Information leakage via electromagnetic emanation and effectiveness of averaging technique

It is well known that there is relationship between electromagnetic emanation and processing information in IT devices such as personal computers and smart cards. In this paper, we show how to estimate amount of information that is leaked as electromagnetic emanation and effectiveness of averaging technique. We assume the area between the IT device and the receiver is a communication channel, and we define the amount of information leakage via electromagnetic emanations by its channel capacity. And we also estimate the maximum amount of information which eavesdropper can get via electromagnetic emanation. By using these estimations, we derive the necessary amount of data for effective averaging technique.