Re: [GNAP] draft-hardt-xauth-protocol-14 update - reworked introduction

Fabien Imbault <fabien.imbault@gmail.com> Mon, 17 August 2020 12:17 UTC

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From: Fabien Imbault <fabien.imbault@gmail.com>
Date: Mon, 17 Aug 2020 14:16:49 +0200
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To: Francis Pouatcha <fpo@adorsys.de>
Cc: Dick Hardt <dick.hardt@gmail.com>, GNAP Mailing List <txauth@ietf.org>
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Subject: Re: [GNAP] draft-hardt-xauth-protocol-14 update - reworked introduction
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Hi Francis,

Thanks for your comments. Mine are inline (marked with "FI"). I think most
of that is clear now (except from the way to make it visible on a diagram).

I'd actually like to focus more specifically on the previous exchange:

Are we sure we need to formally separate B and C? This goes beyond previous
> discussions of separating the front and back channels, and I don't really
> see the advantage (maybe there is: which use cases would be impossible to
> do otherwise?).
>
We have a situation where RP =!= RC. And each of them have their own AS.

> In most cases, getting the asynchronous consent from the RC (distinct
from the end-user) would be an issue (unless the end-user is ok to wait).
> Here I guess you're considering the case where you want to interactively
ask the RC (distinct from the end-user) to consent, instead of making a
policy based decision.

A practical scenario where we may encounter a synchronous consent request
between distinct end-user/RP and RC: a patient has a medical appointment
with a new doctor.
The doctor needs to access the medical record of the patient. Here the
doctor is the end-user/requestor and the patient is the RC.
Since they're already interacting face to face (physically or through
video), the patient takes his decision (yes/no for each requested item) as
soon as the doctor asks him to provide some information.

Is this type of synchronous interaction what you had in mind?

As for SSI, I think there should be a dedicated use case.

Cheers
Fabien


On Mon, Aug 17, 2020 at 1:28 PM Francis Pouatcha <fpo@adorsys.de> wrote:

> Hello Fabian, inline
>
> On Mon, Aug 17, 2020 at 6:56 AM Fabien Imbault <fabien.imbault@gmail.com>
> wrote:
>
>> Hi Francis,
>>
>> I like that alt2 introduces the additional discussions we had previously
>> (on privacy and other topics) but I think this schema is too prescriptive.
>>
> This is why I pushed them into Alt-2.
> In the most common use case at sight (oAuth2), GS, RC-AS,  RP-AS are roles
> that might be represented by the same entity. This means the oAuth2
> instantiated model might look very simple.
>
> FI ; yes

>
>>
>
>> Depending on the situation, one may either require the GS to provide the
>> front-channel, or decide to separate it.
>>
> Yes. This is why exposing RC-AS in the diagram makes that case visible. In
> those situations, [GS]=[RC-AS]=[RP-AS]=GS resulting  in the original model
> of Dick.
>
>
>> Why mandate that interaction B shall always occur through the GC? If I' a
>> GC, I could just as well decide that it's enough to just separate the
>> front-channel from the GS, without handling it myself.
>>
> Having GS +++(B)+++> RP is the oAuth2 model again. THis is what Dick has
> in the original diagram.
>
> There are some cases where GS might need to gain knowledge of some claims
> about RP, but do not need to know their identity. E.g.: age(RP) > 18.
> In those cases [GS] --(3)-->[GC]++(B)++>[RP] makes sense.
>

FI : yes, although in practice most verified credentials are bundled with
some claims about identity. Like I'm a student in a bar, I'm going to show
the proof of age (instead of date of birth) but am still required to show
my name too (or a picture, or whatever that proves I didn't get a proof
which belongs to someone else).

>
> And in some cases RP-AS resides on RP's device (SSI). And we find ourself
> with:
> [GS] --(3)-->[GC]-->(B0)-->[RP-AS]++(B1)++>[RP]
>

FI : this type of interaction with SSI wallets directly on the mobile
device would be interesting to dig into. If it hasn't been done yet, we
should add a use case.

>
>
>> Why mandate that interaction C shall always occur through a GS? (I'm sure
>> Denis will not want this, for instance).
>>
> This is not a mandate, but an abstract model. In SSI/DID most of the time,
> RP-RC will also reside on a user device.
>

FI : problem is that if you show that, most people will assume it's
mandatory (as least for the alt2 part). At least I think that's what most
readers would assume from reading the schema.


