Re: New SVG-based renderMethod examples in VC Playground

On Mon, Aug 5, 2024 at 6:03 PM Alan Karp <alanhkarp@gmail.com> wrote:
> Is there a way to support selective disclosure?

Yes, in fact, we're not that far off in being able to fully demonstrate that.

The SVG template uses markup that looks like this for the claims that
are pulled from the VC data. For example, the SVG markup in the
Employment Authorization Document does this for the photo:

<image xlink:href="{{credentialSubject.image}}" id="photo"
width="2048" height="2048" ...

... and this for the document identifier:

<tspan id="tspan63" x="0"
y="0">{{credentialSubject.employmentAuthorizationDocument.identifier}}</tspan>

Note the Handlebars markup[1], which pulls claims directly from the
signed VC and injects that data into the SVG template expressed in the
renderMethod property in the VC.

Some of the issuers in the VC Playground (like the default one) uses
ECDSA-SD (a selective disclosure cryptography suite) to sign the
document. A selective disclosure of the renderMethod template and a
handful of claims would result in a rendering that only contained data
for the items that were selectively disclosed. All the other templated
variables in the SVG would evaluate to an empty value. We could make
this more apparent by rendering black bars for the missing information
in the visual depiction of the credential.

So, yes, not only is there a way, it's already there in the VC
Playground today. We don't have a verifier that requests a selectively
disclosed VC using a render method yet, nor does it render using those
black bars for the redacted information, but it doesn't feel like a
lot of work to get there based on where we are today. Just a "simple
matter of code" that adds the right query to the playground, and
verifier-based rendering. I'll check with the team to figure out the
lift for such a thing -- I think it would be useful to demonstrate how
we can achieve the question you asked, Alan.

Did I answer the question you asked?

-- manu

[1]https://handlebarsjs.com/

-- 
Manu Sporny - https://www.linkedin.com/in/manusporny/
Founder/CEO - Digital Bazaar, Inc.
https://www.digitalbazaar.com/

Received on Monday, 5 August 2024 22:35:30 UTC