Re: [GNAP] Review of draft-ietf-gnap-core-protocol-00

[Fabien Imbault <[e-mail]>]

Hi Tom,

My answer is completely speculative.
But I guess it would probably involve the end-user paying to some sort of
service provider (just like one pays for having a VPN). With the same
potential risks (i.e free tiers that serve ads or resell your data, or
limit volumes of connections)?

Cheers
Fabien


Le jeu. 19 nov. 2020 à 06:23, Tom Jones <[e-mail]> a
écrit :

> Actually that's not the hard problem, which is, once the user wanders off
> on some path that is not anchored in the browser, how does the path get
> back to the same place in the browser?
> This is "straightforward" when the path from siop to some url in the cloud
> is completely separated from the path between the user and the client, but
> that is not the path usually taken.
> We need some new entity to pull this off. Call it the AS proxy if you
> will. The problem I have with that is who is going to pay the AS proxy?
> If I can figure that payment issue out, I think I can complete the rest of
> the flows.
>
> Peace ..tom
>
>
> On Tue, Nov 17, 2020 at 9:20 AM Justin Richer <[e-mail]> wrote:
>
>> Ultimately, in most situations like these in the real world, the hurdle
>> isn’t technical compatibility so much as it is trust compatibility. The RP
>> (client) needs to have some incentive to trust the assertions and identity
>> information that’s coming from the AS. The same is true for an RS trusting
>> tokens from the AS. The hard question is less “how” to do that (which SSI
>> answers), but more “why” to do that (which SSI doesn’t answer very well,
>> because it’s a hard question).
>>
>> Still: it’s definitely a question about how to support this “AS on
>> device” element. We’ve got the start of it more than OAuth2/OIDC have by
>> allowing the bootstrap of the process from a starting call: the interaction
>> and continuation URIs handed back by the AS don’t need to be the same URIs
>> that the client starts with, so just like SIOP the process can start in
>> HTTP and potentially move to other communication channels. A major
>> difference is that we aren’t dependent on the assumption that the user will
>> always be in a browser at some stage, and so the whole raft of
>> front-channel messages that SIOP relies on doesn’t fly. That said, we’ve
>> got an opportunity to more explicitly open up alternative communication
>> channels here, and that’s something I’d like to see engineered, even if
>> it’s an extension. I’d love to see a concrete proposal as to how that would
>> work over specific protocols, starting with what we’ve got today.
>>
>>  — Justin
>>
>> On Nov 17, 2020, at 12:03 PM, Fabien Imbault <[e-mail]>
>> wrote:
>>
>> Hi Denis, hi Francis,
>>
>> At some point integration with SSI (on the authentication side) will
>> probably occur, including amongst other possibilities SIOP (since they work
>> with OpenID a part of the work will probably be made easier).
>>
>> That being said, Denis is right. It's not an AS. Technically it's
>> entirely possible to rely on a decentralized wallet (for instance on your
>> phone) and a centralized AS. I know of a few studies on how to decentralize
>> the AS itself (for instance
>> https://tools.ietf.org/html/draft-hardjono-oauth-decentralized-02).
>> Maybe it exists, but I'm still looking for real scenarios (or even
>> architectures) where an AS is deployed directly on a phone, and under the
>> sole authority of the RO, while being compatible with the rest of the
>> world.
>>
>> Cheers,
>> Fabien
>>
>> On Tue, Nov 17, 2020 at 5:45 PM Denis <[e-mail]> wrote:
>>
>>> Hello  Francis,
>>>
>>> See two comments in line.
>>>
>>>
>>> B) Current Document
>>>
>>> Roles description shall not hold any assumption on the physical
>>> structure of the party fulfilling the roles.
>>> [FI] not sure what you mean
>>>
>>>  [FP] for example, we assume the AS is a server! In most SSI based use
>>> cases, the AS will be running on the user device. See SIOP (
