Cryptographic Properties Research Articles

Cost efficient management of complex financial energy trading systems: Knowledge-based blockchain technique

Industry 4.0 has led to the growth of smart cities utilizing the Internet of Things (IoT). Wireless sensor network (WSN) has drawn considerable interest as an important element of the IoT. The Energy Internet (EI) is growing in importance as a significant component of constructing the intelligent city, especially in terms of its reliability and security. EI is moving in a new direction of energy trading advancement where distributed energy transaction models are replacing the conventional centralized layout. Blockchain technology, which is the underlying support, has gained interest as a result of its benefits, namely integrity, and nonrepudiation. Privacy disclosure, despite the benefits, is a concern for many blockchain-enabled trading layouts. The paper presents encryption according to the cryptographic text properties as the main scheme for reconstructing the dealing layout in order to resolve the issue in the electricity market. In particular, the blockchain energy trade plan with privacy (BETPWP) has been developed to manage the distributed transaction. Transaction arbitration in ciphertext form is employed for achieving precise access control. As a result of this method, the transaction layout could be made considerably more secure and reliable, as well as maximizing the security of private data. BETPWP also proposes a credibility-enabled equity proof consensus method that would significantly improve operational performance. A study of security and the test assessment of the suggested method are performed in order to demonstrate its effectiveness.

Cybersecurity-Enhanced Encrypted Control System Using Keyed-Homomorphic Public Key Encryption

Encrypted control systems are secure control methods that use the cryptographic properties of a specific homomorphic encryption scheme. This study proposes a cyberattack-detectable encrypted control system and validates its effectiveness using a proportional integration derivative (PID) position-control system for an industrial motor. The proposed encrypted control system uses a keyed-homomorphic public-key encryption scheme for real-time detection of cyberattacks, such as signal and control parameter falsification. Additionally, a novel quantizer is presented to reduce the computation cost and quantization-error effects on control performance. The quantizer demonstrated a significant improvement, reducing the computation time by 47.3 % compared to using our previous quantizer, and decreasing the quantization-error effect by 30.6 % compared to a widely-used gain-multiplying quantizer. Moreover, this study establishes conditions through a theorem to avoid an overflow in the proposed control system. Experimental validation confirms that the proposed control system effectively conceals the control operation, and the presented theorem aids in designing the quantization gains to prevent overflows. Notably, the results of falsification attack tests highlight that the proposed control system enables real-time detection of attacked components within control parameters and signals, representing a significant advantage of this study.

Towards Deep Learning for Efficient Image Encryption

Deep learning has become a topic of great concern in many domains and also in end-to-end image encryption. Traditional image encryption techniques employ rounds of diffusion and confusion to obtain an explicit trade-off between security and efficiency. With deep learning approach adequate solutions are obtained for current challenges in image encryption schemes such as efficiency, cryptographic strength, etc. In this paper, the latest trends in end-to-end encryption schemes based on deep learning are summarized. Firstly, the existing deep learning-based encryption systems are categorized into three categories: encryption with style transfer, Style transfer with enhanced diffusion properties, and Combining Deep Neural networks with chaotic systems. Each of these methodologies is discussed and relevant conclusions are made. Secondly, these methods are compared and analyzed for their achievements and drawbacks in terms of cryptographic properties of generated cipher images and quality of the recovered images. Third, the possibility of new cryptographic attacks are discussed such as Hidden Factors Leakage and Network Architecture Leakage as consequences of combination of deep learning approaches with an encryption system. Finally, conclusions are made based on comparison and analysis of deep learning approach in end-to-end encryption/decryption systems, providing basis for further research.

