> (re-enroll attacker's key or register attacker's passkey).

What is the mechanism to do this? As I understand it, the passkey is basically a public/private key pair. You'd have to download the attacker's key pair into your passkey system? What passkey system allows you to provide a key pair, rather than always generating one? I'd like to see a step-by-step walkthrough that doesn't involve a straightforward phishing scenario, or running privileged commands on the users computer (if you can do that, all bets are off.)