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RE: Suggestions on free XP hard drive wiping utilities?
From: "Craig Searle" <craig.searle () sift com au>
Date: Thu, 13 Feb 2003 12:28:08 +1100

Actually this is an urban myth....DOD standards indicate that 4 passes in
generally enough to render most data unrecoverable to most forensic analysis

You may also want to read a paper by Peter Gutmann, a Auckland University
Professor and IT Security Expert.
His website is http://www.cs.auckland.ac.nz/~pgut001/

Pardon me if I'm wrong, but wasn't this discussed on this mailing list

Craig Searle
SIFT Pty Ltd

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-----Original Message-----
From: Patrick Debois [mailto:Patrick.Debois () sos be] 
Sent: Thursday, 13 February 2003 04:50 AM
To: security-basics () securityfocus com
Subject: RE: Suggestions on free XP hard drive wiping utilities?

I've heard on a radio show there was a study that the number of erases
should be 13 (based on the material of the drive). Nothing to recover only
with computers but rather with microscopes.

If anyone knows a pointer to that research....

On Wed, 12 Feb 2003, David Verty wrote:

Date: Wed, 12 Feb 2003 03:10:58 +0000
From: David Verty <verticalrave () hotmail com>
To: security-basics () securityfocus com
Subject: RE: Suggestions on free XP hard drive wiping utilities?

There is a whole thread on ExtremeTech about this I believe...and it 
stretches on for a long run. You might find some useful information 
there, like DoD (Department of Defense) standards, and software that 
exceeds it for deletation of files.

What the government does right now to permanently get rid of data is 
shred the disk in a metal shredder.

Are there any programs for secure deletation? Never heard of any 
really that were extremely good.

And i've heard of hard disks storing everything in so called 'layers' 
(you have to rewrite your disk three or four times+ with phony data to 
truly get rid of everything.) but the edge thing is something i've 
never heard about. Interesting. Somebody on ExtremeTech also mentioned 
that since the signals are theoretically magnetic, its possible to 
extract the strength of the previous magnetic signal (though weak) and 
rebuild the data from there. Whatever validity that has i'm not so 

From: "MacFerrin, Ken" <Ken_MacFerrin () csgsystems com>
To: <security-basics () securityfocus com>
Subject: RE: Suggestions on free XP hard drive wiping utilities?
Date: Tue, 11 Feb 2003 11:20:16 -0600

There are dozens of tools that will "clean" your hard drive by 
overwriting your data in various patterns and such and most any of 
those will give you "decent" security, but.. none of those are going 
to make the data irretrievable to someone with the right equipment.

I'm no expert but the basics of being able to retrieve data stem from 
the fact that when the HDD head overwrites the data it's never able 
to perfectly write along the same track that it did when writing the 
original data.  This leaves an "edge" of data that wasn't quite 
overwritten and that "edge" is enough for someone with a basic setup 
(about 1500 USD) of specific equipment to go back and pull the 
original 1's and 0's off the disk..  The only way to truly "clean" 
the disk is using equipment specifically designed to drive the head 
at a higher voltage to create a wider write track and re-write random 
patterns many times.  From what I understand though even these 
re-writes will leave some residue that could be picked up by some 
high-end gear and a skilled operator.

Essentially, if the data was really that sensitive, you need to 
physically destroy the disk.. -Ken

-----Original Message-----
From: Joris De Donder [mailto:joris () digitaldefense be]
Sent: Tuesday, February 11, 2003 6:21 AM
To: 'security-basics () securityfocus com'
Cc: Champion, Steve
Subject: Suggestions on free XP hard drive wiping utilities?

Would someone please throw out a URL and suggestions for free 
hard drive wiping utility's?


  "Eraser is a secure data removal tool, which allows you to remove
   sensitive data from your hard drive by overwriting it with carefully
   selected patterns.

   The program is free software, which means that everyone has
   access to the source code,..."

Joris De Donder

MSN 8 with e-mail virus protection service: 2 months FREE* 

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