this post was submitted on 28 Feb 2026
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Privacy
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Tangential to the main point you're going for: when you say fingerprint or biometrics I think you're referring to passkeys.
Passkeys don't share any of your fingerprint or other biometric identifiers with anyone.
https://www.eff.org/deeplinks/2023/10/passkeys-and-privacy
One of the major design criteria of their creation was to be an increase in security without sacrificing privacy. It's made them more finicky to get working but there's a very good reason they're very popular with security professionals.
They are not referring to passkeys. They’re referring to deterministic algorithms for uniquely labeling a particular device or person, despite any privacy enhancing features that device or person employed. It can be as simple as sampling various hardware specs, hashing the result, and using that as an ID for the person. So, if you switch browsers, they know it’s still you. More complex techniques exist, obviously.
I know how device fingerprinting works, thank you though.
To me that sounds like hardware identifiers, but also quite specifically the things passkeys use. Hence I mentioned it as aside from their main point, which was "don't track me", because the biometrics GitHub or any website is going to ask you to use can't be used for that.
Yeah, I see what you’re saying. As far as I am aware, passkeys issue a one-time-token derived from a private key stored on the device. You can only access the private key via your devices own security (i.e., typically biometric). GitHub can only access the resulting one-time token, and it can verify that the token was derived from the private key using some cryptography. So, agreed. It’s not much different from a tracking perspective than just tracking password-based logins.
Though, I got the impression OP was talking about something else. Maybe I misunderstood them.
That's close enough for a privacy perspective. There's also limitations on domains that can request the auth, specifically ”only the one the credential is for", and there's a different key per domain and user typically.
It's also implemented in a way where if the user doesn't choose to disclose their account to the service, the service can't know.
Caring about privacy and caring about the details of a security protocol are distinct. You'd be surprised how many people who care about privacy are deeply wary of passkeys because of the biometric factor, which is unfortunate because the way it authenticates is a lot harder to track across domains by design.
I understood they had a lot of concerns, one of which was biometrics via passkeys since GitHub was a very early adopter due to the supply chain risk they pose.
Passkeys seem to be advertised in ways that puts people off:
TPMs, Secure Enclaves, etc. are deeply closed-source and security by obscurity. Until there is an open TPM implementation available, many users may prefer not to rely on them. It seems like KeepassXC allows circumventing TPM for Passkeys, but most people probably don't know that.
Too much "trust me bro, my cloud is safe" advertising from big Passkey advocates like Google.
A classic hardware key may be indistinguishable from a normal password being entered. But Google has announced they want to push passkeys against user's wishes here: "Is opting-into passkey mandatory? No, [...]. However, over time, as users become more accustomed to passkeys, we might limit where we allow passwords to be used because they’re less secure than passkeys." Again, not a great look.
Collecting biometric data is always dangerous. I'm aware that Passkeys can be used without that, but many people may be put off before they realize that.
I think that's why Passkeys have poor adoption among privacy advocates, even though most problems seem fixable.
I'm not seeing anything that's not a great look about requiring strong authentication for access to sensitive portions of a users account. What you're saying is akin to calling it a bad look that they force users to use complex passwords against user wishes.
I'm not sure what "trust me bro, my cloud is safe" has to do with anything. Passkeys live on your device. There are ways of facilitating device to device migrations of the keys if you want. You don't need to use them to use passkeys. And at least on Android you don't need to even use Google to manage the keys.
Most semiconductors are closed source. The processor, ram, and radio are also more than likely closed. The software interfaces to all of them have open specification and implementation. There's like, six for Linux. Microsoft open sourced theirs.
Tpms are not security through obscurity. They are obscure, but that's not a critical component to their security model.
What they do isn't really what "collecting biometrics" implies. They're storing key points in a hashed fashion that allows similarities to be compared. Even if it wasn't encrypted in a non-exportable way you still can't do anything with it beyond checking for a similarity score.
You've done a good job explaining what I said previously: there's sometimes a disjoint between privacy and security concern, and so sometimes people don't understand something about security.