[117304] in Cypherpunks
Re: Project: Hardening Crypto Against Big Brother
daemon@ATHENA.MIT.EDU (Tim May)
Tue Aug 31 03:48:09 1999
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Date: Tue, 31 Aug 1999 00:09:28 -0700
To: cypherpunks@Algebra.COM
From: Tim May <tcmay@got.net>
Reply-To: Tim May <tcmay@got.net>
At 6:02 PM -0700 1999-08-30, David Honig wrote:
>At 04:06 PM 8/30/99 -0400, Sunder wrote:
>>Hmmm, does it also help tempest shielding? If so where does one obtain leaded
>>crystal glass, say suitable for a 14" LCD monitor again? :)
>
>Tempest shielding requires *conductive* surfaces.
>Possibly also mag-permeable materials.
>
Yep. And there's a lot of physics and EM to RF suppression and TEMPEST
shielding.
More than just being conductive, the _skin depth_ is critical. It depends
on frequency.
By the way, there is no reason to expect that a high-Z material like PbO in
glass will have _any_ significant RF shielding effect. The Z of the atoms
affects x-ray absorbtion a lot more than it affects RF absorbtion!
I really can't understand why we have these half-assed discussions of
TEMPEST every several months or so. If someone wants to bone up on TEMPEST,
read some papers, do some calculations, run some experiments...great,
wonderful, trippy, etc.
For starters, TEMPEST is not "tempest." Nor is it "T.E.M.P.E.S.T." It's
just a program name, standing for nothing in particular. (Though there's a
back formation invented after the fact.)
Folks won't get very far idly speculating about leaded glass....
--Tim May
Don't tread on me.
---------:---------:---------:---------:---------:---------:---------:----
Timothy C. May | Crypto Anarchy: encryption, digital money,
ComSec 3DES: 831-728-0152 | anonymous networks, digital pseudonyms, zero
W.A.S.T.E.: Corralitos, CA | knowledge, reputations, information markets,
"Cyphernomicon" | black markets, collapse of governments.
