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FAPI_Meeting_Notes_2025 07 30_Atlantic

Nat Sakimura edited this page Jul 10, 2026 · 1 revision

FAPI Working Group Meeting Notes

Date: July 30, 2025
Time: 14:00 GMT
Chair: Nat Sakimura

Attendees

  • Nat Sakimura (Chair)
  • Dave Tonge
  • Joe DeCock
  • Filip Skokan
  • Peter Stanley
  • George Fletcher
  • Joseph Heenan (OIDF & Authlete)
  • Brian Campbell
  • Dima Postnikov
  • Imran Ulghar (OBL)
  • Takahiko Kawasaki
  • Kosuke Koiwai
  • Hideki Ikeda
  • Christopher Robbertse
  • Robert Gallagher (Mastercard)

1. Roll Call and Agenda Adoption

Meeting called to order with roll call completed. Agenda adopted as presented.

2. Events

Upcoming Events (reported by Mike Leszcz via Nat):

  • September 8-10: Finance of Tomorrow - Rio de Janeiro
    • Mark Haine and Domingos Creado representing OIDF
  • October 13-16: FIDO Authenticate - Carlsbad, CA
    • Mike Jones likely to represent OIDF
  • October 27: OIDF events including after lunch workshop prior to IIW
    • Host still TBC
  • October 28-30: IIW Fall 2025 - Mountain View
  • November 1-7: IETF 124 Montreal
  • Following week: Web Conference in Lisbon

The OIDF calendar on website is current.

3. Ecosystem Engagement & Liaisons

Ecosystem Support Community Group Update (Dima Postnikov)

  • Kickoff meeting held July 28th
  • Next meeting: August 15th (Pacific call) - 10am Sydney / August 14th 5pm PT/8pm ET
  • Two calls per month: one EU-friendly, one US-friendly (Australia in the middle)
  • Focus on supporting existing and new ecosystems beyond specific specifications
  • Covers conformance testing and rollout requirements
  • Currently in admin phase with participation agreements being signed
  • All ecosystem partners welcome to participate

Recent IETF Developments

  • RFC 7523bis updates discussed above
  • Attestation-based client authentication progressing
  • No other immediately relevant updates for FAPI working group

Foundation Coordination Needs

  • Sync required with IPSE working group on authentication-only requirements
  • Nat to engage with Aaron on IPSE alignment
  • Consider whether separate authentication profile warranted

Joe DeCock Announcement

Joe announced Duende's launch event for IdentityServer SDK version 7.3:

Japan Update

  • Public consultation on customer authentication for stock trading systems open until August 18th
  • Financial Services Agency requiring phishing-resistant authentication methods
  • Expected to end screen scraping and require APIs instead
  • One push towards achievement of original FAPI work group objectives

4. Member Reminders

  • Vote on JARM Errata: Open until August 4th
  • Shared Signals Specifications Vote: Currently active

5. Pull Requests (Dave Tonge)

  • Most PRs discussed in previous call
  • Issue #290 has sufficient approvals but cannot be merged due to conflicts
  • Dave to address merge conflicts across affected PRs

PR #529 Discussion (Joe DeCock)

  • Discussion of PR waiting on RFC 7523bis status
  • Filip confirmed dependency on RFC 7523bis reaching working group last call
  • Joe to revisit PR, address comments, and prepare for next meeting discussion

6. RFC 7523bis Update (Filip Skokan & Brian Campbell)

Key Developments from IETF Madrid

  • Authors requesting FAPI working group feedback on draft
  • Significant changes published around July 23rd
  • Several open issues addressing overly restrictive language concerns
  • Repository: https://github.com/oauth-wg/draft-ietf-oauth-rfc7523bis
  • Specific focus needed from Joe and Dave (FAPI 1 implementers)

Major Proposed Changes

Audience and Type Requirements:

  • Original proposal required string-only audience and mandatory type claim
  • Feedback from ecosystems indicated this would be breaking change
  • New proposal (PR #15): Relaxed requirements allowing array or string audience
  • AS must enforce exactly one audience value matching issuer identifier
  • Removes mandatory type requirement to avoid breaking existing clients