> Are we sure we need to formally separate B and C? This goes beyond
>> previous discussions of separating the front and back channels, and I don't
>> really see the advantage (maybe there is: which use cases would be
>> impossible to do otherwise?).
>>
> We have a situation where RP =!= RC. And each of them have their own AS.
>

FI : see discussion at the start of the message

>
>
>> So overall, I think Alt2 over-complexifies the situation. We need to
>> remain flexible.
>> Why not simply have an (optional) way of separating these flows from the
>> GS?
>>
> With GNAP, we are at an abstraction level-0, like referred to in my former
> post. At level-1 we can address concrete protocols like oAuth, OIDC,
> [SSI/DiD/VC] and the diagram will look simple.
>

FI : yes.

>
>
>> For instance, an (optional) Interact Server (IS) could provide support
>> for a decoupled front-channel:
>> - it does not change the interaction between a GC and a GS. It does
>> change the trust model though, depending on which options are chosen. In
>> practice, the GC may specify which IS it wants to use (it can be his own,
>> for instance). In case nothing is specified, the GS decides.
>> - the IS is able to handle the front-channel for idclaims and consent,
>> and return back to the GS what access tokens are required.
>> - notice that although the IS is focused on front-channel interaction,
>> there are cases where the consent needs to be based on policies instead of
>> a direct human interaction (typically when end-user is not the RC, and
>> therefore the end-user is not the one that is asked for consent / then of
>> course, if the RC logs in, he would be able to manage his consent
>> policies).
>>
> What you mention here is why I display RP-AS and RC-AS!
>
>
>> So there's really no obligation that B occurs through the GC and C occurs
>> through the GS. It depends on where your front-channel is located (GC, GS,
>> third-party).
>>
> Yes. I agree with you. How can we make this  visible in a diagram?
>

FI : let me think about it ;-)


