Is It Possible to Eavesdrop on Electromagnetic Radiation?
Every electronic, electro-optical or electromechanical device gives off some type of electromagnetic signals, whether or not the device was designed to be a transmitter. This is why the use of cellular phones is not permitted on airplanes or in many areas in hospitals — their unintentional signals can interfere with equipment sensitive to picking up electromagnetic radiation (EMR). Since World War II, scientists have known that the EMR that “leaks” from devices can be intercepted and, using the proper equipment, reconstructed on a different device. The EMR that is emitted by electric devices contains the information that the device is displaying or storing or transmitting. With equipment designed to intercept and reconstruct the data, it is possible to steal information from unsuspecting users by capturing the EMR signals. For example, in theory someone sitting in a van outside a person’s house can read the EMR that is emanating from the user’s laptop computer inside the house and rec
