geli - selecting cipher

Michael Sierchio kudzu at
Thu Jul 26 15:54:21 UTC 2012

On Thu, Jul 26, 2012 at 8:47 AM, Ivan Voras <ivoras at> wrote:

> You didn't get an answer because in security, the answer depends on
> exact circumstances of use. The short answer is that if you don't have a
> specific adversary you need to protect your data from, I'd say that
> GELI's CBC is good enough for you.

The specific adversary that XEX / XTS etc. is designed to protect
against is probably unrealistically strong - someone who can write
arbitrary data to raw disk sectors and ask to have them decrypted
(chosen ciphertext attack), etc.

If you don't need to detect modifications/insertions/deletions that
don't go through the GELI layer, I would be perfectly comfortable with
AES-CTR mode - it is many times faster than any of the above methods.

- M

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