Formation of pseudorandom sequences with improved autocorrelation properties

In this article are discussed techniques of hiding information messages in cover image using direct spectrum spreading technology. This technology is based on the use of poorly correlated pseudorandom (noise) sequences. Modulating the information data with such signals, the message is presented as a noise-like form, which makes it very difficult to detect. Hiding means adding a modulated message to the cover image. If this image is interpreted as noise on the communication channel, then the task of hiding user’s data is equivalent to transmitting a noise-like modulated message on the noise communication channel. At the same it is supposed that noise-like signals are poorly correlated both with each other and with the cover image (or its fragment). However, the latter assumption may not be fulfilled because a realistic image is not an implementation of a random process; its pixels have a strong correlation. Obviously, the selection of pseudo-random spreading signals must take this feature into account. We are investigating various ways of formation spreading sequences while assessing Bit Error Rate (BER) of information data as well as cover image distortion by mean squared error (MSE) and by Peak signal-to-noise ratio (PSNR). The obtained experimental dependencies clearly confirm the advantage of using Walsh sequences. During the research, the lowest BER values were obtained. Even at low values of the signal power of the spreading sequences (P≈5), the BER value, in most cases, did not exceed 0,01. This is the best result of all the sequences under consideration in this work. The values of PSNR when using orthogonal Walsh sequences are, in most cases, comparable to other considered options. However, for a fixed value of PSNR, using the Walsh transform results in significantly lower BER values. It is noted that a promising direction is the use of adaptively generated discrete sequences. So, for example, if the rule for generating expanding signals takes into account the statistical properties of the container, then you can significantly reduce the value of BER. Also, another useful result could be increasing PSNR at a fixed (given) value of BER. The purpose of our work is to justify the choice of extending sequences to reduce BER and MSE (increase PSNR).

Section: выводыunclassified

Hiding information in images using pseudo-random sequences

Смірнов¹,

Горбачова²,

Кузнецов³

2020

“…Складність завдань, які вирішуються сучасними системами і засобами обробки цілочисельної інформації (ЗОІ), обумовлює до них підвищені вимоги щодо якості обробки інформації [1][2][3][4][5][6][7][8]. Рішення широкого кола складних обчислювальних задач вимагає (наприклад, реалізація асиметричних криптографічних алгоритмів, оптимізація обчислень в теорії сигналів та шумостійке кодування [4,[8][9][10][11], реалізація симетричних крипто-примітивів [12][13][14][15][16][17][18] та багато іншого [19][20][21][22]) значних обсягів розрахунків, які проводяться в реальному часі функціонування ЗОІ. В цьому аспекті пошук методів і засобів підвищення продуктивності обробки цифрової інформації, є актуальним [23][24][25][26][27][28][29][30].…”

Section: вступunclassified

Mathematical model of the process of tabular’s implementation of the operation algebraic multiplication in the residues class

Краснобаєв¹,

Зуб²,

Reshetniak³

et al. 2019

Based on the properties of the class of residues in the article, a mathematical model of the process of tabular implementation of modular multiplication was synthesized, for both positive and negative numerical ranges of information processing by means of integer information processing. This model is recommended for practical application in the development of methods and algorithms for rapid processing of cryptographic information. Finding ways to simplify the structure of the table operating device integer information processing has led to the need to improve the mathematical model, methods and algorithms for modular operations, which increase the efficiency of the use of table arithmetic in the class of residues. A feature of the implementation of this model is the possibility of reducing the number of equipment operating device integer information by reducing the (50-70)% of logical elements "And" in the nodes of the table permanent storage device, directly implement the operation of modular multiplication by arbitrary mi module residual class. This is possible by using the symmetry properties of the aibi (mod mi) implementation table of the modular multiplication operation.

“…Найбільша ефективність від застосування КЗ досягається в разі, коли реалізовані алгоритми складаються з сукупності таких арифметичних операцій, як додавання і віднімання множення [8][9][10][11][12][13][14]. Необхідність забезпечення відмовостійкого функціонування СОД вимагає розробки і впровадження в КЗ нових методів контролю і корекції помилок інформації, відмінних від методів, використовуваних в звичайних двійкових позиційних системах числення (ПСЧ) [15][16][17][18][19][20][21].…”

Section: вступunclassified

Data control method, which presented by code of non-positioning system of deduction class calculation

2019

The paper proposes a new method of monitoring data presented in non-positional residue class system. For code in residue class system, test bases are included in the general code structure of data containing a set of information bases. In this case, the balances that represent operations for informational and control grounds simultaneously and independently participate in the process of information processing. The result of the information processing can be monitored either step by step or at the end of all calculations, since the error that occurred in any residue, does not apply (does not “multiply”) to the remaining residues. The control method proposed based on the principle of comparison, further creates prerequisites for developing effective methods for diagnosing and correcting errors in deduction class. The disadvantage of the proposed method is the relatively low control efficiency. This circumstance makes it necessary to increase the efficiency of data processing system control in deduction class by reducing the execution time of the above operations by developing and using, for example, methods and means for implementing the positional features of the non-positional deduction class code.