Jamming technique to prevent information leakage caused by unintentional emissions of PC video signals

A working personal computer (PC) and/or a PC display monitor usually produce unintentional electromagnetic fields. Information from a video display unit could be reconstructed by intercepting such emissions at a distance. Proper measures are needed to prevent information leakage through such eavesdropping. We have investigated countermeasures for such a problem and proposed jamming schemes for industrial and home use. We also developed a prototype for protecting devices and evaluated its performance in preventing such emanation eavesdropping.