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The wide spread of smartphones and QR codes for various end-user applications has had an impact beyond traditional fields of use, recently also reaching point-of-care testing (POCT). This work presents the integration of QR code recognition into paper-based analytical devices (PADs) with "distance-based" colorimetric signalling, resulting in semiquantitative readout fully relying on straightforward barcode reader solutions. PADs consist of an array of QR codes arranged in series inside a paperfluidic channel. A mask dye concept has been developed, which enables utilisation of colour changing indicators by initially hiding QR codes. The colour change of the indicator induced by the presence of an analyte of interest results in gradual unmasking of QR codes, which become recognisable by the smartphone barcode reader app. To reproducibly fabricate devices, all fabrication steps were performed by commercial desktop solid ink and inkjet printing. The QR code masking function was optimised by controlling the amount of printed mask dye through adjusting the opacity of printing patterns during the inkjet deposition process. For proof-of-concept, a model assay in the form of colorimetric copper ion (Cu2+) detection in the concentration range of 0.4 mM to 3.2 mM was evaluated. Consistent results independent of the smartphone model and environmental light condition were achieved with a free barcode reader app. To the best of our knowledge, this work is the first demonstration of a semiquantitative assay approach fully relying on QR code readout without digital colour analysis, customised app or hardware modification. [ABSTRACT FROM AUTHOR]

ABSTRACT Shadow is a lightweight AND‐RX block cipher adapted for resource‐constrained devices. In this paper, software and hardware optimizations are proposed respectively for Shadow to enhance its implementation performance. For software optimization, this paper first proposes a data pre‐processing scheme based on the structural characteristics of the round function. It further improves the optimization effect of the barrel shifter instruction while simplifying the implementation process of the round function. Note that the optimization strategy is also applicable to other AND‐RX ciphers. Secondly, this paper proposes a new NX operation implementation scheme that can effectively reduce its instruction cycles. In round‐based architecture, experimental results show that our scheme effectively reduces code size by 24.7%, Flash consumption by 12.6%, and total instruction cycles by 25.1%. Meanwhile, in the fully unrolled architecture, our scheme reduces code size by 30.8%, Flash consumption by 29.8%, and total instruction cycles by 28.1%. For hardware optimization, this paper proposes a low‐resource implementation scheme by constructing a generic formula for NX operation. In ASIC implementation, our scheme reduces hardware resources by 72.3%. In FPGA implementation, the number of LUTs and Slices is reduced by 30% and 28.6%, respectively. Overall, the proposed optimization scheme for Shadow has better performance in hardware and software implementation. [ABSTRACT FROM AUTHOR]

A substitution box (S-Box) is a fundamental component used in DES and AES. This is used to achieve non-linearity in encryption. The use of S-Box also introduces the property of confusion in symmetric cipher systems. A finite field in the multiplicative inverses of GF (28) is the basis for the generation of the S-Box in the AES algorithm. This paper presents a novel approach that utilizes the XOR vector space for generating the S-Box. The XOR vector space is constructed using two-dimensional values comprising vectors of size of 2b. Following this, the resulting S-Box is employed in standard algorithms such as DES and AES to encrypt the image. Furthermore, this paper assesses the security aspects of the proposed algorithm by measuring various parameters. The result is compared with methods that generate various S-Boxes for the DES and AES algorithms. This suggests that the proposed method is relatively better. [ABSTRACT FROM AUTHOR]

Nowadays, it is difficult to imagine a powerful algorithm of cryptography that can continue cryptanalyzing and attacking without the use of unconventional techniques. Although some of the substitution algorithms are old, such as Vigenere, Alberti, and Trithemius ciphers, they are considered powerful and cannot be broken. In this paper we produce the novelty algorithm, by using of biological computation as an unconventional search tool combined with an uninhibited analysis method is the vertical probabilistic model, that makes attacking and analyzing these ciphers possible and very easy to transform the problem from a complex to a linear one, which is a novelty achievement. The letters of the encoded message are processed in the form of segments of equal length, to report the available hardware components. Each letter codon represents a region of the memory strand, and the letters calculated for it are symbolized within the probabilistic model so that each pair has a triple encoding: the first is given as a memory strand encoding and the others are its complement in the sticker encoding; These encodings differ from one region to another. The solution space is calculated and then the parallel search process begins. Some memory complexities are excluded even though they are within the solution paths formed, because the natural language does not contain its sequences. The precision of the solution and the time consuming of access to it depend on the length of the processed text, and the precision of the solution is often inversely proportional to the speed of access to it. As an average of the time spent to reach the solution, a text with a length of 200 cipher characters needs approximately 15 minutes to give 98% of the correct components of the specific hardware. The aim of the paper is to transform OTP substitution analysis from a NP problem to a O(nm) problem, which makes it easier to find solutions to it easily with the available capabilities and to develop methods that are harnessed to attack difficult and powerful ciphers that differ in class and type from the OTP polyalphabetic substitution ciphers. [ABSTRACT FROM AUTHOR]

