Fourier and Chirp-Z Transforms in the Estimation Values Process of Horizontal and Vertical Synchronization Frequencies of Graphic Displays

Abstract

The electromagnetic protection of IT devices includes a number of organizational and technical measures aimed at ensuring control over radiated and conducted revealing emissions. This is of particular importance for ensuring information security in wireless communication and the processing of data presented in graphic form. In each of these cases, the occurring electromagnetic emissions pose the risk of a lack of electromagnetic immunity to the so-called eavesdropping process based on forming revealing emissions. Included in the elements of the security chain preventing electromagnetic eavesdropping on wireless communication and the devices building such systems are activities related to the determination of the Technical Device Security Level (TDSL) or its class. The above is related to the performance of electromagnetic emissions tests and identifying which of them must be treated as revealing emissions, which are only disturbances and do not threaten the security of the processed information. It is intuitively understandable that it is particularly important to ensure the security of interfaces that process video data. The nature of the electromagnetic emission signals generated by these interfaces means that the related information can be intercepted with the use of relatively simple methods, and under favorable circumstances even with the use of a receiving device not very technologically advanced. In the case of the electromagnetic safety assessment of video devices, common practice is therefore activities aimed at reconstructing information related to the video signal. This requires the parameters of the reconstructed image appropriate for the eavesdropped device operation mode and the conditions of recording the revealing emission signals to be determined. The article presents the results of works related to the analysis of the possibility of using spectral analysis methods (Fast Fourier FFT transform and Chirp-Z transform) to automate the process of determining the above-mentioned parameters in the case of reproducing images from emission signals recorded by using the ADC analog-to-digital converter.

Wireless Communication: Applications Security and Reliability—Present and Future

“…At the same time, criteria were indicated that must be met to determine the correct length of the image line for the assumed accuracy of estimation. In [36], preliminary results of the analysis of the possibility of using the Fourier and the CZT transforms to determine image rastering parameters in the process of electromagnetic infiltration were presented. Particular attention was paid to the accuracy of determining the line length of the reconstructed image based on the accuracy of determining the value of the horizontal sync frequency of the eavesdropped display.…”

Pseudo-Coloring as an Effective Tool to Improve the Readability of Images Obtained in an Electromagnetic Infiltration Process

“…Thus, the values of the amplitudes of the pixels building the sought data are not comparable. In addition, for each image the range of changes in these values is different, which results directly from the impact of Side Channel Attack on the form of the compromising emanations [36][37][38][39][40].…”

An RGB Pseudo-Colorization Method for Filtering of Multi-Source Graphical Data

“…It should be borne in mind that electromagnetic compromising emanation signals arise naturally and are the result of the laws of physics, so their nature has not been designed to ensure the best possible propagation, free from losses and distortions [17]. In the case of video signals, they usually reflect only part of the imaged information (edges of shapes) [18] and do not contain information about the colors used to present it [19]. Therefore, they are residual emissions, often distorted and disturbed by other signals accompanying the device's operation.…”