I used Google Authenticator some years ago on a phone that broke. At the time I was unable to restore it to my new phone. The proposed solution used to be to authenticate multiple devices (phones with Authenticator, Yubikeys) but to this day many Services only allow You to link a single second factor to your Account, meaning that upon loosing that factor you’re required to contact support to restore access to your Account. Is there any open source solution that generates a second factor in software and can be easily cloned/restored to multiple devices ? Nobody buys a single set of keys for their front door or car. I know why yubikeys don’t offer „spares“ but usecases can differ are there any yubikey protocol compatible competitors that offer spare keys ?