Hi, I’m running a ubuntu based backup server. And was wondering if there’s a simple way to encrypt my drives in case they get swiped or something by a break in. But also in a way that the computer can be restarted and decrypt the drive without me needing to stick a key in everytime. Any ideas? It seems basic but I’m not an expert on all these newfangled encryption terminology, so would like something idiot proof (by idiot proof, not idiot enough to lose/forget the decryption key)
I think you can encrypt drives by using a key stored in the TPM, if you have one. See the Arch wiki for info.
Though I have heard the TPM is not as secure..
That isn’t possible. I would look into physical security (ie a locked cage)
If someone nicks it, can’t they just use boltcutters? Could hide the drive under the floorboards theoretically
If someone shows up with bolt cutters then you have other issues. They just as well could hold you at gun point
I worte a guide last year on how I do network bound encryption - that is the disk will automatically decrypt at boot if it’s connected to my home network, but not if the disk or machine is removed from my house. The advantage over the dropbear method is that you can set unattended upgrades to auto reboot your server whenever it installs security updates, and it’ll come back up with no manual intervention from you.
Here’s my way of doing it. TLDR: LUKS with a encryption key hosted in my router
https://nowicki.io/self-hosting-lvm-raid1-with-key-over-ftp/
Take some time and really analyze your threat model. There are different solutions for each of them. For example, protecting against a friend swiping the drives may be as simple as LUKS on the drive and a USB key with the unlock keys. Another poster suggested leaving the backup computer wide open but encrypting the files that you back up with symmetric or asymmetric, based on your needs. If you’re hiding it from the government, check your local laws. You may be guilty until proven innocent in which case you need “plausible deniability” of what’s on the drive. That’s a different solution. Are you dealing with a well funded nation-state adversary? Maybe keying in the password isn’t such a bad idea.
I’m using LUKS with mandos on a raspberry PI. I back up to a Pi at a friend’s house over TailScale where the disk is wide open, but Duplicity will encrypt the backup file. My threat model is a run of the mill thief swiping the computers and script kiddies hacking in.
