From: jfricker@vertexgroup.com (John F. Fricker)
Date: Sun, 8 Sep 1996 07:42:40 +0800
To: cypherpunks@toad.com
Subject: Re: What the NSA is patenting
Message-ID: <2.2.32.19960907212748.00ada824@vertexgroup.com>
MIME-Version: 1.0
Content-Type: text/plain


At 02:03 PM 9/6/96 -0700, you wrote:
>At 12:50 AM 9/7/96, Jean-Francois Avon wrote:
>>A maybe usefull program would be a little tsr that constantly
>>overwrite unused sectors of the entire drive with random patterns
>>(maybe seeded with a fast keyboard interval timer).  Like at the very
>>moment I am writing this, my HD has been idle for several minutes...
>>
>
>
>The NSA STM method is related to reading _very subtle_ variations in
>magnetic domain modifications. Jitter in read-write head positions can be
>thought of as a noise (N) added to some signal (S)l. Extraction of signals
>in low S/N ration environments is a well-developed science.
>

This excerpt from a Wired article/interview
http://www.hotwired.com/wired/3.10/departments/electrosphere/data.html

"No data is totally safe," says Sharp, who runs his Data Recovery Labs from
the coincidentally named town of Safety Harbor,
Florida. "But you can recover data that's been overwritten up to nine times.
The only way to permanently remove data is with
programs that can do a 'severe security erase,' when the drive is
over-written 10 consecutive times." 


Believe it or don't!