FAPI 1 Impact Assessment

Peter Stanley's Concerns:

  • UK Open Banking just completed migration to final FAPI 1
  • Need consolidated view of all proposed FAPI 1 changes
  • Require strong justification for any breaking changes
  • Request for clear communication timeline and delivery mechanism

Dave Tonge's Observations:

  • Major change affects audience handling in private key JWT assertions
  • Current ecosystems may need type claim additions
  • Significant change requiring early communication to ecosystems

Working Group Consensus:

  • Bring comprehensive FAPI 1 review back to working group table
  • Consolidate all pending changes for holistic assessment
  • Consider whether changes warrant FAPI 1.1 vs errata approach
  • Schedule dedicated discussion time with full team availability

7. Client Authentication Methods Discussion

Attestation-Based Client Authentication

  • Draft progressing toward finalization at IETF
  • Potential inclusion in FAPI as acceptable client authentication method
  • Complements rather than replaces existing methods (dynamic client registration, OpenID Federation)

Ecosystem Complexity Concerns (George Fletcher)

  • Multiple overlapping solutions: client attestation, OpenID Federation, dynamic client registration
  • Authorization server complexity from supporting multiple combinations
  • Risk of market fragmentation if providers choose different subsets
  • Question of whether foundation should provide guidance

Working Group Discussion Points

  • Solutions not mutually exclusive - can be used in combination
  • Client attestation addresses mobile app challenges with dynamic client registration
  • Need to balance innovation with implementation complexity
  • Consideration of formal methods validation for new combinations

8. Issues Discussion

Issue #737: FAPI Without Long-Lived API Access (Dave Tonge)

Context:

  • Some identity ecosystems only need ID token exchange
  • Want to use FAPI for security benefits without API access requirements
  • Question of relaxing sender-constraining requirements for unused access tokens

Mark's Comment:

  • Current sender-constraining requirements "pointless" when no resource server used
  • Suggests relaxation for cases where resource servers not accessed

Working Group Analysis:

Dima's Perspective (Connect ID ecosystem):

  • Currently implement sender-constraining for conformance testing only
  • Not used in production as no resource servers accessed
  • Request for conformance testing guidance/customization options
  • Distinction between spec changes vs testing flexibility

Filip's Security Concerns:

  • Relaxing requirements would require new attacker model analysis
  • Risk of clients avoiding MTLS/DPoP by claiming no resource access
  • Even authentication-only flows may access userinfo endpoint (resource server)
  • Formal methods validation needed for any relaxations

George's IPSE Context:

  • Similar issues in IPSE SL1 profile (authentication only)
  • Question of whether separate authentication profile needed
  • Challenge of keeping multiple profiles synchronized
  • IPSE participants resist DPoP/MTLS complexity for SSO use cases

Implementation Reality:

  • Connect ID forces participants to support sender-constraining for testing
  • Anticipates future resource endpoint requirements
  • Prefer evolutionary approach within existing spec

Issue #706: Signature Requirements

  • Takahiko added elaborate comments with diagrams
  • Deferred to next meeting for detailed review

9. Versioning Discussion

  • Nat's preference for FAPI 2.1 rather than errata for new features
  • Recognition that new functionality represents feature addition, not bug fix

Action Items

  1. Dave Tonge: Address merge conflicts in pending PRs
  2. Joe DeCock:
    • Review and update PR #529
    • Prepare for next meeting discussion
    • Review RFC 7523bis draft and provide feedback
  3. All esp. Dave Tonge: Review RFC 7523bis repository for open PRs and assess impacts
  4. Dave Tonge: Add RFC 7523bis PR link to Issue #714 for community feedback
  5. Working Group: Schedule dedicated FAPI 1 consolidation discussion
  6. All: Review Issue #706 (Takahiko's diagrams) for next meeting
  7. Nat Sakimura: Engage with Aaron on IPSE working group alignment

Next Meeting

  • Continue RFC 7523bis feedback discussion
  • FAPI 1 comprehensive review
  • Issue #706 detailed analysis
  • Follow up on ecosystem authentication requirements

Meeting adjourned with thanks to all participants for productive and informative discussion.

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