From Rask <>
Date Thu, 28 Oct 1999 01:18:56 +0000
In-reply-to <016101bf20c3$dce267c0$>
References <>

[: hacktivism :]

well, since a monitor display is a matter of lines created successively, I
don't think it should be hard to reconstruct an image, if you can pick up
the subtle differences in the amount of radiation set free at any given
point in time... and if you know the screen's frequency.
According to Wired (if I remember correctly), exactly this has already been
Also, the idea just struck me that tempest could possibly play a valuable
role in collecting specifications for new enemy equipment and such... but
that's just an idea, and it's late and I need sleep.

At 07:40 28.10.99 +1000, you wrote:
>[: hacktivism :]
>sure your monitor might radiate X-Rays (I imagine not very many nor at any
>high power otherwise they would be banned for health reasons) but the real
>question is can that radiation be used to reconstruct what you are doing?
>apart from some intelligence that you've got the computer ON that is.
>Also previsously someone also mentioned TEMPEST scanning from satelittes, I
>would be very dubious about that, some simple radio physics tells you that
>the power the satellite picks up would be miniscule, and (more to the
>point) obliterated by background noise and interference with the other many
>thousands of monitors and other electrical/radio equipment in your area. I
>think its more a "building next door" type scenario. Not even the NSA can
>change the laws of physics.
>----- Original Message -----
>From: Me Uh, K. <>
>To: <>
>Sent: Thursday, October 28, 1999 2:01 AM
>> [: hacktivism :]
>> my best guess is that in order for this to work, you
>> need to actually block ALL electrical emisions from
>> the source - I would assume that you need x-ray
>> sheilding to effectivly protect your computers.  But
>> I'm just talking - I don't really know.
>[: hacktivism :]
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