Symmetric Block Research Articles

Features of Using Large Keys in "Kalyna" Algorithm

The information security is playing an incre- asingly important role nowadays. Therefore, virus can be transmitted through the information in encrypted form. This is also applied to embedded systems. In this regard, the article is assigned to the topic of cryptocurrency pro- tection in embedded systems. The article is focused on the algorithm of symmetric block transformation "Kalyna". The algorithm has been developed in cooperation with the State Special Communications Service and leading Ukrainian scientists. The experience and results of interna- tional and open national competition of cryptographic algorithms have been taken into account. The algorithm is intended for gradual replacement of the interstate standard DSTU GOST 28147: 2009. Its differences from other data encryption standards used, both in Ukraine and in the world, have been ana- lyzed. The stability of the "Kalyna" algorithm has been also analyzed using a high-bit key (512 bits) and its speed has been compared with other cryptographic protection algorithms.

Out-of-time-order correlators of nonlocal block-spin and random observables in integrable and nonintegrable spin chains

Out-of-time-order correlators (OTOC) in the Ising Floquet system, that can be both integrable and nonintegrable is studied. Instead of localized spin observables, we study contiguous symmetric blocks of spins or random operators localized on these blocks as observables. We find only power-law growth of OTOC in both integrable and nonintegrable regimes. In the non-integrable regime, beyond the scrambling time, there is an exponential saturation of the OTOC to values consistent with random matrix theory. This motivates the use of "pre-scrambled" random block operators as observables. A pure exponential saturation of OTOC in both integrable and nonintegrable system is observed, without a scrambling phase. Averaging over random observables from the Gaussian unitary ensemble, the OTOC is found to be exactly same as the operator entanglement entropy, whose exponential saturation has been observed in previous studies of such spin-chains.

Pengamanan Mnemonic Phrase Menggunakan Modified Advanced Encryption Standart

Abstract - Security is an action to prevent the occurrence of dangers, threats, and attacks, especially the security of cryptocurrency storage assets on the smartphone crypto mobile wallet application. Security is important to protect wallet data from asset theft attacks. The results of the observations made by many users store their wallet recovery words (mnemonic phrases) on cloud services such as Google Drive and One Drive, this is very vulnerable to data hacking if the account has been compromised then hackers take valuable data for their own benefit. Computer scientists created a cryptographic security algorithm to steal data from theft. The AES (Advanced Encryption Standard) algorithm is a symmetric block cipher cryptography algorithm where to obtain data that has been encrypted using a secret key or passkey user must enter the same key when encoding data (encryption). AES is divided into three based on key length, namely AES-128 has a key length of 128 bits, AES-192 has a key length of 192 bits, and AES-256 has a key length of 256 bits. The system that will be made in this research is to modify the rotation of the standard AES algorithm which has 10 rounds to 16 rounds. Modifications made by increasing the number of algorithm cycles make the system more secure and stronger from attacks and require longer computational time for hackers to crack encryption. The tests carried out are comparing the results of ciphertext, time and avalanche effects. The test results show differences in ciphertext output in the same file after encryption, then the time required for the modified AES algorithm in the encryption and decryption process is longer than the AES standard. While the test results on the avalanche effect showed a slight change that occurred in the standard AES by 48.6% and then in the modified AES by 55.6%. An avalanche effect has good results if there is a slight change of 45-60% (half or more). The more bits that change the more difficult the cryptographic algorithm to crack.

Development and analysis of the new hashing algorithm based on block cipher

This paper proposes the new hash algorithm HBC-256 (Hash based on Block Cipher) based on the symmetric block cipher of the CF (Compression Function). The algorithm is based on the wipe-pipe construct, a modified version of the Merkle-Damgard construct. To transform the block cipher CF into a one-way compression function, the Davis-Meyer scheme is used, which, according to the results of research, is recognized as a strong and secure scheme for constructing hash functions based on block ciphers. The symmetric CF block cipher algorithm used consists of three transformations (Stage-1, Stage-2, and Stage-3), which include modulo two addition, circular shift, and substitution box (four-bit S-boxes). The four substitution boxes are selected from the “golden” set of S-boxes, which have ideal cryptographic properties. The HBC-256 scheme is designed to strike an effective balance between computational speed and protection against a preimage attack. The CF algorithm uses an AES-like primitive as an internal transformation. The hash image was tested for randomness using the NIST (National Institute of Standards and Technology) statistical test suite, the results were examined for the presence of an avalanche effect in the CF encryption algorithm and the HBC-256 hash algorithm itself. The resistance of HBC-256 to near collisions has been practically tested. Since the classical block cipher key expansion algorithms slow down the hash function, the proposed algorithm is adapted for hardware and software implementation by applying parallel computing. A hashing algorithm was developed that has a sufficiently large freedom to select the sizes of the input blocks and the output hash digest. This will make it possible to create an almost universal hashing algorithm and use it in any cryptographic protocols and electronic digital signature algorithms

