The present study was carried out to evaluate the information leakage of a computer display image that can be reconstructed using the conducted emission on its power leads. The reconstructed images can be generated from the relevant signal that was conducted-emitted by the switching of RGB (Red-Green-Blue) signals in the monitor. The relevant signal was then contained in the frequency region higher than 100 MHz in the conducted emission. From these findings, a measurement system was developed to measure the relevant signal in a conducted emission to 1000 MHz. The relevant signals of three PCs were then measured taking account of the signal-to-noise ratio. The measurement results revealed that the relevant signal level depended on the PC and receiving frequency. In addition, the qualities of the reconstructed images were checked using certain receiving frequencies. The reconstructed image quality and the measured relevant signal level were then compared for the same receiving frequency, and a correlation was found.
"Measurement of Computer Rgb Signals in Conducted Emission on Power Leads," Progress In Electromagnetics Research C,
Vol. 7, 51-64, 2009. doi:10.2528/PIERC09030907
1. ISO/IEC 27001, "Information technology-security techniques-information security management systems-requirements,", International Organization for Standardization and International Electrotechnical Commission, International Standard, 2005. doi:10.1016/0167-4048(85)90046-X
2. ISO/IEC 27002, "Information technology --- security techniques --- code of practice for information security management,", International Organization for Standardization and International Electrotechnical Commission, International Standard, 2005.
3. X.1051, "Information security management system --- Requirements for telecommunications (ISMS-T),", Telecommunication Standardization Sector of the International Telecommunication Union, International Standard, 2004.
5. Van Eck, W., "Electromagnetic radiation from video display units: An eavesdropping risk?," Computers and Security, Vol. 4, No. 4, 269-286, 1985.
6. Kuhn, M .G. and R. J. Anderson, "Soft tempest: Hidden data transmission using electromagnetic emanations," Proc. of the Second International Workshop on Information Hiding, Portland, USA, April 1998.
7. Sekiguchi, H. and S. Seto, "Proposal of an information signal measurement method in display image contained in electromagnetic noise emanated from a personal computer," Proc. of IEEE Conf. on Instrumentation and Measurement Technology, Victoria, Canada, May 2008.
8. Sekiguchi, H. and S. Seto, "Measurement of radiated computer RGB signals," Progress In Electromagnetics Research C, Vol. 7, 1-12, 2009.
9. Sekiguchi, H. and S. Seto, "Evaluation method of information leakage for display image reconstructed from electromagnetic noise of personal computer," Proc. of 2008 IEEJ Symposium, No. 1-S2-9, 25-28, 2008 (in Japanese)..
10. MIL-STD-461E, "Requirements for the control of electromagnetic interference characteristics of subsystems and equipment,", Department of Defense, Interface Standard, 1999.
11. IEC 61000-6-3, "Electromagnetic compatibility (EMC) --- Part 6-3: Generic standards --- Emission standard for residential, commercial and light-industrial environments,", International Electrotechnical Commission, 1996.
12. CISPR 22, "Information technology equipment --- radio disturbance characteristics --- limits and methods of measurement ,", International Electrotechnical Commission, 1997.
13. Monitor Timing Specifications, Version 1.0, Revision 0.8, Video Electronics Standards Association, 1998.