>
> This I think makes it a very flexible model, while enabling what we're
>> after.
>>
> Yes.
> /Francis
>
>>
>> Fabien
>>
>>
>> On Mon, Aug 17, 2020 at 4:38 AM Francis Pouatcha <fpo=
>> 40adorsys.de@dmarc.ietf.org <40adorsys.de@dmarc..ietf.org>> wrote:
>>
>>> Hello Dick,
>>>
>>> Thanks for pointing this out. This is the new diagram where ++++
>>> refers to what Endpoint/Human interaction and ----> refers to interaction
>>> among services.
>>>
>>>     +-------------+                        +----------------+
>>>     | Requesting  |                        |  Resource      |
>>>     | Party (RP)  |                        | Controller (RC)|
>>>     +-------------+                        +----------------+
>>>         +     +                             +
>>>         +      +                           +
>>>        (A)     (B1)                      (C1)
>>>         +        +                       +
>>>         +.        +                     +
>>>         +       +--------+         +--------+
>>>         +       | RP-AS  |         | RC-AS  |
>>>         +  +--->|        |     +-->|        |
>>>         +  |    +--------+     |   +--------+
>>>         +  |                   |
>>>         + (B0)                 |
>>>         +  |                  (C0)
>>>     +--------+                 |             +------------+
>>>     | Grant  |--------(1)------|------------>|  Resource  |
>>>     | Client |                 |             |   Server   |
>>>     |  (GC)  |       +---------------+       |    (RS)    |
>>>     |        |--(2)->|     Grant     |       |            |
>>>     |        |<-(3)->|     Server    |- (6) -|            |
>>>     |        |<-(4)--|      (GS)     |       |            |
>>>     |        |       +---------------+       |            |
>>>     |        |                               |            |
>>>     |        |--------------(5)------------->|            |
>>>     +--------+                               +------------+
>>>
>>>
>>> It is still important to know what is part of the protocol:
>>> Alt-1: only (1..6). This is what you specified in section 1.2, and I am
>>> fine with that.
>>> Alt-2: Alt-1 + (B0, C0). This is a result of the discussion we have been
>>> having around privacy, GS as big brother, aso....
>>>
>>> P.S.: an authentication [RP]+++(A)+++>[GC] can be assumed, but shall be
>>> irrelevant for the protocol. [RP]+++(B1)+++>[RP-AS] is important for later
>>> instantiation of the model. As in many cases, like in oAuth [RP-AS] could
>>> be the same entity like [GS].
>>>
>>> Best regards.
>>> /Francis
>>>
>>>
>>> On Sun, Aug 16, 2020 at 7:04 PM Dick Hardt <dick.hardt@gmail.com> wrote:
>>>
>>>> Hi Francis
>>>>
>>>> I was intentional in stating 1.3 that it is human interactions. The
>>>> connection lines are '+ + +' rather than '-----' to indicate that it is a
>>>> human interaction rather than a protocol between roles. We can't specify
>>>> how a human interaction works, but we can show when they might occur
>>>> relative to the rest of the protocol
>>>>
>>>> In the abstract diagram in 1.3, I show the interactions between the
>>>> User and the GC, the User and the GS, and the RO and the GS. These are NOT
>>>> interactions that can be technically specified. The User and RO are not
>>>> roles in the protocol, but are entities in the trust model.
>>>>
>>>> I debated keeping the interactions abstract and not stating "what"
>>>> happened in each interaction, but thought that might be confusing at this
>>>> stage or our discussions.
>>>>
>>>> Since it is just an interaction between human and software, we can have
>>>> the User authenticate to the GC as well as authorize (provide consent), and
>>>> have no interaction at the GS. We would need to define how to represent the
>>>> authorization and the consent for the GC to pass to the GS, but the roles
>>>> and entities stay the same. The trust model does change though.
>>>>
>>>> /Dick
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Sun, Aug 16, 2020 at 3:46 PM Francis Pouatcha <fpo@adorsys.de>
>>>> wrote:
>>>>
>>>>> Hello Dick, my feedback below:
>>>>>
>>>>> 1.2: Excellent and Focussed
>>>>> -> The word "Grant Client" looks great for me.
>>>>>
>>>>> 1.3:
>>>>> Title: Human Interaction -> End User Interaction
>>>>> I would title this "End User" interaction and not "human ...". It is
>>>>> not about having a human, but a terminating edge of the protocol. An "End
>>>>> User" can be either human on an IOT device or a car or ...
>>>>>
>>>>> Participant: User -> "Requesting Party"
>>>>> I will still insist on replacing the word "User" with a role name.
>>>>> Maybe "Requesting Party" as used by UMA.
>>>>>
>>>>> Participant: "Resource Controller". In past discussions there was a
>>>>> consensus on using "Resource Controller" instead.
>>>>>
>>>>> (B) I which the GS never interacts with the "Requesting Party" in a
>>>>> matter of obtaining a grant to a resource (many reasons: privacy,
>>>>> confidentiality, abstraction, ...). Generally the GS will need information
>>>>> (claims) about the "Requesting Party" to proceed with the authorisation
>>>>> decision. In this case, the GS can instruct the GC to obtain those claims.
>>>>> In some cases, claims on the "Requesting Party" will be obtained from