Construction and Analysis of Models of Increasing Reliability for Modular Encryption Algorithm

This paper describes the development of a model of symmetric block encryption algorithm using nonpositional polynomial notation systems. Computer model this algorithm was created and its properties were investigated. In order to increase the cryptostrength of the algorithm simple substitution and gamming cipher modes were used, methods of the application of these modes are shown. As a continuation of this work, a computer model for managing keys in the encryption algorithm is being developed

Sliding dynamics of ring on a fixed rod-like block copolymer in rotaxane: Molecular dynamics simulations vs Lifson-Jackson formula

Rotaxane is a mechanically interlocked molecule in which ring chains are threaded onto a linear axial polymer chain, and a typical feature of rotaxane is that the ring chains can slide along the axial chain. In this study, molecular dynamics simulations and Lifson-Jackson formula are performed to examine the sliding dynamics of ring chain threaded on a fixed rod-like AB block copolymer consisting of A and B blocks in which the A-block composed of NA monomers is attractive to the ring chain, while the B-block with NB monomers is repelled from the ring chain. From a series of studies on ring sliding along the AB block copolymer with the repeat unit of ANABNB, we find that the sliding dynamics of ring relies strongly on the block length of (NA+NB), the volume fraction fa of A-block as well as the block-ring interaction ε. First, the sliding diffusion coefficient D of ring decreases sharply by several orders magnitude with an increase in block length or block-ring interaction strength. Next, the sliding dynamics has a strongly non-monotonic dependence on fa, and the slowest diffusion motion occurs for ring threaded onto the symmetric block copolymer with fa=0.5. From the view of free energy potential, both the width of free energy potential well and the height of free energy potential barrier govern the sliding diffusion behavior of ring chain. According to potential of mean force (PMF) of ring sliding along the fixed rod-like block copolymer, we find that our results are good agreement with the theoretical analysis using the Lifson-Jackson formula. Our investigation can provide a simple as well as practical model to study the diffusion of particle in a periodic medium, which is one of the interesting problems in many different fields of sciences, such as physics, chemistry and biology.

Blockchain based security framework for sharing digital images using reversible data hiding and encryption

Security is an important issue in current and next-generation networks. Blockchain will be an appropriate technology for securely sharing information in next-generation networks. Digital images are the prime medium attacked by cyber attackers. In this paper, a blockchain based security framework is proposed for sharing digital images in a multi user environment. The proposed framework uses reversible data hiding and encryption as component techniques. A novel high capacity reversible data hiding scheme is also proposed to protect digital images. Reversible data hiding in combination with encryption protects the confidentiality, integrity and authentication of digital images. In the proposed technique, the digital image is compressed first to create room for data hiding, then the user signature is embedded; afterwards the whole image is encrypted. For compression, JPEG lossy compression is used to create high capacity. For encryption, any symmetric block cipher or stream cipher can be used. Experimental results show that the proposed blockchain based framework provides high security and the proposed reversible data hiding scheme provides high capacity and image quality.

An Enhanced Key Schedule Algorithm of PRESENT-128 Block Cipher for Random and Non-Random Secret Keys

The key schedule algorithm (KSA) is a crucial element of symmetric block ciphers with a direct security impact. Despite its undeniable significance, the KSA is still a less focused area in the design of an encryption algorithm. PRESENT is a symmetric lightweight block cipher that provides the optimal balance between security, performance, and minimal cost in IoT. However, the linear functions in KSA lead to a slow and predictable bit transition, indicating the relationship between round keys. A robust KSA should produce random and independent round keys irrespective of the secret key. Therefore, this research aims to improve the KSA PRESENT-128 block cipher with enhanced randomness, round key bit difference, and the avalanche effect. The experiments on round keys and ciphertext with random, low density and high-density secret key datasets endorse the expected improvements. Moreover, the results show that the improved KSA produces random round keys that successfully pass the NIST randomness test. The bit transition from one round key to another is increased from 20% to 40%, where a greater inclination of the avalanche effect has an increased effect with 50% bit change. On the other hand, the improved KSA PRESENT requires an additional 0.001871 s to generate round keys, as a security cost trade-off.

