Floppy recovery

Eric Smith spacewar at gmail.com
Thu Jan 7 14:33:28 CST 2016

On Thu, Jan 7, 2016 at 1:17 PM, Paul Koning <paulkoning at comcast.net> wrote:
> If you want data security and don't like destroying your hardware, SED ("self-encrypting drives") are a solution. Those encrypt all data, and "erase" by discarding and replacing the data encryption key.  So all your sectors instantly turn to random noise.  SSD versions of those are starting to appear, which addresses the invisible old copies problem that regular SSDs have.  The great thing of an SED is not just the security of its erase function, but in particular the speed: it takes only seconds to destroy all the data on the drive.

You're assuming that the SED doesn't store an extra copy of the
decryption key in NVM or on the medium. IMO, that's a very naive
assumption. Also, reverse-engineering has shown that at least some
SEDs have very bad crypto implementations.

Even if your SED doesn't have a back door or badly implemented crypto,
you also have to worry about whether someone has managed to install
compromised firmware on it. People once thought that hacked drive
firmware was too difficult or expensive to develop for anyone other
than three-letter agencies, but that's been proven false.

I'm OK with an SED being a component of the data security solution,
but I'm not willing to count on it exclusively. I'll still run
software disk encryption. Preferably open-source software disk
encryption, so that the source code can be audited, though that's not
a guarantee either.

One might expect that simple security measures would be enough as long
as the threat model you're concerned with isn't three-letter agencies.
Unfortunately any back doors or badly implemented crypto, whether
installed by TLAs or just through incompetence, are likely to be
exploited by many miscreants, not just TLAs.

If your threat model IS three-letter agencies, you're basically doomed
from the outset.

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