Developing Symmetric Encryption Methods Based On Residue Number System And Investigating Their Cryptosecurity

This paper proposes new symmetric cryptoalgorithms of Residue Number System and its Modified Perfect Form. According to the first method, ciphertext is regarded as a set of residues to the corresponding sets of modules (keys) and decryption or decimal number recovery from its residues takes place according to the Chinese remainder theorem. To simplify the calculations, it is proposed to use a Modified Perfect Form of Residue Number System, which leads to a decrease in the number of arithmetic operations (in particular, finding the inverse and multiplying by it) during the decryption process. Another method of symmetric encryption based on the Chinese remainder theorem can be applied when fast decryption is required. In this algorithm, the plaintext block is divided into sub-blocks that are smaller than the corresponding module and serve as remainders on dividing some number, which is a ciphertext, by these modules. Plaintext recovery is based on finding the ciphertext remainders to the corresponding modules. Examples of cryptoalgorithms implementation and their encryption schemes are given. Cryptosecurity of the proposed methods is estimated on the basis of the Prime number theorem and the Euler function. It is investigated which bitness and a number of modules are required for the developed symmetric security systems to ensure the same security level as the largest length key of the AES algorithm does. It is found that as the number of modules increases, their bitness decreases. Graphical dependencies of cryptoanalysis complexity on bitness and a number of modules are built. It is shown that with the increase of specified parameters, the cryptosecurity of the developed methods also increases

High-resolution Multichannel Measurement and Analysis of Cardiac Repolarization

National audienceTime and spatial inhomogeneity of the repolarization phase is considered to be an important, non invasive indication of sudden cardiac death in patients after myocardial infarction. Analysis of spatial variability of the repolarization phase was carried out on signals recorded with the 64-channel system for measurement of high-resolution ECG. The lead position on the torso, according to the University of Amsterdam lead system, was used. A new parameter, called the T-wave shape index and the Distribution Function Method as a method sensitive to shape variations, were applied to examine spatial variability of the T-wave shape in HR ECG maps. A group of 14 healthy volunteers and a group of 12 patients after myocardial infarction were studied. The diversity of spatial distributions of the parameters connected to the shape of the T-wave is clearly noticeable in the group of patients after myocardial infarction. The similarity of spatial distributions of proposed parameters in the group of healthy subjects is observed. The obtained results confirm the hypothesis that the spatial heterogeneity of the repolarization phase increases after myocardial infarction

Функціональна безпека та живучість інформаційно-укравляючих систем на основі еліптичних кривих: моделі і методи

There is an analysis of functional safety and survivability of information control systems relying on elliptic curve-based calculations. Time required for solving a discrete logarithm on GF(p) elliptic curves was worked out. Presented were aspects of the use of FPGA systems whose calculations were based on Rademacher-Krestenson’s remaining classes and parallel summing.Приведен анализ функциональной безопасности и живучести информационно-управляющих систем, в средствах которых применяются вычисления на эллиптических кривых. Оценено время, необходимое для нахождения дискретного логарифма эллиптической кривой над полем GF(р). Освещены аспекты применения устройств ППВМ, в которых вычисления основаны на использовании системы остаточных классов Радемахера-Крестенсона и параллельного суммирования.Наведено аналіз функціональної безпеки та живучості інформаційно-керуючих систем, в засобах яких застосовуються обчислення на еліптичних кривих. Оцінено час, необхідний для знаходження дискретного логарифма еліптичної кривої над полем GF (р). Висвітлено аспекти застосування пристроїв ПКВМ, в яких обчислення ґрунтуються на використанні системи залишкових класів Радемахера-Крестенсона і паралельного сумування

Optimization of FPGA processing of GEM detector signal

This paper presents analysis of processing method of the signal from Gas Electron Multiplier (GEM) detector acquired in our Field-Programmable Gate Array (FPGA) based readout system. We have found that simple processing of GEM signal\ud received from the charge amplifier, sampled at 100MHz with 10-bit resolution, after low-pass filtering with 15 MHz cut-off frequency, provides accuracy similar to obtained by processing of the raw GEM signal sampled at 2.5 GHz frequency with 8-bit resolution. Even when 3 bits are lost due to long term instability of the detector and analog part of the system - resulting in 7-bit effective resolution, the reasonable accuracy is still preserved. Additionally we have analyzed computational power required to perform the real-time analysis of the GEM signal, taking into consideration resources offered by the FPGA chip used in the prototype platform.\u