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FAPI_Meeting_Notes_2025 12 11_Pacific

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

FAPI WG Agenda & Meeting Notes (2025-12-11)

Date & Time: 2025-12-11 17:00 PST

Attendees

  • Anoop

Agenda

  1. Roll Call
  2. Adoption of Agenda
  3. Events
  4. External Orgs & Liaisons
  5. PRs
  6. Issues
  7. AOB

Meeting Notes

1. Roll Call & Agenda Adoption

2. Events Update

** Events Updates ***

Q1 2026 Events Added to Calendars

  • March 9-13: ISO/IEC JTC 1/SC 27 Working Group Meeting – Nürnberg, Germany
  • March 14-20: IETF 125 – Shenzhen, China
  • March 16-17: ISO/IEC JTC 1/SC 27 Plenary – Nürnberg, Germany

Action Item

Please send any 2026 events to be added to the calendar to mike.leszcz@oidf.org

3. External Organizations & Liaisons

Ecosystem Engagement

  • End-of-year coordination calls are being scheduled with all ecosystem partners for input into 2026 planning and budgeting
  • Some meetings have been completed; others are being coordinated
  • No specific ecosystem updates were reported

4. FAPI Working Group Updates

2026 OIDF Board Elections Schedule

  • December 8: Blog to be published noting nominations open with full details
  • December 26: Nominations close
  • December 29: 2026 elections begin
  • January 12: 2026 elections conclude

ITU Submission (Bjorn Hjelm)

Update on the ITU submission:

  • FAPI 2.0 Security Profile and FAPI 2.0 Attacker Model have been submitted to ITU
  • The documents will be discussed for adoption at the upcoming ITU meeting (December 3–11, 2024)
  • Bjorn will attend remotely to represent the submissions (not traveling to Geneva)
  • The documents were reformatted to ITU template format, similar to how OpenID Connect Core was reformatted previously
  • The FAPI 2.0 specs were simpler to reformat than the larger OpenID Connect Core specification
  • The main effort involved correcting references, as ITU handles normative vs. informative bibliography differently from OpenID conventions
  • ITU uses "incorporation by reference" rather than standard reference formatting

5. Issues Discussion

Issue: Cryptographic Algorithms and Key Lengths

Background:

  • FAPI 1 has specific requirements for key lengths:
    • RSA: 2048 bits
    • Elliptic Curve: 160 bits
  • These values are becoming inadequate and will be insufficient in a few years

ISO Feedback:

  • Suggested referencing a living document that gets timely updates rather than hard-coding values in the spec itself
  • FAPI already does this for algorithms but not for key lengths

Current Recommendations (FIPS 186-5):

  • RSA: 3072 bits (vs. FAPI 1's 2048)
  • Elliptic Curve: 256 bits (vs. FAPI 1's 160)

Considerations:

  • Changes would impact existing ecosystems using FAPI 1
  • Open Banking UK has indicated they will continue using FAPI 1 for 5–6 more years
  • Other ecosystems are planning to move to FAPI 2
  • BCP 195 is referenced for algorithms but doesn't provide key length guidance
  • FAPI 2 comments from ISO haven't come back yet
  • With FAPI 2 being submitted to ITU, key length requirements should be verified

Action Items:

  • Nat to proactively reach out to Open Banking UK for their input
  • Working group members to provide feedback on the issue
  • Verify FAPI 2 key length requirements before ITU submission

Issue: Browser Swapping Attack

Background:

  • Discussed at the working group meeting on November 3rd/4th
  • Introduced as a novel attack, but was actually discussed 2–3 years ago
  • Dave has linked the full discussion thread in the issue

Technical Details:

  • Involves a scenario where the user agent is taken over by an attacker
  • Not much can be done in this attack scenario
  • During formal analysis, the attacker's capabilities were weakened slightly to prove security

Resolution:

  • May add to security considerations section
  • Issue to remain open until the OAuth thread discussion is complete

Issue: Non-Standard TLS Port for Conformance Testing

Background:

  • Issue about whether conformance testing should allow non-standard TLS ports

Discussion:

  • Understandable that developers might use non-standard ports for development servers
  • For public-facing servers, using non-standard ports doesn't make sense
  • Since FAPI certification is about real deployment testing, standard port should be required

Consensus Direction:

  • Require port 443 for TLS for certification
  • Open question: Should this be mandated in the spec itself?

Action: Working group members to provide opinions on the issue; will revisit next week

Issue: RFC 9207 – IdP Mix-Up Attack

Background:

  • Comment asking for use of RFC 9207 for IdP mix-up attack protection

Technical Context:

  • RFC 9207 defines AS (Authorization Server) identifier
  • The IDP mix-up attack primarily affects OAuth 2.0 servers that don't have issuer identifier
  • FAPI 1 uses OpenID Connect, which already has issuer identifier
  • OpenID Connect is not subject to this attack when using hybrid flow
  • The issuer identifier goes into the authorization server metadata

Discussion:

  • Could potentially add to security considerations
  • May be relevant to FAPI 2 if not already addressed
  • Formal analysis was done by the team that discovered the IdP mix-up attack, so should catch any issues

7. PR Discussion

PR #552 – ISO Editorial Comments

  • THis PR has conflicts and recommendation is to create separate new PR for remaining minor fixes (hyphen leftovers, capitalization).

8. Any Other Business

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