Re: Interesting One

From: Brad (gryphonn@austarnet.com.au)
Date: 10/30/02 

From: "Brad" <gryphonn@austarnet.com.au>
To: security-basics@security-focus.com
Date: Wed, 30 Oct 2002 16:19:20 +1000

On 29 Oct 2002 at 12:15, John Orr wrote:

Date sent: Tue, 29 Oct 2002 12:15:22 -0600
From: "John Orr" <JOrr@austinbank.com>
To: <dadams@johncrowley.co.uk>, <security-basics@security-
focus.com>
Subject: Re: Interesting One

> Personally, I think he is full of... hot air.
>
> Bits are either "on" or "off", "1" or "0". If you change that pattern (i.e. write over the same data area with a different sequence of bits), then the previous state of that field would not be determinable. Granted, there may be some residual magnetic field left on a particular area that is
now "0" that had been "1", but the converse would not be true. There would be no residual field to read on an area that is now "1" that had been "0".
>
> Sounds like sales fluff to me.

*small snip*

Here are some links to more information concerning the recovery of data
from HDDs etc. Some of the information is a little old, but should still
provide for interesting reading:

'Secure Deletion of Data from Magnetic and Solid-State Memory'
http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html

(more of Peter's writing here)
http://www.cs.auckland.ac.nz/~pgut001/

'Thoughts on secure deletion in 2001 (pt2)
http://www.doxpara.com/read.php/security/secure_deletion2.html

'Secure deletion of data media'
http://secinf.net/info/misc/gshb/s/s2167.htm

'Ghosts'
http://security.tao.ca/ghosts.shtml

Cheers, 

-- 

'When you meet someone better than yourself,
turn your thoughts to becoming his equal. 
When you meet someone not as good as you are, 
look within and examine your own self....'
Confucius
**
Brad Griffin
Gryphonn Design
Computer Security Solutions
Custom designed systems
Ph: 0409057865/(07)4922 2589
Rockhampton QLD 4700
ABN: 12 095 821 961
gryphonn@austarnet.com.au
***************************