Security Of Cipher Research Articles

An Innovative Algorithm Based on Chaotic Maps Amalgamated with Bit-Level Permutations for Robust S-Box Construction and Its Application in Medical Image Privacy

Data security and privacy have become essential due to the increasingly advanced interconnectivity in today’s world, hence the reliance on cryptography. This paper introduces a new algorithm that uses a novel hybrid Tent–May chaotic map to generate pseudo-random numbers, as well as block encryption. We design a robust S-box by combining the Tent and May Maps, which yields a chaotic system with improved cryptographic properties. This S-box is a critical cryptographic primitive that significantly improves encryption security and leverages the strengths of both maps. The encryption process involves two key steps: block-wise substitution and permutation. First, we divide the image into 16×16 blocks, then substitute each pixel with the 8−byte key and S-box. Next, we convert the encrypted image back into vector form, reorganize it using the permutation vector based on the subgroups of S16, and finally return it to its original form. This approach greatly improves block cipher security when used, especially to protect medical images by guaranteeing their confidentiality and noninterference. Performance measures like PSNR, UACI, MSE, NCC, AD, SC, MD, and NAE prove how immune our method is to various cryptographic and statistical attacks, making it more accurate and more secure than the existing techniques.

Quantum-Resistance Meets White-Box Cryptography: How to Implement Hash-Based Signatures against White-Box Attackers?

The adversary model of white-box cryptography includes an extreme case where the adversary, sitting at the endpoint, has full access to a cryptographic scheme. Motivating by the fact that most existing white-box implementations focus on symmetric encryption, we present implementations for hash-based signatures so that the security against white-box attackers (who have read-only access to data with a size bounded by a space-hardness parameter M) depends on the availability of a white-box secure cipher (in addition to a general one-way function). We also introduce parameters and key-generation complexity results for white-box secure instantiation of stateless hash-based signature scheme SPHINCS+, one of the NIST selections for quantum-resistant digital signature algorithms, and its older version SPHINCS. We also present a hash tree-based solution for one-time passwords secure in a white-box attacker context. We implement the proposed solutions and share our performance results.

Enhancing Security in Modern Transposition Ciphers Through Algorithmic Innovations and Advanced Cryptanalysis

Abstract Columnar transposition ciphers have various vulnerabilities and limitations that render them vulnerable to modern cryptographic threats and advanced cryptanalysis techniques. It is imperative to strengthen the security of these ciphers through algorithmic developments and a greater understanding of their vulnerabilities as the need for secure communication increases. A systematic search will be conducted to find peer-reviewed journal articles on columnar transposition ciphers, including variations, weaknesses, and security enhancements. The structured data analysis approach will focus on key elements such as known cipher variants, vulnerabilities, new algorithms, proposed improvements, and evaluation metrics. The review will provide a comprehensive overview of the existing variants of columnar transposition ciphers, including the classical columnar transposition cipher, double columnar transposition cipher, mutable columnar transposition cipher, route transposition cipher. It will critically analyze the vulnerabilities and limitations of these variants, such as limited key space, patterns and periodicities, lack of diffusion, and susceptibility to known-plaintext attacks and statistical analysis. Additionally, the review will explore modern cryptographic threats and advanced cryptanalysis techniques, including machine learning, brute force attack, differential cryptanalysis, and chosen plaint-text attack etc. New algorithmic advancements will be developed to enhance the security of columnar transposition ciphers. These advancements involve dynamic key generation, column permutation, integration with other cryptographic primitives, and key scheduling algorithms. Additionally, an enhanced version of the columnar transposition cipher algorithm will be detailed, covering its mathematical basis, theoretical structure, and anticipated security upgrades. The effectiveness of the improved algorithm will be assessed in various attack scenarios and threat models, emphasizing security, computational, and performance aspects. The research will enhance the security of columnar transposition ciphers through algorithmic innovation and advanced cryptanalysis. It will identify gaps in existing techniques, recommend future research directions, and highlight potential applications. The findings will have significant implications for cryptography, addressing the need for secure communication.