Lightweight VLSI Architectures for Image Encryption Applications

Lightweight cryptography offers significant security service in constrained environments such as wireless sensor networks and Internet of Things. The focus of this article is to construct lightweight SPN block cipher architectures with substitution box based on finite fields. The paper also details the FPGA implementation of the lightweight symmetric block cipher algorithm of SPN type with combinational S-box. Restructuring of traditional look-up-table Substitution Box (S-Box) sub-structure with a combinational logic S-box is attempted. Elementary architectures namely the basic round architecture and reduced datawidth architecture incorporating look-up-table and combinational S-Box substructure are compared in terms of area and throughput. Proposed restructure mechanism occupies less FPGA resources with no comprise in the latency and also demonstrates performance efficiency and low power consumption in Xilinx FPGAs. Robustness of the proposed method against various statistical attacks has been analyzed through comparison with other existing encryption mechanisms.

Odin and Shadow Cretan matrices accompanying primes and their powers

Introduction: Cretan matrices – orthogonal matrices, consisting of the elements 1 and –b (real number), are an ideal object for the visual application of finite-dimensional mathematics. These matrices include, in particular, the Hadamard matrices and, with the expansion of the number of elements, the conference matrices. The most convenient research apparatus is to use field theory and multiplicative Galois groups, which is especially important for new types of Cretan matrices. Purpose: To study the symmetries of the Cretan matrices and to investigate two new types of matrices of odd and even orders, distinguished by symmetries, respectively, which differ significantly from the previously known Mersenne, Euler and Fermat matrices. Results: Formulas for levels are given and symmetries of new Cretan matrices: Odin bicycles (with a border) of orders 4t – 1 and 4t – 3 and shadow matrices of orders 4t – 2 and 4t – 4 are described. For odd character sizes equal to prime numbers and powers of primes, the existence of matrix symmetries of special types, doubly symmetric, consisting of skew-symmetric (with respect to the signs of elements) and symmetric cyclic blocks, is proved. It is shown that the previously distinguished Cretan matrices are their special case: Mersenne matrices of orders 4t – 1 and Euler matrices of orders 4t – 2 existing in the absence of symmetry for all selected orders without exception. Practical relevance: Оrthogonal sequences and methods of their effective finding by the theory of finite fields and groups are of direct practical importance for the problems of noise-immune coding, compression and masking of video information.

Secure Key Management Scheme for Hierarchical Network Using Combinatorial Design

The wireless sensor network (WSN) signifies to a gathering of spatially spread and committed sensors for observing and logging the physical states of the environment and for organizing the information gathered at the central Base station. Many security threats may affect the functioning of these networks. Security of the data in the system depends on the cryptographic procedure and the methods where encryption and decryption keys are developed among the sensors. Symmetric key foundation is one of the best applicable ideal models for safe exchanges in WSNs. The main goal is to improve and evaluate certain issues, such as node attack, to provide better key strength, connectivity, security for node interaction, and throughput. Uniform Balanced Incomplete Block Design (UBIBD) is used to generate the keys allocated by the base station to the cluster head. The cluster head distributes keys to its members using Symmetric Balanced Incomplete Block Design (SBIBD), and the keys are refreshed on a regular basis to avoid out-of-date entries. In wireless sensor networks, compromised nodes can be used to inject false reports. The concept of interacting between sensor nodes using keys and establishing a secure connection aids in ensuring the network's security.

Triangular Topological 2D Covalent Organic Frameworks Constructed via Symmetric or Asymmetric "Two-in-One" Type Monomers.

Most of the reported covalent organic frameworks (COFs) so far are prepared from highly symmetric building blocks, which to some extent limits the expansion of COF diversity and complexity. Low‐symmetric building blocks can be designed through a desymmetrized vertex strategy, which might be used to construct new topological COFs. But reports of COFs constructed by asymmetric building blocks are thus far very rare. Here, a feasible strategy to design asymmetric building blocks for COF synthesis is introduced, by simply varying the positions of functional groups in the monomer. As a proof of concept, two isomeric hexaphenylbenzene‐based “two‐in‐one” type monomers (1,2,4‐HPB‐NH2 and 1,3,5‐HPB‐NH2) are designed and synthesized. To the authors’ surprise, self‐polycondensation of the asymmetric 1,2,4‐HPB‐NH2 (i.e., the isomer of common C3 ‐symmetric 1,3,5‐HPB‐NH2) also affords highly crystalline COF (1,2,4‐HPB‐COF) similar to the symmetric 1,3,5‐HPB‐NH2 counterpart with identical topological structure. The triangular porous structures of both HPB‐based COFs are well resolved by powder X‐ray diffraction (PXRD), theoretical simulations, nitrogen sorption, and morphologies analysis. This work demonstrates the “two‐in‐one” type asymmetric building blocks can also produce highly crystalline frameworks and thus provides a new structural design strategy for reticular chemistry.

