Homomorphic encryption allows us to process data in an encrypted form, and can be effectively used in secure cloud computing systems. To use homomorphic encryption in practice, it is often necessary to support arithmetic and logical operations within a single encryption algorithm. To achieve this goal, it is proposed to represent integers in binary form and implement homomorphic operations on integers through operations on homomorphically encrypted bits. Gentry's algorithm over bits is considered as an example, for which the implementation of addition, subtraction, and multiplication operations is proposed. The analysis of the received results is carried out.

The main purpose to ensure the security for confidential medical data is to develop and implement the architecture of a medical cloud system, for storage, systematization, and processing of survey results (for example EEG) jointly with an algorithm for ensuring the protection of confidential data based on a fully homomorphic cryptosystem. The most optimal algorithm based on the test results (analysis of the time of encryption, decryption, addition, multiplication, the ratio of the signal-to-noise of the ciphertext to the open text), has been selected between two potential applicants for using (BFV and CKKS schemes). As a result, the CKKS scheme demonstrates maximal effectiveness in the context of the criticality of the requirements for an important level of security.

Verification of cryptographic protocols is an urgent and complex task. In view of the development of various e-commerce services, as well as mobile robots, unmanned aerial vehicles, internet of things, in which computing resources are in most cases very limited and it is not always possible to use well-known protocols. Any developed protocol must go through a verification procedure. Mostly formal verification methods are used to evaluate the security of the cryptographic protocol. If the protocol has successfully vitrificated, it is implemented in the selected programming language for the developed system. Even though the protocol was successfully analyzed using formal verification tools, its implementation may be vulnerable. Errors may occur due to the human factor or protocol can be modified during implementation. Thus, the verification of cryptographic protocols source codes is relevant. The paper describes a dynamic analysis method for detecting replay-attacks and integrity violations.

When implementing systems using a secure data connection between components, it is important to analyze the security of data transmission. Secure data transfer is achieved by using cryptographic protocols. It is important to verify the security of cryptographic protocols already implemented in the system, since this is the last iteration of their compilation in the form of their implementation in the selected programming language. The paper proposes a scheme and approaches for creating an automated security verifier of cryptographic protocol implementations. The problems that arise when implementing cryptographic protocols in programming languages are described. A verification scheme based on the use of a source code analyzer for extracting the structure of cryptographic protocols, translating their structure of the Alice-Bob format protocol into the specification language for formal verifiers, and dynamic analysis of the implementation code is presented. The approaches for the implementation of the analyzer, translator and dynamic analyser are described, as well as the future work.

Currently, the Republic of Kazakhstan is creating a new standard for symmetric data encryption. Qamal encryption algorithm developed by the Institute of Information and Computer Technologies (Almaty, Republic of Kazakhstan), which is one of the candidates to be approved as a standard, is the subject of our study. We analyze in detail the basic cipher transforming work principles, approaches to its quick implementation and the results of the implementation experiments in several programming languages. The encryption algorithm under study uses the round subkeys generating procedure, which seems to be several times more complicated than the single block processing procedure.

The development of electronic voting systems is a complex and urgent task in today's time. At the heart of the security of any system using network interaction are cryptographic protocols. Their quality is verified by means of formal verification. However, formal verification tools work with protocols in an abstract form of Alice-Bob format, which does not allow to completely check the protocol for all sorts of attacks. In addition, when implementing the protocol in practice using any programming language, it is possible to change this protocol relative to its original form. As a result, the abstract initial form of the protocol, which was verified by means of formal verification, is considered safe, but a modified implemented protocol that has a different type can no longer be recognized as safe. Thus, verification of the cryptographic protocol of the electronic voting system using source codes is relevant. The paper described an electronic voting system based on blind intermediaries. A parser is described to extract the structure of the cryptographic protocol with which the structure of the voting protocol was obtained. The cryptographic e-voting protocol was translated into the CAS+ specification language for the Avispa automated verifier for protocol security verification.