Summary: The widespread use of Internet of Things devices has increased the demand for lower cost and more efficient lightweight ciphers. However, there is a difficult trade‐off between cost and efficiency for lightweight block ciphers. The optimizations of area and throughput are important for some constrained environments. This paper proposes two novel hardware architectures for the LILLIPUT cipher. In the novel low area structure, a new permutation layer is provided for LILLIPUT. The relationship between encryption algorithm and key scheduling algorithm is utilized to achieve optimal sharing among components, which significantly reduces hardware area. The experimental results show that the number of XOR gates and S‐boxes required for low area optimization is reduced by 52 and 8, respectively. The total area is reduced by about 18%. For high throughput structure, this paper provides 2‐round, 5‐round, and 15‐round loop unrolling designs for LILLIPUT to improve throughput. The experimental results show that the throughput of the 5‐round loop unrolling structure reaches a good level, which is relatively the most cost‐effective. In practical application, ciphers can be unrolled implementations according to the needs of devices to improve the execution speed, which can greatly reduce the execution time and complexity of the algorithm. [ABSTRACT FROM AUTHOR]

This paper conducts a security analysis on an image encryption scheme that incorporates chaos synchronization and DNA encoding techniques. The scheme adheres to the typical Substitution–Permutation structure by introducing the DNA operation as a nonlinear component. Compared to the traditional chaotic ciphers, the designer claims that the scheme achieved better nonlinear properties through the DNA operation. However, the characteristics of the differential between some pairs of plaintexts and the corresponding ciphertexts can be exploited to break the permutation operation. Meanwhile, the substitution operation can also be cracked by checking the mapping between the intermediate variables inversely permuted from ciphertext and the corresponding plaintext. Given the weaknesses of the encryption scheme, we introduce effective strategies for the known-plaintext attack. Both rigorous theoretical analyses and detailed experimental results are provided to demonstrate the effectiveness of the attacks. [ABSTRACT FROM AUTHOR]

During World War II, Leo Marks designed ciphers for the British Special Operations Executive (SOE). Tasked with ensuring that SOE undercover agents could encrypt radio transmissions from Nazi-occupied Europe to British headquarters, Marks introduced one-time pad ciphers with random keys printed on materials like paper and silk. However, carrying such materials was risky for agents. In an attempt to mitigate this risk, Marks experimented with a system he called the "Mental One-Time Pad" (MOP) cipher. Contrary to its name, the MOP cipher was not a genuine one-time pad system, but rather used double columnar transposition with memorized texts to create unique substitution keys. In this article, we'll explore the design, vulnerabilities, and historical significance of the MOP cipher, and discuss potential improvements from US Army cryptographer William Friedman. [ABSTRACT FROM AUTHOR]

Security efficiency and hardware efficiency are equally important when designing a block cipher. In this paper, we propose a new block cipher that uses string transformations and requires less memory and fewer computational resources, making it suitable for highly constrained environments. We compare the performance of our design with AES-128 and quasigroup-based block cipher INRU in the cipher block chaining (CBC) mode of operation using the National Institute of Standards and Technology (NIST) test suite. We then analyze our design against the standard linear, differential, and algebraic attacks. Choosing suitable S-boxes and a quasigroup of a smaller order does not compromise the security of the cipher, but the storage space is reduced compared with AES-128 and INRU. [ABSTRACT FROM AUTHOR]

A new dirty paper coding technique that is robust against the gain attack is presented. Such a robustness is obtained by adopting a set of (orthogonal) equienergetic codewords and a correlation-based decoder. Due to the simple structure of orthogonal codes, we developed a simple yet powerful technique to embed the hidden message within the host signal. The proposed technique is an optimal one, in that the embedding distortion is minimized for a given robustness level, where robustness is measured through the maximum pairwise error probability in the presence of an additive Gaussian attack of given strength. The performance of the dirty coding algorithm is further improved by replacing orthogonal with quasi- orthogonal codes, namely, Gold sequences, and by concatenating them with an outer turbo code. To this aim, the inner decoder is modified to produce a soft estimate of the embedded message. Performance analysis is carried out by means of extensive simulations proving the validity of the novel watermarking scheme. [ABSTRACT FROM AUTHOR]

With the rapid proliferation of the Internet of Things (IoT) in recent years, the number of IoT devices has surged exponentially. These devices collect and transmit vast amounts of data, including sensitive information. Encrypting data is a crucial means to prevent unauthorized access and potential misuse. However, the traditional cryptographic schemes offering robust security demand substantial device resources and are unsuitable for lightweight deployments, particularly in resource-constrained IoT devices. On the other hand, with the automotive industry making strides in autonomous driving, self-driving vehicles are beginning to integrate into people's daily lives. Ensuring the security of autonomous driving systems, particularly in preventing hacker infiltrations, is a paramount challenge currently facing the industry. An emerging lightweight sequence cipher—aiming to strike a balance between security and resource efficiency—has been proposed in this paper based on S-box substitution and arithmetic addition. The designed security threshold is 280. It has been verified that with a slight performance disadvantage, it can reduce memory usage while ensuring the security threshold. The key stream generated by this structure exhibits excellent pseudo-randomness. [ABSTRACT FROM AUTHOR]