Links between Quantum Distinguishers Based on Simon’s Algorithm and Truncated Differentials

In this paper, we study the quantum security of block ciphers based on Simon’s period-finding quantum algorithm. We explored the relations between periodic functions and truncated differentials. The basic observation is that truncated differentials with a probability of 1 can be used to construct periodic functions, and two such constructions are presented with the help of a new notion called difference-annihilation matrix. This technique releases us from the tedious manual work of verifying the period of functions. Based on these new constructions, we find an 8-round quantum distinguisher for LBlock and a 9/10/11/13/15-round quantum distinguisher for SIMON-32/48/64/96/128 which are the best results as far as we know. Besides, to explore the security bounds of block cipher structures against Simon’s algorithm based quantum attacks, the unified structure, which unifies the Feistel, Lai-Massey, and most generalized Feistel structures, is studied. We estimate the exact round number of probability 1 truncated differentials that one can construct. Based on these results, one can easily check the quantum security of specific block ciphers that are special cases of unified structures, when the details of the non-linear building blocks are not considered.

PROVING THE SECURITY OF AES BLOCK CIPHER BASED ON MODIFIED MIXCOLUMN

Block ciphers in general, Substitution-Permutation Network (SPN) block ciphers in particular are cryptographic fields widely applied today. AES is an SPN block cipher used in many security applications. However, there are many strong attacks on block ciphers as linear attacks, differential attacks, and algebraic attacks which are challenging for cryptographers. Therefore, the research to improve the security of block ciphers in general and AES, in particular, is a topic of great interest today. Along with security, the issue of the execution cost of block ciphers is also crucial in practice. In this paper, we clarify the role of the MDS matrix in increasing the branch number of the diffusion layer of the block ciphers, thereby improving the security of the block ciphers. We propose a method improving the security of the AES block cipher by changing the Mixcolumn transformation of AES using execution-efficient MDS matrices of size 4, 8, or 16. We present a method to find a new diffusion matrix of modified AES block ciphers from which to evaluate the number of fixed points and coefficient of fixed points of the modified AES diffusion layers. In addition, we prove the branch number of the modified AES diffusion layers with MDS matrices of sizes 8, and 16. Then we also analyze the security, statistical standards and execution speed of modified AES block ciphers generated from those MDS matrices. The results show that our proposed method can significantly improve the security of the AES block cipher.

Design and analysis of key scheduling algorithm for symmetric cipher security

Design and analysis of key scheduling algorithm for symmetric cipher security

Automated Differential-Linear Cryptanalysis for AND-RX Ciphers

Differential and linear cryptanalysis are two important methods to evaluate the security of block ciphers. Building on these two methods, differential-linear (DL) cryptanalysis was introduced by Langford and Hellman in 1994. This cryptanalytic method has been not only extensively researched but also proven to be effective. In this paper, a security evaluation framework for AND-RX ciphers against DL cryptanalysis is proposed, which is denoted as K6. In addition to modeling the structure of all the possible differential trails and linear trails at the bit level, we introduce a method to calculate this structure round by round. Based on this approach, an automatic algorithm is proposed to construct the DL distinguisher. Unlike previous methods, K6 uses a truncated differential and a linear hull instead of a differential characteristic and a linear approximation, which brings the bias of the DL distinguisher close to the experimental value. To validate the effectiveness of the framework, K6 is applied to Simon and Simeck, which are two typical AND-RX ciphers. With the automatic algorithm, we discover an 11-round DL distinguisher of Simon32 with bias 2−14.89 and a 12-round DL distinguisher of Simeck32 with bias 2−14.89. Moreover, the 14-round DL distinguisher of Simon48 with bias 2−22.30 is longer than the longest DL distinguisher currently known. In addition, the framework K6 shows advantages when analyzing ciphers with large block sizes. As far as we know, for Simon64/96/128 and Simeck48/64, the first DL distinguishers are obtained with our framework. The DL distinguishers are 16, 23, 32, 17, and 22 rounds of Simon64/96/128 and Simeck48/64 with bias 2−24.31, 2−47.57, 2−60.75, 2−22.54, and 2−31.41, respectively. To prove the correctness of distinguishers, experiments on Simon32 and Simeck32 have been performed. The experimental bias are 2−13.76 and 2−14.82, respectively. Comparisons of the theoretical and experimental results show good agreement.

