Re: dm-crypt using kthread (was: Oopsing cryptoapi (orloop device?) on 2.6.*)
From: Christophe Saout
Date: Mon Feb 16 2004 - 04:57:32 EST
Am Mo, den 16.02.2004 schrieb Grzegorz Kulewski um 04:22:
> Did you heard / read about Herring?
No, what is it?
> I found .pdf somewhere (I think I still have it). It is better alternative
> to ECB or CBC algorithms used in cryptoloop (if I understand good). Could
> something like that be implemented in dm-crypt? Is it already?
I can do whatever cryptoapi offers (and isn't too complicated).
> Could somebody write dm-compress (compressing not encrypting)? Is it
> technically possible (can device mapper handle different data size at
> input, differet at output)? (I think there is compressing loop patch.)
> Could dm first compress data (even with weak algorithm), then encrypt, to
> make statistical analysis harder?
Compression is something that is fine in the loop driver but when done
read-only (because it can be backed by something that isn't limited to
do I/O on sector boundaries) but very hard to do in the block layer,
especially read-write. It should really be done in a filesystem because
you have to do dynamic allocation and such things and you can't even
guarantee a certain disk size.
> And, to be sure, does dm-crypto add anything in the begining (ie.
> header) or in other places to the stored data? Or it is the same data
> (same size) but encrypted?
No, it doesn't do anything. These things should be done entirely in
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/