Encryption of images is an important method that can effectively improve the security and privacy of crucial image data. Existing methods generally encrypt an image with a combination of scrambling and encoding operations. Currently, many applications require highly secure results for image encryption. New methods that can achieve improved randomness for both the scrambling and encoding processes in encryption are thus needed to further enhance the security of a cipher image. This paper proposes a new method that can securely encrypt color images. As the first step of the proposed method, a complete bit-level operation is utilized to scramble the binary bits in a color image to a full extent. For the second step, the bits in the scrambled image are processed with a sweeping operation to improve the encryption security. In the final step of encryption, a codebook that varies with evolutionary operations based on several chaotic systems is utilized to encrypt the partially encrypted image obtained in the second step. Experimental results on benchmark color images suggest that this new approach can securely encrypt color images and generate cipher images that remain secure under different types of attacks. The proposed approach is compared with several other state-of-the-art encryption approaches and the results show that it can achieve improved encryption security for cipher images. Experimental results thus suggest that this new approach can possibly be utilized practically in applications where color images need to be encrypted for content protection. [ABSTRACT FROM AUTHOR]

From 1944 the State Department attempted to improve its communications security by creating a Division of Cryptography and mechanising the encryption process. This article assesses the effectiveness of these reforms and shows that State's new cipher equipment had cryptographic vulnerabilities. Moreover, the department was unable to maintain physical security at the Moscow embassy and through espionage and technical surveillance the KGB broke the ciphers and read American communications. The paper concludes by analysing the impact of this security failure, including the claim that intercepted messages influenced Stalin's decision to approve the North Korean invasion of South Korea in 1950. [ABSTRACT FROM AUTHOR]

The purpose of the present article is to contribute to the postphenomenological theory of technological mediation by introducing a new type of 'human-technology' relation named 'transcending mediation'. Previously postphenomenology didn't pay much attention to the role technology plays in mediating human relation to Transcendence. This was because of empirical turn and pragmatism that are anti-metaphysical in their nature. In the present paper, however, I will show that the empirical element of technology can be balanced by some metaphysical findings. Keeping this in mind, I will rely on Karl Jaspers's metaphysics of ciphers in order to demonstrate how technology mediates not only our relation to the world but also shapes human's relation to Transcendence. As I am going to show in the present paper, this sort of mediation becomes possible because technologies are actively participating in so-called self-transcending practices. The latter, according to Karl Jaspers, are practices through which humans can elucidate one's true self (e.g., become an Existenz). In this article, I will take a case of Smart education as a particular type of self-transcending practice and will show how contemporary AI educational systems enable and disable particular forms of becoming true self (Existenz). [ABSTRACT FROM AUTHOR]

This paper proposes an image encryption algorithm based on combined 1D chaotic maps. First, a permutation technique was applied. It was then reorganized into 1D matrices along the rows and columns respectively, which were then shuffled by computing the substituted position indices to obtain the scrambled image. Subsequently, a method of confusion of the scrambled image was used through another generated data map, combined with random sub‐matrices for diffusion, then resulting in an encrypted image. Finally, the proposed cryptosystem was implemented in a single kernel platform developed using the Nios II Software Build Tools processor for Eclipse. A hardware architecture was designed using the Qsys‐built tool which is available in the Quartus II 13.0sp1 environment. The developed single‐core system was implemented using the Cyclone IV EP4CE6E22C8. Robustness evaluation of the cryptosystem was performed through security analysis tests such as histogram analysis, correlation coefficient, differential analysis, and key space analysis to prove that it is of good quality, efficient, fast, and successfully resisting brute force attacks. The hardware performance analysis was also carried out. Then the cryptosystem is compared with those in the literature both in the hardware and security performance aspects. [ABSTRACT FROM AUTHOR]

Researchers have created cryptography algorithms that encrypt data using a public or private key to secure it from intruders. It is insufficient to protect the data by using such a key. No research article has identified an algorithm capable of protecting both the data and the associated key, nor has any mechanism been developed to determine whether access to the data is permissible or impermissible based on the authentication of the key. This paper presents a WEDEx-Kerberotic Framework for data protection, in which a user-defined key is firstly converted to a cipher key using the "Secure Words on Joining Key (SWJK)" algorithm. Subsequently, a WEDEx-Kerberotic encryption mechanism is created to protect the data by encrypting it with the cipher key. The first reason for making the WEDEx-Kerberotic Framework is to convert the user-defined key into a key that has nothing to do with the original key, and the length of the cipher key is much shorter than the original key. The second reason is that each ciphertext and key value are interlinked. When an intruder utilizes the snatching mechanism to obtain data, the attacker obtains data or a key unrelated to the original data. No matter how efficient the algorithm is, an attacker cannot access the data when these methods and algorithms are used to protect it. Finally, the proposed algorithm is compared to the previous approaches to determine the uniqueness of the algorithm and assess its superiority to the previous algorithms. [ABSTRACT FROM AUTHOR]

