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

Justin Richer <> Tue, 11 August 2020 23:38 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 0716C3A0DEC for <>; Tue, 11 Aug 2020 16:38:21 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id 5HMMJDQnzq1N for <>; Tue, 11 Aug 2020 16:38:18 -0700 (PDT)
Received: from ( []) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 99B713A0E11 for <>; Tue, 11 Aug 2020 16:38:18 -0700 (PDT)
Received: from (OC11EXEDGE1.EXCHANGE.MIT.EDU []) by (8.14.7/8.12.4) with ESMTP id 07BNbDFS016074; Tue, 11 Aug 2020 19:37:56 -0400
Received: from ( by ( with Microsoft SMTP Server (TLS) id 15.0.1293.2; Tue, 11 Aug 2020 19:37:18 -0400
Received: from ( by ( with Microsoft SMTP Server (TLS) id 15.0.1365.1; Tue, 11 Aug 2020 19:38:08 -0400
Received: from ([]) by ([]) with mapi id 15.00.1365.000; Tue, 11 Aug 2020 19:38:08 -0400
From: Justin Richer <>
To: Dick Hardt <>, Francis Pouatcha <>
CC: Denis <>, Benjamin James Kaduk <>, "" <>
Thread-Topic: [GNAP] [Txauth] Revisiting the photo sharing example (a driving use case for the creation of OAuth)
Date: Tue, 11 Aug 2020 23:38:08 +0000
Message-ID: <>
References: <> <> <> <> <> <> <> <>, <>
In-Reply-To: <>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-transport-fromentityheader: Hosted
x-originating-ip: []
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
Archived-At: <>
Subject: Re: [GNAP] [Txauth] Revisiting the photo sharing example (a driving use case for the creation of OAuth)
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 11 Aug 2020 23:38:23 -0000

If defined as the party operating the client software, then the user is a role. I believe this is more accurate and inclusive than the definition you have proposed with the user as an entity. 

 - Justin
From: Dick Hardt []
Sent: Tuesday, August 11, 2020 6:21 PM
To: Francis Pouatcha
Cc: Justin Richer; Denis; Benjamin James Kaduk;
Subject: Re: [GNAP] [Txauth] Revisiting the photo sharing example (a driving use case for the creation of OAuth)

Hi Francis

The user is an entity, not a role in the protocol in how I am defining roles, so steps (1) and (7) are confusing to me on what is happening.

I also think that (2) could be an extension to GNAP, rather than part of the core protocol.

On Mon, Aug 10, 2020 at 8:04 PM Francis Pouatcha <<>> wrote:
In this context, I suggest we pick some words to work with, and sharpen them as we move on, discover and map new use cases to the protocol.

In this diagram from the original thread (, I replaced the words:

+-----------+      +--------------+  +----+  +----+  +---------------------+
| Requestor |      | Orchestrator |  |    |  | GS |  | Resource Controller |
|   was     |      |     was      |  | RS |  | or |  |         was         |
|  User     |      |   Client     |  |    |  | AS |  |    Resource Owner   |
+-----------+      +--------------+  +----+  +----+  +---------------------+
  |(1) ServiceRequest     |            |       |                |
  |---------------------->|            |       |                |
  |                       |(2) ServiceIntent:AuthZChallenge     |
  |                       |<---------->|       |                |
  |                       |            |       |                |
  |                       |(3) AuthZRequest(AuthZChallenge)     |
  |                       |------------------->|                |
  |                       |            |       |(4) ConsentRequest:Grant
  |                       |            |       |<-------------->|
  |                       |(5) GrantAccess(AuthZ)               |
  |                       |<-------------------|                |
  |                       |            |       |                |
  |                       |(6) ServiceRequest(AuthZ):ServiceResponse
  |                       |<---------->|       |                |
  |(7) ServiceResponse    |            |       |                |
  |<----------------------|            |       |                |
  +                       +            +       +                +

The purpose of the GNAP protocol is to help negotiate access to a protected resource. It starts with a requestor delegating activity to an orchestrator. These are all roles, no entities. Let focus on mapping the use cases to the protocol roles and interactions so wwe can discover what is missing.

It seems cumbersome to use it in discussions as it is impossible to give the word "Client" a clear definition.

We can mention in the final document, that the "Orchestrator" (or whatever word we finally use) plays the same role as the "Client" in oAuth2.

