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ronys wrote:
<blockquote cite="mid:877F2C69942C415984AD6A370EE4D28D@LYDIA"
type="cite">
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<div><font color="#0000ff" face="Arial" size="2"><span
class="815303314-18082009">Hi Shachar,</span></font></div>
<div><font color="#0000ff" face="Arial" size="2"><span
class="815303314-18082009"></span></font> </div>
<div><font color="#0000ff" face="Arial" size="2"><span
class="815303314-18082009">'urban legend' may be a bit strong. The
reference I had in mind was</span></font></div>
<div><font color="#0000ff"><span class="815303314-18082009"><a
moz-do-not-send="true"
href="http://www.cs.auckland.ac.nz/%7Epgut001/pubs/secure_del.html">http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html</a></span></font></div>
<div><font color="#0000ff" face="Arial" size="2"><span
class="815303314-18082009">which is a bit dated (circa 1996, plus a
couple of undated epilogues), but still an interesting read.</span></font></div>
<div><font color="#0000ff" face="Arial" size="2"><span
class="815303314-18082009"></span></font> </div>
<div><font color="#0000ff" face="Arial" size="2"><span
class="815303314-18082009">Of course, if you're going to keep
sensitive data on magentic media, it's *much* easier to use an
encrypted partition (e.g., dm-crypt <a moz-do-not-send="true"
href="http://www.saout.de/misc/dm-crypt/"><font face="Times New Roman"
size="3">http://www.saout.de/misc/dm-crypt/</font></a> or TrueCrypt <a
moz-do-not-send="true" href="http://www.truecrypt.org/">http://www.truecrypt.org/</a>)
and securely destroy the keys.</span></font></div>
<div><font color="#0000ff" face="Arial" size="2"><span
class="815303314-18082009"></span></font> </div>
<div><font color="#0000ff" face="Arial" size="2"><span
class="815303314-18082009">Rony</span></font></div>
</blockquote>
Thanks. That seems like an excellent resource (with reasoning, unlike
what I'm used to :-).<br>
<br>
I haven't delved into it, yet, but its description of how the drive
actually writes data to the disk differs dramatically from what I
remember described the last time I saw a description of the recovery
process (it claims the 1 and 0 are merely encoded as magnetic polarity,
while I remember them being modulated on a sine wave). Which it
actually is, I'm not sure, but the reasoning your article states for
using random data (create as low a frequency as possible given the
disk's RLE) is negated if the data is actually modulated.<br>
<br>
Unfortunately, I have lost track of my previous source, but pending
further analysis, I'm willing to retract my definitive claim that
needing to use random data is an urban myth.<br>
<br>
Shachar<br>
<br>
<pre class="moz-signature" cols="72">--
Shachar Shemesh
Lingnu Open Source Consulting Ltd.
<a class="moz-txt-link-freetext" href="http://www.lingnu.com">http://www.lingnu.com</a>
</pre>
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