[GRLUG] Data wiping / recovery / paranoia

[Michael Mol]

On 9/15/06, Tim Schmidt <timschmidt at gmail.com> wrote:
> On 9/15/06, Justin Denick <justin.denick at gmail.com> wrote:
> > I think the name of the prog Jorge is thinking of is called "shred" You can
> > even psecify how many time the data will be over written.
> >
> > But in the name of security, wouldn't Flah drives be the most secure an
> > easiest to sanitize. With the size of theses drives now they can hold a
> > pretty serious amount of Data.
>
> Flash drives are worse...  the wear-leveling logic in any modern flash
> drive transparently changes the effective location of bits any time it
> wants.  So, for instance, if you were to de-solder the actual flash
> chip and read the information from it in raw form, there would likely
> be lots more available than on a typical hard drive.  Even after using
> something like shred (unless of course you're shredding the entire
> drive - and not just the partition or file).
>
> That said...  modern hard drives do the same thing.  It's impossible
> to make a multi-trillion bit basket without quite a few errors...  so
> all drives have reserve sections of bits that they can remap into bad
> areas of the disk.  They come that way from the factory, and most can
> do it on the fly as well.  The reserve area isn't very large in
> relation to the total size of the drive, but it's just one more layer
> of indirection that makes 100% assurance that your data is sanitized a
> very hard thing to guarantee.

I've heard about tools that allow you to remap that reserved area of
some hard drives as part of the LBA-accessible range.  I don't know
their names, though. (I read about it on Slashdot back when
overclocking was all the rage, and the run-above-spec attitude was
being applied to components other than the processor, FSB and PCI
bus.)

It stands to reason that one could then fashion a tool that would wipe
those areas of those drives.


-- 
:wq