Passkeys, under the hood, use a way of proving your identity that doesn’t require you to actually send your password, and also doesn’t require you to send your username either.
Because of how it’s implemented, the system managing the passkeys also gets to authenticate that the website is who it says it is.
So no private data actually gets sent anywhere, but you can prove your identity while also checking the identity of the site you’re talking to, like the SSL lock icon but automated.
It’s often implemented such that the device that holds they keys can’t actually have them stolen from it, and it’s integrated with a biometric sensor.
This means it’s possible to have a high degree of confidence that the person logging in is physically the same person who created the credential, and not just someone who had their password stolen.
The final perk, is that if you’re using something like a phone with a fingerprint scanner, passkeys work as two factors of authentication, despite only feeling like one.
Because the phone verifies your identity via fingerprint (something you are), it can then unlock the key that is uniquely available to the phone (something you have).
Combine that with being generally easier to use, and it’s pretty clear why most security experts are pushing them. Security that users will use is better than security they won’t, and finally we have easier to use security that’s also better than the more difficult options.
coffinwood@feddit.de 8 months ago
The advantage - from my very incomplete understanding - is that your passkeys cannot be phished or stolen from you. So only you from your device can log-in to the site. Which leaves me with the question, how cross-device passkeys work.
ricecake@sh.itjust.works 8 months ago
There are different ways.
One way is to use an encryption module on the device that, rather than storing the keys just encrypts the keys and holds an encryption key that you can’t extract, and can do various crypto operations.
Now you ask the module to do a secure key exchange algorithm with the new device, meditated by a party the module trusts, like apple or something.
Now both devices share a secret key, and they trust that the other is owned by the same user because the owner verified with apple who then signed the exchange messages.
Old device decrypts with the old key, and encrypts with the new key, never letting the data leave the secure module. Send the data to the new device which can do the reverse, and both devices forget the shared password.
Overall, minor weaknesses like storing keys in the cloud encrypted by a key derived from a password that the cloud never sees, while objective weaknesses, are still significant net improvements to security over passwords.
coffinwood@feddit.de 8 months ago
Thank you for explaining. That’s a thing most sites leave out: tell people how the keys cannot be stolen while still working on a different device.
ricecake@sh.itjust.works 8 months ago
Big reason for that is the spec for how this all works being around for a while, giving people a lot of time to write about the core of how it works, but the viable popular implementations are far newer, so articles still haven’t been updated, and doing the key transfers is still one of the newest parts that the big vendors don’t want to talk about yet, because they still have to get their patents fully approved and everything.
What I described above is one way to move data between two devices in a secure way with a trusted intermediary to verify identity, but I have no idea if it’s how any major vendor actually does it, because they haven’t made that data public. It’s just what’s obvious to a sufficiently informed subject matter expert.
Kusimulkku@lemm.ee 8 months ago
That would be a really nice advantage but yeah, I wonder how cross-device passkeys or recovery passkeys would work