[sf-lug] Full Disk Encryption options?
asheesh at asheesh.org
Mon Mar 24 00:13:36 PDT 2008
On Sun, 23 Mar 2008, Tom Haddon wrote:
> On Sun, 2008-03-23 at 18:11 -0700, Kristian Erik Hermansen wrote:
>> On Sun, Mar 23, 2008 at 3:09 PM, Tom Haddon <tom at greenleaftech.net> wrote:
>>> Hope this isn't too irrelevant, but why would you want to do full disk
>>> encryption? You're slowing down your machine by forcing it to do extra
>>> processing and you're encrypting many many files that are publicly
>>> available and don't have any personal information in them. I don't
>>> really see the point of encrypting /usr/bin, /usr/sbin, /usr/lib, /lib,
>>> Why not just encrypt the stuff that's specific to you?
>> That's a great question Tom. There are a few reasons. Let's just
>> assume for a moment that I only encrypt /home, so that all my user
>> data is protected. I leave for lunch and some guy happens to snag my
>> laptop for the hour I am gone. During this hour, he is able to boot
>> my machine with a LiveCD and plant a backdoor libc library that does
>> bad stuff. I log into my computer after lunch. Upon running some
>> applications, unbeknownst to me, data is being leaked out to the
> Interesting, hadn't thought of that as a possibility before. On the
> other hand, you could just set your BIOS to have a boot option password
> so that someone can't boot from a different device than the one intended
> without a password.
Also, he could trojan the program that checks your password to:
(a) email him a copy of the hard disk passphrase,
(b) remove the encryption on the disk, rather than just decrypting to RAM,
(c) send all the photos in your $HOME to your mother, and
(d) patch the kernel so that it appears that your disk contains random
data if accessed from userspace (thereby appearing to be encrypted),
whereas kernel-space code like filesystem drivers read the real data
so nothing appears amiss.
>> Who knows what an attacker might do...heh.
>> This is why FDE is important. Perhaps Ubuntu can work it into the next
>> LTS release two years from now, whatever that solution might be :-)
Debian already includes full-disk encryption schemes. I think dm-crypt is
the best-maintained of your options.
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