>>>>> another "Authorization Server" (AS). The word AS is intentionally chosen
>>>>> here. In this same login, the path (C0, C1) below will not only return the
>>>>> RC consent, but might also return some claims on RC.
>>>>>
>>>>> ASs provide authentication "of" and consent collection "from" End
>>>>> Users. End users are in this case the Requesting Party, and the Resource
>>>>> Controller).
>>>>>
>>>>> The result can look like the modified diagram below. With this we can
>>>>> address some privacy concerns that are being discussed on the list.
>>>>>
>>>>>     +-------------+                        +----------------+
>>>>>     | Requesting  |                        |  Resource      |
>>>>>     | Party (RP)  |                        | Controller (RC)|
>>>>>     +-------------+                        +----------------+
>>>>>         +     +                             +
>>>>>         +      +                           +
>>>>>        (A)     (B1)                      (C1)
>>>>>         +        +                       +
>>>>>         +.        +                     +
>>>>>         +       +--------+       +--------+
>>>>>         +       | RP-AS  |       | RC-AS  |
>>>>>         +       |        |       |        |
>>>>>         +       +--------+       +--------+
>>>>>         +         +                  +
>>>>>         +       (B0)                +
>>>>>         +       +                (C0)
>>>>>     +--------+ +                  +          +------------+
>>>>>     | Grant  | - - - -(1)- - - - + - - - - ->|  Resource  |
>>>>>     | Client |                  +            |   Server   |
>>>>>     |  (GC)  |       +---------------+       |    (RS)    |
>>>>>     |        |--(2)->|     Grant     |       |            |
>>>>>     |        |<-(3)->|     Server    |- (6) -|            |
>>>>>     |        |<-(4)--|      (GS)     |       |            |
>>>>>     |        |       +---------------+       |            |
>>>>>     |        |                               |            |
>>>>>     |        |--------------(5)------------->|            |
>>>>>     +--------+                               +------------+
>>>>>
>>>>> (B0, B1) replace (B). Occur inside step (3), GS asks GC to collect the
>>>>> claims. GC contacts RP-AS to negotiate those claims. But it is important to
>>>>> mention that those Claims-RP are not the target Grant being negotiated for
>>>>> the resource access. They are generally used by GS (and later RS) as input
>>>>> into performing authz decisions.
>>>>>
>>>>> (C0, C1) replace (C). They occur after step (3) (Beware of the
>>>>> difference to Bs that occur inside 3). This separation address the Big
>>>>> Brother problem we have been discussing in the list.
>>>>>
>>>>> Essential is to mention that in an instantiation of this model for
>>>>> oAuth for example:
>>>>> - GS, RP-AS and RC-AS might be the same entity.
>>>>> - RP and RC might refer to the same "End User".
>>>>>
>>>>> Off-topic: The splitting of GS and AS was suggested in some
>>>>> discussions on the mailing list. But we have no mean yet to isolate good
>>>>> inputs for later reuse. This is why I suggest we compile some inputs into
>>>>> tickets or wiki pages (like use cases).
>>>>>
>>>>> 1.4:
>>>>> The Trust model introduces what I would rather call the trust
>>>>> framework. The purpose of the trust framework will be to address topics
>>>>> mentioned in this section. There is still a lot of discussion needed to
>>>>> have a structure for this section.
>>>>>
>>>>>
>>>>> 1.5
>>>>> I suggest again we replace Human with "End User" and still make them
>>>>> roles. This is:
>>>>> Terminology (Are all roles)
>>>>>   -> These roles can be borne by End Users
>>>>>      -> Requesting Party (RP)
>>>>>      -> Resource Controller (RC)
>>>>>   -> These role can be borne by Services
>>>>>      -> GS
>>>>>      -> GC
>>>>>      -> RS
>>>>>      -> RP-AS
>>>>>      -> RC-AS
>>>>>
>>>>> I will stop here, as the fundamental agreement on this structure is
>>>>> necessary for a qualified review of section 2++.
>>>>>
>>>>> Best regards
>>>>> /Francis
>>>>>
>>>>> On Sat, Aug 15, 2020 at 7:03 PM Dick Hardt <dick.hardt@gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hello
>>>>>>
>>>>>> I just pushed an updated version of XAuth:
>>>>>>
>>>>>> https://tools..ietf.org/id/draft-hardt-xauth-protocol-14.html
>>>>>> <https://tools.ietf..org/id/draft-hardt-xauth-protocol-14.html>
>>>>>>
>>>>>> Highlights:
>>>>>>
>>>>>>    - renamed Client -> Grant Client
>>>>>>    - Introduced Client Owner, Grant Server Owner as new entities
>>>>>>    - renamed Authorizations -> Access
>>>>>>    - An Access contains an array of RAR objects now
>>>>>>    - Reworked diagram an intro to focus on Grant, and separate
>>>>>>    protocol roles from human interactions.
>>>>>>
>>>>>> New introduction included below for your convenience
>>>>>>
>>>>>> /Dick
>>>>>>
>>>>>>    -
>>>>>>
>>>>>> 1.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1>
>>>>>> Introduction
>>>>>> <https://tools..ietf.org/id/draft-hardt-xauth-protocol-14.html#name-introduction>
>>>>>>
>>>>>> *EDITOR NOTE*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-1>
>>>>>>
>>>>>> *This document captures a number of concepts that may be adopted by
