Re: [GNAP] [Txauth] Revisiting the photo sharing example (a driving use case for the creation of OAuth)

[Justin Richer <[e-mail]>]

In my perspective, the focus should be on defining the protocol: what you’d call the transaction pattern. We can potentially use a API language to describe how an entity can perform a role within that protocol, but ultimately we should be defining the protocol.

 — Justin

> On Aug 19, 2020, at 6:31 AM, Fabien Imbault <[e-mail]> wrote:
> 
> Just wondering if that might be a way to compose the generic transaction/continuation pattern (XYZ style, layer 1) from a lower-level GS-API (layer 0).
> Fabien
> 
> On Thu, Aug 13, 2020 at 9:28 PM Dick Hardt <[e-mail] <mailto:[e-mail]>> wrote:
> Hi Francis
> 
> I have come to a similar conclusion. I'll be posting my thoughts in a concrete proposal and am keen to hear how it fits into how your mental model.
> 
> /Dick
> ᐧ
> 
> On Thu, Aug 13, 2020 at 12:00 PM Francis Pouatcha <fpo=[e-mail] <mailto:[e-mail]>> wrote:
> Lots of mails, so I will summarize my opinion in this single mail:
> 
> We are dealing with different levels of abstraction here, this is why we are always falling back to wording battles.
> 
> oAuth2/OIDC vs. GNAP
> AS vs. GS/DS/IS
> Entity vs. Roles
> User (human) vs. Requestor
> Client vs (Orchestrator/Requesting Party/Negotiator...)
> front-channel & back-channel
> 
> To direct the discussion, we have to agree on the level of abstraction at which we want a certain discussion to take place.
> 
> Abstraction Level-0: GNAP
> 
> Level-0 deals with roles (participants) and messages (request/responses). Level-0 does not consider entities (users) or the nature of any other participants, neither Level-0 deals with the way a message is transported (synchronous/asynchronous) or the type of interaction used to materialize the message (front-channel, back-channel). The purpose of this abstraction layer is to provide a common understanding of the core elements of the protocol. 
> 
> Level-0 can still provide some basic definition of messages including information schema as long as we are not limiting the protocol with constraints from lower layers.
> 
> Level-0 is ideal to address some fundamental privacy and confidentiality matters that will be materialized in lower layers.
> 
> Abstraction Level-1: OAuth2 / OIDC / [SSI/DiD/VC]
> Instantiation of Level-0 for a constrained application space. This is why we will meet the world Client, User, RO, AS, .... here roles defined in Level-0 will be mapped to entities, interaction will be used to materialize messages defined in Level-0. 
> The protocol mapping at this layer also takes into consideration that some of those participants are human or only pieces of software, running on the user device or on a server with consequences on the protocol design.
> 
> Abstraction Level-2: Trust Frameworks like IAM / PSD2,FAPI / ....
> 
> In Summary:
> Level-0: Roles, Messages
> Level-1: Entities, Interactions
> ...
> 
> And if it happens we want to define GNAP at Level-1 (instead of 0), let declare it as such and limit the application space before we proceed with further discussions.
> 
> Best regards.
> /Francis
> 
> 
> 
> 
> On Thu, Aug 13, 2020 at 1:30 PM Denis <[e-mail] <mailto:[e-mail]>> wrote:
>  Justin,
> 
> Your response does not address my point. I am talking of two different channels with the RS, i.e. not with the AS.
> 
> Denis
> 
>> Denis, I want to focus on one point here:
>> 
>>> In OAuth 2.0, the user consent is performed by the AS using an authorize endpoint where the user consent is solicited and captured.
>>> 
>>> Since a user, with no prior experience, shall first connect to a RS to perform an operation, the user consent shall be performed by the RS, 
>>> instead of the AS. This means that we should define a "consent" endpoint at the RS.
>> 
>> One of my goals with XYZ’s design was to be able to separate the interaction with the user from the web-based flows for the delegation protocol, and that aspect is enshrined in the GNAP charter as well.
>> 
>> It points to the reality that there are two different aspects of the traditional AS that we might need to talk about separately now. One deals with delegation, issuing tokens, returning data directly to the client (not through a separate API, since that’s the RS), and other back-channel stuff. The other aspect deals with interacting with the user and/or resource owner. 
>> 
>> We already saw bits of this in OAuth 2: the AS is defined by the pair of the token endpoint and authorization endpoint, each filling the respective roles above. What if we formally separate these? Strawman names:
>> 
>> Delegation Server (DS) - handles the back-channel stuff
>> 
>> Interaction Server (IS) - handles the front-channel stuff
>> 
>> 
>>  — Justin
>> 
> 
> -- 
> TXAuth mailing list
> [e-mail] <mailto:[e-mail]>
> https://www.ietf.org/mailman/listinfo/txauth <https://www.ietf.org/mailman/listinfo/txauth>
> 
> 
> -- 
> Francis Pouatcha
> Co-Founder and Technical Lead
> adorsys GmbH & Co. KG
> https://adorsys-platform.de/solutions/ <https://adorsys-platform.de/solutions/>-- 
> TXAuth mailing list
> [e-mail] <mailto:[e-mail]>
> https://www.ietf.org/mailman/listinfo/txauth <https://www.ietf.org/mailman/listinfo/txauth>
> -- 
> TXAuth mailing list
> [e-mail] <mailto:[e-mail]>
> https://www.ietf.org/mailman/listinfo/txauth <https://www.ietf.org/mailman/listinfo/txauth>