[sebk]

100k devices is the minimum. Also I already agreed that this is an expansion of information, were it to be requested in practice and the user chose to provide it. And I don't believe the use case for attestation in enterprise settings is narrow. For the "own locked down devices" is that Enterprise Attestation exists, which has management overhead in both its configurations, wheras normal attestation does not.

I can't comment on the intent link, as there's no information. But the "practice" link is simply incorrect. Google does in fact allow a Yubikey to be used as a passkey, I have one configured myself. It shows up as "FIDO2 security key". What I assume is happening in that link you sent is that the user's yubikey does not have a PIN set for the FIDO2 interface, which means that it can't provide user verification and therefore is not a passkey as far as Google is concerned. This is the kind of reasoning about the capabilities of the authenticator that I was talking about, and it doesn't have to do with attestation.

> it's their job to build a standard that appeals to me if they want me to use it

They're appealing to OEMs, vendors and service providers as well. I also don't quite see how merely having attestation in the standard is harmful. RPs and users can chose not to require or provide it. If RPs decided they needed it for malicious purposes, would not having it in the standard suffice for them to be benign?

> That wouldn't solve any of my problems; the sync fabric isn't the important part -- I want to control my own keys.

It would, because then the sync fabric is free to provide you with an exported version that's wrapped in a key of your choosing. It's open in the sense that any one software can import/export keys out of hardware devices that are currently restricted to the hardware vendor.

[JohnFen]

> I also don't quite see how merely having attestation in the standard is harmful.

Because having it there makes it an option, and I think that history is pretty clear that if you give the tech industry a bat, they will beat their users with it sooner or later.

[danShumway]

> This is the kind of reasoning about the capabilities of the authenticator that I was talking about, and it doesn't have to do with attestation.

It seems like it does though... correct me if I'm wrong, but attestation is how Google knows that it's a Yubikey and that it doesn't have a PIN/biometrics set. And in practice, it's not allowed to be used to provide user verification; there's a restriction on functionality. Yes, you can use it as a Yubikey, but you can't use it for the new passkey system.

> For the "own locked down devices" is that Enterprise Attestation exists, which has management overhead in both its configurations, wheras normal attestation does not.

Good? Attestation should have an overhead. Getting rid of the overhead is exactly what I don't want. You can have attestation today through existing methods, and they're basically sufficient for enterprises that need them. It costs a bit of money, which is good because it'll force enterprises to think about it. And importantly, it doesn't really work for restricting consumer accounts, it's mostly useful for orgs where devices are controlled. Which is again, good, that's the best outcome. Enterprises can restrict their devices, but there are barriers to entry that prevent those restrictions from being applied to general consumers using their own devices.

The other thing you can do if you don't want to go the hardware route is you can have a custom login app for your enterprise. You shouldn't, you should provide users with devices if you're going to restrict those devices -- but there's nothing stopping an org from having a custom authenticator that works outside of the standard.

The only problem they'll have is if they want general users outside of the org to install that app just to log in. Which again, is very good. It's good that you can build a custom solution for within an enterprise, but that there are significant challenges in front of trying to force that solution on regular users.

Heck, you can even use the Play Integrity API to help. Should the Play Integrity API exist? No, probably not. But it does and it's usable for dedicated authenticators, so we certainly don't need another solution on top of it.

This is a rare use-case, and it's probably fine for the orgs that need it to use something other than passkeys. There's no real danger to them of lock-out, they're already doing this today so they can just keep doing what they're already doing.

> I also don't quite see how merely having attestation in the standard is harmful.

Because every single time that we've had attestation in the past -- literally every single time -- it's been used for DRM. Hopefully this conversation doesn't matter because Apple is just blocking attestation, but what do you see in the industry that makes you think this time would be different? Has something radically changed at Netflix over the past couple of years?

When has attestation ever not been abused?

Here's the Chromium team expressing similar fears: https://www.chromium.org/security-keys/ Are those fears unfounded? I don't generally assume that Google is going to be leading the charge on user freedom, and if even they are kind of creeped out about the potential here, then I trust that there's a real risk of abuse.

> It's open in the sense that any one software can import/export keys out of hardware devices that are currently restricted to the hardware vendor.