>>>>>> the proposed GNAP working group. Please refer to this document as:*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-2>
>>>>>>
>>>>>> *XAuth*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-3>
>>>>>>
>>>>>> *The use of GNAP in this document is not intended to be a declaration
>>>>>> of it being endorsed by the GNAP working group.*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-4>
>>>>>>
>>>>>> This document describes the core Grant Negotiation and Authorization
>>>>>> Protocol (GNAP). The protocol supports the widely deployed use cases
>>>>>> supported by OAuth 2.0 [RFC6749
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#RFC6749>
>>>>>> ] & [RFC6750
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#RFC6750>
>>>>>> ], OpenID Connect [OIDC
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#OIDC>] -
>>>>>> an extension of OAuth 2.0, as well as other extensions. Related documents
>>>>>> include: GNAP - Advanced Features [GNAP_Advanced
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#GNAP_Advanced>
>>>>>> ] and JOSE Authentication [JOSE_Authentication
>>>>>> <https://tools.ietf..org/id/draft-hardt-xauth-protocol-14.html#JOSE_Authentication>
>>>>>> ] that describes the JOSE mechanisms for client authentication.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-5>
>>>>>>
>>>>>> The technology landscape has changed since OAuth 2.0 was initially
>>>>>> drafted. More interactions happen on mobile devices than PCs. Modern
>>>>>> browsers now directly support asymetric cryptographic functions. Standards
>>>>>> have emerged for signing and encrypting tokens with rich payloads (JOSE)
>>>>>> that are widely deployed.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-6>
>>>>>>
>>>>>> GNAP simplifies the overall architectural model, takes advantage of
>>>>>> today's technology landscape, provides support for all the widely deployed
>>>>>> use cases, offers numerous extension points, and addresses many of the
>>>>>> security issues in OAuth 2.0 by passing parameters securely between parties
>>>>>> rather than via a browser redirection.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-7>
>>>>>>
>>>>>> While GNAP is not backwards compatible with OAuth 2.0, it strives to
>>>>>> minimize the migration effort.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-8>
>>>>>>
>>>>>> The suggested pronunciation of GNAP is "guh-nap".
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1-9>
>>>>>> 1.1.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.1>The
>>>>>> Grant
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#name-the-grant>
>>>>>>
>>>>>> The Grant is at the center of the protocol between a client and a
>>>>>> server. A Grant Client requests a Grant from a Grant Server. The Grant
>>>>>> Client and Grant Server negotiate the Grant. The Grant Server acquires
>>>>>> authorization to grant the Grant to the Grant Client. The Grant Server then
>>>>>> returns the Grant to the Grant Client.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.1-1>
>>>>>>
>>>>>> The Grant Request may contain information about the User, the Grant
>>>>>> Client, the interaction modes supported by the Grant Client, the requested
>>>>>> identity claims, and the requested resource access. Extensions may define
>>>>>> additional information to be included in the Grant Request.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.1-2>
>>>>>> 1.2.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.2>Protocol
>>>>>> Roles
>>>>>> <https://tools..ietf.org/id/draft-hardt-xauth-protocol-14.html#name-protocol-roles>
>>>>>>
>>>>>> There are three roles in GNAP: the Grant Client (GC), the Grant
>>>>>> Server (GS), and the Resource Server (RS). Below is how the roles interact:
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14..html#section-1..2-1>
>>>>>>
>>>>>>     +--------+                               +------------+
>>>>>>     | Grant  | - - - - - - -(1)- - - - - - ->|  Resource  |
>>>>>>     | Client |                               |   Server   |
>>>>>>     |  (GC)  |       +---------------+       |    (RS)    |
>>>>>>     |        |--(2)->|     Grant     |       |            |
>>>>>>     |        |<-(3)->|     Server    |- (6) -|            |
>>>>>>     |        |<-(4)--|      (GS)     |       |            |
>>>>>>     |        |       +---------------+       |            |
>>>>>>     |        |                               |            |
>>>>>>     |        |--------------(5)------------->|            |
>>>>>>     +--------+                               +------------+
>>>>>>
>>>>>>
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.2-2>
>>>>>>
>>>>>> (1) The GC may query the RS to determine what the RS requires from a
>>>>>> GS for resource access. This step is not in scope for this document.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.2-3>
>>>>>>
>>>>>> (2) The GC makes a Grant request to the GS (Create Grant Section 3.2
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#CreateGrant>).
>>>>>> How the GC authenticates to the GS is not in scope for this document. One
>>>>>> mechanism is [JOSE_Authentication
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#JOSE_Authentication>
>>>>>> ].
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.2-4>
>>>>>>
