>From the subject line I had expected you to be asking what sources of entropy 
/dev/urandom was using.

On Tuesday 26 October 2010 23:13:11 adam shea wrote:
> For sake of discussion assume a partitioning scheme is such:
> /dev/sda1 => /boot
> /dev/sda2 => /
> /dev/sda3 => swap
> /dev/sda4 => spare
> 
> The *spare* partition will be encrypted and then mounted during startup.

Note that since you're using a /boot partition, you also have the option of 
running the / partition encrypted also.

> I know next to nothing about cryptography, cryptanalysis, and the like. All
> I know is that it is suggested to write random data over the disk before
> encrypting.
> 
> For example,
> http://duncanelliot.com/blog/?p=7

Note that you can do this same thing using 'wipe' or 'scrub'.

> In the above blog entry the claim is that if you do not somehow write
> random data over the entire disk an attacker can analyze the disk, locate
> the edges of the encrypted data, and greatly increase his/her chances of
> breaking the encryption. However, does this apply if one is only
> encrypting a single partition? By my understanding, the partition table is
> unencrypted and could potentially used to locate the starting edge of the
> encrypted partition.

That's my understanding also.

> Does this fact negate whatever added security one
> gains by writing random data over the disk prior to encryption.

I'd say no.

  -- Chris

--

Chris Knadle
[email protected]
_______________________________________________
Mid-Hudson Valley Linux Users Group                  http://mhvlug.org
http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug

Upcoming Meetings (6pm - 8pm)                         MHVLS Auditorium
  Nov 3 - Open Source Hardware: Bugs, Beagles and Beyond
  Dec 1 - IBM's Open Client Deployment
  Jan 5 - Building a Comunity Site with Drupal

Reply via email to