Eavesdropping the display image from conducted emission on network cable of a PC  

作　　者：DU Yu-lei LU Ying-hua ZHANG Jin-ling 

机构地区：[1]School of Telecommunication Engineering, Beijing University of Posts and Telecommunications

出　　处：《The Journal of China Universities of Posts and Telecommunications》2013年第3期78-84,共7页中国邮电高校学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (61072136, 61171051)

摘　　要：The display image of a PC can be reconstructed by using the conducted emission on the PC＇s network cable. The relevant signals which be used to reconstruct the original image are coupling from the radiation of the switching of red, green, blue （RGB） signals in PC. These pertinent signals are partly contained in the frequency region higher than 30 MHz in the conducted emission. From these findings, the near-field coupling principle from PC to the network cable is analyzed firstly. And then, a multi-conductor transmission model for the RGB signals which transmit in the network cable is proposed. In addition, the maximum safe distance is estimated by using this model. In order to check the validity of the estimating distance, the eavesdropping experiment is carried out to reconstruct the original display image. The results demonstrate that the blurred display image can be retrieved at the place of 29.5 m.The display image of a PC can be reconstructed by using the conducted emission on the PC＇s network cable. The relevant signals which be used to reconstruct the original image are coupling from the radiation of the switching of red, green, blue （RGB） signals in PC. These pertinent signals are partly contained in the frequency region higher than 30 MHz in the conducted emission. From these findings, the near-field coupling principle from PC to the network cable is analyzed firstly. And then, a multi-conductor transmission model for the RGB signals which transmit in the network cable is proposed. In addition, the maximum safe distance is estimated by using this model. In order to check the validity of the estimating distance, the eavesdropping experiment is carried out to reconstruct the original display image. The results demonstrate that the blurred display image can be retrieved at the place of 29.5 m.

关 键 词：electromagnetic secure conducted emission unshielded twisted pair cables EAVESDROPPING multi-conductor transmission model 

分 类 号：TN911.7[电子电信—通信与信息系统]