Smartphones, digital cameras, and other imaging devices generate vast amounts of high-resolution colored images daily, stored on devices equipped with multi-core central processing units or on the cloud. Safeguarding these images from potential attackers has become a pressing concern. This paper introduces a set of six innovative image ciphers designed to be stronger, faster, and more efficient. Three of these algorithms incorporate the State-Based Tent Map (SBTM) Chaotic Pseudo Random Number Generator (CPRNG), while the remaining three employ a proposed modified variant, SBTMPi. The Grayscale Image Cipher (GIC), Colored Image Cipher Single-Thread RGB (CIC1), and Colored Image Cipher Three-Thread RGB (CIC3) showcase the application of the proposed algorithms. By incorporating novel techniques in the confusion and diffusion phases, these ciphers demonstrate remarkable performance, particularly with large colored images. The study underscores the potential of SBTM-based image ciphers, contributing to the advancement of secure image encryption techniques with robust random number generation capabilities. [ABSTRACT FROM AUTHOR]

Several properties of the products of finite maximal prefix, maximal biprefix, semaphore, synchronous, maximal infix and maximal outfix codes are discussed respectively. We show that, for two nonempty subsets X and Y of A * such that the product XY being thin, if XY is a maximal biprefix code, then X and Y are maximal biprefix codes. Also, it is shown that, for two finite nonempty subsets X and Y of A * such that the product XY being unambiguous, if XY is a semaphore code then X and Y are semaphore codes. Finally, two open problems to the product of finite semaphore and maximal infix codes are presented. [ABSTRACT FROM AUTHOR]

This paper proposes a dynamic RNA-encoded color image encryption scheme based on a chain feedback structure. Firstly, the color pure image is decomposed into red, green, and blue components, and then a chaotic sequence based on plaintext association is introduced to encrypt the red component. Secondly, the intermediate ciphertext is obtained by diffusion after encryption by bit-level permutation, RNA dynamic encoding, RNA dynamic operation rules, and RNA dynamic decoding. Finally, to enhance the security of the image cryptosystem, the green and blue components of the image are repeatedly encrypted using the chain encryption mechanism associated with the intermediate ciphertext to obtain the color cryptographic image. In this paper, a 2D-SFHM chaotic system is used to provide pseudo-random chaotic sequences, and its initial key is calculated by combining the hash function and external parameters of the image, and the one-time ciphertext encryption strategy causes the proposed encryption to effectively resist cryptographic attacks. Experimental results and security analysis show that our encryption algorithm has excellent encryption effects and security performance against various typical attacks. [ABSTRACT FROM AUTHOR]

Let n be a positive integer. An NFSR of n stages is called irreducible if the family of output sequences of any NFSR of stages less than n is not included in that of the NFSR. In this paper, we prove that the density of the irreducible NFSRs of n stages is larger than 0.39. This implies that it is expected to find an irreducible NFSR of n stages among three randomly chosen NFSRs of n stages. [ABSTRACT FROM PUBLISHER]

This paper presents an image encryption scheme with data and appearance security, by adopting inter-intra-block scrambling and weighted diffusion. The 2D robust hyper-chaotic map with flexible geometric distribution and rich hyper-chaotic parameter space is employed to generate the key stream for encryption, by considering the characteristics of plaintext. The plain image is first preprocessed by Huffman coding for getting compressed image. Then, the compressed image is divided into four sub-blocks and is further permuted by the designed inter-intra-block scrambling scheme, which can improve the scrambling effect by making the pixel far away from the original adjacent pixels. After that, a weighted diffusion method strongly related to plaintext and key stream is introduced to diffuse the shuffled image to obtain the noise-like cipher image. And in pursuit of higher security, the meaningless noise-like image is embedded into host image to create the visually meaningful cipher image. A series of experiment tests and analyses are carried out to further demonstrate the excellent performances of the encryption scheme. [ABSTRACT FROM AUTHOR]

Mixed-integer linear programming (MILP) techniques are widely used in cryptanalysis, aiding in the discovery of optimal linear and differential characteristics. This paper delves into the analysis of block ciphers KLEIN and PRINCE using MILP, specifically calculating the best linear and differential characteristics for reduced-round versions. Both ciphers employ matrix multiplication in their diffusion layers, which we model using multiple XOR operations. To this end, we propose two novel MILP models for multiple XOR operations, which use fewer variables and constraints, proving to be more efficient than standard methods for XOR modeling. For differential cryptanalysis, we identify characteristics with a probability of 2-59 for 7 rounds of KLEIN and a probability of 2-56 for 7 rounds of PRINCE. In linear cryptanalysis, we identify characteristics with a bias of 2-27 for 6 rounds of KLEIN and a bias of 2-29 for 7 rounds of PRINCE. These results establish the best single-key differential and linear distinguishers for these ciphers in the literature. [ABSTRACT FROM AUTHOR]

