Stduy On Unintentional Electromagnetic Emissions Of The Digital Equipment And Its Information Electromagnetic Fingerprint

The information technology equipment(ITE)can generate radiated and conducted electromagnetic(EM)emissions unintentionally.Generally speaking,these EM emissions are always considered to be EM disturbance.But in fact,some kind of mapping relationship exists between these EM noises and the processed confidential information by the ITE devices.If these EM disturbances which contain confidential information are intercepted,the original information can be retrieved through analyzing and signal processing.Therefore,this can pose a serious threat to the information security.With the development of the information technology,many ITE devices are used in our daily activities.The technology associated with emission security has become a hot topic and attracted more attention in national governments.This paper is supported by the National Natural Science Foundation of China under Grant 61072136.In Chapter two,the technologies on detecting the video information that contained in unintentional leakage EM waves and reconstructing the original information have been researched in the office environment when computer systems are working.In Chapter three,the leakage mechanism and leakage pathways of EM waves from the computer systems with some protection methods are analyzed.In Chapter four,the theories and methods on estimating the maximum eavesdropping distance are proposed based on some research achievements of Chapter two.In Chapter five,the technologies on designing a practical system for eavesdropping video information are proposed.Lastly,the equipment for eavesdropping keystrokes information is researched and designed.The main work and innovations included in this dissertation are as follows:1.The relationship between the white-black vertical stripes image and the fundamental frequency components of the video signal is analyzed,because of the specificity of the video security surveillance.And,the methods of detecting video information security threshold and choosing the best frequency range for receiving the EM compromising emanations are proposed.For radiated and conducted emission leakage pathways,an assessment system for video Information EM leakage security in office environment is proposed.2?For the video information leakage,the leakage mechanism and leakage pathways of EM waves from the computer systems are analyzed.And,the theories and methods on estimating the maximum eavesdropping distance are proposed for the radiated and conducted emission.Based on the noise jamming technology and space EM cancellation principle,two new protection methods for preventing video information leakage are proposed,which are multi-antenna noise jammer and video cable space EM cancellation.For the video leakage of VGA,the VGA EM cancellation device has been made.And,the experiment results show that it can reduce the strength of EM leakage effectively.3?The system which has split architecture for eavesdropping video information is proposed.And,the eavesdropping experiments are conducted for baseband and modulated video signal leakage.A novel method for eavesdropping video information is proposed,and this eavesdropping system consists of the near field probe,high sample storage receiver and information recognition software.Finally,the verification experiment is conducted.4?The leakage mechanism for the EM radiation and conducted emission is analyzed when the key is pressing.The method for intercepting leakage signals,theoretical analysis and numerical simulation are also analyzed.Then,a novel method and a set of equipment for intercepting the information of keystrokes are proposed based on the ground line network.The eavesdropping experiment demonstrates that this method and equipment are usefully and practicality.Lastly,the information EM fingerprint of keystrokes is extracted and identified.