (e.g. have the RP do the linking). But there may also be other ways.

[Sakurann]

i think this is a duplicate of #298
closing in a week, unless it is not a duplicate