Thanks all for your great input and careful consideration, but I wanted to officially close the loop on this thread that we no longer plan to ship PRTs given the decision not to ship IP Protection.
Eric On Wed, Aug 20, 2025 at 11:07 AM Yoav Weiss (@Shopify) < [email protected]> wrote: > LGTM3 > > I'd have loved getting more feedback from the broader community on this, > but given the fact that the team is willing to ship breaking changes to the > feature based on future feedback, that's an acceptable risk. > > On Wednesday, August 20, 2025 at 5:02:20 AM UTC+2 Rick Byers wrote: > >> On Tue, Aug 19, 2025 at 7:08 AM eric trouton <[email protected]> >> wrote: >> >>> Hi folks, >>> >>> Yoav, thank you for your suggestions, we reached out to the MASQUE >>> listserv for feedback and responded >>> <https://github.com/w3ctag/design-reviews/issues/1125#issuecomment-3186532009> >>> to TAG reviewers with more details about the utility and privacy >>> properties. >>> >>> Rick, as to your question, we have a reference implementation >>> <https://github.com/explainers-by-googlers/prtoken-reference> (covering >>> issuance, re-randomization & decryption), with tooling support for websites >>> that can easily be used to validate other implementations. We commit to >>> providing more conformance test support if another browser expresses >>> interest in building PRTs. >>> >> >> Thanks, that's good enough for me in this case. None of the other engines >> seem to be investing in balanced anti-fraud features like this so while I'd >> love there to be an automated conformance test suite for this somewhat >> unconventional API, I don't feel it's reasonable to ask for it as a >> condition of shipping. But please keep your ears open, perhaps interest >> from other engines will materialize if major sites start to challenge users >> more when using IP anonymization from a browser without PRT support. >> >> LGTM2 >> >> To be clear, we are committed to responding to ecosystem needs and >>> evolving PRTs over time. >>> >>> Finally, thank you Scott and David for commenting about your interest in >>> testing PRTs! >>> >>> Thanks all, >>> >>> >>> Eric >>> >>> >>> On Mon, Aug 18, 2025 at 4:09 PM Rick Byers <[email protected]> wrote: >>> >>>> Thank you Scott (and David), understanding the developer adoption >>>> interest is really helpful in weighing the tradeoffs around enabling this >>>> by default in Chromium! >>>> >>>> Rick >>>> >>>> On Mon, Aug 18, 2025 at 12:23 PM Scott Pierce <[email protected]> >>>> wrote: >>>> >>>>> Integral Ad Science (IAS) is looking forward to testing PRTs to >>>>> determine the impact obfuscated IPs within Incognito sessions may have on >>>>> ad fraud. >>>>> >>>>> Cheers, >>>>> Scott Pierce, Head of Fraud >>>>> Integral Ad Science >>>>> >>>>> On Monday, August 18, 2025 at 11:02:24 AM UTC-7 Rick Byers wrote: >>>>> >>>>>> On Fri, Aug 8, 2025 at 2:39 PM 'David Turner' via blink-dev < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> As a member of Google's Ad Traffic Quality team, we're excited to >>>>>>> see the development of PRTs and to better understand ad fraud in IP >>>>>>> protected traffic. >>>>>>> >>>>>>> On Wed, Aug 6, 2025 at 8:31 AM Yoav Weiss (@Shopify) < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> Presenting this to various IETF groups in November sounds like a >>>>>>>> good idea, but it'd be great to try and shorten the feedback loop and >>>>>>>> shop >>>>>>>> around this I-D with relevant IETF mailing list. >>>>>>>> >>>>>>>> That would enable the relevant communities to give this some >>>>>>>> attention and provide some feedback before it ships. >>>>>>>> >>>>>>>> On Wednesday, August 6, 2025 at 4:45:27 PM UTC+2 Mike Taylor wrote: >>>>>>>> >>>>>>>>> LGTM1 >>>>>>>>> >>>>>>>>> I think this strikes the right balance between protecting users >>>>>>>>> from known trackers and the ability to detect fraud and abuse. I'm >>>>>>>>> not sure >>>>>>>>> that 10% reveal after 24 hours is the magic recipe, but appreciate >>>>>>>>> that >>>>>>>>> these are configurable such that the team will be able to adapt to >>>>>>>>> feedback >>>>>>>>> / new information. >>>>>>>>> >>>>>>>>> aside: I don't think we need to block on TAG review