Placement Delivery Arrays Based on Combinatorial Designs

As an effective technique to reduce network congestion during peak-traffic times, coded caching is being widely studied in wireless network. Yan <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> proved that the problem of designing a coded caching scheme can be converted into constructing a placement delivery array (PDA). It is meaningful to design coded caching schemes with low transmission rate and small packet number. In this letter, from the perspective of combinatorial designs, we construct a class of PDA using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(v,k,2)$ </tex-math></inline-formula> -symmetric balanced incomplete block design which has advantages in transmission rate. Additionally, two classes of PDAs based on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$t$ </tex-math></inline-formula> -designs are constructed. Compared with some known schemes, new schemes have advantages in packet number.

Some families of integral mixed graphs

A mixed graph Gˆ is a graph where two vertices can be connected by an edge or by an arc (directed edge). The adjacency matrix, Aˆ(Gˆ), of a mixed graph has rows and columns indexed by the set of vertices of Gˆ, being its {u,v}-entry equal to 1 (respectively, −1) if the vertex u is connected by an edge (respectively, an arc) to the vertex v, and 0 otherwise. These graphs are called integral mixed graphs if the eigenvalues of its adjacency matrix are integers. In this paper, symmetric block circulant matrices are characterized, and as a consequence, the definition of a mixed graph to be a block circulant graph is presented. Moreover, using this concept and the concept of a g-circulant matrix, the construction of a family of undirected graphs that are integral block circulant graphs is shown. These results are extended using the notion of H-join operation to characterize the spectrum of a family of integral mixed graphs. Furthermore, a new binary operation called mixed asymmetric product of mixed graphs is introduced, and the notions of joining by arcs and joining by edges are used, allowing us to obtain a new integral mixed graph from two original integral mixed graphs.

The extended symmetric block Lanczos method for matrix-valued Gauss-type quadrature rules

This paper describes methods based on the extended symmetric block Lanczos process for computing element-wise estimates of upper and lower bounds for matrix functions of the form VTf(A)V, where the matrix A∈Rn×n is large, symmetric, and nonsingular, V∈Rn×s is a block vector with 1≤s≪n orthonormal columns, and f is a function that is defined on the convex hull of the spectrum of A. Pairs of block Gauss–Laurent and block anti-Gauss–Laurent quadrature rules are defined and applied to determine the desired estimates. The methods presented generalize methods discussed by Fenu et al. (2013), which use (standard) block Krylov subspaces, to allow the application of extended block Krylov subspaces. The latter spaces are the union of a (standard) block Krylov subspace determined by positive powers of A and a block Krylov subspace defined by negative powers of A. Computed examples illustrate the effectiveness of the proposed method.

A unified kinetic Monte Carlo approach to evaluate (a)symmetric block and gradient copolymers with linear and branched chains illustrated for poly(2-oxazoline)s

Kinetic modeling is used to verify if PAOx synthesis routes can deliver ideal products such as (a)symmetric (block-)gradients and block copolymers. It is shown that a variation in chain length and topology affects the overall compositional deviation.

CF блокты шифрлау алгоритмi және оны биттiк шашырау эффектiне зерттеу

The article is about the importance, features and scope of symmetric block ciphers used to ensure theconfidentiality of data in the era of rapid development of modern computing technologies. In this paper, the structure ofthe symmetric block encryption algorithm CF, developed in the "Laboratory of Information Security" of the "Institute ofInformation and Computational Technologies", the round keys generating mechanism based on it’s secret key are described. A computer program of the created encryption algorithm was developed, on the basis of which the performance was studiedand the bit scattering between the plaintext and the ciphertext (the property of the "avalanche effect" and "strong avalancheeffect") was checked. In order to optimize the hardware implementation of the algorithm, the conversion of the S-block,which is considered as a nonlinear node, was obtained in 4x4 bit size.

