Re: [TSCM-L] Re: Acoustic Absorbing Materials

From: <d..._at_geer.org>
Date: Mon, 18 Sep 2006 23:13:36 -0400

trixter aka Bret McDanel writes:
>
> And if no one is paying attention but someone does a frequency
> sweep they will know the frequency its tuned to (because as soon
> as they hit a carrier on the given freq it goes silent - this can
> be done at night when no one is around).
>

By one theory, public key cryptography was created by
the US Navy in WW2 when someone noted that if you
broadcast white noise on a known channel, then the
person wanting to communicate with you has only to
transmit on that self-same channel and, from that
person's point of view, they can do so in the clear.

An eavesdropper hears white noise but the base station,
as it knows what it is transmitting, has no difficulty
subtracting it out and thus recovering the counterparty
talking. So, in your example, you replace the naturally
occuring white noise with your own white noise and,
bingo, you can silence the room, so to speak. This
would be oh such a nasty gotcha if one's opponent were
to get physical access to your white noise generator
and could thus pull this on you in reverse...

--dan
Received on Sat Mar 02 2024 - 00:57:21 CST