here, but >>>>>>>>> encourage the team to follow up with the relevant IETF groups to get a >>>>>>>>> broader review on the design. >>>>>>>>> On 8/1/25 12:48 p.m., 'Theodore Olsauskas-Warren' via blink-dev >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>> Thanks for the feedback, Reilly. While the original IP Protection >>>>>>>>> feature’s TAG review covers some ground on PRTs, you’re right that >>>>>>>>> it’s >>>>>>>>> possible the TAG may want to weigh in differently on PRTs >>>>>>>>> specifically as >>>>>>>>> opposed to IP Protection generally. We’ve filed a TAG request here >>>>>>>>> <https://github.com/w3ctag/design-reviews/issues/1125>. >>>>>>>>> >>>>>>>>> At the same time, we also recognize that the protocol introduced >>>>>>>>> here is likely best reviewed in an IETF forum, and would just flag for >>>>>>>>> reviewers that we do hope to pursue discussions at IETF 124 this fall. >>>>>>>>> >>>>>>>>> Theo. >>>>>>>>> On Tuesday, July 29, 2025 at 11:13:10 AM UTC-7 Reilly Grant wrote: >>>>>>>>> >>>>>>>>>> Can you request a separate TAG review for this feature? The TAG's >>>>>>>>>> response to the IP protection review request seemed to be about >>>>>>>>>> standardizing the complete system. However this individual piece >>>>>>>>>> could be >>>>>>>>>> adopted by other browsers even if their particular implementations >>>>>>>>>> of a >>>>>>>>>> complete IP protection system are implementation-specific. >>>>>>>>>> Reilly Grant | Software Engineer | [email protected] | Google >>>>>>>>>> Chrome <https://www.google.com/chrome> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Mon, Jul 28, 2025 at 1:52 PM 'Theodore Olsauskas-Warren' via >>>>>>>>>> blink-dev <[email protected]> wrote: >>>>>>>>>> >>>>>>>>>>> Contact emails >>>>>>>>>>> >>>>>>>>>>> [email protected], [email protected], [email protected], >>>>>>>>>>> [email protected], [email protected], [email protected] >>>>>>>>>>> >>>>>>>>>>> Explainer >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> https://github.com/GoogleChrome/ip-protection/blob/main/prt_explainer.md >>>>>>>>>>> >>>>>>>>>>> Specification >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> https://datatracker.ietf.org/doc/html/draft-pfeiffenberger-prtokens-00 >>>>>>>>>>> >>>>>>>>>>> Summary >>>>>>>>>>> >>>>>>>>>>> To enable businesses to estimate the amount of fraud on their >>>>>>>>>>> systems, train models to defend against fraud, and analyze emerging >>>>>>>>>>> fraudulent behavior while still mitigating the ability to track >>>>>>>>>>> users at >>>>>>>>>>> scale using IP addresses, we propose the introduction of a delayed >>>>>>>>>>> IP >>>>>>>>>>> sampling mechanism called Probabilistic Reveal Tokens (PRTs) >>>>>>>>>>> alongside IP >>>>>>>>>>> Protection for use in proxied traffic. Chrome plans to launch IP >>>>>>>>>>> Protection <https://github.com/GoogleChrome/ip-protection> in >>>>>>>>>>> incognito mode later this year. >>>>>>>>>>> >>>>>>>>>>> PRTs will be included on proxied requests in a new HTTP header >>>>>>>>>>> added by the browser for domains that indicate they want to receive >>>>>>>>>>> them >>>>>>>>>>> via a signup process. Each PRT contains a ciphertext, generated by >>>>>>>>>>> an >>>>>>>>>>> Issuer and re-randomized by the browser for unlinkability prior to >>>>>>>>>>> the >>>>>>>>>>> request, that the recipient can decrypt after a delay. Google will >>>>>>>>>>> be the >>>>>>>>>>> issuer for Chrome's implementation. A minority of the decrypted PRTs >>>>>>>>>>> contain the client's pre-proxy IP address (i.e. non-masked, and as >>>>>>>>>>> observed >>>>>>>>>>> by the token issuer), while the remaining PRTs provide no >>>>>>>>>>> information about >>>>>>>>>>> the client's original IP address. This results in only a small >>>>>>>>>>> percent of >>>>>>>>>>> PRTs containing and revealing the user's IP. >>>>>>>>>>> >>>>>>>>>>> Our explainer introduces key tunable parameters >>>>>>>>>>> <https://github.com/GoogleChrome/ip-protection/blob/main/prt_explainer.md#tunable-parameters> >>>>>>>>>>> for this proposal: >>>>>>>>>>> >>>>>>>>>>> - >>>>>>>>>>> >>>>>>>>>>> Reveal rate: the percentage of the time that the tokens are >>>>>>>>>>> revealed >>>>>>>>>>> - >>>>>>>>>>> >>>>>>>>>>> Epoch and