On Tue, May 27, 2014 at 10:11:02AM -0400, Jeff Mahoney wrote:
A lot of (if not most) SSDs set trimmed sectors to all nulls.
Doing that on an encrypted partition would allow a cracker to identify encrypted data from encrypted garbage. That is not a good thing, especially if the partition is significantly underfilled. Ie a drive with only 10% utilization would have 90% nulls, so you have drastically simplified life for an attacker.
Wouldn't that also imply that anyone using an encrypted partition should also fill it with random data prior to using it?
Otherwise an attacker can definitely see how full the filesystem is.
I doubt that's happening in even a small minority of deployments.
YaST at least writes some random data to the beginning of the
encrypted device. But I cannot recall details of the reasoning.
Regards,
Arvin
--
Arvin Schnell,