Method to Improve the Cryptographic Properties of S-Boxes

Method to Improve the Cryptographic Properties of S-Boxes

Construction of nonlinear component of block cipher using coset graph

<abstract> <p>In recent times, the research community has shown interest in information security due to the increasing usage of internet-based mobile and web applications. This research presents a novel approach to constructing the nonlinear component or Substitution Box (S-box) of block ciphers by employing coset graphs over the Galois field. Cryptographic techniques are employed to enhance data security and address current security concerns and obstacles with ease. Nonlinear component is a keystone of cryptography that hides the association between plaintext and cipher-text. Cryptographic strength of nonlinear component is directly proportional to the data security provided by the cipher. This research aims to develop a novel approach for construction of dynamic S-boxes or nonlinear components by employing special linear group $ PSL(2, \mathbb{Z}) $ over the Galois Field $ GF\left({2}^{10}\right) $. The vertices of coset diagram belong to $ GF\left({2}^{10}\right) $ and can be expressed as powers of α, where α represents the root of an irreducible polynomial $ p\left(x\right) = {x}^{10}+{x}^{3}+1 $. We constructed several nonlinear components by using $ {GF}^{*}\left({2}^{10}\right) $. Furthermore, we have introduced an exceptionally effective algorithm for optimizing nonlinearity, which significantly enhances the cryptographic properties of the nonlinear component. This algorithm leverages advanced techniques to systematically search for and select optimal S-box designs that exhibit improved resistance against various cryptographic attacks.</p> </abstract>

Reconfigurable Electronic Physically Unclonable Functions Based on Organic Thin‐Film Transistors with Multiscale Polycrystalline Entropy for Highly Secure Cryptography Primitives

AbstractIn this study, organic thin‐film transistors (OTFTs) are investigated as a promising platform for cost‐effective, reconfigurable, and strong electronic physically unclonable functions (PUFs) for highly secure cryptography primitives. Simple spin‐casting of solution‐processable small‐molecule organic semiconductors forms unique and unclonable fingerprint thin films with randomly distributed polycrystalline structures ranging from nanoscale molecular orientations to microcrystalline orientations, which provides a stochastic entropy source of device‐to‐device variations for OTFT arrays. Blending organic semiconductors with polymer materials is a promising strategy to improve the reliability of OTFT‐based PUFs. Studies on the relationship between the phase‐separated polycrystalline microstructure of organic semiconductor/polymer blend films and PUF characteristics reveal that the 2D mosaic microcrystalline structure of organic semiconductors in the vertically phase‐separated trilayered structure enables the implementation of OTFT‐based PUFs that simultaneously satisfy the requirements of being unclonable and unpredictable, with reliable cryptographic properties. The inherent multiscale randomness of the crystalline structure allows random distribution in OTFT‐based PUFs even with various channel dimensions. The secret bit stream generated from the OTFT‐based PUF developed in this study is reconfigurable by simply changing the gate bias, demonstrating the potential to counter evolving security attack threats.

Research on computer 3D image encryption processing based on the nonlinear algorithm

Abstract This article uses the nonlinear digital chaos theory algorithm to generate the corresponding encryption system initial parameters, by analysing the correlation degree of image elements from the angles of horizontal, vertical, and diagonal direction, in order to study computer three-dimensional (3D) image encryption processing. The correlation degree of the cypher text obtained by the nonlinear algorithm is weak in the image's adjacent pixels, and the adjacent pixels are not related at all, horizontal angle: 0.915989, vertical angle: 0.968184, diagonal angle: 0.913533. The nonlinear algorithm distributes the image's statistical features into the random cypher text. By applying permutations and replacements in 3D space, the proposed approach improves performance parameters and widens key space in comparison to previous image cryptography investigations. The important qualities of such a secure system are its simplicity and efficacy. Simulations and analysis show that the proposed method can produce a large key space while also surviving standard cipher attacks. Because of its powerful cryptographic properties, it is suited for image applications. The nonlinear algorithm has very high sensitivity to the secret key and plaintext, as well as better statistical performance, higher security, and higher efficiency in the operation of the algorithm.

