Add section on enveloped verifiable presentations.

[msporny]

This PR is an attempt to address issue #1431 by adding a way of expressing an enveloped verifiable presentation.

/cc @ChristopherA

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[iherman]

@msporny this requires a change on the vocabulary as well, including a change in the vocabulary diagram. Do you prefer I do a modifiation on this branch directly (ie, adding the necessary changes) or should I do a separate PR on top of this branch? The former might be more efficient...

[msporny]

@iherman wrote:

Do you prefer I do a modifiation on this branch directly (ie, adding the necessary changes)

Yes, please. Thank you!

[iherman]

@iherman wrote:

Do you prefer I do a modifiation on this branch directly (ie, adding the necessary changes)

Yes, please. Thank you!

Done in 43ed6e7

[OR13]

Non blocking comment here:

The @context configuration controls how edges form between credentials and the presentation.

In the case that JSON-LD extensibility mechanisms of the presentation object are used, implementers may want to do custom RDF processing to maintain associations between a single outer presentation and inner credentials.

In those cases, the RDF context defined in the spec does not actually control how the information graph grows.

[iherman]

The issue was discussed in a meeting on 2024-03-06

• no resolutions were taken

View the transcript

2.14. EnvelopedVerifiablePresentation missing in data model (issue vc-data-model#1431)

See github issue vc-data-model#1431.

See github pull request vc-data-model#1453.

Brent Zundel: 1431, PR1453 which has approvals and on track to be merged.
… we're headed toward wrapping this up.
… so expect to be bothered by us to get the work done...probably weekly.

[TallTed]

Distinctly, envelop is probably what we want, rather than envelope. Assuming general concurrence, the last e gets removed from envelope and envelopes, but remains in enveloped; no change is needed for enveloping. Note that there is a pronunciation change (accent on ve rather than en).

Suggested change

	using a securing mechanism that "envelopes" the payload, such as
	using a securing mechanism that "envelops" the payload, such as

[msporny]

@OR13 wrote:

In the case that JSON-LD extensibility mechanisms of the presentation object are used, implementers may want to do custom RDF processing to maintain associations between a single outer presentation and inner credentials.

I added some wording to highlight your concern in 2cf9040.

In those cases, the RDF context defined in the spec does not actually control how the information graph grows.

Debatable; an implementation might want it the @context to apply, or it might decide to not propagate it into the referenced object.

Given that this feature is largely meant to just encapsulate a VP encoded in just about any media type, and most of those media types won't really care about the RDF-ness of the outer-most object, it's probably fine to just stay silent on this point until the next round of the VC spec. We'd want to gather implementation experience of what people do with this before we provide more specific guidance (if that becomes necessary).

[msporny]

Normative, multiple reviews, changes requested and made, no objections, merging.