[OAUTH-WG] Feed back on draft-sh-rats-oidc at-00

[George Fletcher <[e-mail]>]

Hi Ned/Thomas,

Thanks so much for the conversation at IETF on the potential value of
combining the attestation work with OpenID Connect and OAuth. Given the
spec references a lot of OpenID Connect artifacts, I’ve used OpenID Connect
points in this response. However, from an IETF perspective, this would be
connected to OAuth and the Authorization Server. It might be useful to map
the work to OAuth directly and then let OpenID Connect (which is built on
top of OAuth) to “inherit” the capability.

As promised, here is some feedback on the presented draft…

Section 2.1
* The userinfo endpoint is an API specified by the OpenID Connect protocol.
It’s usually part of the OpenID Provider. Regardless it’s not a
useragent/browser.

Section 3.1
* userinfo (see previous comment)
* End user (EU/Alice) is not an application. In OAuth the end user is
called the Resource Owner. The application is called the ‘client’. So the
Resource Owner uses the client to access the RO’s resources.
* Relying Party - generally in OAuth/OpenID Connect the relying party is
not looking for attestations. It’s looking for an authorization token to be
presented by a client. In the case of attestations… it would be the OpenID
Provider that would be interested in the attestations (in this context it
may be possible to consider the OpenID Provider playing the role of a RRP).

Section 3.2.1
* this isn’t really how the OpenID connect protocol works. In a general
mobile app flow, the mobile app (aka the client) will open a browser to the
OpenID Provider’s /authorization endpoint which starts the
authentication/consent/authorization flow. Once the user has authenticated,
the OpenID Provider provides a ‘code’ back to the native application which
then exchanges that ‘code’ for the ‘id-token and access-token’ at the
/token endpoint of the OpenID Provider

Beyond this part of the spec I got confused on how the protocol is supposed
to work and who the core agents are in the flow. A diagram would be really
helpful showing the core steps.

In my view, it’s more likely that the OpenID Provider will be the entity
desiring an attestation about the client making the request. This could be
just an attestation about the client software, or could also include an
attestation about general characteristics of the device (e.g. is it jail
broken or not).

There are two main use cases…
1. The client is a mobile app in which case it may be able to obtain an
attestation before starting the authorization flow
2. The client is a web service (or relying party) and the OpenID Provider
wants some attestation about the software and environment in which that
client is running.

I suspect we can address both cases with the same flow. We might need an
initial step for the client to obtain a nonce from the OpenID Provider
before presenting the attestation so that the attestation can contain the
nonce allowing the OpenID provider to know this is a fresh attestation and
bound into the authorization process requested by the client.

Thanks,
George
-- 
[image: Capital One]

George Fletcher (he/him)

Executive Distinguished Engineer • Identity Architect
[image: address]8020 Towers Crescent Drive, Vienna, VA 22128
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