You can also, with a bit of fiddling use hardware security keys like Yubikey: https://gist.github.com/cmedianu/470a49038e919cf5bc98cd0d2299c484 if you don't want to remember passwords (You can also install a password in another LUKS slot and it will fall-back to the password if your key fails)

But don't forget to upload a recovery key to your favorite pastebin site. It is easy to loose access otherwise!