Hello, I have laptop where I set up full disk encryption following this tutorial: https://xo.tc/setting-up-full-disk-encryption-on-debian-jessie.html
It works great, but since LUKS can have up to 8 key slots, I would like to add another way to decrypt the laptop: key on a external usb. So, if there is a usb with the key plugged in, laptop doesn't ask for the passphrase and just continue booting; if there isn't - it asks for the passphrase. Can this be done?