Internet of Things (IoT) has gained popularity in recent years and has engulfed nearly every industry. The widespread use of numerous ubiquitous computing devices in the low-resource domain has resulted in a new set of privacy and security concerns. To address the problem of security in resource-constrained devices, many lightweight algorithms have been developed. This paper proposes optimized hardware implementations of the lightweight PRINCE block cipher, with the aim of providing adequate security while maximizing resource efficiency. The proposed architecture uses fewer resources and provides a reasonable trade-off between area footprint and efficiency. In the proposed unrolled pipelined architecture, the encryption round is divided into three sub-stages, with registers inserted in between. Using this design approach, the operating frequency is greatly improved. As a result, this architecture adapts itself effectively to high-performance applications. This paper also proposes serial-based and round-based architectures for resource-constrained devices. The proposed unrolled sub pipeline PRINCE block cipher is implemented on the Virtex-6-FF784 and Virtex-4-FF668 FPGA device families and achieved substantial improvements in throughput of 13.057% and 113%, respectively, as well as efficiency of 8.109% and 113.734% respectively. The proposed architecture is evaluated on a variety of grayscale images, and the security analysis is performed using MATLAB software. Aside from that, the proposed architecture uses the CBC-mode of operation. The security analysis and encryption outputs show that the proposed architecture is an effective choice for image encryption and provides sufficient security to the cipher images. • Propose a serial architecture which reduces the number of utilized resources that suggests reduction in area for resource constrained devices. • Propose an unrolled pipeline architecture which achieves high throughput, and low latency implementation. • Propose a round-based architecture and provides a comparison of all proposed designs with existing implementations. • All the implementations are analyzed by using different security analyses for image encryption applications that secure their immunity against various statistical and differential attacks. [ABSTRACT FROM AUTHOR]

Rémi Géraud-Stewart and David Naccache have recently discovered historical documents from the late 19th century, written by Major H.D. Josse of the French Army, that describe a proposal for a new cipher. In our paper, we provide an in-depth analysis of the cipher and a revised formal description of the cipher based on the examples given by Josse. We also present classes of cryptologically equivalent keys, and a possible attack based on ciphertext isomorphs, that can be implemented with only pen-and-paper. We also describe a new ciphertext-only stochastic attack, based on simulated annealing, that can recover the key and the plaintext from ciphertexts with only 75 letters. We are planning to implement the cipher in CrypTool 2, an e-learning platform for cryptography. [ABSTRACT FROM AUTHOR]

Due to the vigorous and ever-evolving demands of the IoT field, resource-constrained devices are being deployed in such areas and several new challenges like sequestration and surveillance, have come into the picture. Multiple lightweight designs have been recommended to overcome the security issues for resource-constrained devices. In applications requiring data to be transmitted fast between various devices, loop unrolling and subsequent pipelining architectures are extremely efficient. In this paper, several efficient hardware implementations of Simeck cipher such as loop unrolling architecture and outer round pipelining technique have been proposed in order to achieve high throughput. This paper has also proposed a bit serialized architecture of the Simeck cipher that reduces the area footprint and used in less resource applications. Our Simeck Serial architecture is 29.5 times more efficient than LiCi cipher and occupies only 7% of the area occupied by LiCi cipher. Similarly, our proposed serial architecture occupies only 13% and 25% of total slices occupied by X 192 and XTEA respectively while still performs 184% and 161% more efficiently. All three architectures are evaluated and compared on the basis of throughput, area utilization, and power consumption for their implementations in different FPGA platforms. • In unroll loop architecture of Simeck cipher, all rounds are unrolled which ultimately vastly reduces the latency while providing an optimum trade-off between area footprint and performance. This makes the design fit for applications demanding less latency. • The proposed outer round pipelining architecture is in turn derived from the full loop unrolling architecture where the loop unrolling greatly simplifies the key scheduling and the round function of the Simeck cipher. With the installation of registers in between each round, throughput is significantly improved and the area footprint is also reduced making design relevant for low resource and high-speed applications. • The proposed serial architecture for Simeck cipher utilizes only 17 slices making it extremely area efficient. [ABSTRACT FROM AUTHOR]

In 2019, a chaotic image encryption scheme based on a variant of the Hill cipher (VHC-CIES) was proposed by the Moroccan scholars. VHC-CIES introduces a Hill cipher variant and three improved one-dimensional chaotic maps to enhance the security. In this paper, we conduct a comprehensive cryptanalysis, and find that VHC-CIES can resist neither chosen-plaintext attack nor chosen-ciphertext attack due to its inherent flaws. When it comes to chosen-plaintext attack, firstly, we select a plaintext with the pixel values are all 0 and its corresponding ciphertext, and then use algebraic analysis to obtain the equivalent key stream for cracking VHC-CIES. Secondly, we select a plaintext which the pixel values are invariably 1 and obtain its corresponding ciphertext to obtain some Hill cipher variant parameters of VHC-CIES. Finally, we use the resulting steps of the first two to recover the original plain image from a given target cipher image. Similarly, a chosen-ciphertext attack method can also break VHC-CIES. Theoretical analysis and experimental results show that both chosen-plaintext attack and chosen-ciphertext attack can effectively crack VHC-CIES with data complexity of only O (2). For color images of size 256 × 256 × 3 , when our simulation encryption time is 0.3150 s, the time for complete breaking by chosen-plaintext attack and chosen-ciphertext attack is about 0.6020 s and 0.9643 s, respectively. To improve its security, some suggestions for further improvement are also given. The cryptanalysis work in this paper may provide some reference for the security enhancement of chaos-based image cryptosystem design. [ABSTRACT FROM AUTHOR]

