Comment by what
5 days ago
What’s PQ story with passkeys? Considering all the hype that everything needs to be pq safe by 2029 (or whatever), wouldn’t it make sense to delay adoption? Otherwise a db leak would compromise every single account in a pq world.
Authentication is safer than encryption, because harvest-now-decrypt-later is not available. Currently PQ is not standardized for passkeys, and at least Firefox fails if the authenticator advertises unknown algorithms.
Most Passkeys use PQ PKI algorithms. From statistics I've seen most are Elliptic Curve on currently recommended PQ curves.
For better and worse, Webauthn is one of the "choose your own adventure" PKI systems where the keys themselves suggest which PKI algorithm/details they use. This is partly because Webauthn has been around a long time and has had to backwards compatibly support a wide variety of physical security keys over the ages.
Most good open source libraries for implementing passkeys will do a good job of limiting passkeys to known good algorithm choices, including any PQ requirements/suggestions. The Passkey standard itself also sets a "higher water" baseline above Webauthn's supported algorithm list.
I don’t follow? What is a “currently recommended PQ curve”? As far as I understand, the entire point is that all ECC is broken by quantum computers, hence the hype to move to something else by 2029. Anyone that can see your public key can compute your private key.
My understanding is that some of the curves are still considered high enough entropy that the number of qubits needed is "unreasonable". The important point remains though that passkeys don't have a fixed encryption suite and can be updated over time.
Passkeys aren’t permanent, you can change or revoke them. If the algorithm used suddenly becomes vulnerable, you would need to rotate all your passkeys.
Sure. You’re assuming every site will revoke your passkey when that happens though. It also feels like a great time to trick people into registering an attacker passkey instead.
You would revoke it yourself, I am saying.
Also, the same risk applies, but to an even greater degree, with a password.
4 replies →