Compromising Emanations: Information Reconstruction And Defense Countermeasure

With the increasing development of Information, Networks and Communications Technology and the widely application of computer, the society has stepped into an information times. However, electronic devices used for the processing of information can emit unintentionally electromagnetic waves which can be eavesdropped. Thus, the information data within some range can be reconstructed. The western countries have paid close attention to compromising emanation of military electronic devices for more than half century. Until 1985, the van Eck's report had provoked civilian computer-security community to be aware of the threatened safety of civilian computers. The military TEMPEST is still a highly confidential standard. Being lack of public experiment data, the problem has always been ignored in the Information security textbooks.We demonstrate the experiments of eavesdropping for current computer, our works involve the information reconstruction for compromising emanation the CRT displayer and computer under noise and no noise background. We further discuss the technology from the two basic aspects of TEMPEST, the detection and eavesdropping of compromising emanation of confidential devices and the defense against the eavesdropping.Since the TEMPEST is a newly technique developed in the basis of Electro Magnetic Compatibility (EMC). We first review the principles and methods of EMC and analyze the mechanism of compromising emanation of computer and peripherals which is a great threat to information security. It is impossible to obtain the methods against the TEMPEST ATTACK from the public publications. So, the latest foreign civil approaches against the TEMPEST ATTACK have been introduced for more efficient protection of our country information security system against TEMPEST ATTACK. Especially, we present the attack experiment with the computer virus and complete the information reconstruction of compromising emanation experiment in professional non-reflection Shielded Enclosures laboratory. The results have proper suggestions to prevent the national information security from the potential threatening. The newly developed Soft Tempest technology is introduced, which is worthy of our more researching efforts for its cheap and efficient characteristics.This research report mainly focuses on the detection and eavesdropping of the compromising emanation from the confidential devices. The approach Van Eck supposed is to change a white and black TV set into a receiver of the computer compromising emanation. The synchronization signal is produced by adjustable extra-oscillator. This is also called a traditional TEMPEST ATTACK device. We also implement the experiment according to the same model.In theory, it is feasible to successfully implement in the non-reflection ShieldedEnclosures laboratory. But. we have to meet the unsynchronized situation in the information reconstruction experiment. Sometimes, the reconstruction can not complete for the emitted information at all. How to receive the synchronized compromising emanation is very critical in the information reconstructing and also an obsessed question in our country. Our work gives the approaches from two aspects. With the low level noise, the synchronized signal from video port of TEMPEST ATTACK device has larger amplitude than the video signal in the non-reflection Shielded Enclosures laboratory. H-sync signal is easily extracted by Comparison Circuit and V-sync signal is obtained via DDS Circuit. This method can substitute for the expensive extra synchronization generator and enhance the stability of information reconstruction for further software processing. But it is only suitable for the detection of compromising emanation intensity of confidential devices in the shielded enclosure laboratory (for example, cryptogrammic machine, computer of processing confidential information, etc.) and demo experiments .The other is under high level noise condition, which meets the practical situation of eavesdropping of electronic devices where the signals are buried in surround noi...