White‐box cryptography protects the secret key extraction from software implementations of cryptographic primitives. The principle is to white‐box the key by using obfuscation and hide the key in the whole encryption process to ensure that the key cannot be traced and extracted. The idea of adding internal perturbed terms and additional random equations is given by Bringer et al. to implement white‐box encryption, which has been attacked due to the defect in structure. In this paper, we propose a new secure white‐box encryption method by combining the random perturbation mechanism of local differential privacy protection and adding internal interference term, which can protect the privacy of the intermediate secret key more securely. The further disrupted cipher can also obtain the correct result by voting without increasing the number of parallel systems, and also gives the practical white‐box representation to AEw/oS. Compared with the white‐box implementation proposed by Bringer et al., the memory space of the new white‐box scheme will be 44 bytes more, but in terms of security, it can resist traditional attacks and Mulder's attacks. [ABSTRACT FROM AUTHOR]

In recent years, meaningful visual image encryption schemes that the plain image is compressed and encrypted and then hidden into the carrier image have received increasing attention. This paper proposes a new meaningful visual image encryption scheme, which consists of three stages: compression (compression network)—encryption (2D‐SLC hyperchaotic map)—hiding (matrix encoding). First, the advantages of deep learning are explored. It can compress the width, height, channel, and pixel values of the plain image simultaneously. Second, a new 2D‐SLC hyperchaotic map is designed to ensure security. It has a larger chaotic space and better randomness. Finally, to obtain a high‐quality cipher image, the secure secret image is hidden in the grey carrier image by matrix encoding. The scheme can compress and encrypt the grey or colour plain image and then hide it in a grey carrier image. In addition, the theoretical peak signal‐to‐noise ratio (PSNR) between the cipher image and the carrier image is improved from 40.9292 to 42.1785 dB. The total running time is only about 0.35, 0.87 and 3.1 s for a 256 × 256, 512 × 512 and 1024 × 1024 grey or colour plain image, respectively. [ABSTRACT FROM AUTHOR]

Even though many applications provide infrastructure for ease of group communication, securing its data is very much needed and easily be achieved by using Group Key Management. The Group key which is used to encrypt and decrypt the data has to be generated and distributed efficiently. This paper attempts to give security solution for Multicast communications in fog environment. The existing protocols suffers from performance bottleneck due to the overload of centralized server. This also results in single point of failure. The proposed method uses XOR vector space and Pseudo Random Number Generator to efficiently compute and distribute the group keys. This method of Group Key Management is comparatively more efficient than the existing one because of the novel hybrid protocol. Also, this protocol reduces communication overhead, computation overhead and storage requirement. This is achieved by calculating the tuples of group keys in local area by a server called 'Area Leader'. Since it stores only key pairs at any given point of time, the storage requirement is minimal. [ABSTRACT FROM AUTHOR]

Cryptanalysis has been studied and gradually improved with the evolution of cryptosystems over past decades. Recently, deep learning (DL) has started to be used in cryptanalysis to attack digital cryptosystems. As computing power keeps growing, deploying DL-based cryptanalysis becomes feasible in practice. However, since these studies can analyze only one cipher type for one DL model learning, it takes a lot of time to analyze multi ciphers. In this paper, we propose a unified cipher generative adversarial network (UC-GAN), which can perform ciphertext-to-plaintext translations among multiple domains (ciphers) using only a single DL model. In particular, the proposed model is based on unified unsupervised DL for the analysis of classical substitutional ciphers. Simulation results have indicated the feasibility and good performance of the proposed approach. In addition, we compared our experimental results with the findings of conditional GAN, where plaintext and ciphertext pairs in only the single domain are given as training data, and with CipherGAN, which is cipher mapping between unpaired ciphertext and plaintext in the single domain, respectively. The proposed model showed more than 97% accuracy by learning only data without prior knowledge of three substitutional ciphers. These findings could open a new possibility for simultaneously cracking various block ciphers, which has a great impact on the field of cryptography. To the best of our knowledge, this is the first study of the cryptanalysis of multiple cipher algorithms using only a single DL model [ABSTRACT FROM AUTHOR]

Due to Grover's algorithm, any exhaustive search attack of block ciphers can achieve a quadratic speed-up. To implement Grover's exhaustive search and accurately estimate the required resources, one needs to implement the target ciphers as quantum circuits. Recently, there has been increasing interest in quantum circuits implementing lightweight ciphers. In this paper, we present the quantum implementations and resource estimates of the lightweight ciphers LBlock and LiCi. We optimize the quantum circuit implementations in the number of gates, require qubits and the circuit depth, and simulate the quantum circuits on ProjectQ. Furthermore, based on the quantum implementations, we analyze the resources required for exhaustive key search attacks of LBlock and LiCi with Grover's algorithm. Finally, we compare the resources for implementing LBlock and LiCi with those of other lightweight ciphers. [ABSTRACT FROM AUTHOR]