Right, but if you're talking about trusted devices, unless that's something the user controls, exporting/importing doesn't matter. The point is that the user should be able to export their key and import it to any authenticator they choose without fear that their authenticator is going to be blocked from logging in to a service.

[sebk]

Attestation doesn't carry that information. Also consider that Apple zeroes out attestation for its devices and works just fine with Google as passkeys. What's happening here is that when an RP is registering an authenticator, it can include a property that's called userVerification which in a Yubikey is backed by a PIN, and Google sets it as required. The restriction in functionality that you mention is exactly what Google wants though, but not for malicious purposes. Google doesn't want someone stealing your yubikey and having that suffice to log in to your account. They want user verification so that if that Yubikey is stolen, an attacker also needs to know the PIN, thus providing two factors. Again, Google does not prevent you from using Yubikeys. It prevents you from using security keys that aren't configured for user verification, and they don't do that through attestation.

> Right, but if you're talking about trusted devices, unless that's something the user controls, exporting/importing doesn't matter. The point is that the user should be able to export their key and import it to any authenticator they choose without fear that their authenticator is going to be blocked from logging in to a service.

No, not just physical devices. Anything that represents a device with a wrapping key. That could be a software implementation that's just a file you control. What I'm saying though is that for the general case which is what a standard is concerned with, we won't see the standard-mandated ability to export passkeys across sync fabrics. I don't see a world where you can export passkeys from Apple iCloud Keychain and import them into Google Password Manager. But I do see a world where you create passkeys in your Mac with KeePassXC, and can use an open sync fabric from KeePassXC to sync them to your Android device, and a flat file as well, and I believe this will happen not under the purview of FIDO. Whether those flat files can then hop on to another sync fabric (say, 1Password) to later be imported into hardware devices will definitely not be a part of a standard, but given the analogy to password managers, it doesn't matter; those capabilities can still be built.

As far as the Chromium post, I find that one slightly more dystopic than attestation as a feature. They say If Chrome becomes aware that websites are not meeting these expectations, we may withdraw Security Key privileges from those sites, and similar other warnings. They don't say that they will warn users, they say that they will withdraw privileges. Do you want your browser deciding for you what websites you can log in to?

[JohnFen]

> Google doesn't want someone stealing your yubikey and having that suffice to log in to your account.

But it's not Google's place to make that decision for me.

[danShumway]

> Also consider that Apple zeroes out attestation for its devices

This may be the saving grace because it may end up being that whether or not attestation is part of the standard doesn't matter because companies won't be able to use it. But it doesn't mean that attestation is harmless, it means that we're very lucky that (for now) Apple is deciding to effectively make it impossible for a commercial service to actually use it reliably.

> It prevents you from using security keys that aren't configured for user verification, and they don't do that through attestation.

Fair point, I don't know that this is actually using attestation and that it's not just the Yubikey reporting back that it doesn't support that field. I do quibble somewhat with "they're not blocking Yubikeys, they're just blocking <description of a Yubikey>." But... yeah, I'll grant you're probably right that this is not using attestation.

> I don't see a world where you can export passkeys from Apple iCloud Keychain and import them into Google Password Manager.

That's exactly what I mean when I say it wouldn't be sufficient. When I talk about syncing, I'm talking about transferring into and out of ecosystems, not just specific devices. What you're describing is a system where I can use the KeePassXC ecosystem to use keys across multiple devices. But I can't transfer those keys out of the KeePassXC ecosystem (unless hopefully other vendors like 1Password add support), and if someone starts using iCloud, they're stuck with same vendor lock-in.

This is effectively saying, "you'll have a closed ecosystem for most people, but people who know enough beforehand to avoid it can somewhat avoid it." We should expect better from a standards body that purports to be building an Open standard.

I really don't see how this is an out-of-scope problem for the FIDO Alliance. They have input from every single major OS. All of the players are in the same space. And their entire job is to dictate how this is going to work. I'm just asking them to do that job. A spec for portability is not that big of an ask compared to everything else they're already working on as part of this.

It's not really that different than a spec for logging in using a standardized QR code, or over Bluetooth -- all of which was considered in-scope for them to to work on. Portability is just part of the general interoperability work that we should be expecting them to do.

