off topic: volatile USB stick available

[Aaron Rainbolt]

On Fri, Jun 24, 2022 at 2:43 PM Andre Tann <atann at alphasrv.net> wrote:
>
> On 24.06.22 17:23, ubuntu at howorth.org.uk wrote:
>
> > Why do you need the stick? Just store the key in the computer's RAM and
> > it will have the same effect, no? You could use a file in a tmpfs.
>
> How would the key survive a reboot then?
> Or a power down, followed by a wake-on-LAN a few hours later?
>
> The content of a volatile stick would survive these events if plugged
> into a always-on USB port.

If you wanted to do a lot of fiddling, you could possibly rig a
Raspberry Pi Zero to do exactly this.
https://learn.adafruit.com/turning-your-raspberry-pi-zero-into-a-usb-gadget/overview
Set it up as an Ethernet gadget, ensure that the Pi Zero doesn't have
a swapfile, mount a tmpfs to a folder in the Pi, and store the key
there. The server could then retrieve the key from the Pi at boot time
and decrypt the drive - possible solutions for doing so are available
here: https://serverfault.com/questions/884704/luks-automatic-unlock-of-with-key-file-on-remote-ubuntu-server
Server loses power, Pi loses power, key vanishes.

Also have a recovery strategy (key backed-up on a non-volatile flash
drive that you store somewhere safe) so that when the fateful day
comes that everything does lose power, you're not permanently locked
out of the server data.