Algebraic side‐channel attacks on Trivium stream cipher

AbstractAlgebraic Side‐Channel Attacks (ASCAs), first proposed by Renauld and Standaert in 2009, are a potent cryptanalysis method against block ciphers. In this paper, the authors initially utilize ASCAs to analyze the security of the Trivium stream cipher, given its concise algebraic structure. Considering its efficiency in both hardware and software implementations, the authors deploy ASCAs to target Trivium implemented both in application specific integrated circuit (ASIC) under the Hamming Distance Leakage Model (HDLM) (noted as CASE 1) and in microcontrollers of various buses (i.e. some common 8‐bit, 16‐bit, and 32‐bit architectures, noted as CASE 2, CASE 3, and CASE 4, respectively) under the Hamming Weight Leakage Model (HWLM). Here, the authors’ attacks are conducted on power‐simulated targets and not on real devices. For a single power consumption trace without measurement errors, this paper presents experimental results using MiniSat 2.0. Unfortunately, the authors were unable to break the ASIC implementation of Trivium under HDLM (CASE 1) with a time complexity of 2109 s or so, which is worse than the exhaustive key attack. For CASEs 2 to 4, the authors can find the complete 288‐bit state of Trivium within a reasonable timeframe. Specially, the success rate can reach 100% with an average solving time of less than 1 s when only measuring the leakages of the first eight consecutive rounds for CASE 2. Furthermore, the authors can still successfully recover the internal state even when obtaining leakages of the first 41 rounds with a random loss rate. In fact, it can tolerate a 74% random loss rate for the first 223 rounds. With regard to the potential errors in the measurements, the authors mitigate them using Tolerant ASCA (TASCA). Similarly, CASE 1 cannot be compromised even in error‐free situations, while the authors can still successfully recover the internal state of CASEs 2 to 4 from a single power trace, even with a high error rate, including 100% incorrect measurements. Surprisingly, for CASEs 2 to 4, the authors can recover the internal state with a 100% success rate, regardless of the error rate. As a result, the security of Trivium will not be enhanced when transitioning from a smaller 8‐bit platform to a larger 32‐bit platform. In the end, the authors will consider some more abstract attack models. The results can provide us with additional insights into the security of Trivium from a different perspective.

Semi-Permanent Stuck-At Fault injection attacks on Elephant and GIFT lightweight ciphers

Fault attacks pose a potent threat to modern cryptographic implementations, particularly those used in physically approachable embedded devices in IoT environments. Information security in such resource-constrained devices is ensured using lightweight ciphers, where combinational circuit implementations of SBox are preferable over look-up tables (LUT) as they are more efficient regarding area, power, and memory requirements. Most existing fault analysis techniques focus on fault injection in memory cells and registers. Recently, a novel fault model and analysis technique, namely Semi-Permanent Stuck-At (SPSA) fault analysis, has been proposed to evaluate the security of ciphers with combinational circuit implementation of Substitution layer elements, SBox. In this work, we propose optimized techniques to recover the key in a minimum number of ciphertexts in such implementations of lightweight ciphers. Based on the proposed techniques, a key recovery attack on the NIST lightweight cryptography (NIST-LWC) standardization process finalist, Elephant AEAD, has been proposed. The proposed key recovery attack is validated on two versions of Elephant cipher. The proposed fault analysis approach recovered the secret key within 85 − 240 ciphertexts, calculated over 1000 attack instances. To the best of our knowledge, this is the first work on fault analysis attacks on the Elephant scheme. Furthermore, an optimized combinational circuit implementation of Spongent SBox (SBox used in Elephant cipher) is proposed, having a smaller gate count than the optimized implementation reported in the literature. The proposed fault analysis techniques are validated on primary and optimized versions of Spongent SBox through Verilog simulations. Further, we pinpoint SPSA hotspots in the lightweight GIFT cipher SBox architecture. We observe that GIFT SBox exhibits resilience towards the proposed SPSA fault analysis technique under the single fault adversarial model. However, eight SPSA fault patterns reduce the nonlinearity of the SBox to zero, rendering it vulnerable to linear cryptanalysis. Conclusively, SPSA faults may adversely affect the cryptographic properties of an SBox, thereby leading to trivial key recovery. The GIFT cipher is used as an example to focus on two aspects: i) its SBox construction is resilient to the proposed SPSA analysis and therefore characterizing such constructions for SPSA resilience and, ii) an SBox even though resilient to the proposed SPSA analysis, may exhibit vulnerabilities towards other classical analysis techniques when subjected to SPSA faults. Our work reports new vulnerabilities in fault analysis in the combinational circuit implementations of cryptographic protocols.

