This paper presents a new approach to the TEMPEST compromising signals emitted by the printing devices. From the TEMPEST point of view, only the laser printer diodes and the printer-computer communication signals have been considered as compromising signal generators so far. In this paper we will present some examples of video signal recovery from the compromising signal generated by the laser printer LCD display as well as a number of measurement results of the video signal parameters for particular video display signals which have been selected for this reason.
The objective of this study is to provide an overview of basic technical elements and security risks of RFID communication systems and to analyze the possible threats arising from the use of RFID systems. A number of measurements are performed on a communication system including RFID transponder and the tag reader, and it has been determined that the uplink signal level is 62 dB larger than the average value of the noise at the distance of 1m from the tag, therefore the shielding effectiveness has to exceed this threshold. Next, the card has been covered with several shielding materials and measurements were carried, under similar conditions to test the recovery of compromising signals. A very simple protection measure to prevent unauthorized reading of the data stored on the card has been proposed, and some electromagnetic shielding materials have been proposed and tested.