cryptsetup VS tang

Overall, “dm-crypt” is a device-mapper target (https://elixir.bootlin.com/linux/v6.5-rc3/source/drivers/md/dm-crypt.c#L3689) supported from kernel version 2.6.4 (https://elixir.bootlin.com/linux/v2.6.4/source/drivers/md/dm-crypt.c). It is responsible for transparent (aka real-time/on-the-fly encryption) block device encryption while using the kernel crypto API (https://gitlab.com/cryptsetup/cryptsetup/-/wikis/DMCrypt) .

For more information check section 5.21 Why is there no "Nuke-Option"? of LUKS FAQ.

Please read the section 5.21 Why is there no "Nuke-Option"? of the LUKS FAQ for more information (eg. when a "wipe" option could actually harm you).

Check out the section 5.2 and 5.18 of the LUKS FAQ for more information.

See section 5.2 of LUKS FAQ and Key disclosure law all over the world.

References: - Frequently Asked Questions Cryptsetup/LUKS - Question 2.15: "neither dm-crypt nor LUKS1 stores partition size and LUKS2 uses a generic "whole device" size as default." - Stackexchange: What does cryptsetup resize do if LUKS doesn't store partition size?

LUKS is probably what you want

Have a look at clevis and tang. These allow you do have one server - which could be your remote you want to pull from - to be source of the LUKS decryption on the system using tang.

I found that running tang[1] at home and needing to decrypt that box (can be a Pi or whatever) requiring a complex passphrase is very sufficient. You can even just unplug it at night if it makes you sleep better.

https://github.com/latchset/tang

There are 3 ways to unlock a volume in a headless environment: - use a keyfile, located on an already available volume - use your device's TPM and utilize systemd-cryptenroll - use Clevis/Tang to unlock volumes remotely

This is why on headless servers you use tang (ideally, multiple tang servers)

Sharing my notes on running a Tang server on OPNSense, in case it is useful for somebody else.

We use clevis against multiple tang servers to provide Network Bound Disk Encryption (NBDE). It's possible to also use TPM2 but it's easier to use multiple tang servers (requiring more than one server to decrypt) in the datacenter.

For automating unlocking of encrypted drives, look into tang . Here is a red hat guide on setting it up. You will want to be running this on another device on your network, i run it on my router with openwrt since its a local device thats on 24/7. Basically it will unlock your disks as long as your server is on your network, so if your machine or drives are stolen or removed from your network they will just be encrypted as usual. Obviously use a strong encryption password.

There are other ways to bind data, e.g. "network binding" with Tang server.

I wonder if https://github.com/latchset/clevis and https://github.com/latchset/tang (complementary projects) will help here.

Yes you can, using either Mandos or Clevis and Tang. https://www.recompile.se/mandos https://github.com/latchset/clevis https://github.com/latchset/tang. Basically on boot the server gets the key from another(s) servers. You could use a hidden raspberry pi for example.