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<div class="moz-cite-prefix">On 1/7/26 1:59 PM, John Levine wrote:<br>
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cite="mid:20260107215925.588DFEF69EF6@ary.qy">
<pre class="moz-quote-pre" wrap="">T-7 is about shredding magnetic media, not paper. I don't see what relevance that has.</pre>
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<p>Thank you.</p>
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cite="mid:20260107215925.588DFEF69EF6@ary.qy">
<pre class="moz-quote-pre" wrap="">The spec says that T-7 shreds magnetic media into chips no larger than 2.5mm�. I agree
that it seems implausible that one could recover data from those.
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<p>Given crazy disk densities, I can imagine that there might be
recoverable data on that. And, as erased data isn't necessarily
erased, maybe there is some strategy for recovering files that get
copied and more than once? Maybe it is a bit like piecing together
DNA sequences.</p>
<p>Were I paranoid about such things I would be happy with the
current shredding size, but then insist on some post processing
step. Heat? A caustic solvent? Stirring a cooking slurry of said?</p>
<p>It is possible that the benefit of shredding is the destruction
if data where the cuts are made not in the jigsaw puzzle of the
remaining bits. </p>
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<p>Not that this answers the original question: What has prompted
this?</p>
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<p>As for wiping data I like the approach of storing lots of high
quality random data and then read it back out, the only way the
storage device can regurgitate the data correctly is by honestly
storing it. Do this repeatedly and any old data that could be
recovered has to be small, or the device is leaving too much
capacity unsold. But the approach I really like is full disk
encryption. I am suspicious of letting the device claim to do the
encryption, so I like the idea of the opensource OS doing it. (And
no Microsoft tricks of not encrypting because the device said it
will do it.)</p>
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<p>I have long done full-disk encryption of my laptops, but what
about the boot partition? Only with my most recent machine have I
done <i>full</i>-full-disk encryption: I don't have boot
partition, the machine (as it sits in the hotel room awaiting the
evil main) is not bootable at all. I boot with a tiny external
thumbdrive I keep separately. There is still plenty the evil made
can do, no doubt.</p>
<p>To prove to some security person that it is a working computer
(do they still do that?) boot from a "live CD" thumbdrive and
don't decrypt the internal storage at all.</p>
<p><br>
</p>
<p>-kb, the Kent who doesn't think anyone is really after his data
(excepting that time he visited China), but who crafts his
personal security as more of an intellectual exercise.</p>
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