Yes, see https://askubuntu.com/questions/599825/yubikey-two-factor-authentication-full-disk-encryption-via-luks https://askubuntu.com/questions/599825/yubikey-t

Yes, see https://askubuntu.com/questions/599825/yubikey-two-factor-authentication-full-disk-encryption-via-luks https://askubuntu.com/questions/599825/yubikey-two-factor-au... Note that this is via a second slot, the original passphrase-only key still works unless you take steps to remove it.