Re: [OAUTH-WG] FW: Call for consensus on SPICE charter

[Orie Steele <[e-mail]>]

Inline:

On Mon, Feb 19, 2024, 7:34 PM <[e-mail]> wrote:

> Orie, thanks for the response
>
>
>
> I’m still confused on this charter proposal as I read this charter it is
> to create architecture, patterns and definitions for electronic
> credentials. The charter should be free of any technology including W3C, if
> people want clarity about what an electronic credential is then they can
> help out with the definitions since that is an output, so I don’t agree
> with how W3C is mentioned in the charter.
>

As you pointed out below, W3C has defined credentials that are simply
public keys bound to an origin (used as authenticators), and issuer signed
claims about a subject (like JWTs)

So far the people who have been most active seem interested in generalizing
the "signed public key and attributes" version of a digital credential.
That definition lines up well with JWT and CWT with the cnf claim, and mDoc
(as I understand it).

Most of the value W3C VC Data Model provides is focused on creating a
structure for the claims that go in the credential. The security of W3C VCs
based on JWT, SD-JWT, and COSE comes from the IETF drafts not from W3C.

Some of the protocol connection points also come from IETF documents, for
example aud, nonce and cnf.

Most of the value JWT and CWT provide, is through the public claims and
private claims in the associated IANA registries. For example, this is
where the cnf claim that ties proof of possession to credentials is
registered.

It's my understanding that mdocs have a namespace approach to claims as
well.

Creating conventions for claims in a credential format is profiling. iso
mdoc is a profile of COSE Sign1 in that sense.

You can consider the W3C documents that rely on JWT, CWT and COSE as
profiles of those IETF standards. Instead of using JWT or CWT claimsets,
the W3C uses JSON-LD.

A major reason for spice forming was to explore alternative claims
structures, and to align CWT and JWT conventions for credentials that DO
NOT require JSON-LD.

The way I read the charter is that interested parties will work on various
> profiles to map/profile various technologies to the create architecture, patterns
> and definitions documents, this will be done with various members that
> submit drafts.
>
>
>
> Relative to WebAuthn what is produced is a credential, its not a JWT or
> SD-JWT but as the charter reads that is not the only credentials under
> consideration, if this is the case then the charter severely lacks clarity
> on what is the goal.
>

I don't think there is utility in IETF creating a profile for webauthn
based credentials, because they are not meant to be presented beyond the
origin they are bound to.


>
> ISO is just another standards org, W3C, OIDF, OASIS, etc work with ISO
> with no issues, I assume profile will be created by various members that
> submit drafts, if no one is interested in mDL/ISO then that’s fine.
>
>
>
> I still think this charter needs more clarity as I point out
>

Can you suggest text?

