Re: Interesting One

From: Carol Stone (
Date: 10/29/02

Date: Tue, 29 Oct 2002 13:57:45 -0700
From: "Carol Stone" <>

I don't know much about this, but yesterday I read in one of the later
chapters of Bruce Schneier's book, "Secrets and Lies," (link to amazon
follows) that over-writing data on a disk does *not* completely
obliterate it, it just makes it a lot more difficult to recover with
each over-write. I believe he said just how many re-writes were still
recoverable was a secret one of our governmental organizations wasn't
about to give up. I'll look at my book later when I have it in my
hands and see if I can't find part and post a pointer to *his*


> Greetings Folks,
> I had an interesting conversation today with someone from FAST
> (Federation
> Against Software Theft) They pretend not to be a snitch wing of the
> Anyway, to get to the point, the guy that came to see me said that
> forensics guys could read data off a hard drive that had been written
> over
> up to thirty times. I find this very hard to believe and told him I
> thought
> he was mistaken but the guy was adamant that it could be done. My
> question
> is, does anyone have any views on this, or, can anyone point me to a
> source
> of information where I can get the facts on exactly how much data can
> retrieved off a hard drive and under what conditions etc etc.
> Thanks
> Dave Adams
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