This group is chartered to develop a fine-grained delegation protocol for authorization, API access, user identifiers, and identity assertions. The protocol will also allow the client to present unverified identifiers and verifiable assertions to the AS as part of its request. 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 channels used by the protocol participants to communicate 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 protocol will include a means of specifying how the user can potentially be involved in an interactive fashion during the delegation process. The client and Authorization Server (AS) will use these interaction mechanisms to involve the user, as necessary, to make authorization decisions. 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. The group will seek to minimize assumptions about the form of client applications, allowing 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 - Multiple access tokens in a single request and response - AS-directed dispatch of access tokens to the appropriate RS - Separation between the party authorizing access and the party operating the client requesting access 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 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 (including identifiers and identity assertions) through the delegation process Additionally, the group will provide mechanisms for management of the protocol lifecycle including: - Discovery of the authorization server - Revocation of active tokens - Data model for granted access and mechanisms for the AS and RS to communicate the granted access model 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 directed to 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 existing 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. The initial work will focus on using HTTPS for communication between the client and the authorization server, taking advantage of optimization features of HTTP/2 and HTTP/3 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 - (if needed) Guidelines on migration paths, implementation, and operations 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 working group will cooperate and coordinate with other IETF WGs such as OAUTH, and work with external organizations, such as the OpenID Foundation, as appropriate.