The Search and Reconstruction of Compromising Emanations of Laser Printers in Three Media

In this paper, the emissions of a laser printer, which may process classified information, are investigated in the media of electromagnetic radiation (ER), Power Line Conductors (PLC), and Signal Line Conductors (SLC). First, the candidate frequency points of Compromising Emanations (CE) are examined in the frequency domain. Second, the emitted signal is AM-demodulated with the proper bandwidth, and then sampled by a high storage oscilloscope in these frequency points. Third, the collected data is converted to 2D image by applying signal and image processing techniques. In addition, this study introduces some practical measurement methods to reveal the possible CEs of laser printers. Finally, the procedure of the image reconstruction of CEs of the laser printer data is explained in detail. KeywordsCompromising Emanations; Information Leakages; Printers; TEMPEST; Electromagnetic Radiation; Power and Signal Line Conductors.