Evaluation and improvement of the Tempest Fonts

Abstract

Information leakage via electromagnetic emanation, usually known as Tempest, has been recognized as a threat and countermeasures have been proposed. In particular, Kuhn and Anderson developed a protective measure for Tempest called the Tempest fonts. Through experiments, we have investigated and evaluated the effectiveness of the Tempest fonts. Furthermore, we propose a new measure based on a similar approach to prevent successful Tempest attacks. While Kuhn and Anderson use Fourier transformation as a low-pass filter, our approach uses a Gaussian filter in addition to Fourier transformation. Our experimental results show that this approach is more effective. © Springer-Verlag Berlin Heidelberg 2004.