In this paper, we propose a method for malware classification, by applying a statistical methods to an extended data set of system function calls, it becomes possible to improve the classification quality of malware samples. Applying the method of classification with unsupervised learning, it is possible to achieve a quality of classification comparable with classification methods based on supervised learning, including neural networks. Thus, the proposed method allows to perform detection of previously unknown families and more efficiently to detect unknown samples of small families.

The development of electronic voting systems is an important direction of work due to the ubiquitous transfer of all spheres of human activity to the information technology environment. Electronic voting in comparison with traditional methods of voting has a lower cost, more reliable and convenient in the context of the modern world. We present a distributed electronic voting system that uses an intermediary site to verify the correctness of components, which does not process any information about votes and user authentication data, as well as using the principle of blind intermediaries to ensure user authentication while maintaining their anonymity. In addition, we use the principle of homomorphic encryption and the threshold scheme for sharing the secret at the most important stage - the counting of votes. The groups of people participating in voting are characterized by a degree of confidence in them. The architecture of the service is described by the components that interact in it. We describe the process of voting, which consists of several stages. Cryptographic protocols are used to transfer data between components, which are based on establishing a secure connection using security certificates and generating session keys. We use symmetric encryption in CBC mode using random numbers and HMAC to ensure security in the form of party authentication, integrity control, and confidentiality during data transmission. The voting protocol supports the re-voting function. We describe the algorithms for counting votes based on the use of homomorphic encryption, distributed computations, and the threshold secret sharing scheme. We also describe the procedure for verifying votes after counting.

The method of detecting malicious software proposed in this paper makes it possible to detect malicious samples as a separate class, without reference to the specific features of a particular family. To solve this problem, we use a set of quantitative characteristics, developed on the basis of qualitative data on the test sample, obtained as a result of static and behavioral analysis of samples. At the same time, a key role in the formation of the feature space is played by meta-information about the system functions used, obtained as a result of behavioral analysis. According to the results of experimental studies, it was revealed that the error in the clustering of malware samples is up to 42% less than in competing classification methods.

Information technology is being increasingly introduced into our lives. Most areas of human activity are widely associated with information technology, and electronic voting is no exception. At the moment, there are a number of ready-made solutions, but all of them are not sufficiently safe and open, and most importantly most of them are produced outside the Russian Federation. In such strategically important areas as e-government, in particular electronic elections, it is necessary to be completely confident in the algorithms, principles and systems used. The issue is raised about creating a secure and trustworthy system, and most importantly, an open one and implemented using standardized cryptographic algorithms of the Russian Federation. A model of the system is proposed based on the principle of blind intermediaries developed by the authors and using cryptographic algorithms such as the symmetric cipher GOST R 34.12-2015 (Kuznyechik), hash function GOST R 34.11-2012 (Stribog). The system model proposed by the authors is characterized by a comprehensive approach to electronic voting, namely detailing decisions at all stages of voting. The basic techniques for correct and safe conduct of electronic voting are described, such as the security of transmitted confidential data, the distribution of secret keys, the authentication of the parties, the verification of the transmitted data for integrity, the time control of the transmitted data. It shows how these techniques are implemented. Based on the developed algorithms, a model of the electronic voting system was implemented in C# .Net Framework programming language consisting of a set of window interface applications that interact with each other via network. The efficiency of the developed system is shown. Areas of improvement of the system are noted.

Kuznyechik cipher is a new symmetric block cipher declared as a state standard in Russian Federation. The cipher is based on SP (Substitution Permutation) network principle, the block size is 128 bits, the key size is 256 bits, and encryption takes nine rounds. Round subkeys are generated from the original secret master key with Feistel scheme. Many modern standard including DES and AES have simplified versions. These versions can be used in education in order to demonstrate encryption and decryption operations to students. In addition to that, simplified versions are used for simulation of various attack scenarios and cryptanalysis methods. In this paper we propose two simplified versions of Kuznyechik algorithm. The first one is extremely simple and can be used in education. All transformations can even be performed manually in reasonable time. The second version is more complicated. This one is designed for simulation of different types of attacks and we offer it for the demonstration of Kuznyechik's basic principles.

