From: Chuck Kuecker (ckuecker@mcs.net)
Date: Sun May 07 2000 - 09:36:21 MDT
At 02:19 AM 5/7/00 -0400, Mike Lorrey wrote:
>This data deals with air broadcast radiofrequencies. One area that is
>not public knowledge, or what I haven't seen much of to date, are
>signals transmitted in the sinewave harmonic patterns through the power
>lines. These are quite present, and they can be amplified by a
>surveillance system through use of a few simple components to boost the
>harmonic output of the surveilled facility.
Really? I would imagine any small transients present from the internal
components of the computer would be hopelessly scrambled by the switching
power supply. I know that modern signal processing can do wondrous things,
but this seems like too much of a miracle.
The recent proliferation of power factor corrected switching power supplies
should make short work of that avenue of attack, anyway. If not, well, a
good line filter should not be to difficult to build. There's a big push
toward having a clean load with no harmonics, especially in Europe.
Another defense would be to intentionally put out "data" on the line
generated by another device. This could be plain text, or something
innocuous encrypted to make it look like secure data. Swamp out the
important stuff with garbage.
Chuck Kuecker
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