Re: [RFC] crypto: xts - limit accepted key length

From: Milan Broz
Date: Tue Mar 03 2020 - 07:35:57 EST


On 02/03/2020 09:33, Van Leeuwen, Pascal wrote:
> Hmm ... in principle IEEE-1619 also defines XTS *only* for AES. So by that same
> reasoning, you should also not allow any usage of XTS beyond AES. Yet it is
> actually being actively used(?) with other ciphers in the Linux kernel.
Just FYI - yes, it is actively used with other ciphers.

There is a lot of LUKS devices that use Serpent or Twofish with XTS mode.

The same for TrueCrypt/VeraCrypt, here sometimes it is used also in cipher chain
(both native binaries or cryptsetup code use dm-crypt with crypto API here).

XTS mode is designed for storage encryption only - and at least for disk encryption
I have never seen request for 192bit keys...

Milan