For a quick test I projected a flat QR code onto the surface of a cylinder, printed the distorted image on a household printer, wrapped the paper around a 3 mm diameter wire. The result is readable from a still image made by a smartphone.

It haven't worked with 2 mm image / cable, but I'm pretty sure that's just limit of my printer's resolution. With 600 DPI there is only 2-3 dots per QR code pixel.

You could repeat that pattern with few degrees of rotation so one will always be in the right enough orientation to decode.

That only works if the device has working camera and bluetooth. What if I want to log in from my new desktop PC to an account whose Passkey is stored on my old desktop PC?

If you are not using Passkeys for your email (and the site supports that type of account recovery), then you still have only the security of passwords, just with additional steps.

Computer monitors doesn't exists about something like 32".

With a quick calculation 50 ms time offset would mean about 20 meter difference. You can get that accuracy with NTP over residential internet and a better TCXO could hold that for a day. You could sync clocks and download the almanac at each airport. The almanac could be digitally signed and NTP has an option for authentication, too. That's about 10 USD of hardware (plus what you need for image capture and processing).

I'm pretty sure with dedicated hardware and better solutions you could get much better accuracy.

True, but no sane way to mass revoke Passkeys from stolen / lost device is just bad design.

Also it could be vulnerable to MFA fatigue attack, if people would constantly get new "confirm this login" popups, they would press anything to make it go away.

So you would need something that is explicitly initialized from a trusted session, then you need something to connect the trusted session to the new login. If you want that to be user friendly you need some short codes and can't rely on QR code / Bluetooth, or two-way interaction. And that brings up the phishing / MitM attacks again.

Then passkeys doesn't provide any real value if you have other less secure recovery option.

Let's say I have a bank account, going to the branch and doing an in person ID check is a valid recovery option, but nobody would want to do that just to log in from a new device.

> It isn’t useless, point is you don’t get to type in your password on a device that has passkey generated already, or get phished on a fake web address for example.

That's solved by letting the browser to remember the passwords.

> Passkeys are meant to be protected by either PIN or biometrics, however they are also meant to be revocable on the web, at least they are for services i’ve been using with passkeys.

PIN and biometrics doesn't have any inherent security. They rely on some hardware (or software separated from main system) feature, and even those can have vulnerabilities.

How can I do that, if Passkeys are the only option to log in?

If I can just use a password to log into a website without Passkeys, then Passkey is useless and doesn't add any security benefit.

> Why would you need to delete invalid passkeys? You wouldn't.

I sell my old (and no longer updated) phone or PC and don't want someone to get access to my account by getting access to the secret keys.

An non-revocable authentication mechanism is just stupid.

Let's say I have a new account and a single Passkey in the TPM of PC1. I want to log in from PC2, too. How can I do that? (I know there is some trickery with Bluetooth, but I haven't seen anything supporting it, and desktop PCs usually doesn't have Bluetooth connectivity.)

AFAIK some browsers can do some magic to use a Passkey from your smartphone on a PC, but you need to log in to the same browser-sync account from both device (which brings back us to the same issue).

Also the whole thing becomes a mess when you change devices. You need to log into all the services you have ever used to delete the Passkeys from devices you no longer have, and you need to add a new passkey from a new device you bought to all the services you use.

In the text nothing prevents the manufacturer to stream the vide of your face to their servers all over the world and do the image processing there. It would even comply with GDPR if everybody pinky promised they not using that data for anything else.

And now you can use time correlation attack to unmask people.

I suspect the ZKP proof or token is practically unique and related to you, so I could be personal data if you use the definition from GDPR.

With ZKP the entity and the original verifier shouldn't be able to match your identity to the ZKP proof or token, but the app on your phone of course can do that.

The app probably will be made some government contractor and there is no technical measure that would prevent them to just share all that data with whoever they want.

https://ageverification.dev/av-doc-technical-specification/d...

You are. Nothing prevents the manufacturers to support other better charging solutions than USB-C. In fact many notebooks has their proprietary connectors and some smartphones use custom signaling over custom USB cable to provide better experience while complying with the regulation and support USB-C charging, too.

From an users' perspective paying with digital Euro would work more-or-less the same as you pay today with card, bank transfer or something based on QR codes. But it will have very different guarantees and trusts behind the scene.

Today you don't really think about keeping your money in a bank and paying with card as a different thing than having physical cash, because banks and payment services have very strict regulations and insurance schemes. Banks rarely goes bankrupt and even if they do, most of the people are not affected, because they get back their money from deposit insurance.

Banks can create money from thin air (without the approval of the central bank) and lend it to you (and destroy when you pay your loan back), they can not do that with Digital Euro.

Everybody would be able to convert all their Digital Euro to banknotes at the same time, but that would bankrupt any commercial bank.

Banks can deny your request to open an account or provide payment services to you (e.g. what happened with the ICC judge), you can own Digital Euro without having a bank account.

Banks pay interest for using your money (and the risk you take), this could even be negative that means some people even willing to loose money if they can have Euro instead of their original currency. Banks wouldn't be able to use your Digital Euro, you wouldn't get any interest on it.

Digital Euro (the same way as physical cash), is a legal tender, money in bank and card payments are not.

The value of Digital Euro doesn't depend on your bank, the numbers on your bank account could worth nothing if your bank goes bankrupt, central banks can not go bankrupt.

Digital Euro (for a limited amount) could be exchanged directly between two peers like physical cash (offline, without connection to internet or any bank).

By the way, here banks even have daily bank / wire transfer limit that can be changed only by a personal visit to a branch, so even if your online banking credentials are stolen, the attacker can not empty your account.