>>> https://identity.foundation/did-siop/).
>>>
>>> I browsed through the two drafts, i.e. :
>>>
>>>    - Decentralized Identifiers (DIDs) v1.0 Core architecture, data
>>>    model, and representations W3C Working Draft 08 November 2020
>>>    - Self-Issued OpenID Connect Provider DID Profile v0.1. DIF Working
>>>    Group Draft
>>>
>>> At no place within these two documents, it is possible to imagine that
>>> "the AS will be running on the user device".
>>>
>>> From section 3 of the DIF Working Group Draft:
>>>
>>>       "Unlike the OIDC Authorization Code Flow as per [OIDC.Core], the
>>> SIOP will not return an access token to the RP".
>>>
>>> An Identity Wallet is not an AS.
>>>
>>>
>>> Roles:
>>> -> grant endpoint of the AS: Why is this a post request? This eliminates
>>> the chance of having user device hosted AS (no server).
>>> [FI] what would you propose instead?
>>> Would also be interested to understand better the deployment model when
>>> there is no server. That's something that was discussed several times but
>>> I'm still missing the underlying architecture and use case.
>>>
>>>  [FP] See above (SIOP). There will be a lot of identity wallets operated
>>> on end user device.
>>>
>>> See the above comment. Please, do not confuse an Identity Wallet with an
>>> Authentication Server (AS).
>>>
>>> Denis
>>>
>>>
>>> -> Resource Owner (RO) : Authorizes the request? Does it authorize the
>>> request or the access to a resource?
>>> [FI] yes, we should make the wording clearer
>>>
>>> Missing Section Interactions:
>>> --> This section shall introduce the notion of interaction before we
>>> start listing interaction types.
>>> [FI] yes
>>>
>>> Interaction Types:
>>> --> I prefer a classification with Redirect, Decoupled and Embedded is.
>>> In the draft, we have one redirect and 2 decouple interactions and nothing
>>> else.
>>> [FI] this should be handled as a specific discussion item. As a
>>> reminder, how would you define embedded?
>>>
>>> In practice there's at least these modes:
>>> - redirect and redirect back
>>> - redirect to different browser or device
>>> - user code
>>> - CIBA
>>>
>>> [FP] This classification is limited.
>>>
>>>    - Redirect: same device, same or different user agents (browser,
>>>    mobile app, desktop app, ...)
>>>    - Decoupled: different devices
>>>    - Embedded : RC carries RO authorization to AS
>>>
>>>
>>>
>>> Resource Access Request vs. Resource Request
>>> --> Both are mixed up. No clarification of the context of each section.
>>> [FI] could you clarify what you'd expect.  Btw on this topic, there's a
>>> more general discussion on whether we should make a distinction or not.
>>>
>>> ​[FP]: Here:
>>>
>>>    - Resource Access Request: Requesting Access to a resource. Response
>>>    is an access token (or any type of grant)
>>>    - Resource Request: Request the resource. Response is the resource
>>>    (or a corresponding execution)
>>>
>>>
>>> Token Content Negotiation
>>> --> Not expressed as such. This is central to GNAP and not represented
>>> enough  in the document.
>>> [FI] right. This should be a specific discussion item.
>>>
>>> Requesting "User" Information
>>> we identify two types of users: RQ and RO. It will be better not to
>>> refer to a user in this draft, but either to a RQ or an RO.
>>> [FI] yes that would avoid potential misunderstandings. Although in the
>>> end, people will translate RQ into user or end-user most of the time. Cf in
>>> definition, currently we have Requesting Party (RQ, aka "user")
>>>
>>>
>>> Interaction Again
>>> -> For each interaction type, we will have to describe the protocol flow
>>> and the nature and behavior of involved Roles (Parties), Elements, Requests.
>>> [FI] yes
>>>
>>>
>>> [FP] Will these and into tickets?
>>>
>>> Best regards.
>>> /Francis
>>>
>>>
>>>
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>>>
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