>>>>>> (3) The GC and GS may negotiate the Grant.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.2-5>
>>>>>>
>>>>>> (4) The GS returns a Grant to the GC (Grant Response Section 4.1
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#GrantResponse>
>>>>>> ).
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.2-6>
>>>>>>
>>>>>> (5) The GC accesses resources at the RS (RS Access Section 6
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#RSAccess>
>>>>>> ).
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.2-7>
>>>>>>
>>>>>> (6) The RS evaluates access granted by the GS to determine access
>>>>>> granted to the GC. This step is not in scope for this document.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.2-8>
>>>>>> 1.3.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3>Human
>>>>>> Interactions
>>>>>> <https://tools..ietf..org/id/draft-hardt-xauth-protocol-14.html#name-human-interactions>
>>>>>>
>>>>>> The Grant Client may be interacting with a human end-user (User), and
>>>>>> the Grant Client may need to get authorization to release the Grant from
>>>>>> the User, or from the owner of the resources at the Resource Server, the
>>>>>> Resource Owner (RO)
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-1>
>>>>>>
>>>>>> Below is when the human interactions may occur in the protocol:
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-2>
>>>>>>
>>>>>>     +--------+                               +------------+
>>>>>>     |  User  |                               |  Resource  |
>>>>>>     |        |                               | Owner (RO) |
>>>>>>     +--------+                               +------------+
>>>>>>         +     +                             +
>>>>>>         +      +                           +
>>>>>>        (A)     (B)                       (C)
>>>>>>         +        +                       +
>>>>>>         +         +                     +
>>>>>>     +--------+     +                   +     +------------+
>>>>>>     | Grant  | - - -+- - - -(1)- - - -+- - ->|  Resource  |
>>>>>>     | Client |       +               +       |   Server   |
>>>>>>     |  (GC)  |       +---------------+       |    (RS)    |
>>>>>>     |        |--(2)->|     Grant     |       |            |
>>>>>>     |        |<-(3)->|     Server    |- (6) -|            |
>>>>>>     |        |<-(4)--|      (GS)     |       |            |
>>>>>>     |        |       +---------------+       |            |
>>>>>>     |        |                               |            |
>>>>>>     |        |--------------(5)------------->|            |
>>>>>>     +--------+                               +------------+
>>>>>>
>>>>>> Legend
>>>>>> + + + indicates an interaction with a human
>>>>>> ----- indicates an interaction between protocol roles
>>>>>>
>>>>>>
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-3>
>>>>>>
>>>>>> Steps (1) - (6) are the same as Section 1.2
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#ProtocolRoles>.
>>>>>> The addition of the human interactions (A) - (C) are *bolded* below.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-4>
>>>>>>
>>>>>> *(A) The User is interacting with a GC, and the GC needs resource
>>>>>> access and/or identity claims (a Grant)*
>>>>>> <https://tools..ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-5>
>>>>>>
>>>>>> (1) The GC may query the RS to determine what the RS requires from a
>>>>>> GS for resource access
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-6>
>>>>>>
>>>>>> (2) The GC makes a Grant request to the GS
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-7>
>>>>>>
>>>>>> (3) The GC and GS may negotiate the Grant
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-8>
>>>>>>
>>>>>> *(B) The GS may interact with the User for grant authorization*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-9>
>>>>>>
>>>>>> *(C) The GS may interact with the RO for grant authorization*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-10>
>>>>>>
>>>>>> (4) The GS returns a Grant to the GC
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-11>
>>>>>>
>>>>>> (5) The GC accesses resources at the RS
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-12>
>>>>>>
>>>>>> (6) The RS evaluates access granted by the GS to determine access
>>>>>> granted to the GC
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-13>
>>>>>>
>>>>>> Alternatively, the Resource Owner could be a legal entity that has a
>>>>>> software component that the Grant Server interacts with for Grant
>>>>>> authorization. This interaction is not in scope of this document.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.3-14>
>>>>>> 1.4.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4>Trust
>>>>>> Model
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#name-trust-model>
>>>>>>
>>>>>> In addition to the User and the Resource Owner, there are three other
>>>>>> entities that are part of the trust model:
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14..html#section-1.4-1>
>>>>>>
>>>>>>    - *Client Owner* (CO) - the legal entity that owns the Grant
>>>>>>    Client.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-2.1>
>>>>>>    - *Grant Server Owner* (GSO) - the legal entity that owns the
