TPAC Recap (2022 Edition)

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After a three-year hiatus, W3C held TPAC 2022 in person in Vancouver. It was really great to be back in person, and I heard that sentiment from just about everyone. More than 360 people registered to attend TPAC in person and another 250 joined remotely.

Below I summarize discussions of the meetings I attended: the Web Payments Working Group, the Web Payment Security Interest Group, and joint meetings with the Web Authentication Working Group and the Antifraud Community Group.

Web Payments Working Group

The Web Payments Working Group agenda opened with a focus on Secure Payment Confirmation (12 September minutes):

  • Adyen and Airbnb shared some information about their SPC pilot. The discussion led us to topics such as the importance of user education (for the new user experience), some ideas for the timing of user registration (post-transaction), and the potential value of sharing a FIDO attestation when using SPC in a delegated authentication flow.
  • Google presented their current work to bring SPC to Chrome on Android. That led to discussion about (and strong interest in) SPC availability beyond browsers in native Android apps.
  • FIS shared thoughts on three topics of interest: shops making the transition from brick and mortar to digital-first, online stores looking to create a seamless shopping experience, and merchants that prefer strong control over the user experience. Across these topics there were three main themes:
    • Merchants want to know who their customers are prior to authorization. On this point we discussed the impact of tokenization and potential benefits of ensuring that the Payment Account Reference (PAR) can be communicated during an EMV® 3-D Secure transaction that involves SPC.
    • Data is not always available based on payment types or implementations.
    • Cart abandonment is a problem due to extra friction and payment problems.
  • Microsoft shared some perspectives as a merchant that adopted strong customer authentication in Europe. They emphasized the important of frictionless authentication and indicated (as FIS also indicated) that stronger authentication can lead to cart abandonment; see the Microsoft slides for details. Key takeaways were thus that a great SCA user experience is very important (hence our emphasis on SPC) but that frictionless risk assessment is still very important. Microsoft reiterated during the talk that merchants do not like to hand over the authentication experience to banks, which, to me, reinforced the value proposition of SPC where merchant controls the authentication ceremony, and the bank can still validate the results.
  • We then revisited some EMVCo observations about SPC and some changes that the EMVCo 3-D Secure Working Group has requested, including support for non-payments use cases, recurring payments, and more alignment with user experience requirements defined in the EMV® 3-D Secure specification.

We opened the second day of the WPWG meeting (13 September minutes) with discussion about the Payment Request API, which advanced to Recommendation just before the start of TPAC. Both Apple and Google expressed interest in restoring some capabilities related to address collection that are implemented in their respective browsers, but that were removed from version 1 of the specification for privacy-related reasons. I expect the features will be re-introduced so that interoperable implementations are documented, even if not recommended in their current form. The Working Group is likely to try to evolve the feature to address the previously registered privacy concerns.

After that:

  • Apple then described some changes to ApplePay.js over the past couple of years that could be integrated into Payment Request. This was useful for helping the group develop a potential roadmap for new work on the API.
  • We then discussed some upcoming changes to browsers related to "Bounce Tracking Mitigations." Bounce tracking refers to very quick redirects from one site to another and back, usually without the user knowing that the redirect has happened. As with previous discussions about privacy-related changes to browsers (e.g., IP address masking, user agent string masking, removal of third party cookies) we discussed the likely impact on user recognition and fraud prevention.
  • In the same vein, we then heard about changes that the Chrome team plans to make to their Payment Handler implementation based on other changes on the Web related to privacy. The theme of data collection and risk mitigation continued into the Thursday joint meeting (below).

Tuesday Joint Meeting

On Tuesday afternoon, four groups met: the Web Payments WG, the Web Payment Security IG, the Web Authentication WG, and the Antifraud CG (13 September joint meeting minutes):

  • The Antifraud CG, launched in early 2022, has developed as set of use cases; these include both payments and advertising use cases. Proposals to address these use cases are emerging, and we heard about several of them during the joint meeting, in particular about device integrity attestations. We also discussed trust tokens, currently in development in the Web Incubator CG.
  • The Web Authentication Working Group summarized the state of specification and deployment of passkeys (cross-device FIDO credentials) and device public keys. I have the impression that device public keys —not yet implemented— could play an important role in payments use cases so that a Relying Party make make risk decisions based on previously seen devices. Those decisions may also rely on attestation availability, and it was pointed out that attestations are optional with Device Public Keys and may not always be available. We then discussed technology developments around a user experience question that we've heard before: if, for privacy reasons, a party cannot query the browser to determine whether the user has already enrolled credentials, how does that party know when to offer the user a registration experience?
  • In the final session of the joint meeting, we discussed the status of SPC and broached several topics of ongoing coordination with the Web Authentication WG. We heard that our proposed "cross-origin bit" is now part of FIDO CTAP (and will be made public soon). The Web Payments Working Group next needs to register the extension with IANA. The WPWG re-raised the topic of cross-origin credential creation, which is permitted in SPC but not in Web Authentication. While there is some support within the Web Authentication WG to reconsider this capability in Web Authentication Level 3, there is not yet consensus.

Antifraud discussion, in particular about Device Public Keys used for fraud prevention, continued during a Wednesday breakout on Antifraud.

Thursday Joint Meeting

On Thursday, both the Web Payment Security Interest Group and the Antifraud Community Group held individual meetings as well as a 90-minute joint session on patterns of payment fraud (15 September WPSIG/Antifraud minutes):

  • Entersekt presented some payment fraud patterns (e.g., account takeover through phishing, SIM swap, or social engineering; chargeback fraud, and card skimming attacks). We discussed current mitigation techniques (e.g., IP address monitoring) with attention to how those might be affected by privacy-related changes to browsers. As it was put in the meeting, "Browser fingerprinting is not good enough anymore." Our colleagues from Entersekt evaluated some of the Antifraud CG Proposals in development to see which might help with payments fraud use cases. I anticipate we will soon discuss a proposed new risk signal based on the joint discussion.
  • Our colleague from the University of Illinois Chicago presented findings from research Phish in Sheep's Clothing: Exploring the Authentication Pitfalls of Browser Fingerprinting. One interpretation of the research is that it illustrates the limits of current approaches data collection used for payment fraud mitigation.

We made good progress at TPAC in understanding use cases, formulating the value proposition of SPC, and emphasizing the need for more fraud prevention tools (with some useful whiteboarding in the mix). I anticipate the groups will want to meet again in person well before TPAC 2023.

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