Re: The world of credential engine

Hello Snorre, there are a couple of us on this list who work with 
Credential Engine and contribute to VC-Edu: me, Stuart Sutton and 
Deborah Everhart. I am also cc-ing Jeanne Kitchens, our technical lead. 
It's great to see you exploring these possibilities.

I will try to answer your questions below, but feel free to contact us 
directly for more details.

On 11/01/2022 11:22, Snorre Lothar von Gohren Edwin wrote:
> Hi guys!
>
> I have started to venture into: https://credreg.net/ 
> <https://credreg.net/>
> From my understanding of VCs and JSON-LD, it should be quite easy to 
> model these registry domains into VCs? One example done by this space 
> here: 
> https://w3c-ccg.github.io/vc-ed-models/#example-7-using-a-credential-definition-that-exists-in-credential-engine 
> <https://w3c-ccg.github.io/vc-ed-models/#example-7-using-a-credential-definition-that-exists-in-credential-engine>
>
Yes, it should. One factor to be aware of is that there is a difference 
in what is covered by Credential in Credential Engine compared to 
Verifiable Credentials. Credential Engine describes the credentials (and 
related things like learning opportunities, skills...) offered by 
educational institutions, training organizations etc, whereas Verifiable 
Credentials are about the credentials that an individual has. They are 
closely related, and totally complementary, like different sides of the 
same coin. You can think of VCs as equivalent to the piece of paper that 
says someone has a degree, lots of people can have such a piece of paper 
for the same degree; Credential Engine will provide a description of 
that degree, of which there is only one. If you know the Open Badge 
standard, Credential Engine aligns with the Badge Class, not the 
assertion that someone has been awarded to badge.
> But the more I dig into the https://credreg.net/ 
> <https://credreg.net/>, it is trying to solve many of the VC 
> objectives it seemes. And because my lack of knowledge of what comes 
> where, I start getting questions.
>
> I will list some questions here, but if you guys know of any fora, or 
> any person that can introduce me deeper into building solid education 
> credentials, let me know!
>
> ❓❓Questions❓❓
> How do I follow requirements for certain types on the: 
> https://credreg.net/ <https://credreg.net/>
> F.ex what is needed of a microCredential, 
> https://credreg.net/ctdl/terms/MicroCredential#MicroCredential 
> <https://credreg.net/ctdl/terms/MicroCredential#MicroCredential>, to 
> be valid?
>
The language we use to describe credentials, CTDL, is like a dictionary 
that defines terms, i.e. Classes and properties, and concept schemes; it 
defines what type of thing may be the subject and object of a property 
(the domain and range). But it does not say what terms must be used. 
That would be like a dictionary telling you what words you had to use. 
It is up to anyone implementing CTDL, e.g. by building an app, to define 
what their application needs. The Credential Engine has different 
requirements depending on what type of thing you are describing, and 
these are listed in our minimum data policy, 
https://credreg.com/registry/policy
> I have an example micro credential here in JSON playground: 
> https://tinyurl.com/3czurwnm <https://tinyurl.com/3czurwnm>
>
> Is this technically valid or who decides that?

No, that's not valid. You have used ceterms:MicroCredential as a 
property when it is defined as a class (so it must be used as a value 
for type).

You need something more like:

"credentialSubject": {
     "id": "did:web:matthew's_did",
     schema:hasCredential: {
       "type": "ceterms:MicroCredential";
       "ceterms:name": "Test micro",
       "ceterms:description": "This will describe the credential"
     }

   }

(NB: the merits of using of schema:hasCredential in a VC is the sort of 
thing we need to discuss in this group)

> Why do I have to use ceterms:name, infront of name when it is wrapped 
> in a micro credential type?
>
> Is that becaus the JSON-ld of https://credreg.net/ 
> <https://credreg.net/>, might not follow same format when doing 
> schema.org <http://schema.org>?
>
>
I am not quite sure I understand your question properly. Do you mean why 
do you need the "ceterms:" prefix? That identifies the namespace, so 
that we know you mean the CTDL version of name not the schema.org or 
FOAF version of name (not that there any real difference in this case). 
It's a common requirement when JSON-LD builds on more than one 
vocabulary, see section 4.1.5 of the JSON-LD spec, 
https://w3c.github.io/json-ld-syntax/#compact-iris Often this is hidden 
in the JSON-LD context file.


> I hope anyone have some thoughts around this :D
>
> I would love to jump on a chat with anyone, or discuss this further 
> somewhere it makes sense
>
Let us know if you have any further questions.

Phil


>
> -- 
> *Snorre Lothar von Gohren Edwin
> *
> Co-Founder & CTO, Diwala
> +47 411 611 94
> www.diwala.io <http://www.diwala.io/>
> <http://www.diwala.io/>/
> /
> /Stay on top of Diwala news on social media! //Facebook 
> <https://www.facebook.com/diwalaorg>// / //LinkedIn 
> <https://www.linkedin.com/company/diwala>// / //Instagram 
> <https://www.instagram.com/diwala_/>// / //Twitter 
> <https://twitter.com/Diwala>/
-- 

Phil Barker <http://people.pjjk.net/phil>. http://people.pjjk.net/phil
CETIS LLP <https://www.cetis.org.uk>: a cooperative consultancy for 
innovation in education technology.
PJJK Limited <https://www.pjjk.co.uk>: technology to enhance learning; 
information systems for education.

CETIS is a co-operative limited liability partnership, registered in 
England number OC399090
PJJK Limited is registered in Scotland as a private limited company, 
number SC569282.