Google employee responds to negative feedbacks on WEI

Granted, I don't fully understand how they intend to holdback, but even if they cache the results of the attestation such that 10 calls in a row fails to attest, they can't cache it infinitely. Website can employ traditional fingerprinting techniques/cookies in combination with attestation to build pretty foolproof systems to not serve the user based on attestation results.

The overall goal for the spec is described in the comment:

> The WEI experiment is part of a larger goal to keep the web safe and open while discouraging cross-site tracking and lessening the reliance on fingerprinting for combating fraud and abuse. Fraud detection and mitigation techniques often rely heavily on analyzing unique client behavior over time for anomalies, which involves large collection of client data from both human users and suspected automated clients.

In other words, the intended goal of this spec is to discourage the development and use of fingerprinting techniques, login screens, and other invasive user-validation techniques on websites.

However, the goal of holdbacks is then described in the following way:

> This is designed to prevent WEI from becoming “DRM for the web”. Any sites that attempted to restrict browser access based on WEI signals alone would have also restricted access to a significant enough proportion of attestable devices to disincentivize this behavior. [...] The hold-back and the lack of browser identification in the response provides cover to browsers that spoof their user agents that might otherwise be treated differently by sites. This also includes custom forks of Chromium that web developers create.

In other words, one of the goals for the holdback system is to make it practically impossible for a website not to have fallback mechanisms for validating user trust when encountering requests that don't have attestation. And a essential part of that design is that even implementing browsers like Chrome will refuse to verify the environment integrity 10-15% of the time.

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So why is this a problem? Because holdbacks are on-purposed designed to make it so that fallback mechanisms have to exist and that sites can't skip including them; but the whole point of this spec as stated is to discourage developers from building those same fallbacks they're required to include because the fallbacks violate privacy or are are invasive or are essentially login walls.

And 10-15% of the time even users in participating browsers will be subjected to those fallback strategies. So you're still basically guaranteed to have your device fingerprinted, and any site that uses login as a backup verification method still will require you to make an account.

The only thing that this would affect is the frequency of user-annoyances in front of websites -- essentially, if sites started using this as a substitute for captchas, this would encourage them to drastically increase the number of captchas they use since Chrome browsers would only see 10-15% of those captchas.

And that's also a problem if you're trying to guarantee that competing browsers won't be affected, because "your users see 9x as many captchas on every website" is a pretty stinking big competitive moat.

Forgive me for thinking that "you can build a browser that competes with us, but unless we specifically approve of your browser, anyone who uses it on Android will be solving captchas over and over at a massively increased rate until they eventually give up and move back to Chrome like a good little consumer" still kind of has a lot antitrust implications.

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This proposal doesn't make sense; assuming the best of the authors I can only assume they haven't really thought through what they're trying to build. But you can not build an attestation method that simultaneously improves the web substantially for your own users over non-attestation methods, but that also magically does not hurt the web for any of your competitors who don't get those improvements.

And holdbacks only make those goals even more contradictory: because privacy, paywalls, and logins will still affect Chrome if it decides randomly that it's not going to attest to the NYT for the duration of today. The only aspect that this makes sense for is specifically user annoyances; and where annoyances are concerned an attestation method that excludes most mainstream users on unmodified devices from annoyances while leaving niche browsers out is an invitation for websites to discriminate against those browsers -- holdbacks change nothing about that situation.

You can't tell me this is about discouraging fingerprinting in the same comment that you tell me that you're going to guarantee that sites will still need to build fingerprinting solutions and will still need to use those solutions even on participating browsers.

The TLDR is that I don't see how I'm supposed to believe that this discourages sites from using invasive fingerprinting techniques if those sites are essentially required by holdbacks to still have those invasive fingerprinting techniques at the ready: and 1 in 10 requests even from a browser that implements WEI will still be subjected to those fallback techniques, so your browser/device is still basically guaranteed to be fingerprinted by any site you visit regularly.

You can't discourage the development of something and require it at the same time.

And if the experience of non-participating browsers is so much worse that it's obviously better to implement WEI, then we're right back to the same DRM and competition questions that we had before.

If holdbacks are rare enough that sites can ignore them (or statistically filter them out and determine if a browser actually implements the spec), then those sites don't need to have a fallback mechanism and we're right back to DRM. However, if holdbacks are common enough that sites can't ignore them (and if they can't statistically determine whether or not holdbacks are holdbacks or a non-implementing browser), then everyone is still going to be subjected to the fallback techniques that Google says it's trying to discourage.

Part of the job of web specification development is to determine what potential bad actors could do in the future. If a spec was proposed that easily allowed blocking users from certain countries, I would want that listed in the potential risks. Mitigations and technical requirements are introduced into specs all the time that only exist to stop a potential future attack.