Best regards.

On Wed, Aug 5, 2020 at 9:05 PM Dick Hardt <<>> wrote:
I agree with Justin. Redefining well used terms will lead to significant confusion. If we have a different role than what we have had in the past, then that role should have a name not being used already in OAuth or OIDC.

Given what we have learned, and my own experience explaining what a Client is, and is not, improving the definition for Client could prove useful. I am not suggesting the term be redefined, but clarified.

For example, clarifying that a Client is a role an entity plays in the protocol, and that the same entity may play other roles at other times, or some other language to help differentiate between "role" and "entity".


On Wed, Aug 5, 2020 at 8:20 AM Justin Richer <<>> wrote:
I’m in favor of coming up with a new term that’s a better fit, but I’m not really in favor of taking an existing term and applying a completely new definition to it. In other words, I would sooner stop using “client” and come up with a new, more specific and accurate term for the role than to define “client” as meaning something completely different. We did this in going from OAuth 1 to OAuth 2 already, moving from the even-more-confusing “consumer” to “client”, but OAuth 2 doesn’t use the term “consumer” at all, nor does it use “server” on its own but instead always qualifies it with “Authorization Server” and “Resource Server”.

GNAP can do something similar, in my opinion. But what we can’t do is ignore the fact that GNAP is going to be coming up in a world that is already permeated  by OAuth 2 and its terminology. We don’t have a blank slate to work with, but neither are we bound to use the same terms and constructs as before. It’s going to be a delicate balance!

 — Justin

On Aug 4, 2020, at 3:32 PM, Warren Parad <<>> wrote:

I think that is fundamentally part of the question:
We are clear that we are producing a protocol that is
conceptually (if not more strongly) related to OAuth 2.0, and reusing terms
from OAuth 2.0 but with different definitions may lead to unnecessary

If we say that this document assumes OAuth2.0 terminology, then we should not change the meanings of any definition. If we are saying this supersedes or replaces what OAuth 2.0 creates, then we should pick the best word for the job and ignore conflicting meanings from OAuth 2.0. I have a lot of first hand experience of industries "ruining words", and attempting to side-step the problem rather than redefining the word just confuses everyone as everyone forgets the original meaning as new documents come out, but the confusion with the use of a non-obvious word continues.

Food for thought.
- Warren


Warren Parad
Founder, CTO

Secure your user data and complete your authorization architecture. Implement Authress<>.

On Tue, Aug 4, 2020 at 8:53 PM Benjamin Kaduk <<>> wrote:
Hi Denis,

On Tue, Aug 04, 2020 at 11:31:34AM +0200, Denis wrote:
> Hi Justin,
> Since you replied in parallel, I will make a response similar to the one
> I sent to Dick.
> > Hi Denis,
> >
> > I think there’s still a problem with the terminology in use here. What
> > you describe as RS2, which might in fact be an RS unto itself, is a
> > “Client” in OAuth parlance because it is /a client of RS1/. What you
> > call a “client” has no analogue in the OAuth world, but it is not at
> > all the same as an OAuth client. I appreciate your mapping of the
> > entities below, but it makes it difficult to hold a discussion if we
> > aren’t using the same terms.
> >
> > The good news is that this isn’t OAuth, and as a new WG we can define
> > our own terms. The bad news is that this is really hard to do.
> >
> > In GNAP, we shouldn’t just re-use existing terms with new definitions,
> > but we’ve got a chance to be more precise with how we define things.
> In the ISO context, each document must define its own terminology. The
> boiler plate for RFCs does not mandate a terminology or definitions section
> but does not prevent it either. The vocabulary is limited and as long as
> we clearly define what our terms are meaning, we can re-use a term already
> used in another RFC. This is also the ISO approach.

Just because we can do something does not necessarily mean that it is a
good idea to do so.  We are clear that we are producing a protocol that is
conceptually (if not more strongly) related to OAuth 2.0, and reusing terms
from OAuth 2.0 but with different definitions may lead to unnecessary
confusion.  If I understand correctly, a similar reasoning prompted Dick to
use the term "GS" in XAuth, picking a name that was not already used in
OAuth 2.0.


Txauth mailing list<>
Txauth mailing list<>

TXAuth mailing list<>
TXAuth mailing list<>

Francis Pouatcha
Co-Founder and Technical Lead
adorsys GmbH & Co. KG