By  Oauth "client" key you actually mean the subject's (in VC terminology) public key. Thus the subject ID is the natural place to put this. Using a DID as the subject's ID is either a direct or indirect way of referencing the subject's public key. So all VCs do this. 

Kind regards

David

On 01/04/2021 15:38, Nikos Fotiou wrote:
The exact use case is an OAuth 2.0 Authorization Server that issues JWTs that include the "client" public keys. For a number of reasons we want to replace these JWTs with VCs, but we cannot find a straightforward way to include the "client" key in the VC.

Best,
Nikos 
--
Nikos Fotiou - http://pages.cs.aueb.gr/~fotiou
Researcher - Mobile Multimedia Laboratory
Athens University of Economics and Business
https://mm.aueb.gr

On 1 Apr 2021, at 5:34 PM, Adrian Gropper <agropper@healthurl.com> wrote:

@Nikos Fotiou You seem to be describing the authorization use-case based on VCs. This is reasonable and has been extensively discussed already but I'm having a hard time remembering which thread. 

- Adrian

On Thu, Apr 1, 2021 at 10:20 AM Nikos Fotiou <fotiou@aueb.gr> wrote:
Hi,

The VC includes a list of "IoT devices" that a "user" can access. The subject is the "user" and each "user" can be authenticated by a public key. We do not want the VC to be used as a bearer token.  

Best,
Nikos 
--
Nikos Fotiou - http://pages.cs.aueb.gr/~fotiou
Researcher - Mobile Multimedia Laboratory
Athens University of Economics and Business
https://mm.aueb.gr

On 1 Apr 2021, at 4:57 PM, Manu Sporny <msporny@digitalbazaar.com> wrote:

On 4/1/21 7:56 AM, Nikos Fotiou wrote:
I find the latter approach "cleaner" but I am not sure if it is correct.
Any opinion?
Could you elaborate more on the use case, Nikos?

What are you trying to express with the VC? That might help us answer your
question with more specific guidance.

Note that a DID Document is one example of a data structure that does what
you're trying to do.

Have you considered the type of relationship between the subject and the
public key? Or is the VC subject the public key?

-- manu

-- 
Manu Sporny - https://www.linkedin.com/in/manusporny/
Founder/CEO - Digital Bazaar, Inc.
blog: Veres One Decentralized Identifier Blockchain Launches
https://tinyurl.com/veres-one-launches