As tweakable block ciphers from public permutations, tweakable Even–Mansour ciphers are widely used in disk sector encryption and data storage encryption. With the rapid improvement of computing power, especially the development of quantum computing technology and quantum computers, the quantum security of tweakable Even–Mansour ciphers should be concerned and studied. This paper focuses on the security of tweakable Even–Mansour ciphers in the quantum setting. For one-round tweakable Even–Mansour cipher, we give its quantum circuit, present a quantum key recovery attack in polynomial time by Simon's algorithm and show the concrete resource estimation. For two-round tweakable Even–Mansour cipher, we present a better quantum key recovery attack by BHT-meets-Simon algorithm than that by Grover-meets-Simon algorithm from a new perspective of variable tweaks and show the concrete resource estimation. Finally, we generalize to r-round tweakable Even–Mansour cipher and present a quantum key recovery attack by combining Grover's algorithm and Simon's algorithm. Our work is of great importance. We use BHT-meets-Simon algorithm to achieve better quantum key recovery attacks than Grover-meets-Simon algorithm for the first time. [ABSTRACT FROM AUTHOR]

In 1940 the US Army's Signal Intelligence Service (SIS) cracked PURPLE, the Japanese diplomatic cipher. Shortly after that accomplishment, William Friedman, legendary cryptographer and civilian head of SIS, wrote his Preliminary Historical Report on the Solution of the "B" Machine. In it he introduced the mysterious "Identification of Homologs" and stated there that it had been a crucial technology to the success of cracking PURPLE. Despite that dramatic assessment, the concept simply disappeared, ignored by all subsequent authors of PURPLE histories and technical analyses. So what exactly is the Identification of Homologs and what role did it play in the cryptanalysis of PURPLE? That is the subject of this paper. We give a complete technical description, as well as historical information, some newly uncovered, about how SIS collected PURPLE "data". [ABSTRACT FROM AUTHOR]

Differential-linear cryptanalysis, as the combination of differential and linear cryptanalysis, is an efficient way to attack many kinds of ciphers. Recently, various refinements to this cryptanalytic technique have been proposed, especially with good effects on ARX ciphers. In the current framework of a differential-linear attack, a cipher |$E$| is often divided into three parts: a differential part |$E_1$|⁠ , a linear part |$E_2$| and a connective part |$E_m$|⁠. It is a challenging problem to deal with the connective part when building a differential-linear distinguisher, and for ARX ciphers, estimating the correlation of |$ E_m $| experimentally under given input difference |$\Delta _m$| and output linear mask |$\Gamma _m$| is the main approach so far. In this paper, we discuss the effects of |$ \Delta _{m} $| and |$ \Gamma _{m} $| on the correlation of |$ E_m $| for the first time. As a result, we propose a new strategy to find |$\Delta _m$| and |$\Gamma _m$| to build differential-linear distinguishers with high correlations for ARX ciphers based on algebraic equations derived from their round functions. For the key recovery parts of differential-linear attacks, we also find a new partitioning technique which will reduce the time complexity. Based on our new methods, we improve the differential-linear attack on 7-round Chaskey. [ABSTRACT FROM AUTHOR]

SMS4 is the Chinese national standard for WLAN, which is also an ISO/IEC international standard. This paper presents a linear cryptanalysis on 25‐round SMS4 for the first time. Firstly, this paper adopts a new statistic in linear cryptanalysis, which is aimed to compute the distance between one cipher system and one random permutation, which can be used to distinguish the right key from the wrong keys by the different probability distributions they follow. Secondly, the attack principal and data complexity are given when this new statistic is used in multiple linear cryptanalysis. Thirdly, this paper presents 21‐round linear approximations with absolute correlation 2−62${2^{ - 62}}$ by fixing the least significant input bit of the Sbox with nonzero mask in the first round to be 1. Furthermore, this paper gives 48 21‐round linear approximations with absolute correlation 2−62${2^{ - 62}}$. Based on the restrictions between those 48 linear approximations and fast Fourier transformation technique, the whole attack needs 2125.62${2^{125.62}}$ known plaintexts, 2126.56${2^{126.{\rm{56}}}}$25‐round SMS4 encryptions along with 2113.75${{\rm{2}}^{{\rm{113}}{\rm{.75}}}}$ memory accesses, and 2111.7${{\rm{2}}^{{\rm{111}}{\rm{.7}}}}$ bytes of memory, which is the best cryptanalysis result on SMS4 so far. Finally, this paper generalizes the linear cryptanalysis method with conditioned linear approximation, which can also be adopted in attacking other ciphers. [ABSTRACT FROM AUTHOR]

