Oh I completely agree. There is a reason it took me a while and careful observation before I figured it out.
I assume it’s part of, or started as, a little password dance. Something like, “abc123DEF”.
Or maybe it just comes from the idea that only a single key can be pressed at a time?
Either way I completely agree, insane.
As you mentioned elsewhere it’s encrypted.
Take a look at
/etc/crypttab
and creating and adding a key file that can unlock the drive.Essentially your additional SSD will have both a password and a file containing a password that can unlock the drive. When you unlock your root filesystem (I’m guessing at boot) it will then have the key file that can unlock the SSD.
Something like
cryptsetup luksAddKey /dev/pathtossd --new-keyfile /etc/newpassword
Systemd might make this easier to setup nowadays.
Edit: Also, yes, the password to unlock your SSD is just sitting in a file in your root drive. Be sure to restrict it to only be readable by root.