Web Payments Working Group

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.

TPAC 2022 will be a hybrid event: in-person in Vancouver, with remote participation. I believe more than 600 people have registered, and it looks like more than 350 people will attend in person. This will be my first in-person meeting in about 3 years.

I have been working with multiple groups on a coordinated agenda about payments, authentication, and fraud prevention:

• Monday and Tuesday morning: Web Payments Working Group
• Tuesday afternoon: joint meeting of WPWG, Web Payment Security Interest Group, Web Authentication WG, and Antifraud CG
• Wednesday afternoon: Breakout sessions
• Thursday: Web Payment Security IG, with joint discussion about payment fraud patterns with the Antifraud CG. That agenda link requires W3C Member access.

I’m looking forward to discussion about Secure Payment Confirmation (SPC). We expect to hear about a pilot from Airbnb/Adyen, emerging support for SPC on Android, and other industry perspectives about the current version as well as next use cases.

I’ll summarize the meetings in a few weeks!

In early May the Web Payments Working Group held an energetic remote meeting; see the agenda and minutes.

While we were meeting, the FIDO Alliance released a press release with headline Apple, Google and Microsoft Commit to Expanded Support for FIDO Standard to Accelerate Availability of Passwordless Sign-Ins. This type of strong industry support for Web Authentication/FIDO is very exciting because Secure Payment Confirmation (SPC) builds on those technologies and benefits from the momentum.

In preparation for advancing SPC to Candidate Recommendation we have been working through our issues list and stabilizing the version 1 feature set. We closed 7 issues in the past month including through joint discussion with the Privacy Interest Group and the Web Authentication Working Group. We have also labeled some issues as “after version 1.” See below for details about how we plan to manage the remaining 10 issues.

At the meeting we heard a bit about recent changes to the Chrome implementation of SPC and upcoming plans. Modirum colleagues provided a demonstration of their EMV® 3-D Secure implementation (version 2.3) that integrates SPC. Airbnb and Adyen shared a brief update on their SPC pilot. We will continue to look for support in more browser engines and refine the specification based on feedback from pilots.

We also discussed Web Authentication more broadly. Best Buy has deployed Web Authentication for login and shared some of their experiences with the group. We also heard about some PSD2 use cases from (French bank) BPCE. In addition to SCA and dynamic linking for payments —the use case for SPC— they have similar requirements for authentication and signatures over transactions involving sensitive data. General browser support for signing transaction data with authenticators has been discussed previously in the Web Authentication Working Group; our recent joint discussion with them may re-energize the topic.

Remaining Issues

Here is a quick summary of our remaining 10 issues and how we plan to address them on the road to Candidate Recommendation.

Web Authentication Topics

The bulk of our remaining issues relate to the SPC dependency on FIDO. In some cases, we think the proper long-term solution will involve enhancements to WebAuthn and/or CTAP:

• Issue 12: support for roaming authenticators. This issue involves both UX challenges and the need for support in CTAP for silently querying roaming authenticators for available credentials.
• Issue 124: determining when to enroll the user (in a way that protects user privacy)
• Issue 157: support for a “cross-origin” bit and CTAP; issue 154 relates to this and is about user consent to allow cross-origin reuse of a credential>.
• Issue 175: impact of multi-device credentials on SPC.
• Issue 187: improving understanding of who is authenticating for whom

I expect the Working Group will try to (1) balance the desire to advance SPC to Candidate Recommendation in a timely fashion with (2) remaining in sync with FIDO advances. It may be that SPC implementations support short-term solutions to some of these issues (e.g., involving caching information) and then evolve as underlying specifications support new capabilities.

Privacy Topics

Stripe asked in issue 172 how to enable a user to opt-out of stored payment credentials for compliance with regulation such as GDPR. In scenarios where the user authenticates in a first-party context, it is straightforward to offer an opt-out feature. With SPC, authentication may happen in a third-party context where it is less obvious how best to offer an opt-out solution. We have been discussing when it would be most appropriate to provide the user with information about how to opt-out:

• At registration time.
• At transaction time, before authentication starts
• At transaction time, during authentication. Overall I’ve not heard much support for opt-out during authentication.
• At other times.

