YubiKeys can't have copies of themselves, that's a big portion of their selling point. As far as I know and strictily in FIDO, there is no solution here. The cl

YubiKeys can't have copies of themselves, that's a big portion of their selling point. As far as I know and strictily in FIDO, there is no solution here. The closest that Yubico has is this draft: https://github.com/Yubico/webauthn-recovery-extension https://github.com/Yubico/webauthn-recovery-extension which will roughly make an authenticator register two keys with an RP. The draft itself is not implemented anywhere as far as I know and while better than the current state of hardware key backups, it's still not problem free. I personally would love to see it implemented, so it can be used for logging in to the service that provides a WebAuthn sync fabric.