| > What about /boot - encrypted and tamper proof? Resists evil maid attack? > Rabbit hole, I know, but so fascinating if you solved it all :) Encrypting `/boot/` is the wrong thing to do. One can just replace it with something that logs the encryption key instead (and sends it off to somewhere). You actually need to verify that what you expect to be there is actually there and a encryption isn't gonna do that for you. A reasonably secure boot chain looks roughly as follows: bootloader is checked by the UEFI (read secure-boot), bootloader chain loads a signed UKI which also uses secure boot verification (or just skip the bootloader if you only have a single kernel with no fallback), this then loads a signed dm-verity `/usr/` which brings you to the login screen. Root is just data (e.g. mounted `noexec`) and is encrypted using e.g. PCR 11 so that it only unlocks if the UKI is the one that is expected (with some other backup unlock method). This is basically #2 of the "Design Goals" of Poetterings "Fitting everything together"[0]. It's a good read if you are looking to designing your own Linux image and are looking for some inspiration. There is ParticleOS[1] which somewhat dogfoods this kind of system, though I don't think it is anything remotely considered for a production system. [0]: https://0pointer.net/blog/fitting-everything-together.html [1]: https://github.com/systemd/particleos |