Method for Determining Whether or Not Information is Contained in Electromagnetic Disturbance Radiated From a PC Display

To evaluate the possibility of information leakage by observing the electromagnetic disturbance radiated from a PC display, we propose an evaluation method by using a spectrum analyzer that is commonly used for electromagnetic interference measurement without reconstructing the displayed image. In this method, we measured the spectrum when the white and time-varying stripe patterns are displayed, and determined whether or not the disturbance contains the frequency component of the display pattern from the level difference. By using the patterns, we can easily evaluate the possibility of information leakage in radiated disturbance from a PC display in a wide frequency range.