In this paper, author have proved properties of Sandip transform with Incomplete Hfunctions. Author expressed Sandip transform of functions in terms of H-functions. Author used Sandip transform and Sandip's method to create cipher text with two secure keys. Laplace transform, Melin transform, Stlieltje's transform can be obtained form Sandip Transform, so with the help of algorithm to computer programming author have shown the way to create different key's and cipher text for one message. [ABSTRACT FROM AUTHOR]

On 20 February 1939, a new Japanese diplomatic cipher machine that U.S. Army codebreakers would name PURPLE came into use. By 10 April 1939, the Army's Signal Intelligence Service (SIS) had made startling progress. SIS codebreakers had discovered that, for no cryptographic reason, PURPLE maintained the split of the Roman alphabet into a set of 6 letters and a set of 20 letters—the sixes and the twenties—a split that had been observed in PURPLE's predecessor RED. They had a familiar problem, and they were quickly able to recover the enciphering table for the sixes But 18 months later they were still puzzled by the enciphering of the twenties Then, on 20 September 1940, Genevieve Grotjan, an SIS codebreaker, made a discovery that opened the way for the recovery of the PURPLE machine. This paper explores the patterns for which Grotjan was searching and concludes with what she found. [ABSTRACT FROM AUTHOR]

The use of the web is developing for surreptitious and non-surreptitious communication with the expansion of brilliant innovations. In this circumstance, there is a need to improve the security level of the covert information. Our motive is to propose a unique algorithm by using steganography along with cryptography which provides a better solution for secret communication and improves security with more levels. In this paper, the two-level stationary wavelet transform technique is applied to cover image to acquire HH2 sub-band alongside the remaining sub-bands. The data are implanted into the HH2 sub-band of the cover image by utilizing the random pixel embedded strategy to accomplish the stego image. To improve the security of the stego image, the surreptitious text data are changed into cipher form with a novel cryptography algorithm that incorporates unique data conversion and gray-code techniques. The resultant stego image undergoes to split-logical algorithm to create numerous imperceptible stego images. The main purpose of imperceptible stego images is to provide better security to covert information and also it increases the payload capacity. The concept of generating imperceptible stego images is, each of them will be treated as a stego image for hackers. But original stego image is reconstructed by combining all generated imperceptible stego images. These imperceptible stego images are ready to oppose the diverse steganalysis assaults like visual, noise, rotational assaults, and so forth. [ABSTRACT FROM AUTHOR]

A quantum version of the linear cryptanalysis technique is presented in this paper. So far, only a certain part of some classical cryptanalysis techniques was converted for quantum processing to gain speed-up while analysing a symmetric primitive. However, none of the quantum version of these attacks, including linear cryptanalysis, completely uses quantum computing for all the steps. We developed a quantum version for all the steps of the linear cryptanalysis. The proposed quantum linear cryptanalysis is applied on the quantum version of a toy cipher. Performance analysis shows that the quantum version of the linear cryptanalysis offers quadratic speed-up in different steps of the attack. It can be used to attack any cipher that is vulnerable against linear cryptanalysis. [ABSTRACT FROM AUTHOR]

With the rapid increase in the practical applications of secure computation protocols, increasingly more research is focused on the efficiency of the symmetric-key primitives underlying them. Whereas traditional block ciphers have evolved to be efficient with respect to certain performance metrics, secure computation protocols call for a different efficiency metric: arithmetic complexity. Arithmetic complexity is viewed through the number and layout of nonlinear operations in the circuit implemented by the protocol. Symmetric-key algorithms that are optimized for this metric are said to be algebraic ciphers. It has been shown that recently proposed algebraic ciphers are greatly efficient in ZK and MPC protocols. However, there has not been many algebraic ciphers proposed targeting Fully Homomorphic Encryption (FHE). In this paper, we evaluate the behavior of Vision when implemented as a circuit in an FHE protocol. To this end, we present a state-of-the-art comparison of AES and Vision implemented using HElib. Counterintuitively, Vision does not deliver a better performance than AES in this setting. Then, by attempting to improve a bottleneck of the FHE implementation evaluating Vision we present a new cipher: Seljuk. Despite the improvement with respect to Vision , Seljuk does not deliver the expected performance. [ABSTRACT FROM AUTHOR]

The Pilsung cipher is part of the North Korean Red Star operating system, which was leaked to the West in 2014. Initial analysis by Kryptos Logic reported a possibility of a class of weak keys due to the use of pseudo-random diffusion. Following this lead, we analyzed the cipher and identified a small class of such weak keys. We developed techniques for searching for a key that belongs to the class. After spending thousands of CPU hours, we found a supposedly weak key for a slightly weaker version of Pilsung, but the key did not behave as we expected. On further investigation we found out a crucial misunderstanding in a critical part of the cipher and that no such class of weak keys exists in Pilsung. Thus, this paper makes two main contributions to the art of cryptanalysis. First, it identifies and shows how to investigate a potential weakness in randomizing diffusion, which although does not exist in Pilsung, may affect future designs. Second, it highlights the need for early verification of results in order to identify errors before expending significant resources. [ABSTRACT FROM AUTHOR]