On Sat, 3 Jul 2004, Major Variola (ret) wrote:

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And digital edges are sharp, in the Ghz even when the "clock" is in

At 04:35 AM 7/4/04 +0200, Thomas Shaddack wrote: the

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Mhz.

How much do the "spread spectrum clock" feature on the modern motherboards help here?

They do complicate things. But I bet their spread-spectrum jitter is derived from a PRNG. All your PRNGs are belong to us. 'Specially because you can just buy them and either analyze their output, or strip the layers and get back to the Verilog.

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And boxes need ventilation slots.

Not necessarily.

Indeed Centaur/Via's x86 w/ crypto is advertized as "fanless"

There are other ways of heat transfer. A good way could be water cooling for transport of the heat from the CPU and other parts to a massive metal heatsink that's the part of the case, with an optional fan on its outside. Voila, water cooling is not only for case mod freakz anymore.

Just put the ventilated box in a bigger box and use some steel wool in the ductwork to the outside...

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Any questions?

I expect much bigger problem in the attached cables and connectors. How to solve this?

Shielding. Shielded room. Shielded building. Basic idea: electro-magnetic disturbances penetrate only a short distance into conductors. Folks who deal with low noise amplifiers deal with this all the time. Ground loops. Faraday cages. Low voltage differential signalling. Grounded thin metal layer over your LCD display. I once worked for a chipmaker and they had a metal room. Horrible ventilation. Copper gaskets on all the seams. You could probe a chip in there, with a microscope and micromanipulators. But they also had a PC which kinda nulled out the RFI issue. However that PC's output would not have escaped. The power cables from the outside to inside are an issue too. As Schneier says, pros go after people, not tech; which is not to say you can ignore RF tracking if you're a target. I don't think you can "fish" with van Ecyk (sp?) tech, although wardriving/flying sorta counts, except that those are intentional emitters. If I promise you a green card or citizenship, and give you a grand, will you install this gizmo between the keyboard and computer for me when you're cleaning the office? (Assuming you're an 'illegal' working for shit wages and the Suit has credentials, or cash, or both. Ask Nicky Scarfo about this..) Or plug a camoflaged 802.11blah AP into a RJ-45 and listen from the van... (Succeptible to sweeps, but how often are they done? And real pros use bursty bugs that aren't broadcasting all the time, eg in the woodwork of the State Dept.)