Re: [Rats] Interoperability ... RE: EAT Profiles

["Smith, Ned" <[e-mail]>]

Thanks Hannes and Laurence (per your reply on Friday), this all is helpful insight on how RATS / EAT views profiles. The RATS WG can reference the various threads on profiles if IESG or other reviews produces questions about interoperability and profiles. 
-Ned

On 9/26/22, 2:36 AM, "Hannes Tschofenig" <[e-mail]> wrote:

    Hi Ned,

    I would like to respond to your statement about the AISS token being an extension to the CWT/JWT rather than the EAT token.

    EAT intentionally builds on CWT/JWT. This is a good design approach.

    The AISS token re-uses claims in EAT and therefore extends EAT and indirectly the CWT/JWT.

    Should the draft provide more information regarding the recommendations in Section 6 of draft-ietf-rats-eat? Yes. Definitely.

    In a nutshell, I don't see a problem. FWIW I have implemented a prototype of the AISS token using the EAT library Laurence released.

    Ciao
    Hannes

    -----Original Message-----
    From: Thomas Fossati <[e-mail]>
    Sent: Thursday, September 22, 2022 3:04 PM
    To: Smith, Ned <[e-mail]>
    Cc: Laurence Lundblade <[e-mail]>; Hannes Tschofenig <[e-mail]>; Henk Birkholz <[e-mail]>; Michael Richardson <[e-mail]>; [e-mail]
    Subject: Re: [Rats] Interoperability ... RE: EAT Profiles

    hi Ned,

    On Wed, Sep 21, 2022 at 5:51 PM Smith, Ned <[e-mail]> wrote:
    > On 9/21/22, 1:55 AM, "RATS on behalf of Thomas Fossati" <[e-mail] on behalf of [e-mail]> wrote:
    > > On Tue, Sep 20, 2022 at 8:55 PM Smith, Ned <[e-mail]> wrote:
    > > > Profiles should extend standardized statements at a defined
    > > > extension point; but existing seem to go beyond this in several
    > > > ways.
    > >
    > > Can you point me to where that is happening?  Speaking for PSA, we
    > > do not extend any standardised EAT statement.
    >
    > [nms]    aiss-token = {
    >        aiss-nonce,
    >        aiss-instance-id,
    >        aiss-profile,
    >        aiss-implementation-id,
    >        aiss-lifecycle,
    >        aiss-boot-odometer,
    >        aiss-watermark,
    >    }
    >
    > Aiss-token seems to be an extension of a CWT/JWT token (rather than an
    > EAT token). However, this token does integrate with some claims found
    > in the EAT draft such as nonce, profile, UEID, and hash-type. Hence,
    > it is both a subset of EAT claims as well as a superset of an EAT
    > token.

    I am not sure I see a problem here.  An EAT can (and typically will) be a CWT/JWT, so anything claiming to be an EAT "profile" can a) inherit the CWT/JWT wrapping, b) extend the claims set using newly registered CWT/JWT claims if the available EAT claims are not sufficient.

    > Philosophically, EAT claims could be incorporated into other container
    > structures besides CWT/JWT tokens.

    True, but.
    In order to extend the top-level type one needs a "IETF standards track document." (see §3), so it's not going to be cheap to do that.

    > For example, an X.509 certificate
    > could define an extension that contains UCCS expression of EAT claims

    This X.509 extension would be wrapped in a UCCS which is a top-level EAT (when it gets its RFC number), so this is not the right example of "new bounding container", I think.

    > or a protocol frame could do something similar.

    If by "similar" you mean UCCS wrapping the EAT/CWT claims then there's no need to define anything for the profile.  Just reference [UCCS].

    > It seems reasonable that a profile could specify the bounding
    > container for EAT defined claims.

    yes, but in order to be called an EAT it needs to be defined in a STD track document.

    cheers,
    --
    Thomas
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