> Do you want your browser deciding for you what websites you can log in to?

Of course not; in very typical fashion Google's solution to the problem may be worse than the problem itself. Google is very fond of recognizing that a feature is abusable and saying, "well, how about we prevent that abuse by giving ourselves even more capricious power?"

But I do think it shows I'm not being paranoid, that this is a legitimate worry that even Google recognizes is worth worrying about. Google is part of the FIDO Alliance and it's not looking at attestation as a theoretical risk; it's looking at it as a very plausible risk that it needs to have policies around.

Which I think is pretty reasonable given that every single instance of attestation in the past has been used for DRM, and there's nothing special about attestation in this spec that would stop that from happening. I really do think the burden of proof here is on you to describe why you think Netflix/Banks/etc... are suddenly going to act differently now than they have with every other attestation method they've had access to leading up to now.

The only answer I can think of is, "they'll act differently because Apple is effectively killing attestation for platform keys for everyone." But that's not really a defense of attestation, it's just something to thank Apple for.

[sebk]

let me restate, they're not "blocking the description of a Yubikey" either. You can register one, and in fact I just did to try it out. The Yubikey needs to be configured with a PIN which you do through Yubikey manager. They're blocking authenticators that don't have additional protection other than just presence.

> That's exactly what I mean when I say it wouldn't be sufficient

I think we're confusing what the role of a standard is, versus what other features can be built around a standard capability. With an open fabric, vendors like KeePassXC can allow exports in formats that can then be imported by other sync fabrics as I described previously. The standard mandating it would be a good reason for vendors not to adopt the standard, or adopt a crippled version. Given the fact that WebAuthn ties capabilites to the authenticator at registration time I think it's understandable that vendors like Apple want give RPs assurance that keys are entirely contained in an ecosystem that guarantees those assertions. You will have options, including not using Apple/Microsoft/Google's sync fabrics, and to move off these sync fabrics if you consider them insufficient, but not by exporting keys directly.

> I really don't see how this is an out-of-scope problem for the FIDO Alliance (...) It's not really that different than a spec for logging in using a standardized QR code

Logging in using a QR code or BLE is part of the hybrid transport in CTAP, which deals with how authenticators communicate with clients. It's very much within FIDO. Establishing trust between devices in different ecosystems to form a circle of trust so that key material can be shared doesn't really have anything to do with logging in to services, so it's not WebAuthn. It also doesn't deal with client to authenticator communication as there's no client. If anything, a standard like TPM (ISO/IEC 11889) is a better fit, but probably too low level for that exact use case.

> Which I think is pretty reasonable given that every single instance of attestation in the past has been used for DRM

Going back to attestation, I don't think that in general it's in the best interest of services to not allow you to log in to them, but I can see a bank in their typical backwards-fashion issuing some branded keys and only letting you use those (Symantec, I'm looking at you). The reality is that standard or not, if RPs want this functionality, it'll be there. Standards simply attempt to provide the bare minimum for interoperability that every party can agree to. The alternative is not an attestation-free world. It's a bank asking you to log in with a flawed key they purchased from an ancient vendor because there's no standard offering that does what they want. I'd much rather have a Bank of America branded Yubikey with enterprise attestation using WebAuthn than some weak and poorly implemented proprietary token like the ones they issue today.

[danShumway]

> They're blocking authenticators that don't have additional protection other than just presence.

I know this isn't strictly attestation, but this is blocking authentication based on attributes of the device, correct? I'm sort of quibbling over details here I know, but this is basically saying "we are checking for a pin protection or biometric protection and limiting how an authenticator is used based on the presence of that feature."

> You will have options, including not using Apple/Microsoft/Google's sync fabrics, and to move off these sync fabrics if you consider them insufficient, but not by exporting keys directly.

And that is a good reason to reject the standard as harmful.

I'd love to use keys for log-in, it would be a huge boost to security. But if portability between sync fabrics as you call them isn't supported, then we can stick with passwords. I'm fine with that, and I think other people are as well. Ultimately, passkeys have to be better than what we have, and out of luck or history or whatever reason password vaults are extremely portable between different ecosystems. Even ecosystems that try to lock down passwords struggle to do so, because ultimately passwords are text and in the worst case they can be copied and pasted between managers. So if passkeys aren't similarly portable and they become another tool for holding people down into a single OS ecosystem (even if there are options that allow avoiding that), then they're harmful -- the security gains are not worth the downside.

