Alexandr Kuznetsov

Work place: V. N. Karazin Kharkiv National University, Svobody sq., 4, Kharkiv, 61022, Ukraine



Research Interests: Coding Theory, Number System, Fault Tolerance, Applied Cryptology


Alexandr Kuznetsov

Doctor of Sciences (Engineering), Full Professor, Academician of the Academy of Applied Radioelectronics Sciences, Professor of the Department security information systems and technologies of the V. N. Karazin Kharkiv National University, Ukraine. Areas of scientific interests: applied cryptology and coding theory.

Author Articles
Synthesis of the Structure of a Computer System Functioning in Residual Classes

By Victor Krasnobayev Alexandr Kuznetsov Kateryna Kuznetsova

DOI:, Pub. Date: 8 Feb. 2023

An important task of designing complex computer systems is to ensure high reliability. Many authors investigate this problem and solve it in various ways. Most known methods are based on the use of natural or artificially introduced redundancy. This redundancy can be used passively and/or actively with (or without) restructuring of the computer system. This article explores new technologies for improving fault tolerance through the use of natural and artificially introduced redundancy of the applied number system. We consider a non-positional number system in residual classes and use the following properties: independence, equality, and small capacity of residues that define a non-positional code structure. This allows you to: parallelize arithmetic calculations at the level of decomposition of the remainders of numbers; implement spatial spacing of data elements with the possibility of their subsequent asynchronous independent processing; perform tabular execution of arithmetic operations of the base set and polynomial functions with single-cycle sampling of the result of a modular operation. Using specific examples, we present the calculation and comparative analysis of the reliability of computer systems. The conducted studies have shown that the use of non-positional code structures in the system of residual classes provides high reliability. In addition, with an increase in the bit grid of computing devices, the efficiency of using the system of residual classes increases. Our studies show that in order to increase reliability, it is advisable to reserve small nodes and blocks of a complex system, since the failure rate of individual elements is always less than the failure rate of the entire computer system.

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Performance Analysis of Cryptographic Hash Functions Suitable for Use in Blockchain

By Alexandr Kuznetsov Inna Oleshko Vladyslav Tymchenko Konstantin Lisitsky Mariia Rodinko Andrii Kolhatin

DOI:, Pub. Date: 8 Apr. 2021

A blockchain, or in other words a chain of transaction blocks, is a distributed database that maintains an ordered chain of blocks that reliably connect the information contained in them. Copies of chain blocks are usually stored on multiple computers and synchronized in accordance with the rules of building a chain of blocks, which provides secure and change-resistant storage of information. To build linked lists of blocks hashing is used. Hashing is a special cryptographic primitive that provides one-way, resistance to collisions and search for prototypes computation of hash value (hash or message digest). In this paper a comparative analysis of the performance of hashing algorithms that can be used in modern decentralized blockchain networks are conducted. Specifically, the hash performance on different desktop systems, the number of cycles per byte (Cycles/byte), the amount of hashed message per second (MB/s) and the hash rate (KHash/s) are investigated. The comparative analysis of different hashing algorithms allows us to choose the most suitable candidates for building decentralized systems type of blockchain.

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Detecting Hidden Information in FAT

By Kyryl Shekhanin Alexandr Kuznetsov Victor Krasnobayev Oleksii Smirnov

DOI:, Pub. Date: 8 Jun. 2020

Various steganographic methods are used to hide information. Some of them allow you to reliably hide the fact of storage and transmission of information data. This paper analysis the methods of technical steganography that are based on hiding information messages into the structure of the FAT file system by reordering particular clusters of specially selected files (cover files). These methods allow you to reliably hide information in the file system structure, while redundancy is not explicitly entered anywhere. This means that the hidden information is not explicitly contained in the service fields or individual clusters of the file system, the size of the data stored on the physical storage medium does not change. Such steganographic systems are very difficult to detect, it is almost impossible to identify the fact of hiding information by traditional methods. The steganographic analysis technique based on the study of file system properties was developed. In particular, we analyzed the fragmentation of various files stored on a physical medium, and examine the statistical properties of various types, sizes and uses of files. Identification of anomalous properties may indicate a possible reordering of clusters of individual files, i.e. this will detect hidden information. The study of these principles is important for a better understanding of the design and counteraction of steganographic systems based on the methods of reordering clusters of cover files in the structure of the FAT. Thus, this article substantiates new approaches to steganoanalysis of cluster file systems for information hiding—é. They are based on a statistical analysis of file systems of various data carriers, as well as an assessment of the fragmentation level of both individual files and the entire file system.

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