>
>
>
>
> *From:* Orie Steele <[e-mail]>
> *Sent:* Friday, February 16, 2024 10:11 AM
> *To:* [e-mail]
> *Cc:* Roman Danyliw <[e-mail]>; oauth <[e-mail]>
> *Subject:* Re: [OAUTH-WG] FW: Call for consensus on SPICE charter
>
>
>
> Hey Tony,
>
>
>
> On Thu, Feb 15, 2024 at 1:36 PM <[e-mail]> wrote:
>
> 1) Do you support the charter text? Or do you have objections or blocking
> concerns (please describe what they might be and how you would propose
> addressing the concern)?
>
> Not sure I support at this point, I understand the need for an
> architecture document with patterns and definitions, etc.
>
> There is a lot of work going on outside the IETF in this area such as the
> mDL work in ISO that already has patterns and definitions along with
> credential formats (mdoc)  and transports (ble/http/nfc). I don’t believe
> the IETF should ignore these efforts since most of the driving licence and
> passport communities/companies are adopting this as one of the standards
> that issuers and verifiers will use. The same is true for W3C WebAuthn.
>
>
> WebAuthN cannot produce standard digital signatures, and so it cannot be
> used to produce standard digital credentials (for example it cannot be used
> to produce JWT or SD-JWT).
> It could produce authentications for public keys that could be bound to
> credentials, but because of the origin binding in WebAuthN, this would not
> fit well with the "audience" typically used for digital credentials
> (usually there is no audience)
>
> You might find this thread on possible relation between mDoc and CWT
> interesting:
>
> https://mailarchive.ietf.org/arch/msg/spice/xiRpmd-Bexv94qentlGg1Snjw1A/
>
>
> The architecture, patterns and definitions should be free from technology,
> I don't know why W3C is mentioned in the introduction as the only
> technology, this should not be in the introduction but along with other
> technologies such as mDL/mdoc, webauthn, etc when describing profiles. As
> the goal would be for interested parties to produce profiles of other
> technologies to fit the architecture document with patterns and definitions.
>
>
> W3C is mentioned because some W3C members asked for a term other than
> "Verifiable Credentials" to be used... and they asserted the "Verifiable
> Credentials" implies the JSON-LD data model developed in W3C.
>
> ISO was not emphasized because formal coordination would require
> contribution from ISO experts, and we have had relatively low
> engagement from them.
>
>
>
> I believe that the WG if formed should also think about holder
> verification and patterns and attestations that can be used.
>
>
>
> Interesting. I think this is covered under the metadata discovery
> deliverable, but if you feel it could be made more clear, please send text.
>
>
>
> Also there needs to be a notion of a "reader/wallet/etc" that can
> potentially store credentials (not necessarily the user or verifier) and
> release/store credentials upon "user" consent.
>
>
> This sounds like an application to me.
> How do you see this related to "credential formats" or
> "issuer/holder/verifier metadata"?
>
>
>
>
> There are other models than the 3 party that VCs use, so these also need
> to be considered in the architecture,  patterns and definitions documents
> to enable profiles for other technologies.
>
>
> Agreed, OAuth JWTs/SD-JWTs, and ISO mDocs are examples we have discussed.
> Are there others you would like to see considered?
>
>
>
> I believe in the 1st 3 items in Goals but  I don't believe it would be in
> the best interest to define a metatdata protocol, as this sounds like this
> would be a protocol for obtaining DID documents, there are already many
> protocols out there for metadata retrieval, not sure there is a need for
> another one, if one is needed for DIDs then that may be better done in W3C
> as this does not seem to fit well with the charter
>
>
> Discovering attestations for wallets seems to fit here, why should URLs or
> URNs (DIDs) be specifically marked as out of scope?
>
> For consideration, JWK / COSE Key Thumbprints are good alternatives to
> DIDs which have been standardized / are being standardized in the IETF:
>
> - https://datatracker.ietf.org/doc/draft-ietf-cose-key-thumbprint/
>
>
>
> This charter seems to be very scoped to W3C technology, I understand that
> interested parties will have to contribute if they want to have other
> technologies included but the charter in general does not seem to allow
> this, so removing specific technology will allow this to happen.
>
>
>
> We chose to use "Digital Credential" and "Digital Presentation"
> specifically to keep the door open to CWT and COSE Sign1 structures which
> are used in IETF and ISO.
>
>
>
>
> I would be happy to give provide specific text changes to the charter.
>
>
> I think it would be great if you could offer text that refines your
> comment about format support, and holder/wallet metadata / attestations.
>
>
>
>
> 2) If you do support the charter text:
>
>
> 3) Are you willing to author or participate in the developed of the WG
> drafts?
>
> yes
>
> • Are you willing to review the WG drafts?
>
> yes
>
> • Are you interested in implementing the WG drafts?
>
> I'm willing to see how we can use these outputs with the other industry
> technologies.
>
>
> Thank you for your comments.
>
>
>
>
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>
> --
>
>
>
>
> *ORIE STEELE*Chief Technology Officer
> www.transmute.industries
>
> <https://transmute.industries/>
>