Randall A Sindlinger on 14 Jul 2009 13:10:46 -0700

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Re: [PLUG] EMI shielding on the power line

On Tue, Jul 14, 2009 at 03:17:30PM -0400, TuskenTower wrote:
> I happened to see this sensationalist piece about eavesdropping
> keystrokes over the ground power line.
> http://news.bbc.co.uk/2/hi/technology/8147534.stm
> I was wondering if powering a computer with a UPS or a power line
> conditioner would eliminate this problem.  How would something like
> this affect a laptop or anything with a transformer in the middle.  My
> knowledge of electronics involved is minimal, which is why I'm asking.
> Amul

I think you can take off the tin foil hat.  :-) This was done with a PS/2
keyboard.  The electronics in USB are different enough that, if the
attack could still work, it would need to be largely re-engineered.

Furthermore, as you suspect, anything that isolates the source current 
from the computer circuitry in some way (UPS, power brick, etc) would 
sharply decrease the fluctuations if not eliminate them all together.

 (but who would listen to a Chemical Engineer?  :-)
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