1,720,975 research outputs found
Lightweight stream ciphers for green IT engineering
No full textAt the moment the most widely used are symmetric cryptographic transformations, in particular, stream ciphers. The development of an efficient synchronous stream cipher is reduced to the construction of a pseudo-random sequence generator with defined cryptographic properties. It should be noted that in devices with limited computing power, low volume and low power consumption the implementation of reliable cryptographic methods is extremely complicated. Limited physical parameters, low power consumption, low computing power and other characteristic attributes of “green” IT engineering forces the use of new approaches for designing cryptographic protection tools. The main cryptographic transformations are considered and experimental studies of performance and statistical security are conducted. We propose new methods and hardware and software tools for lightweight stream encryption that meet the current requirements of “green” IT engineering. It is proposed synthesis method for the construction of nonlinear-feedback shift register, which allows creating nonlinear registers with design features that correspond to the certain predefined criteria
Research of Second-Order Properties of NLFSR. Comparative Analysis of M-NLFSR and M-LFSR
No full textThe linear complexity (Li) of PRS is the shortest shift register, which generates a given periodic sequence, provided that the first L values of the sequence are the initial filling of the register
Comparison of Stream Modes in Block Symmetric Ciphers
No full textIn this chapter are being carried out the statistical researches of the pseudorandom bits sequences, which have been formed by the national BSC of Ukraine «Kalyna» with using of electronic codebooks modes (ECB) or of simple substitution (base conversion) and of stream modes: CTR, CFB, CBC, OFB. For comparison of statistical security indices the researches of properties of the pseudorandom sequences are being performed, which are being formed by the block symmetric ciphers AES (FIPS-197) and the GOST 28147:2009
Criteria and Indices Substantiation of the Stream Cryptoconversion Efficiency
No full textThe efficiency of the functioning of cryptographic data conversion schemes must be estimated from the point of view of their immunity to various methods of information disclosure, as well from the point of view of imposed restrictions on the cryptoconversion velocity and on the using particularity. This section discusses the efficiency indices and criteria of stream ciphers, which characterize cryptographic strength, performance, versatility, etc
Analysis of Stream Cryptoconversion Principles
No full textThis section analyzes various approaches of constructing and analyzing the properties of stream ciphers. In addition, the section discusses the formal description of the cryptographic transformation, in particular, abstract models of the theory of automata are used
Conclusions
No full textBased on the results of the analysis of modern streaming encryption systems, as well as some of its primitives, conducted and presented in this paper, the following conclusions can be made
Analysis of Synchronous Stream Cryptoconversions
No full textMethods of construction of synchronous SSC are divided into two large groups: with uniform movement of shift registers and PRS generators with uneven movement (shift) of registers. In the first case, all LFSR used in the PRS generator are shifted by the same clock signals, i.e the movement of registers is uniform (uniform). This greatly simplifies the implementation of generators and usually increases their performance. Compared to this approach, in non-uniform motion generators, different LFSR can be shifted by different clock signals. This is achieved either through the use of the so-called control register—one of the used in the scheme of the generator LFSR performs the function of controlling the clock frequency of other LFSR. Another approach is to build generators in which the clock speed of the individual LFSR is determined by the logic of the feedback or certain functional transformations between the outputs or contents of the LFSR used in the generator. Such schemes are commonly called self-managed generators. Methods of construction of synchronous SSC with uneven movement of registers, as a rule, have a more complex structure, which reduces the performance of the respective generators. However, cryptographic analysis of such algorithms is usually much more complicated, in particular, the linear complexity of the formed SSC is usually higher than in the schemes with uniform movement of registers
Analysis of Bitstreamed Cryptographic Conversion Algorithms from the International Project eSTREAM
No full textThe winner of the international project for discovering of new stream ciphers eSTREAM, organized by the European Union, are determined: software-oriented SSC: HC-128; Rabbit; Salsa20/12; SOSEMANUK; hardware-oriented SSC: Grain; MICKEY; Trivium. Let us analyze the respective stream cryptoconversions more in details. The keystreams generator Rabbit was analyzed earlier, because of this it is not discussed further. To the analysis was involved also the SSC CryptMT, which was presented to the contest eSTREAM as well, but was not recognized as winner
COMBINING AND FILTERING FUNCTIONS IN THE FRAMEWORK OF NONLINEAR-FEEDBACK SHIFT REGISTER
No full textStrong cryptography of stream ciphers is determined according to the ability of the generated pseudorandom sequence to resist analytical attacks. One of the main components of the pseudorandom stream cipher sequence generating algorithm is Boolean functions for combining and filtering. The paper considers the possibility of applying nonlinear-feedback shift registers that generate a maximum length sequence as a combining or filtering function. The main indicators of cryptographic strength of such functions as: balance, the prohibitions presence, correlation immunity and nonlinearity are examined in this work. The study analyzes and demonstrates correlation immunity and nonlinearity experimental values for all nonlinear feedback shift registers that generate a maximum length sequence, for register sizes up to 6 cells inclusively, and register sizes up to 9 cells inclusively with algebraic degree of the polynomial under 2. The possibility of optimizing the process of selecting Boolean functions according to the criteria of maximum correlation immunity and nonlinearity with various algebraic degrees and minimization of the number of monomials in the polynomial is studied.© 2020 Research Institute for Intelligent Computer Systems. All rights reserved
COMBINING AND FILTERING FUNCTIONS IN THE FRAMEWORK OF NONLINEAR-FEEDBACK SHIFT REGISTER
No full textStrong cryptography of stream ciphers is determined according to the ability of the generated pseudorandom sequence to resist analytical attacks. One of the main components of the pseudorandom stream cipher sequence generating algorithm is Boolean functions for combining and filtering. The paper considers the possibility of applying nonlinear-feedback shift registers that generate a maximum length sequence as a combining or filtering function. The main indicators of cryptographic strength of such functions as: balance, the prohibitions presence, correlation immunity and nonlinearity are examined in this work. The study analyzes and demonstrates correlation immunity and nonlinearity experimental values for all nonlinear feedback shift registers that generate a maximum length sequence, for register sizes up to 6 cells inclusively, and register sizes up to 9 cells inclusively with algebraic degree of the polynomial under 2. The possibility of optimizing the process of selecting Boolean functions according to the criteria of maximum correlation immunity and nonlinearity with various algebraic degrees and minimization of the number of monomials in the polynomial is studied.© 2020 Research Institute for Intelligent Computer Systems. All rights reserved
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