Subject: Re: [Txauth] TxAuth Charter

From: Justin Richer <[email-masked]>
Date: Mon, 6 Apr 2020 15:50:23 -0400

I’ve added the line to cover the use of things like formal analysis and other tools for spec development within the group that have been brought up on the list. The new text is as follows:

This group is chartered to develop a fine-grained delegation protocol for authorization and API access, as well as requesting and providing user identifiers and claims. This protocol will allow an authorizing party to delegate access to client software through an authorization server. It will expand upon the uses cases currently supported by OAuth 2.0 and OpenID Connect (itself an extension of OAuth 2.0) to support authorizations scoped as narrowly as a single transaction, provide a clear framework for interaction among all parties involved in the protocol flow, and remove unnecessary dependence on a browser or user-agent for coordinating interactions. 

The delegation process will be acted upon by multiple parties in the protocol, each performing a specific role. The protocol will decouple the interaction channels, such as the end user’s browser, from the delegation channel, which happens directly between the client and the authorization server (in contrast with OAuth 2.0 which is initiated by the client redirecting the user’s browser). The client and AS will involve a user to make an authorization decision as necessary through interaction mechanisms indicated by the protocol. This decoupling avoids many of the security concerns and technical challenges of OAuth 2.0 and provides a non-invasive path for supporting future types of clients and interaction channels.

The group will define interoperability for this protocol between different parties, including
 - client and authorization server;
 - client and resource server; and
 - authorization server and resource server.

Additionally, the delegation process will allow for:

- Fine-grained specification of access
- Approval of AS attestation to identifiers and other identity claims
- Approval of access to multiple resources and APIs in a single interaction
- Support for multiple access tokens in a single request and response
- Support for directed, audience-restricted access tokens
- Separation between the party authorizing access and the party operating the client requesting access
- A variety of client applications, including Web, mobile, single-page, and interaction-constrained applications

The group will define extension points for this protocol to allow for flexibility in areas including:

- Cryptographic agility for keys, message signatures, and proof of possession 
- User interaction mechanisms including web and non-web methods
- Mechanisms for conveying user, software, organization, and other pieces of information used in authorization decisions
- Mechanisms for presenting tokens to resource servers and binding resource requests to tokens and associated cryptographic keys
- Optimized inclusion of additional information through the delegation process (including identifiers and identity assertions)

Additionally, the group will provide mechanisms for management of the protocol lifecycle including:

- Discovery of the authorization server
- Revocation of active tokens
- Mechanisms for the AS and RS to communicate the access granted by an access token

Although the artifacts for this work are not intended or expected to be backwards-compatible with OAuth 2.0 or OpenID Connect, the group will attempt to simplify migrating from OAuth 2.0 and OpenID Connect to the new protocol where possible.

This group is not chartered to develop extensions to OAuth 2.0, and as such will focus on new technological solutions not necessarily compatible with OAuth 2.0. Functionality that builds directly on OAuth 2.0 will be developed in the OAuth Working Group, including functionality back-ported from the protocol developed here to OAuth 2.0.

The group is chartered to develop mechanisms for applying cryptographic methods, such as JOSE and COSE, to the delegation process. This group is not chartered to develop new cryptographic methods.

The group is chartered to develop mechanisms for conveying identity information within the protocol including identifiers (such as email addresses, phone numbers, usernames, and subject identifiers) and assertions (such as OpenID Connect ID Tokens, SAML Assertions, and Verifiable Credentials). The group is not chartered to develop new formats for identifiers or assertions, nor is the group chartered to develop schemas for user information, profiles, or other identity attributes, unless a viable existing format is not available. 

The initial work will focus on using HTTP for communication between the client and the authorization server, taking advantage of optimization features of HTTP2 and HTTP3 where possible, and will strive to enable simple mapping to other protocols such as COAP when doing so does not conflict with the primary focus.

Milestones to include:
- Core delegation protocol
- Key presentation mechanism bindings to the core protocol including TLS, detached HTTP signature, and embedded HTTP signatures
- Conveyance mechanisms for identifiers and assertions
- Guidelines for use of protocol extension points

Where possible, the group will seek to make use of tools to guide and inform the standardization process including formal analysis, architecture documents, and use case documents. These artifacts will not be considered as working group milestones or deliverables.

The diff link is http://www.mergely.com/RehoJJvW/?wl=1 <http://www.mergely.com/RehoJJvW/?wl=1> and the diff file is attached. If there are not major objections to the updates (which there have not been to the other changes), I would like to formally request that the BoF chairs consider this text as the proposal for WG charter and call for consensus on its adoption and submission to the IESG.

Thanks to everyone who provided input and feedback!
 — Justin