It does not address my concerns to say that a user who knows about the dangers of vendor lock-in in advance can avoid it in some situations.

> Establishing trust between devices in different ecosystems to form a circle of trust so that key material can be shared doesn't really have anything to do with logging in to services

It absolutely does, it dictates how that login information gets shared between devices. As far as I'm concerned it's just another part of transport.

It's also relevant to FIDO in the sense that it is a major barrier of entry to getting passkeys to be accepted by the general public. At the end of the day, the highest-level responsibility for FIDO is to figure out a standard that's usable. The lack of portability keeps the standard from being usable. It is the single biggest complaint that people have about passkeys.

Yes, that is a problem they should solve, particularly because everyone who would be required to be in the same room to solve that problem is currently in the same room, and all of them have a vested interest in getting rid of barriers to passkey adoption.

Ultimately, does FIDO want this to be adopted by normal people or not? If the answer is yes, then portability is a problem they need to tackle. Again, every single company required to tackle this problem is currently a member of that alliance.

> Standards simply attempt to provide the bare minimum for interoperability that every party can agree to.

That bare minimum of interoperability should not exist for abusive uses of the technology. Like you said, there are solutions for this today. Companies that are abusing their customers should not get extra support from OSes and standard bodies to help them do it.

Bank of America can already use a Yubikey today. Or they can use a poorly implemented proprietary token. And maybe if that goes badly for them, they'll use an actually more secure option instead of LARPing security.

But look, this is exactly what people said about web video DRM, it's exactly what people say every time these conversations around DRM and fingerprinting come up. Companies are going to fingerprint your device anyway, we might as well give them a device ID for advertising. Companies are going to build weird browser extensions, we might as well get rid of them and make DRM part of the spec. It's really just an excuse, the standards make it easier to do this stuff. They're pursued because they get rid of the inconvenient parts of abusing users. And in doing so, they remove a barrier of entry that should exist.

And integrating this into web browsers on desktop platforms is a huge gift to companies that want to do this. I already can't use my bank's app on a deGoogled phone but at least I can sign in on a web browser, because in the world that currently exists attestation through a general web browser is just difficult and just annoying enough that my bank isn't willing to do it. Please stop trying to change that.

When a company is doing something awful, it should have to leave the beaten path and work outside of the standard to do it. Because that helps us call out that they are doing something awful, and it helps us point to their solution and say, "no, that's not intended."

[sebk]

> but this is blocking authentication based on attributes of the device, correct?

Not precisely. It's requesting capabilities that the Yubikey is not configured to deliver so the browser doesn't show it as an option. There is no attestation or in fact no signed communication other than the RP requesting it in the registration. I don't understand what your desired behavior is here. Do you want to log in to Google with a bearer Yubikey (what do you do when it gets stolen?). Do you want all FIDO2 keys to require PINs, even if they're being used in a traditional "something you have" 2FA fashion?

> It absolutely does, it dictates how that login information gets shared between devices. As far as I'm concerned it's just another part of transport. (...) The lack of portability keeps the standard from being usable

In the same way that a keyboard dictates how a password is typed. Transport has a very well defined meaning in FIDO and it's not about transporting key material but rather signed challenges and responses.

Remember I'm suggesting a mechanism for open sync fabrics to exist, not the opposite. I simply don't see either the value in mandating interoperable sync fabrics, or for a particular vendor in control of the ecosystem like Apple or Google wanting to weaken the security posture of their keys given how the standard works if they allow them to be exported. Also remember that the standard doesn't just cater to users, it caters to these vendors implementing it as well, and more so.

> it's exactly what people say every time these conversations around DRM and fingerprinting come up

Except Webauthn doesn't have any fingerprinting capabilities beyond those in enterprise attestation (not regular attestation). In fact, it's much more privacy preserving that past alternatives. And fully realized, you wouldn't even need a username as an identifier with an RP that can be used to correlate you across services.