Re: [Question] Distinction responsibilities LUKS and dm-crypt

[Christoph Anton Mitterer <calestyo@scientia.org>]

On Thu, 2022-03-31 at 18:56 +0000, Surmont Jasper wrote:
> So, would I be correct to write that the ability to have
> authenticated encryption depends on the underlying storage format
> (where eg LUKS1 does not support it, and LUKS2 does)?

Well practically (as of now), yes,... but that's more from an
engineering PoV.
You simply need some place where the integrity data is stored - with
cryptsetup+AEAD this is done within the LUKS2 container (not supported
with LUKS1)... but if you use dm-verity alone, there is no LUKS and the
integrity data is stored in an extra (hash_)device.


> You also mentioned encryption without LUKS has more pros than cons.

Oops,... I've meant the otherway round: it's in nearly all cases better
to use LUKS.


> so what are the main advantages of using something else than LUKS?

The "else" is only plain dm-dmcrypt devices (i.e. no meta-data stored
on disk)... unless you count 3rd party formats in like bitlocker.

Some people may say that with "plain" you get some level of plausible
deniability - i.e. you could say there is no encrypted data on the
device.
Whether that works out in practise is another question - I'd kinda
doubt that the <random evil country>-torturer would believe you, if
you'd insist that you've filled some good parts of your device with
seemingly random data just for the fun of it.

It may have some tiny advantages when using it for temporary devices
(like temporarily encrypted swap devices).


Cheers,
Chris.