Re: JFF Plugfest question

@Dmitri, thanks for replying with your thoughts.

> I want to suggest that -- the achievement.id field is a non-idiomatic way
of fulfilling that usecase. achievement.type would make a lot more sense,
and would match the usage in the general Verifiable Credentials community.

I think you haven't quite grasped the use case for "Does the user have
credential X?", for example for a credential certifying a user as being
qualified to use a specific 3D printer in a specific maker space.

The scenario here is not "holder, please present any VCs that may be
related to 3DPrinterAuthorization from any issuer", it is "holder, can you
present that you hold the specific achievement issued by this specific
organization that claims you have met the criteria of its specific training
program for using this specific 3D printer?".

In Open Badges, a particular Defined Achievement has criteria and
assessment that are particular to the creator. Other issuers are not
permitted to issue valid credentials that are created by a particular
achievement creator; this is pretty core to how Open Badges works. If we
didn't have this default restriction, Harvard University might define a
particular achievement for a Bachelor's Degree in Computer Science, and we
wouldn't be able to differentiate between the real deal Harvard degree and
impersonations. Open Badges has its mechanisms for doing this based on
achievement.id and achievement.issuer/creator, and the workgroup will need
to ensure that verification of this core feature still works efficiently
under 3.0. It is use case #1 for Open Badges, so it's critical to deliver.

Open Badges 3.0 spec introduces a separate set of use cases (not "defined
achievement") that correspond to something more akin to what you have
paraphrased, "holder, please present any VCs that may be related to
3DPrinterAuthorization from any issuer", under the heading of "skills".
That would be to ask for any VC that claims a user holds a particular
skill, as recognized by any issuer, you would ask "holder, please present
any VCs that claim that you hold skill 'htttps://
sharableskills.example.org/skills/3DPrintingAdvanced'." I expect the
approach for this will depend on the "result.alignment.targetUrl" but am
open to suggestions for alternate approaches. It's the critical 2 week
period right now to deliver on this use case, so discussion
<https://github.com/IMSGlobal/openbadges-specification/issues/339> is very
welcome.

If it's your suggestion that IMS/1EdTech implement a significantly
different mechanism in OB 3.0 for serving the most important use case in
Open Badges than was used in 2.0, that's something that should be brought
to the attention of the chairs of that workgroup immediately so that they
can schedule appropriate time to address it before candidate final vote and
release.

Nate