Re: [swsusp] encrypt suspend data for easy wiping

From: Grzegorz Kulewski
Date: Thu Jul 07 2005 - 14:40:12 EST


On Thu, 7 Jul 2005, Pavel Machek wrote:

Hi!

Hi!

To prevent data gathering from swap after resume you can encrypt the
suspend image with a temporary key that is deleted on resume. Note
that the temporary key is stored unencrypted on disk while the system
is suspended... still it means that saved data are wiped from disk
during resume by simply overwritting the key.

hm, how useful is that? swap can still contain sensitive userspace
stuff.

At least userspace has chance to mark *really* sensitive stuff as
unswappable. Unfortunately that does not work against swsusp :-(.

[BTW... I was thinking about just generating random key on swapon, and
using it, so that data in swap is garbage after reboot; no userspace
changes needed. What do you think?]

I (and many others) are doing it already in userspace. Don't you know
about dm-crypt? I think the idea is described in its docs or wiki...

I could not find anything in device-mapper/*; do you have pointer to
docs or wiki?

Just type dm-crypt in google and the first match is http://www.saout.de/misc/dm-crypt/ (the second is its wiki). Then grep that page for 'swap' and you are done. :-)


Grzegorz Kulewski
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