In January 2016, a new block encryption standard came into force in the Russian Federation - GOST R 34.12-2015. It includes two algorithms of encryption. The first cipher was previously known under the name GOST28147-89 (or simply GOST). The second algorithm was called Kuznyechik. Kuznyechik is a new symmetric encryption algorithm, based on the SP-network. Up to now there are no publications about the differential properties of the algorithm Kuznyechik. We are the first to examine the properties of main operations and suggest a scheme of 3 rounds differential analysis of cipher Kuznyechik. We examined the differential properties of the non-linear transformation S and the linear transformation L and found out that it's possible a situation when, 1 non-zero byte difference, being a result of the transformation L, is expanded into 16 non-zero bytes, then it passes through the S-boxes, and then collapses again into 1 nonzero byte. The developed scheme allows to affect the active S-boxes a minimum number of times. As a result, for the suggested scheme the possibility of finding the correct pairs of texts is equal to 2-108. We also developed the algorithm of finding a secret key, the complexity of which is equal to 6*2−120. In this way, the total complexity of the analysis, including searching for the correct pairs of texts and bits of the secret encryption key is equal to 2108 + 6*2120 encryptions.

In this paper we present results of algebraic analysis of GOST⌖ algorithm in SageMath environment. Using the GOST⌖ as the example we explore basic stages of algebraic analysis of any symmetric block cipher based on Feistel network. We construct sets of boolean equations for five encryption rounds and determine the number of known text pairs for which the key can be found with the probability of 1. The algebraic analysis of five rounds of GOST⌖ allowed to find a 160-bit encryption key with the probability of 1 for five known text pairs within 797.21 s; the search for the solution took 24.66 s.

The new cryptographic standard GOST R 34.12-2015 "Information technology. Cryptographic Data Security. Block ciphers." [7] came into force on January 1st, 2016. The standard contains two encryption algorithms. One of those is a former standard encryption algorithm GOST 29147-89 (also known as simply GOST) with fixed S-boxes. This algorithm is denoted as Magma in the new standard. The second algorithm is a new symmetric block cipher based on SP-network, which is denoted as Kuznyechik (also transliterated as "Kuznechik"). Nowadays, a lot of attention is paid to the issues of quality of the new cipher, namely its cryptographic strength, performance, portability, implementation, etc. In this paper we are offering to consider the possibility to use parallel computations based on MPI and NVIDIA CUDA technologies for cryptanalysis of Magma and Kuznyechik. We choose slide attack for the implementation. The slide attack is applicable to Magma and Kuznyechik ciphers only with significant weakening modifications to their original descriptions. However, research on applicability of parallel implementation of cryptanalysis is important, because the parallel approach can be applied to other more efficient methods of cryptanalysis. The proposed parallel algorithms implemented for two different technologies demonstrate close to linear growth of analysis speed with the increase of involved processor cores. Also we propose a fast implementation of Kuznyechik data encryption based on precomputed tables.

The paper considers the problem of organization the computations over encrypted data. This problem has become increasingly important due to the expansion of the cloud computing and the need for suitable measures to protect it. Different primitives were proposed to solve the problem in a limited context, such as garbled circuits, fully homomorphic encryption, functional encryption, secure multiparty computations and so on. However, the development of real secure computing system requires some general theory for organization of secure computing, using a systemic approach. We propose to divide all the functionality that the secure computing system must support into the several layers; the interaction between them would be done through the interfaces. Presented six-layer analytical model under the title "Secure computing interface stack" ("SCIS") is intended to standardize and facilitate the work of researchers and developers in the field of cryptographically secure computing, i.e. such systems in which the untrusted parties process the sensitive data in encrypted form without decrypting at the any stage of processing.

This paper deals with fully homomorphic cryptosystems exploiting the problem of big integers factoring. We give a short review of them and highlight two main types of such fully homomorphic cryptosystems (FHCs): polynomial-based and matrix-based. The main focus of the discussion is placed on one recently proposed polynomial-based FHC. Its construction is recalled, but mainly we concentrate on security issues. And here our contribution is twofold.