ИССЛЕДОВАНИЕ СВОЙСТВ МИНИВЕРСИИ ПСЕВДО-СЛУЧАЙНОЙ ФУНКЦИИ PCOLLAPSER

The aim of the work is to evaluate the cryptographic properties of the pCollapser family of pseudo-random functions (PRF) based on the study of the properties of its mini_pCollapser_12x12 miniversionusing fixed substitutions with extremely low cryptographic properties. As a comparison element,we used a mini-version of a typical function based on an SP-net, containing a similar number of fixedsubstitutions, and having a similar input/output dimension equal to 12 bits. To achieve this goal, thefollowing tasks were solved: – determination of the structure of the studied functions and the number ofrounds; – definition of a model for the formation of fixed substitutions with extremely low cryptographicproperties; – generation of sets of 6-bit fixed substitutions with extremely low cryptographic properties; – inclusion of the substitutions obtained into the functions under study and determination of the maincryptographic properties of functions – the maximum dominance value for individual key values and themaximum dominance value averaged over the entire set of keys, the maximum and averaged over theentire set of keys value in the difference distribution table, algebraic degree and algebraic immunity;– analysis of the obtained results. The paper presents two models for the formation of fixed substitutionswith extremely low cryptographic properties – based on the mixing of cell values in a pre-filled tableand based on the simplest ARX function (consisting of modulo addition, cyclic shift and XOR). The useof fixed substitutions with extremely low non-linearity makes it possible to estimate how complex (nonlinear)the function under study is and what minimum level of non-linearity is necessary to effectivelydestroy the statistical dependencies between input/output data. In addition, it becomes clear that ARXfunctions can be used as non-linear elements, which often have controversial and clearly low cryptographicproperties, but allow creating high-speed software and hardware implementations. It has beendetermined that the PRF pCollapser mini-version, in contrast to the typical function based on the SPnetwork, makes it possible to obtain a high-quality non-linear function from the set of ARX-functionswith extremely low cryptographic properties, given that no other non-linear elements are presented inpCollapser. The obtained results reflect the existence of a fundamental difference between thepCollapser PRF and a typical SP-network based PRF and confirm the correctness of the concept ofPD-sbox pseudo-dynamic substitutions and the pCollapser function consisting of them as a whole.

Resiliency and Nonlinearity Profiles of Some Cryptographic Functions

Boolean functions are important in terms of their cryptographic and combinatorial properties for different kinds of cryptosystems. The nonlinearity and resiliency of cryptographic functions are crucial criteria with respect to protection of ciphers from affine approximation and correlation attacks. In this article, some constructions of disjoint spectra Boolean that function by concatenating the functions on a lesser number of variables are provided. The nonlinearity and resiliency profiles of the constructed functions are obtained. From the profiles of the constructed functions, it is observed that the nonlinearity of these functions is greater than or equal to the nonlinearity of some existing functions. Furthermore, in the security analysis of cryptosystems, 4th order nonlinearity of Boolean functions play a crucial role. It provides protection against various higher order approximation attacks. The lower bounds on 4th order nonlinearity of some classes of Boolean functions having degree 5 are provided. The lower bounds of two classes of functions have form Tr1n(λxd) for all x∈F2n,λ∈F2n*, where (i) d=2i+2j+2k+2ℓ+1, where i,j,k,ℓ are integers such that i>j>k>ℓ≥1 and n>2i, and (ii) d=24ℓ+23ℓ+22ℓ+2ℓ+1, where ℓ>0 is an integer with property gcd(ℓ,n)=1, n>8 are provided. The obtained lower bounds are compared with some existing results available in the literature.

On security aspects of the ciphers T-310 and SKS with approved long-term keys

The cipher T-310 was developed by the Central Cipher Authority of the German Democratic Republic in the 1970s and widely used for protection of teletype communication up to security level secret. After publication of the cipher algorithm in 2006, several articles appeared aiming at the cryptographic properties of the cipher T-310. The cryptographic strength of the cipher T-310 must be assessed as a combination of both the cipher algorithm and the approved long-term keys. This article provides a rationale of the design decisions and the selection of approved long-term keys for T-310. We demonstrate that the attacks involving fundamental equations, linear characteristics, and some of their generalizations do not work if historical approved long-term keys are used. The results are also valid for the cipher SKS and block ciphers, whose groups of round functions are the alternating groups over the blocks.