МЕТОД ВИЯВЛЕННЯ ПОРУШЕННЯ ЦІЛІСНОСТІ ЦИФРОВОГО ЗОБРАЖЕННЯ, ЗАСНОВАНИЙ НА СПЕКТРАЛЬНОМУ РОЗКЛАДАННІ СИМЕТРИЗОВАНОЇ МАТРИЦІ БЛОКУ

The work considers an important scientific and practical task of increasing the effectiveness of detecting violations of the integrity of information, in particular digital images, which is its common representation, which is becoming one of the main ones for specialists in the field of information and cyber security today. Undetected, unauthorized changes to information in a timely manner can lead to negative, catastrophic consequences for individuals, enterprises, banks, firms, and for humanity as a whole, when it comes to information that constitutes a state secret, contains data from the military industry, nuclear energy, chemical industry, etc., which determines the relevance of the problem under consideration. The main result 102 of the work is an improved universal method for detecting violations of the integrity of a digital image, ready for practical implementation, the theoretical basis of which is based on the analysis of eigenvalues and eigenvectors of symmetric blocks of the image matrix, which correspond to the original blocks. The paper substantiates the method of symmetrization of the block matrix, which allows to significantly (by more than 23%) reduce computational and, as a result, time costs for image examination in comparison with the time costs of the prototype method. It is proved that for the majority of the obtained symmetric blocks that correspond to the blocks of the original CG, the angle between the eigenvector corresponding to the maximum eigenvalue of the block and the normalized vector of the modules of the eigenvalues is equal to a certain value that does not depend on the specifics of the original image, but is sensitive to its changes, which made it possible to ensure the universality of the method and increase its efficiency in the sense of the accuracy of detecting a violation of the integrity of the image by more than 5%, compared to the analogue. The significance of the obtained results lies in ensuring, due to the use of the proposed method, an increase in the efficiency of the process of detecting violations of the integrity of the image according to the criteria of computing (time) costs for the examination of one image and the accuracy of detection.

Automated Deep Learning BLACK-BOX Attack for Multimedia P-BOX Security Assessment

Resistance to differential cryptanalysis is a fundamental security requirement for symmetric block ciphers, and recently, deep learning has attracted the interest of cryptography experts, particularly in the field of block cipher cryptanalysis, where the bulk of these studies are differential distinguisher based black-box attacks. This paper provides a deep learning-based decryptor technique for investigating the permutation primitives used in multimedia block cipher encryption algorithms.We aim to investigate how deep learning can be used to improve on previous classical works by employing cipher text pair aspects to maximize information extraction with low-data constraints by using convolution neural network features to discover the correlation among permutable atoms to extract the plain text from the ciphered text without any P-box expertise. The evaluation of testing methods has been conceptualized as a regression task in which neural networks are supervised using a variety of parameters such as variations between input and output, number of iterations, and P-box generation patterns. On the other hand, the transfer learning skills demonstrated in this study indicate that discovering suitable testing models from the ground is also achievable using our model with optimum prior cryptographic expertise, where we contribute the results of deep learning in the field of deep learning based differential cryptanalysis development.Various experiments were performed on discrete and continuous chaotic and non-chaotic permutation patterns, and the best-performing model had an MSE of 1.8217 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-04</sup> and an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of 1, demonstrating the practicality of the suggested technique.

Hyperchaos and MD5 Based Efficient Color Image Cipher

While designing and developing encryption algorithms for text and images, the main focus has remained on security. This has led to insufficient attention on the improvement of encryption efficiency, enhancement of hyperchaotic sequence randomness, and dynamic DNA-based S-box. In this regard, a new symmetric block cipher scheme has been proposed. It uses dynamic DNA-based S-box connected with MD5 and a hyperchaotic system to produce confusion and diffusion for encrypting color images. Our proposed scheme supports various size color images. It generates three DNA based S-boxes for substitution namely DNA_1_s-box, DNA_2_s-box and DNA_3_s-box, each of size . Next, the 4D hyperchaotic system followed by MD5 is employed in a novel way to enhance security. The three DNA-based S-boxes are generated from real DNA sequences taken from National Center for Biotechnology Information (NCBI) databases and are dependent on the mean intensity value of an input image, thus effectively introducing content-based confusion. Finally, Conservative Site-Specific Recombination (CSSR) is applied on the output DNA received from DNA based S-boxes. The experimental results indicate that the proposed encryption scheme is more secure, robust, and computationally efficient than some of the recently published similar works. Being computational efficient, our proposed scheme is feasible on many emergent resource-constrained platforms.