Summary
International Symposium on Electromagnetic Compatibility
2009
Session Number:21P1
Session:
Number:21P1-4
Synchronization Clock Frequency Modulation Technique for Compromising Emanations Security
T. Watanabe, H. Nagayoshi, H. Sako, T. Uemura,
pp.13-16
Publication Date:2009/7/20
Online ISSN:2188-5079
Summary:
The security problem of screen image leakage on a display unit through electromagnetic radiation from several meters away has attracted wide interest by security researchers since van Eck wrote about this problem. To solve the problem, techniques for reducing the S/N ratio of emanating information by signal reduction and noise generation have been proposed as countermeasures. Different from them, we investigate a technique that fluctuate frequencies of synchronization signals in display image transmission to reduce correlation between timings of display and transmission. We not only explore the most effective modulation target but also realize a real-time signal modulation unit by a FPGA board, and verified the effectiveness of the technique using a system of a PC and LCD.