Development and Study of an Encryption Algorithm

A new symmetric block cipher algorithm called AL02 has been developed. The algorithm scheme provides five-round encryption of 128-bit blocks, while the data size at the input and output of the S-box is 8 bits. The main transformation is the F transformation. The difference between the proposed algorithm and the classical scheme is that the F transformation provides the maximum possible dependence of the output vector bits on the input bits and is based on “modulo 2 addition” and a substitution S-box. To assess the strength of the AL02 algorithm, it was programmatically implemented in the C programming language. During the analysis, the cryptographic properties of the developed encryption algorithm were tested. The algorithm was tested for statistical security. For an experimental assessment, in order to ensure that the ciphertext is not inferior to a random sequence in its properties, the well-known sets of statistical tests by NIST (National Institute of Standards and Technology) and Donald Knuth were used. The property of the avalanche effect was also checked. The strength was evaluated using the methods of differential and linear cryptanalysis.

Transparency Order and Cross-Correlation Analysis of Boolean Functions

Transparency order is considered to be a cryptographically significant property that characterizes the resistance of S-boxes in opposition to differential power analysis attacks. The S-box having low transparency order is more resistant to these attacks. Until now, little attempts have been noticed to examine theoretically the transparency order and its relationship with other cryptographic properties. All constructions associated with transparency order are relying on search algorithms. In this paper, we discuss the new interpretation of bent functions in terms of their transparency order. Using the concept of vector concatenation and correlation characteristics, we find the transparency order of Boolean functions. The notion of complementary transparency order is given. For a pair of Boolean functions, we interpret complementary transparency order by their Walsh-Hadamard transform. We establish a relationship of transparency order with cross-correlation for a pair of Boolean functions. We find a relationship of transparency order with <img src=image/13428361_01.gif>−variable decomposition bent functions. We generalize the bounds on sum-of-squares of autocorrelation in terms of transparency order of Boolean functions using Walsh-Hadamard spectra. Further the transparency order of a function fulfilling the propagation criterion about a linear subspace is evaluated.

From Theory to Code: Identifying Logical Flaws in Cryptographic Implementations in C/C++

Cryptographic protocols are often expected to be provably secure. However, this security guarantee often falls short in practice due to various implementation flaws. We propose a new paradigm called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cryptographic program analysis (CPA)</i> which prescribes the use of program analysis to detect these implementation flaws at compile time. The principal insight of the CPA is that many of these flaws in cryptographic implementations can be mapped to the violation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">meta-level properties</i> of implementations. A program property that is necessary to realize a cryptographic property is referred to as meta-level property. We show that violations of these meta-level properties can be identified at compile-time that can serve as sufficient evidence of the encompassing flaws. We investigated existing literature on cryptographic implementation flaws and derived 25 corresponding meta-level properties. To instantiate the abstract paradigm of CPA, we develop a specification language based on deterministic finite automaton (DFA) and show that most of the meta-level properties can be expressed in terms of our language. We then develop a tool called <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TaintCrypt</small> which uses static taint analysis to identify meta-level property violations of C/C++ cryptographic implementations at compile-time. We demonstrate the efficacy of <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TaintCrypt</small> by analyzing open-source C/C++ cryptographic libraries (e.g., OpenSSL) and observe that <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TaintCrypt</small> could have helped to avoid several high-profile flaws. We also evaluated <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TaintCrypt</small> on 5 popular applications and libraries, which generated new security insights. The experimental evaluation on large-scale projects indicates the scalability of our approach.

Application of SAT-Solvers to the Problem of Finding Vectorial Boolean Functions with Required Cryptographic Properties

Application of SAT-Solvers to the Problem of Finding Vectorial Boolean Functions with Required Cryptographic Properties

The LBC-3 lightweight encryption algorithm

Abstract This article presents a developed lightweight data encryption algorithm called LBC-3. Its essential difference from the known algorithms is the R1 function and the procedure for generating round keys. The main characteristics of this lightweight algorithm and all the transformations used in the encryption and decryption processes are described. The process of generating the round keys of the algorithm is also considered. The results of the study of the cryptographic properties of the algorithm using the “avalanche effect” and statistical tests are presented. The avalanche property was tested for each round with each bit of the source text changing. Based on the work carried out, it was found that the proposed encryption algorithm is effective in providing a good avalanche effect, and the binary sequence obtained after encryption is close to random. The research revealed good cryptographic properties of this algorithm.

