From: ghoast@gnu.ai.mit.edu
Date: Sat, 27 Mar 93 12:33:31 PST
To: cypherpunks@toad.com
Subject: Re:  TEMPEST in a teapot
Message-ID: <9303272031.AA36215@hal.gnu.ai.mit.edu>
MIME-Version: 1.0
Content-Type: text/plain


> 
> ----- Begin Included Message -----
> 
> It is speculated that poorly protected systems can
> be effectively monitored up to the order of one kilometer from the target
> equipment.
> 
> ----- End Included Message -----
> 
> The "readability" of the relatively high energy sweeps in a standard CRT monitor
> is well known. Any idea of similar effects on LCD screens ?  The energy involved
> would be orders of magnitude less, just for starters.  Also, since the whole screen
> is effectively oscillating, I'm not sure that there is any 'raster' sweep per se
> going on here at all.  This could be a factor for the truly paranoid :-) using 
> portables with LCD screens.
> 
> 
> Pete Carpenter                           pete@cirrus.com
>                                 

I've been told that the CRT is not what is generating the signals at all, rather
that it is the CPU, and that having an LCD screen won't save you, strength of
signal reduced or otherwise.