[Cryptography] RFI Exploitation (was RE: 'The intelligence coup of the century')

[Dennis E. Hamilton]

Theodore Tso commented

> This wasn't just IBM mainframes.  There was a program (I think from DECUS,
but I could be wrong) that would broadcast music from a PDP-8/i to an AM
radio.  As I recall one of songs that it would play was "Flight of the
Bumblebee".

> In this case, though, I don't think we could call it a "side channel"
since the whole *point* of the program was to force radio "interference"
(I'm pretty sure the PDP-8/i wasn't certified by the FCC as a radio
transmitter).  :-)

That this is also a means for covert-channel communication as well as
surveillance has continued to this day, and there have been RFI warnings on
all manner of mini-computer, micro-computer, PC, tablet, smartphones, and
their accessories.  I am typing this message on a computer equipped with
wireless mouse and keyboard, and my smartphone is sitting here lurking on
the WiFi of my residential broadband router.

The frequencies differ, and multi-threading/-processing make direct
connection of audio devices more appealing for those who want to hear music.
I suspect that harmonics down to AM frequencies might not be so controllable
as in days past.  There are far more attractive exposures in place instead.

 - Dennis