Device of Protection of Analog Telephone Communication Based on Scrambler with Change of Wavelet Conversion Coefficients

Abstract

The paper proposes a device for providing protection of speech information transmitted over an analog telephone line against unauthorized interception based on a scrambler with modified Latin square wavelet transform coefficients. The developed device consists of hardware and software parts, the hardware part is implemented on the microcontroller platform of the Arduino family, the software part of the device is implemented using the Proteus software environment. As the main part of the functions of the device is performed by a microcontroller, the general structure of the device comprises a microphone, a power supply and an Arduino board. Taking into account the results of the research, it is proposed to modernize the scrambling algorithm by performing permutation operations, matching XOR to the scrambler key, which displays the Latin square itself. A statistical and spectral analysis of the improved method was carried out and a comparison of the execution speed of scrambling algorithms was performed. To improve the security, it was proposed to carry out several stages of permutations of the received coefficients of wavelet transformations. Increasing the variability of the permutations of the wavelet transformation coefficients made it possible to increase the time spent by the attacker on going through all possible combinations. And taking into account that the permutation does not take place in one part of the signal, but in a set of n parts, this in its turn further complicates the procedure of sorting through all possible options. The implementation of the elements of this device with the help of electronic computing equipment and available components makes it an accessible, as well as an effective tool for solving technical information protection tasks, which can ensure the improvement of information protection systems at various business entities.