Optical Tempest FAQ

Sunder sunder at sunder.net
Thu Dec 2 14:52:26 PST 2004


IMHO, if you light up two or more other identical CRT's and have them 
display random junk it should throw enough noise to make it worthless - 
(and would put out enough similar RF to mess with RF tempest) there might 
be ways to filter the photons from the other monitors out, but, it would 
be difficult.

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On Thu, 2 Dec 2004, Tyler Durden wrote:

> Interesting.
> Contrary to what I thought (or what has been discussed here), only a 
> 'scalar' of detected light is needed, not a vector. In other words, merely 
> measuring overall radiated intensity over time seems to be sufficient to 
> recover the message. This means that certain types of diffusive materials 
> will not necessarily mitigate against this kind of eavesdropping.
> 
> However, his discussion would indicate that the various practical concerns 
> and limitations probably limit this to very niche-type applications...I'd 
> bet that it's very rare when such a trechnique is both needed as well as 
> useful, given the time, the subject and the place.
> 
> -TD
> 
> >From: Sunder <sunder at sunder.net>
> >To: cypherpunks at al-qaeda.net
> >Subject: Optical Tempest FAQ
> >Date: Thu, 2 Dec 2004 10:27:04 -0500 (est)
> >
> >http://www.cl.cam.ac.uk/~mgk25/emsec/optical-faq.html
> >
> >Along with tips and examples.
> >
> >Enjoy, and don't use a CRT in the dark. :-)





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