delay period length: the periods after which >>>>>>>>>>> tokens are made available >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> We will initially set reveal rate to 10% and epoch and delay >>>>>>>>>>> period length both to 24 hours each. >>>>>>>>>>> >>>>>>>>>>> Developers that want to receive PRTs will need to request them >>>>>>>>>>> at console.privacysandbox.google.com. Sign ups will open when >>>>>>>>>>> PRTs are available in pre-Stable channels. >>>>>>>>>>> >>>>>>>>>>> Blink component >>>>>>>>>>> >>>>>>>>>>> Privacy>Fingerprinting>IPProtection >>>>>>>>>>> <https://issues.chromium.org/issues?q=customfield1222907:%22Privacy%3EFingerprinting%3EIPProtection%22> >>>>>>>>>>> >>>>>>>>>>> TAG review >>>>>>>>>>> >>>>>>>>>>> The IP Protection TAG review, for which this feature is closely >>>>>>>>>>> tied, was closed by the TAG as “Resolution: Decline” ( >>>>>>>>>>> https://github.com/w3ctag/design-reviews/issues/1083) >>>>>>>>>>> >>>>>>>>>>> TAG review status >>>>>>>>>>> >>>>>>>>>>> Resolution Decline >>>>>>>>>>> >>>>>>>>>>> Risks >>>>>>>>>>> >>>>>>>>>>> Interoperability and Compatibility >>>>>>>>>>> >>>>>>>>>>> None >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Gecko: No signal ( >>>>>>>>>>> https://github.com/mozilla/standards-positions/issues/1273) >>>>>>>>>>> >>>>>>>>>>> WebKit: No signal ( >>>>>>>>>>> https://github.com/WebKit/standards-positions/issues/529) >>>>>>>>>>> >>>>>>>>>>> Web developers: Positive signal from invalid traffic detection >>>>>>>>>>> providers, though open questions >>>>>>>>>>> <https://github.com/GoogleChrome/ip-protection/issues/81> >>>>>>>>>>> remain about the impact on fraud detection with initial parameter >>>>>>>>>>> settings. >>>>>>>>>>> As IP Protection launches, we’ll continue to solicit feedback. >>>>>>>>>>> >>>>>>>>>>> Other signals: >>>>>>>>>>> >>>>>>>>>>> WebView application risks >>>>>>>>>>> >>>>>>>>>>> Does this intent deprecate or change behavior of existing APIs, >>>>>>>>>>> such that it has potentially high risk for Android WebView-based >>>>>>>>>>> applications? >>>>>>>>>>> >>>>>>>>>>> None >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Debuggability >>>>>>>>>>> >>>>>>>>>>> Attached PRTs are visible in the Chrome DevTools Network panel. >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Will this feature be supported on all six Blink platforms >>>>>>>>>>> (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)? >>>>>>>>>>> >>>>>>>>>>> No, supported everywhere IP Protection is supported (no >>>>>>>>>>> WebView). >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Is this feature fully tested by web-platform-tests >>>>>>>>>>> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> >>>>>>>>>>> ? >>>>>>>>>>> >>>>>>>>>>> No, as there is no browser API for actuating PRTs (only a header >>>>>>>>>>> attached as part of IP Protection), we don’t plan to add any. >>>>>>>>>>> >>>>>>>>>> If another browser wanted to implement PRTs in a way compatible >>>>>> with Chrome in the future, how might they validate the compatibility of >>>>>> their implementation? This doesn't have to be WPT necessarily (though >>>>>> that >>>>>> is preferable since browsers are all trying to maximize their WPT pass >>>>>> rates). >>>>>> >>>>>>> >>>>>>>>>>> >>>>>>>>>>> DevTrial instructions >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> https://github.com/explainers-by-googlers/prtoken-reference/blob/main/prt_dev_testing.md >>>>>>>>>>> >>>>>>>>>>> Flag name on about://flags >>>>>>>>>>> >>>>>>>>>>> None >>>>>>>>>>> >>>>>>>>>>> Finch feature name >>>>>>>>>>> >>>>>>>>>>> EnableProbabilisticRevealTokens - Note that there are many >>>>>>>>>>> subtleties to enabling this feature, please see DevTrial >>>>>>>>>>> instructions for >>>>>>>>>>> enabling locally. >>>>>>>>>>> >>>>>>>>>>> Rollout plan >>>>>>>>>>> >>>>>>>>>>> Will ship enabled for all users >>>>>>>>>>> >>>>>>>>>>> Requires code in //chrome? >>>>>>>>>>> >>>>>>>>>>> False >>>>>>>>>>> >>>>>>>>>>> Launch bug >>>>>>>>>>> >>>>>>>>>>> https://launch.corp.google.com/launch/4367692 >>>>>>>>>>> >>>>>>>>>>> Estimated milestones >>>>>>>>>>> >>>>>>>>>>> Shipping on desktop >>>>>>>>>>> >>>>>>>>>>> 140 >>>>>>>>>>> >>>>>>>>>>> DevTrial on desktop >>>>>>>>>>> >>>>>>>>>>> 138 >>>>>>>>>>> >>>>>>>>>>> Shipping on Android >>>>>>>>>>> >>>>>>>>>>> 140 >>>>>>>>>>> >>>>>>>>>>> DevTrial on Android >>>>>>>>>>> >>>>>>>>>>> 138 >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Anticipated spec changes >>>>>>>>>>> >>>>>>>>>>> None >>>>>>>>>>> >>>>>>>>>>> Link to entry on the Chrome Platform Status >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> https://chromestatus.com/feature/4914046966693888?gate=6289919137546240 >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> -- >>>>>>>>>>> >>>>>>>>>>> Theodore Olsauskas-Warren >>>>>>>>>>> >>>>>>>>>>> Software Engineering Manager >>>>>>>>>>> >>>>>>>>>>> [email protected] >>>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>>> You received this message because you are subscribed to the >>>>>>>>>>> Google Groups "blink-dev" group. >>>>>>>>>>> To unsubscribe from this group and stop receiving emails from >>>>>>>>>>> it, send an email to [email protected]. >>>>>>>>>>> To view this discussion visit >>>>>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CA%2B0Xr79QUTJt7bi443Ax5eMD2z%3DCsqV0o4__0tNvqKbMmLb5fg%40mail.gmail.com >>>>>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CA%2B0Xr79QUTJt7bi443Ax5eMD2z%3DCsqV0o4__0tNvqKbMmLb5fg%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>>>>> . >>>>>>>>>>> >>>>>>>>>> -- >>>>>>>>> You received this message because you are subscribed to the Google >>>>>>>>> Groups "blink-dev" group. >>>>>>>>> >>>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>>> send an email to [email protected]. >>>>>>>>> To view this discussion visit >>>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/98e6b10c-f5c5-4852-b4b5-ff4da46c43bdn%40chromium.org >>>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/98e6b10c-f5c5-4852-b4b5-ff4da46c43bdn%40chromium.org?utm_medium=email&utm_source=footer> >>>>>>>>> . >>>>>>>>> >>>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "blink-dev" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to [email protected]. >>>>>>>> To view this discussion visit >>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/17308ea5-3320-4d26-bc1f-067615267ccdn%40chromium.org >>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/17308ea5-3320-4d26-bc1f-067615267ccdn%40chromium.org?utm_medium=email&utm_source=footer> >>>>>>>> . >>>>>>>> >>>>>>> -- >>>>>>> You received this message because you are subscribed to the Google >>>>>>> Groups "blink-dev" group. >>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>> send an email to [email protected]. >>>>>>> >>>>>> To view this discussion visit >>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAODJ6YNy664F2PP%2BDYmFbA682fgG%2BOG56f5A%2BDt826x2WU4zRw%40mail.gmail.com >>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAODJ6YNy664F2PP%2BDYmFbA682fgG%2BOG56f5A%2BDt826x2WU4zRw%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>> . >>>>>>> >>>>>> >>>>> ------------------------------ >>>>> This message (including any attachments) may contain confidential, >>>>> proprietary, private and/or privileged information. The information is >>>>> intended to be for the use of the individual or entity designated above. >>>>> If >>>>> you are not the intended recipient of this message, please notify the >>>>> sender immediately, and delete the message and any attachments. Any >>>>> disclosure, reproduction, distribution or other use of this message or any >>>>> attachments by an individual or entity other than the intended recipient >>>>> is >>>>> strictly prohibited. In addition, emails sent from and to this >>>>> integralads.com >>>>> domain are monitored, archived, and subject to disclosure, including >>>>> in connection with regulatory or other legal processes. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "blink-dev" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion visit >>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAFUtAY-v52s%3DpYGCHV4YeomgB12HQ4TEX8nsWaictnzZ_EtZ4w%40mail.gmail.com >>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAFUtAY-v52s%3DpYGCHV4YeomgB12HQ4TEX8nsWaictnzZ_EtZ4w%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAHvQSR6QstjxY2zUMBDfxQwbE%2Bhij_3cwQGJHLLN5EXzmB0RiA%40mail.gmail.com.
