xxxxx@lists.osr.com wrote on 09/14/2005 09:15:45 AM:
I would actually suggest that rather than use a password based
encryption scheme, a physical token (smart card, biometric device) plus
password would be stronger.
This is certainly feasible. 
The risk with passwords is that they can be compromised. By using two
points of identification (something you have - like a fingerprint,
something you know - like a password).
Another interesting point here is that you don’t want to necessarily
disclose that the media is itself encrypted, so you don’t want the disk
drive to be specially identified. In that way, someone analyzing it
will merely see a “pile of garbage”. I haven’t done detailed analysis
of disk drives but I know that there are often regions of the drive that
are unused; provided that those unused regions return the same values on
your firmware encrypted drive that they would on an ordinary drive it
would further lower the detection threshold.
There’s no secret sauce here, just industry standard algorithms that have
stood up quite well so far. If you can crypto-analyze the industry
standards in use, you can do that with the drive. Though you have to
persuade the drive to give you the data off the platters in the first
place, and the way it comes out of the box, it won’t. Spin-stands and such
aren’t much use any more, as the tracks are so narrow and the bits so close
together, not to mention the black magic inherent in the various flavors of
PRML, anyway, that you pretty much have to have the original heads and
nonvolatile adaptives to read the media reliably.
Of course, all of this depends very much upon your threat model, too.
I’m assuming a rather hostile environment in which the physical device
itself has been compromised and is available for a leisurely study.
Fortunately, if this came out of a PC class machine I at least have a
good idea of what I expect to “see” in the MBR so it will simplify my
differential cryptanalysis attacks (for example). In that type of
hostile environment I want a biometric device with feedback capabilities
(e.g., a fingerprint reader that checks for stress levels - galvanic
response, heart rate, blood pressure).
As I said, if you have enough horsepower to cryptanalyze some very robust
industry standard algorithms, you can probably figure out the data from the
drive. But first you have to get the data off the platters, and that’s no
simple task. I do suspect that with enough budget, like those agencies
that don’t admit their existence, funded through $5000 hammers, you could
do this. Aside from that, it’s a pretty robust data hiding repository.
I’m assuming that these are standard options for this disk drive - e.g.,
standard model number so there’s no way to determine (externally) that
it supports encryption and it has some interface mechanism for a
biometric key system? This sounds wonderful - I want a 120GB one for my
laptop. 
Umm, no, if you want to do biometrics, you are going to have to trust the
host to provide whatever biometric attestation you choose to use. But the
capability is there to validate the biometric data inside the drive, as
part of your decision to allow data off the drive, if you choose to arrange
things that way.
Sorry for the blatant advertising, but you asked… I don’t know of
any release dates yet, but take a look at http://www.seagate.com, there is
some preliminary info on this thing there.
Phil
Philip D. Barila
Seagate Technology LLC
(720) 684-1842
