We had originally planned to go all-in on passkeys for ONCE/Campfire, and we built the early authentication system entirely around that. It was not a simple setup! Handling passkeys properly is surprisingly complicated on the backend, but we got it done. Unfortunately, the user experience kinda sucked, so we ended up ripping it all out...
Can you elaborate a bit more? If I create a passkey on https://passkeys.io on my Mac, then store the passkey in a password manager like Bitwarden, I can log into that site on my phone. I was kinda under the impression that Bitwarden stored the private key on their servers, so if their site gets hacked, then the attacker has access to my passkey.io account?
Bitwarden stores your passkeys on your local device. It can sync the passkey between devices but that’s end to end encrypted, bitwarden never has access to any of your passkeys or even your passwords.
Your vault is encrypted on your device before it’s sent to Bitwarden’s servers, so even they don’t have access to your passwords and passkeys.
More info on how it is encrypted is here:
https://bitwarden.com/help/what-encryption-is-used/
Pretty much every password manager works like this. Having access to your data would be a liability for them.