Investigation of Unintentional Video Emanations From a VGA Connector in the Desktop Computers

This paper focuses on the compromising video emanations from a desktop computer with a liquid-crystal display (LCD). Near-field tests are performed in a common unshielded office environment to investigate the video information leakage, and the tests show that the video graphics adapter (VGA) connector is a leaking source. To illustrate the mechanism of the video leakage, a wire antenna model is developed according to the physical dimensions of the connector. The radiated fields of the connector are calculated in the time domain from this model, the results are verified by the tests. Combining the expressions of the radiated fields and the transfer function of the test probe, the function relationship between the original red/green/blue signal and the intercepted signal is established. Finally, a readable text is reconstructed from the intercepted signal when a Chinese document is displayed on the LCD.

[1]  Yasunao Suzuki,et al.  Jamming technique to prevent information leakage caused by unintentional emissions of PC video signals , 2010, 2010 IEEE International Symposium on Electromagnetic Compatibility.

[2]  M. Kanda.  Standard probes for electromagnetic field measurements , 1993 .

[3]  Jong-Gwan Yook,et al.  Noise-Jamming Effect as a Countermeasure Against TEMPEST During High-Speed Signaling , 2015, IEEE Transactions on Electromagnetic Compatibility.

[4]  Wim van Eck,et al.  Electromagnetic radiation from video display units: An eavesdropping risk? , 1985, Comput. Secur..

[5]  Yu-ichi Hayashi,et al.  A Threat for Tablet PCs in Public Space: Remote Visualization of Screen Images Using EM Emanation , 2014, CCS.

[6]  Takashi Watanabe,et al.  Introduction to the Special Section on Electromagnetic Information Security , 2013, IEEE Transactions on Electromagnetic Compatibility.

[7]  Y. Yamanaka,et al.  Method for Determining Whether or Not Information is Contained in Electromagnetic Disturbance Radiated From a PC Display , 2011, IEEE Transactions on Electromagnetic Compatibility.

[8]  Markus G. Kuhn,et al.  Compromising Emanations , 2002, Encyclopedia of Cryptography and Security.

[9]  A. A. Sokolov,et al.  Transient radiation of traveling waves by wire antennas , 1995 .

[10]  Jong-Gwan Yook,et al.  Modeling of Leaked Digital Video Signal and Information Recovery Rate as a Function of SNR , 2015, IEEE Transactions on Electromagnetic Compatibility.

[11]  Hidema Tanaka,et al.  A Trial of the Interception of Display Image Using Emanation of Electromagnetic Wave , 2005 .

[12]  Markus G. Kuhn,et al.  Electromagnetic Eavesdropping Risks of Flat-Panel Displays , 2004, Privacy Enhancing Technologies.

[13]  Shih-Chung Tuan,et al.  Investigation of electromagnetic interferences caused by the stacked I/O connectors , 2011, 2011 IEEE International Symposium on Antennas and Propagation (APSURSI).

[14]  M. G. Kuhn,et al.  Compromising Emanations of LCD TV Sets , 2013, IEEE Transactions on Electromagnetic Compatibility.

[15]  Jong-Gwan Yook,et al.  An information recovery technique from radiated electromagnetic fields from display devices , 2016, 2016 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC).

[16]  Degang Sun,et al.  A novel method for computer video leaking signal detection , 2014, 2014 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining (ASONAM 2014).