Re: [OAUTH-WG] OAuth Digital Credential Status Attestations

Hi Hannes,

Thank you for your quick reaction and also to Orie for sharing.
I've submitted the draft, here:
https://datatracker.ietf.org/doc/draft-demarco-status-attestations/

Regarding the term Attestation: good point. We have decided to use this
term since in several IETF and OpenID drafts this term seems pretty
established, the term Attestation is found at least in the following
specifications:
  - Attestation based client-authentication (it's in the title)
  - OpenID4VC High Assurance Interoperability Profile with SD-JWT VC
(wallet attestation)
  - OpenID for Verifiable Presentations - draft 20 (verifier attestation)
  - OpenID for Verifiable Credential Issuance (section "Trust between
Wallet and Issuer": Device Attestation)

Meantime in the eIDAS Expert group this term is going to be changed to
"Wallet Trust Evidence".

<https://datatracker.ietf.org/doc/draft-demarco-status-attestations/>
I don't have a strong opinion on what would be the best semantic for this,
I just have realized the functional difference between a Digital Credential
and an Attestation:
the first requires the user to be authenticated and give consent for using
the secure storage. The second is obtained with a machine2machine flow
where no user interaction is required, the secure storage is not required,
no user information is contained in it since the subject is the wallet
instance and not the user, it cannot be (re)used without the cryptographic
proof of possession. Probably a discussion could start about this term
aiming to align several specifications on the same terminology. I could say
that Status Attestation is a specific artifact defined for a specific
context, other attestations can be defined outside the functional perimeter
of this specification. Let's talk about it, it doesn't matters changing
terms (eventually mindsets on perceivable meanings).

Here I share some notes I picked along the last two months about this brand
new individual draft:

- it is related to digital credential only, I don't expect to use it in
legacy infrastructure different from wallet. I really don't need this kind
of mechanism in OIDC or any other traditional infrastructure since these
doesn't show the privacy issues the wallet ecosystem has;
- it would interesting mentioning in the introduction that's pratically an
ocsp stapling like mechanism, just to give some context (credit: Paul
Bastien);
- The Rationale section needs to clarify better problems and solutions, where
it seems that the problem does not exist or that it is weak. A review is
necessary to clearly bring the benefits;
- Editorials mistake are still along the reading.

thank you for your time and interest,
best

Il giorno mer 17 gen 2024 alle ore 21:06 <hannes.tschofenig=
40gmx.net@dmarc.ietf.org> ha scritto:

> Hi Guiseppe, Francesco, Orie,
>
>
>
> @Orie: Thanks for sharing the draft.
>
>
>
> As a quick reaction: It would be good to invent a new term for
> “attestation” in draft-demarco-status-attestations.html because this term
> is already widely used in a different context (see RFC 9334).
>
>
>
> @Guiseppe and Francesco: It would be great if you could submit your draft
> to OAuth or SPICE for discussion.
>
>
>
> Ciao
>
> Hannes
>
>
>
>
>
> *From:* OAuth <oauth-bounces@ietf.org> *On Behalf Of *Orie Steele
> *Sent:* Mittwoch, 17. Jänner 2024 19:07
> *To:* spice@ietf.org
> *Cc:* oauth <oauth@ietf.org>
> *Subject:* [OAUTH-WG] OAuth Digital Credential Status Attestations
>
>
>
> Hello Digital Credential Enthusiasts,
>
> See:
> https://peppelinux.github.io/draft-demarco-status-attestations/draft-demarco-status-attestations.html
>
> Note the use of the term digital credential, and the alignment to CWT
> based credentials and CWT based credential status lists.
>
> As a quick summary of the editors draft above:
>
> It is basically a refresh-token-like approach to dynamic state, where the
> holder retrieves updated state from the issuer at regular intervals, and
> can then present that dynamic state directly to the verifier.
>
> This eliminates the herd privacy and phone home issues associated with W3C
> Bitstring Status Lists.
>
> And it informs the holder of dynamic state, so the digital wallet can
> provide a better user experience.
>
> However, an issuer (government or ngo) could use the interval of
> requesting dynamic state, to track the holder... so the guidance from
> https://datatracker.ietf.org/doc/draft-steele-spice-oblivious-credential-state/
>
> Is also relevant to this draft.
>
> I also learned that
> https://datatracker.ietf.org/doc/draft-ietf-oauth-sd-jwt-vc/
>
> Has defined a new property for expressing "Verifiable Credential" "type"
> `vct`, which is different from how W3C defines credential types.
>
> W3C uses the expanded IRI for the graph node type, based on the JSON-LD
> context.
>
> For example with:
>
> {
>   "@context": [
>     "https://www.w3.org/ns/credentials/v2",
>     "https://www.w3.org/ns/credentials/examples/v2"
>   ],
>   "id": "http://university.example/credentials/1872",
>   "type": ["VerifiableCredential", "ExampleAlumniCredential"],
>   ...
> }
>
> The credential type in RDF becomes "
> https://www.w3.org/ns/credentials/examples#ExampleAlumniCredential"
>
> Which is different from "ExampleAlumniCredential" in JSON... More evidence
> that RDF leads to developer confusion regarding safe typing.
>
> The OAuth solution does not have this confusing issue, they set the type
> explicitly:
>
> {
>  "vct": "https://credentials.example.com/identity_credential",
>  "given_name": "John",
>  "family_name": "Doe",
>  "email": "johndoe@example.com",
>  "phone_number": "+1-202-555-0101",
>  "address": {
>    "street_address": "123 Main St",
>    "locality": "Anytown",
>    "region": "Anystate",
>    "country": "US"
>  },
>  "birthdate": "1940-01-01",
>  "is_over_18": true,
>  "is_over_21": true,
>  "is_over_65": true,
>  "status": {
>     "status_attestation": {
>         "credential_hash_alg": "S256",
>     }
>  }
> }
>
> Regards,
>
> OS
>
> --
>
>
>
>
> *ORIE STEELE*Chief Technology Officer
> www.transmute.industries
>
> <https://transmute.industries/>
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