These discussions are ongoing; Stripe plans to conduct a deeper analysis of their requirements.

I raised issue 77 with the hope that we would find a technology solution to preserve privacy as SPC credentials are shared across origins. We have not found a practical technology solution. Our current plan (see pull request) is to provide guidance to relying parties and others on how to manage identifiers.

Internationalization

Our issue 93 on the localization of displayed strings is shared with other groups (including Web Authentication) whose specifications involve data outside of markup. I believe the Internationalization Working Group will seek support at the JavaScript level in the long run. In the short run, I would like to see W3C publish a standalone specification that describes how to support localizable strings, and that can be “imported” into SPC and other specifications.

UX Topics

In order to better align with EMV® 3-D Secure requirements we’ve received a request that the Chrome implementation of SPC display larger icons (issue 184). EMVCo colleagues have also suggested additional UX enhancements such as the display of additional icons.

I look forward to our next extended meeting —TPAC 2022 in Vancouver— by which time I hope that we will have reached Candidate Recommendation (or come very close).

The Web Payments Working Group held a remote meeting 25-28 October (agenda, minutes) as part of TPAC 2021.

The meeting took place one week after TPAC breakouts, which included sessions I think were of particular interest to the payments industry, including: Anti-Fraud for the Web, The State of Web Monetization, Cross-Device Security (caBLE), The state of browser storage partitioning, and The intersection of Web Monetization, the Creative Economy and Diversity. Some of these topics infused the Working Group agenda.

The main themes of our agenda were: strong authentication, user recognition and privacy, and Payment Request reviews. In addition, we heard updates on two incubation topics: Google on Digital Goods API and Coil on Web Monetization.

Strong Authentication

On Monday we jumped into discussion about Secure Payment Confirmation (SPC), our primary deliverable related to strong customer authentication (SCA). The Chrome team reported on implementation status, including the fact that SPC support now ships in Chrome 95 stable. We also made progress on some key SPC issues.

On the second day Adyen described the SPC pilot they are currently running with Airbnb. I recommend checking out the user experience featured in Adyen’s registration video and Authentication video; descriptions are available.

We met with the Web Authentication Working Group on the third day to discuss care and feeding of the relationship between SPC and Web Authentication. For example, in the current draft specification SPC credentials are FIDO credentials with subtype “payment.” SPC credentials can be used for login use cases, but (at least in the current implementation) vanilla Web Authentication credentials cannot be used with SPC. In the current model, it is not possible to alter the nature of existing credentials (from vanilla-to-SPC or vice versa). This led to conversations about whether the ecosystem might find itself creating SPC credentials “by default” to make them useful for both login and payments. We also discussed ways to help FIDO server operators avoid accidentally allowing an SPC credential to be used for login use cases.

The Web Authentication Working Group also shared their vision for new features in WebAuthn Level 3, including:

• Delegation (of authentication rights to others).
• User experience improvements. Relying parties may at time hesitate to use Web Authentication because they don’t know whether there is a credential on the current device. The label “non-modal UI” was used to refer to mechanisms that would help create an acceptable user experience without revealing device information to the relying party.
• Support for relying parties signaling a desire for re-authentication.
• Backups and recovery, including potentially synchronizing keys across boundaries (that is, not requiring all keys be hardware-bound).

In the current implementation of SPC, any SPC credential may be used by any origin to initiate an authentication ceremony. During the meeting it was suggested that some relying parties might want to benefit from the transaction confirmation dialog, but might not want other origins to be able to initiate the authentication ceremony. (Following the meeting we logged this as Issue 157: Consider separating the SPC powers of Third Party invocation and Payment display.)

That topic in turn suggested that the current implementation of the SPC credential as a “payment” subtype may not suffice. And the current implementation prevents credential behavior from changing over time: a credential cannot start life as a login credential, be changed with user consent into a login+payment credential, have the login power revoked, etc. I anticipate ongoing productive discussions with the Web Authentication Working Group about which functionalities migrate from SPC to Web Authentication and keeping everything in sync.

