Comment by bryantwolf
1 day ago
The advantage is that the password never leave the device. It has a public key and signs challenges with the private key but nothing sensitive goes over the wire on every login
1 day ago
The advantage is that the password never leave the device. It has a public key and signs challenges with the private key but nothing sensitive goes over the wire on every login
It should be noted that that is not an inherential advantage of passkeys over passwords. It is possible to achieve the same with passwords, e.g. by using a hash-cascade.
Sure, but then you still need a protocol between user agent and website. If you just do this in Javascript, you're not protected against phishing sites just forwarding the password entered directly.
Passkeys can in fact be backed by exactly this, i.e. a HMAC-only stateless implementation backed by a single password: https://github.com/lxgr/brainchain
> Sure, but then you still need a protocol between user agent and website.
Yes of course. Just like you do for passkeys.
> Passkeys can in fact be backed by exactly this, i.e. a HMAC-only stateless implementation backed by a single password: https://github.com/lxgr/brainchain
No, not quite. It's written on there:
> "Login" with your passphrase, and you can create non-discoverable WebAuthN credentials (don't call them passkeys, but definitely be reminded of them) at ~all~ some websites supporting them (...)
That's the thing: with passwords, a website/app cannot prevent you from controlling the password yourself. With passkeys and attestation it can.
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is it fair to say all passkey implementations have this advantage while only some password implementations can match?
It is absolutely unfair to say it. Just like passwords stored in a password manager, passkeys can be copied out of the device for safekeeping. Because you can copy them out, a user can be induced to give them to someone.
I saw passkey boosters go very, very rapidly from "Passkeys are immune to phishing!" to "Passkeys are phishing resistant!" when lots of real-world people started using passkeys and demonstrated that you absolutely must have a way to back them up and move them around.
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