Re: Inquiry:How to totally wipe out the entire hard drive

On Sun, Sep 6, 2009 at 3:08 PM, Boyd Stephen Smith Jr. <
bss@xxxxxxxxxxxxxxxxx> wrote:

In <4AA40AC8.2050804@xxxxxxxxxxxxx>, Napoleon wrote:
John Hasler wrote:
I wrote:
If you want to destroy all the data for security purposes install and
use shred. It will take quite a while on a large disk.

Ron Johnson writes:
This really is a myth.

What is?

In actual fact, overwriting with zeros once probably suffices for a
modern drive (but there is the problem of bad blocks...)

(Should have gone to the list but I screwed up the first time - sorry).

Overwriting with zeros (or ones) once is not at all secure.

This is totally, absolutely a myth. The 1996 paper used a recovery
technique
that doesn't work on modern drives, and admitted that only one random write
would likely be more than enough to prevent recovery. More recently,
actual
research was done on the topic, and a single-pass, fixed-pattern (all
zeros)
was still impossible to recover more than a few bytes from a modern hard
drive.

Zac, do you have the URL for that paper handy? I know you sent it out end
of
last year or the beginning of this one, but I seem to have misplaced it.


Yes I've attached the research paper titled "Overwriting Hard Drive Data:
The Great Wiping Controversy"(PDF) that shows this is only a myth. These
guys did the work and it's very enlightening. See the chart on page 10 to
see how impossible it is to recover bits from an overwritten drive.

--
Zac Slade
krakrjak@xxxxxxxxx

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