User Recognition and Privacy

SPC is gaining traction as our mechanism for strong customer authentication for Web payments. However other user recognition use cases also remain of high interest. At least for now there seem to be two important user recognition use cases:

• Risk calculations. For example, the EMV® 3-D Secure Protocol “frictionless flow” relies on data collection for risk assessment, and some aspects of that data collection may become more difficult as browser behaviors change around cookies. (We had already begun to document some requirements related to EMV® 3-D Secure.)
• Stored user profile information available cross-origin. Some applications want to know who the user is in order, for example, to display that user’s available payment instruments.

For the risk calculation use case, our colleague from Entersekt described the pertinent question this way: Have I seen this user on this device with this instrument, and has the user consented to be identified with this device to make this payment experience better? We heard that billions of transactions fail due to inadequate risk assessment, and so this is a serious problem that requires attention.

Can we devise a browser capability to help minimize friction in the user payment experience (e.g., no additional challenge to the user after pushing the “pay” button, no redirects to a first party context) while protecting the user’s privacy (e.g., by not sharing strongly identifying information silently across origins)? We acknowledged that there are other anti-fraud use cases that might (or might not) overlap in scope so we should join those discussions. We also recognized the need to be attentive to the potential for abuse of any strongly identifying capability.

We lightly discussed several ideas during the meeting (please refer to the minutes) and it is clear that there is strong interest in more discussion of these use cases.

For conversations about both SPC and user recognition, we were fortunate to meet with representatives from both the W3C Privacy Interest Group and the Privacy Community Group.

Payment Request Reviews

The W3C Membership recently reviewed Proposed Recommendations for Payment Request API and Payment Method Identifiers; I hope that we will soon wrap up our work on those specifications.

We met with the Internationalization Working Group during our meeting to discuss approaches to support the internationalization of human-readable strings in specifications (both Payment Request (pull request 971) and SPC (issue 93)). The Internationalization Working Group seeks to define a Web-wide approach for specifications to define human-readable strings and so the Web Payments Working Group will likely adopt it as the proposal advances.

Next Steps

I think these are the main next steps for the Working Group:

• Publish version 1 Recommendations of Payment Request and Payment Method Identifiers.
• For SPC:
  • Address SPC issues
  • Make improvements based on pilots from Adyen/Airbnb and Stripe
  • Seek implementation in other browsers, and flesh out the test suite to encourage interoperability.
  • Continue to coordinate with the Web Authentication Working Group, Web Payment Security Interest Group, and horizontal review groups.
• Refine use cases and requirements around user recognition use cases. (Following the meeting an Anti-Fraud Community Group was launched.)
• Recharter. I hope to send our draft charter for W3C Member review within the next month.

A Moment of Gratitude

At the meeting, Adrian Hope-Bailie announced to the Working Group that he plans to step down as co-Chair (but remain involved). The Working Group shared their appreciation of Adrian’s commitment. I would like here to emphasize how important Adrian has been to this project and to the Web. And we’ve had great fun. Thank you, Adrian!

We are building the agenda of the Web Payments Working Group’s next virtual meeting, 25-28 October. The meeting is part of TPAC 2021, and so are planning several joint discussions with other W3C groups, notably on topics of Web Authentication, Internationalization, and Privacy. In addition to those conversations, our main focus will be Secure Payment Confirmation (SPC). I anticipate we will discuss SPC experiments (Adyen/Airbnb and Stripe), the integration of SPC into EMV® 3-D Secure version 2.3, other potential integrations, and deployment status in Chrome.

We typically organize some future looking sessions. This time around Coil is leading a discussion on “Unlocking the Potential of the Internet of Value”. A session like this is particularly timely because we are in the process of rechartering the group and want to be sure that we can accommodate emerging participant interests.

I expect our agenda to solidify over the next couple of weeks, so check back soon.