A safe text editor // why??

Robert J. Hansen rjh at sixdemonbag.org
Mon Sep 10 23:55:38 CEST 2012

On 9/10/2012 3:37 PM, MFPA wrote:
> What about TEMPEST as a potential eavesdropping vector?

First, it's "Van Eck phreaking."  TEMPEST refers to a NATO standard for
*defending* against Van Eck phreaking.

Second, no, of course the distro-on-a-stick doesn't defend against Van
Eck phreaking.  The only defenses against Van Eck phreaking involve the
laws of physics, not mathematics.  Working inside a Faraday cage may
(may!) give some benefit.  Not quite sure, myself.[*]

[*] Although a Faraday cage blocks signals from coming *in*, the jury's
out on whether it blocks signals from *leaving*.  As an example, imagine
you have a Faraday cage that's hooked up to electrical ground.  You step
into the cage while carrying a balloon that you've rubbed on your head a
few times.  You're locked in the cage.  To signal your conspirator that
you want out, you touch your balloon to the cage.  The conspirator sees
a couple of picocoulombs of charge stream to ground, and unlocks the
cage.  From inside a Faraday cage you've just electrically signaled
someone outside the cage, thus demonstrating Faraday cages are *not* an
absolute bar against electrical signaling from the inside going out.
Whether this thought experiment is applicable to Van Eck is a different
matter, of course... but the naive "you can't get any electrical signal
out of a Faraday cage" view appears to be wrong, as a matter of physics.

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