Re: [PATCH encrypted swsusp 1/3] core functionality

From: Andreas Steinmetz
Date: Mon Apr 11 2005 - 11:34:35 EST


Pavel Machek wrote:
> I'd like to retain ability to read suspend image in any order (so that
> code can be reused for swap encryption, etc).
> Pavel

This is not possible with cipher block chaining as used right now. One
would have to use a non-random iv set needs to set for every page. And
this leads to exactly the same problem why dm-crypt now offers the
'essiv' mode. I don't know if a random access feature is worth this
effort as sequential disk access (sequential write, sequential read) is
usally the fastest method anyway.

For regular swap encryption I do hope that the initrd feature of swsup2
will eventually find its way into the mainline kernel. This way you can
have an external key for dm-crypt to access the encrypted swap partition.

dm-crypt thus would guard the system during suspend/poweroff while the
encrypted suspend image guards against data gathering after
resume/reboot (the latter when mkswap is used).
--
Andreas Steinmetz SPAMmers use robotrap@xxxxxxxx
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