Unintentional Emanations and TEMPEST

CS 463/480 Lecture, Dr. Lawlor

Electromagnetic radiation can transmit secrets for miles: see TEMPEST standards for radio transmission shielding. CRT displays are notorious for leaking information, and even an unused VGA cable can act as a passive transmitter capable of short-range FM broadcast.  Clever folks with telescopes have reconstructed ethernet packets from the blinking pattern of the activity LED.

In 1945, the Soviets (at the time our allies) presented a carved wooden Great Seal of the United States to the US ambassador.  In 1952, a passive audio-to-radio converter was discovered under the eagle's beak, later found to be a sort of passive bug like RFID.