Differential Analysis of a Cryptographic Hashing Algorithm HBC-256

The article observes the new hashing algorithm HBC-256. The HBC-256 algorithm is based on the block cipher of the compression function CF (Compression Function) and produces a 256-bits hash value. Like any new cryptographic structure, the HBC-256 algorithm requires careful research process in order to confirm its cryptographic properties, namely: pre-image resistance and resistance to collisions of the first and second order. As a result of the research, for the HBC-256 hashing algorithm differential properties of nonlinear elements (S-boxes) and various options for constructing round characteristics are considered. A hypothesis has been advanced about the existence of paired differences, which will make it possible to construct round characteristics for hashing and for the function of round keys generating. It is shown that even for the most optimal way of constructing chains of differences, the probability of finding correct pairs of texts is less than the probability of a complete enumeration of one 128-bit block of input data, which makes the method of differential cryptanalysis unsuitable for finding collisions.

Improved cryptographic properties of Boolean functions obtained from the neighbourhood of Patterson-Wiedemann functions

Improved cryptographic properties of Boolean functions obtained from the neighbourhood of Patterson-Wiedemann functions

Algebraic methods for generating optimal s-blocks

The paper presents a review of algebraic methods for generating cryptographic S-boxes. In this paper, we consider methods for generating S-boxes based on the use of polynomial transformations (linear, quadratic, cubic), fractional linear transformations, and other special types of algebraic transformations. A number of examples of generating S-boxes using quasigroups and other algebraic structures are also given. The considered methods for generating S-boxes make it possible to obtain new S-boxes that have the necessary cryptographic properties that are the same or even better than those of the S-box built for the Rijndael algorithm.

A comprehensive analysis of lightweight 8-bit sboxes from iterative structures

Massive data needs to be cryptographically handled in emerging IoT applications. Therefore the design and analysis of lightweight symmetric-key primitives become a research hotspot. Theoretically, symmetric-key cryptograms should be secure against differential, linear and other proposed structural cryptanalysis. In addition to these cryptographic properties, software and hardware costs are also pivotal for resource constrained devices. Traditionally, 4-bit sboxes are widely used in lightweight cryptography due to their efficiency. In this paper, we investigate the iterative constructions of lightweight 8-bit sboxes. Our proposals contain 8-bit sboxes constructed with the Feistel, Lai–Massey and SPN structures, which are iterated with the published lightweight 4-bit sboxes or non-bijective functions. Moreover, we propose 8-bit sboxes under the generalized Feistel network (GFN), which are suitable for software and hardware implementations. Based on the bitslicing method, software and hardware performances are analyzed with their CPU cycles and Gate Equivalent (GE). Compare to the published lightweight 8-bit sboxes with iterative structures, our proposals achieve similar software performance, whilst enjoying better algebraic degrees and less GE costs in hardware implementation.

Quaternion keyed Least Square Approximation for image encryption

Securing image data from prying hackers is crucial in safeguarding the secrecy of data. Over the years, this was done by encrypting the image using an algorithm and a key, where the visible image was converted into a meaningless object. It is a difficult problem to design an image encryption technique based on chaotic systems with predictable cryptographic features. In this paper, the Quaternion, along with the Rossler attractor, was used to generate the key combination. The ciphering was done using the Least Square Approximation Algorithm (LSA). The algorithm was tested on a grayscale image database. The algorithm was initially tested in software using MATLAB R2018b, and was implemented in the Cyclone II EP2C35F672C6 device FPGA. On average, for a cipher image, the Peak Signal to Noise ratio (PSNR) was 9.09303 dB and the entropy was 7.9990 bits. For the cipher image, the Number of Pixels Change Rate (NPCR) and Unified Average Change Intensity (UACI) were 99.6039 and 33.4980, respectively. This proved that the algorithm could effectively mitigate the statistical and differential attacks. The key space was 2 (M ×N ×7 ×8), which was sufficiently high and mitigated the brute force attacks. The obtained results confirm that the cipher images resulting from the proposed ciphering scheme possess good cryptographic properties in terms of entropy, PSNR, UACI, NPCR, and keyspace analysis. Furthermore, the strength of the key is evaluated by the NIST test suite.