>>>>>>    Grant Server.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-2.2>
>>>>>>    - *Claims Issuer* (Issuer) - a legal entity that issues identity
>>>>>>    claims about the User. The Grant Server Owner may be an Issuer, and the
>>>>>>    Resource Owner may be an Issuer.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-2.3>
>>>>>>
>>>>>> These three entities do not interact in the protocol, but are trusted
>>>>>> by the User and the Resource Owner:
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-3>
>>>>>>
>>>>>>   +------------+           +--------------+----------+
>>>>>>   |    User    | >> (A) >> | Grant Server |          |
>>>>>>   |            |           | Owner (GSO)  |          |
>>>>>>   +------------+         > +--------------+          |
>>>>>>         V              /          ^       |  Claims  |
>>>>>>        (B)          (C)          (E)      |  Issuer  |
>>>>>>         V          /              ^       | (Issuer) |
>>>>>>   +------------+ >         +--------------+          |
>>>>>>   |  Client    |           |   Resource   |          |
>>>>>>   | Owner (CO) | >> (D) >> |  Owner (RO)  |          |
>>>>>>   +------------+           +--------------+----------+
>>>>>>
>>>>>>
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-4>
>>>>>>
>>>>>> (A) User trusts the GSO to acquire authorization before making a
>>>>>> grant to the CO
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-5>
>>>>>>
>>>>>> (B) User trusts the CO to act in the User's best interest with the
>>>>>> Grant the GSO grants to the CO
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-6>
>>>>>>
>>>>>> (C) CO trusts claims issued by the GSO
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-7>
>>>>>>
>>>>>> (D) CO trusts claims issued by the RO
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-8>
>>>>>>
>>>>>> (E) RO trusts the GSO to manage access to the RO resources
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.4-9>
>>>>>> 1.5.
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1..5>
>>>>>> Terminology
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#name-terminology>
>>>>>>
>>>>>> *Roles*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-1>
>>>>>>
>>>>>>    -
>>>>>>
>>>>>>    *Grant Client* (GC)
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.1.1>
>>>>>>    - may want access to resources at a Resource Server
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.1.2.1>
>>>>>>       - may be interacting with a User and want identity claims
>>>>>>       about the User
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.1.2.2>
>>>>>>       - requests the Grant Service to grant resource access and
>>>>>>       identity claims
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.1..2.3>
>>>>>>    -
>>>>>>
>>>>>>    *Grant Server* (GS)
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.2.1>
>>>>>>    - accepts Grant requests from the GC for resource access and
>>>>>>       identity claims
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14..html#section-1.5-2.2.2.1>
>>>>>>       - negotiates the interaction mode with the GC if interaction
>>>>>>       is required with the User
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.2.2.2>
>>>>>>       - acquires authorization from the User before granting
>>>>>>       identity claims to the GC
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.2.2.3>
>>>>>>       - acquires authorization from the RO before granting resource
>>>>>>       access to the GC
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.2.2.4>
>>>>>>       - grants resource access and identity claims to the GC
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.2.2.5>
>>>>>>    -
>>>>>>
>>>>>>    *Resource Server* (RS)
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.3.1>
>>>>>>    - has resources that the GC may want to access
>>>>>>       <https://tools.ietf..org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.3.2.1>
>>>>>>       - expresses what the GC must obtain from the GS for access
>>>>>>       through documentation or an API. This is not in scope for this document
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.3.2.2>
>>>>>>       - verifies the GS granted access to the GC, when the GS makes
>>>>>>       resource access requests
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-2.3.2.3>
>>>>>>
>>>>>> *Humans*
>>>>>> <https://tools.ietf..org/id/draft-hardt-xauth-protocol-14.html#section-1.5-3>
>>>>>>
>>>>>>    -
>>>>>>
>>>>>>    *User*
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-4.1.1>
>>>>>>    - the person interacting with the Grant Client.
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-4.1.2.1>
>>>>>>       - has delegated access to identity claims about themselves to
>>>>>>       the Grant Server.
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-4.1.2.2>
>>>>>>       - may authenticate at the GS...
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-4.1.2.3>
>>>>>>    -
>>>>>>
>>>>>>    *Resource Owner* (RO)
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-4.2.1>
>>>>>>    - the legal entity that owns resources at the Resource Server
>>>>>>       (RS).
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1..5-4.2.2.1>
