Research On Signal Processing And Recovering Technology Of Computer Video Leakage Information

The processing of human social information industry goes at a tremendous pace. As an instrument to dispute information resource, informing counterwork has much more attention all over the world. The interrelated information war, information security, electronic warfare and so on would be the hot topics. The beginning of 20C50s, the military authority of the United States discovered miscellaneous emanation of electromagnetism in the computer system will cause sensitive information leaked, thought that this will become the new realm of information resist, launching the technique research to information electricity magnetic leakage protection and interception of the information technology equipments. The computer system is the most common information technology equipment to process sensitive information, so the most researches are pointed to the computer and its peripheral equipments.In the computer system, CRT is the display equipment that radiates most strongly, having most visible information, and the video information can be intercepted most easily. In point of information leakage intercepting, the thesis studies the related theory of intercepting the computer video leakage information, analyses the key techniques and methods to realize, discusses the recovering technique from the video leakage information, and the reconstruction of the text leakage information is realized.This thesis studies electromagnetic information leakage mechanism on the basis of electromagnetic radiation. Electromagnetic information leakage mechanism of electron beam in cathode ray tube (CRT) of computer video display unit (VDU) is analyzed as a special example. The video information leakage mechanism and synchronization characteristic is analyzed and the theory basis to intercept video leakage information is pointed out. This thesis mainly researches the recovering of intercepted image information, and the methods of recovering and shaping the image are described. In the experimentations of intercepting the video leakage information, not only reconstructing the leakage information directly is realized, but also reconstructing by extracting synchronization characteristic signals from leakage video information. The leakage information, sampled and memorized by the high precision memory, processed by the computer to process the signals, analyze the characteristic, extract the synchronization characteristic signals, and realize the reconstruction of the video leakage information. The design of digital signal processing software provides a reference to realize the design of information electromagnetic leakage interception system based DSP.The interception technology, signal processing and recovering technology of computer video leakage information is studied theoretically and experimentally in this thesis. The author expects to lay a solid foundation for further research.