Modern smart card is a multi-purpose tool that is used in many areas of science and technology [5]. Microprocessor cards are used for access control, e-commerce, identification and authentication, used as personal data protected storages, as the core of e-passports and documents. In circulation there are tens of millions of devices simultaneously, and it is all the more credible by both the producers and by users [7]. All this leads to increase of attention from both developers (to protect information) and intruders.

This paper presents the security analysis of symmetric homomorphic cryptosystems based on polynomial ring homomorphisms.

The talk is devoted to the issues of computational complexity check of various attacks on GOST 28147-89 cryptographic algorithm (commonly known as GOST). The primitives that comprise different cryptanalysis techniques and conditions of their applicability are considered in detail. The results of application of differential, algebraic, and linear cryptanalysis for different number of rounds are given. Particular attention is paid to the possibility to implement parallel cryptanalysis algorithms. As soon as possible allocations of S-box values are not defined by GOST, detection of potentially weak S-box layouts is particularly important. The talk summarizes several approaches, methods and algorithms that make it possible find out whether a particular S-box has weaknesses. The talk is concluded with relevant experimental data.

This work is devoted to finding the influence of S-Boxes to resistance of GOST 28147-89 algorithm (GOST) against linear cryptanalysis. The universal algorithm for searching particular layouts of S-Boxes, which are vulnerable to linear cryptanalysis is presented. The possibility of building of efficient linear statistical expressions for simplified GOST with weak S-Boxes has been shown. This research is aimed to ensuring that certain arbitrary S-Box layouts are not weak when they are not fixed. Applicability of the presented method was tested by analyzing S-Boxes used in GOST. Application of the designed method made it possible to discover a number of weak S-Boxes, which make the overall cryptographic strength of GOST much lower.

In this paper, the problem of performance analysis of the developed mandatory access control system (DBMS) is considered. An additional program module (access manager), which implements the principle of mandatory access instead of the existing discretionary access was developed in the DBMS. The mathematical models of DBMS have been designed with the help of the mathematical formalism of the theory of queuing networks. Important results about performance of the fixed protection systems DBMS and developed system were received by analyzing the mathematical models.

This work proposes a method of connectivity determination between malicious pages on the Internet. We have developed a method which allows to find linkage between pages and to determine malicious links. The method was tested with actual malware URLs.

The present study considers the improvement of existing cryptanalytical methods in relation to Russian standard of GOST 28147-89 symmetric encryption. This paper researches encryption transformations in GOST 28147-89 algorithm constructed on the principles of Feistel network simplifying attacks by methods of differential and algebraic cryptanalysis. Finally, for fixed encryption keys plain texts were obtained reducing 32 encryption rounds to 16.

This work proposes a new method of malware classification based on behavior features. We developed a proximity measure for programs, which takes into account WinAPI calls, their arguments, and files handled by these programs. Cluster analysis is used for grouping. The method was tested with actual malware samples.

This paper is devoted to the investigation of GOST algorithm with regard to its resistance against algebraic cryptanalysis. GOST algorithm is a state standard of Russian Federation. Its characteristic feature is the use of variable S-blocks and simple mathematical operations. It is considered that any initial values of S-blocks provide enough strength to resist any attacks. The general idea of algebraic analysis is based on the representation of initial encryption algorithm as a system of multivariate quadratic equations, which define relations between a secret key and a cipher text. Extended linearization method is evaluated as a method for solving the nonlinear system of equations.

In this article we explore the resistance of the GOST 28147-89 algorithm (commonly referred to as GOST) to the attack based on differential cryptanalysis. GOST algorithm is used as a national standard in the Russian Federation. GOST uses variable substitution boxes. It is commonly believed that any values of S-boxes for 32-round GOST encryption algorithm provide sufficient degree of resisting against attacks based on techniques such as linear and differential cryptanalysis.

This work is devoted to development of a formal mandatory access model, which takes into account the structure and the features of current database management systems (DBMS). We introduce the requirements of correctness and completeness. Implementation of these requirements makes it possible to prevent side-channel attacks.

No abstract available.