>>>>>>       - has delegated resource access management to the GS.
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-4.2.2..2>
>>>>>>       - may be the User, or may be a different entity that the GS
>>>>>>       interacts with independently.
>>>>>>       <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-4.2.2.3>
>>>>>>
>>>>>> *Reused Terms*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-5>
>>>>>>
>>>>>>    - *access token* - an access token as defined in [RFC6749
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#RFC6749>
>>>>>>    ] Section 1.4.. An GC uses an access token for resource access at
>>>>>>    a RS.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-6.1>
>>>>>>    - *Claim* - a Claim as defined in [OIDC
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#OIDC>
>>>>>>    ] Section 5. Claims are issued by a Claims Issuer.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-6..2>
>>>>>>    - *Client ID* - a GS unique identifier for a Registered Client as
>>>>>>    defined in [RFC6749
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#RFC6749>
>>>>>>    ] Section 2.2.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1..5-6.3>
>>>>>>    - *ID Token* - an ID Token as defined in [OIDC
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#OIDC>
>>>>>>    ] Section 2. ID Tokens are issued by the GS. The GC uses an ID
>>>>>>    Token to authenticate the User.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-6.4>
>>>>>>    - *NumericDate* - a NumericDate as defined in [RFC7519
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#RFC7519>
>>>>>>    ] Section 2.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-6.5>
>>>>>>    - *authN* - short for authentication.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-6.6>
>>>>>>    - *authZ* - short for authorization.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-6.7>
>>>>>>
>>>>>> *New Terms*
>>>>>> <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-7>
>>>>>>
>>>>>>    - *GS URI* - the endpoint at the GS the GC calls to create a
>>>>>>    Grant, and is the unique identifier for the GS.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-8.1>
>>>>>>    - *Registered Client* - a GC that has registered with the GS and
>>>>>>    has a Client ID to identify itself, and can prove it possesses a key that
>>>>>>    is linked to the Client ID. The GS may have different policies for what
>>>>>>    different Registered Clients can request. A Registered Client MAY be
>>>>>>    interacting with a User.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-8.2>
>>>>>>    - *Dynamic Client* - a GC that has not been previously registered
>>>>>>    with the GS, and each instance will generate it's own asymetric key pair so
>>>>>>    it can prove it is the same instance of the GC on subsequent requests.. The
>>>>>>    GS MAY return a Dynamic Client a Client Handle for the Dynamic Client to
>>>>>>    identify itself in subsequent requests. A single-page application with no
>>>>>>    active server component is an example of a Dynamic Client.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-8.3>
>>>>>>    - *Client Handle* - a unique identifier at the GS for a Dynamic
>>>>>>    Client for the Dynamic Client to refer to itself in subsequent requests.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-8.4>
>>>>>>    - *Interaction* - how the GC directs the User to interact with
>>>>>>    the GS. This document defines the interaction modes: "redirect",
>>>>>>    "indirect", and "user_code" in Section 5
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#InteractionModes>
>>>>>>    .
>>>>>>    <https://tools..ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-8.5>
>>>>>>    - *Grant* - the user identity claims and/or resource access the
>>>>>>    GS has granted to the Client. The GS MAY invalidate a Grant at any time.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-8.6>
>>>>>>    - *Grant URI* - the URI that represents the Grant. The Grant URI
>>>>>>    MUST start with the GS URI.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14..html#section-1.5-8.7>
>>>>>>    - *Access* - the access granted by the RO to the GC and contains
>>>>>>    an access token. The GS may invalidate an Access at any time.
>>>>>>    <https://tools.ietf.org/id/draft-hardt-xauth-protocol-14.html#section-1.5-8.8>
>>>>>>    - *Access URI* - the URI that represents the Access the GC was
>>>>>>    granted by the RO. The Access URI MUST start with the GS URI.. The Access
>>>>>>    URI is used to refresh an access token.
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> TXAuth mailing list
>>>>>> TXAuth@ietf.org
>>>>>> https://www.ietf.org/mailman/listinfo/txauth
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Francis Pouatcha
>>>>> Co-Founder and Technical Lead
>>>>> adorsys GmbH & Co. KG
>>>>> https://adorsys-platform.de/solutions/
>>>>>
>>>>
>>>
>>> --
>>> Francis Pouatcha
>>> Co-Founder and Technical Lead
>>> adorsys GmbH & Co. KG
>>> https://adorsys-platform.de/solutions/
>>> --
>>> TXAuth mailing list
>>> TXAuth@ietf.org
>>> https://www.ietf.org/mailman/listinfo/txauth
>>>
>>
>
> --
> Francis Pouatcha
> Co-Founder and Technical Lead
> adorsys GmbH & Co. KG
> https://adorsys-platform.de/solutions/
>