Method for determining whether or not text information is leaked from computer display through electromagnetic radiation

Abstract

Confidential information might be leaked through electro-magnetic radiation from a computer display. To detect the electromagnetic radiation that contains text information, this paper proposed an evaluation method without reconstructing the displayed image. In this method, sparse decomposition in wavelet is used to describe the characteristics of electromagnetic radiation signals contain text information. By using this method, it is easy to detect text information leakage in electromagnetic radiation from a computer display.