Enhancing block cipher security with key-dependent random XOR tables generated via hadamard matrices and Sudoku game

The XOR operator is a simple yet crucial computation in computer science, especially in cryptography. In symmetric cryptographic schemes, particularly in block ciphers, the AddRoundKey transformation is commonly used to XOR an internal state with a round key. One method to enhance the security of block ciphers is to diversify this transformation. In this paper, we propose some straightforward yet highly effective techniques for generating t-bit random XOR tables. One approach is based on the Hadamard matrix, while another draws inspiration from the popular intellectual game Sudoku. Additionally, we introduce algorithms to animate the XOR transformation for generalized block ciphers. Specifically, we apply our findings to the AES encryption standard to present the key-dependent AES algorithm. Furthermore, we conduct a security analysis and assess the randomness of the proposed key-dependent AES algorithm using NIST SP 800-22, Shannon entropy based on the ENT tool, and min-entropy based on NIST SP 800-90B. Thanks to the key-dependent random XOR tables, the key-dependent AES algorithm have become much more secure than AES, and they also achieve better results in some statistical standards than AES.

Differential Fault and Algebraic Equation Combined Analysis on PICO

In modern information technology, research on block cipher security is imperative. Concerning the ultra lightweight block cipher PICO, there has been only one study focused on recovering its complete master key, with a large search space of 264, and no fault analysis yet. This paper proposes a new fault analysis approach, combining differential fault and algebraic equation techniques. It achieved the recovery of PICO’s entire master key with 40 faults in an average time of 0.57 h. S-box decomposition was utilized to optimize our approach, reducing the time by a remarkable 75.83% under the identical 40-fault condition. Furthermore, PICO’s complete master key could be recovered with 28 faults in an average time of 0.78 h, indicating a significant 237 reduction in its search space compared to the previous study. This marks the first fault analysis on PICO. Compared to conventional fault analysis methods DFA (differential fault analysis) and AFA (algebraic fault analysis), our approach outperforms in recovering PICO’s entire master key, highlighting the cruciality of key expansion complexity in block cipher security. Therefore, our approach could serve to recover master keys of block ciphers with comparably complicated key expansions, and production of more secure block ciphers could result.

A Novel Method for Hill Cipher Encryption and Decryption Using Gaussian Integers Implemented in Banking Systems

Cryptographic tools like Hill's encryption algorithm protect digital data. In this work, we present a novel Hill cipher security method that utilizes Gaussian integers from number theory. Using these intriguing mathematical entities to disguise plaintext values dramatically boosts assault resistance and duration. This research includes a three-pass protocol for encryption and decryption without key exchange, ensuring a safe, efficient, and dependable solution. Pandas is used for efficient data processing, and Numpy for computational tasks, notably matrices. Hill cipher-based encryption and decryption can be utilized in real life. It also demonstrates how to save Pandas DataFrame data to Excel. This strategy assures progress in cryptography. Uniquely designed for banking, it emphasizes its applicability and possible influence on present financial systems.

Design of S-box multi-objective optimization algorithm based on combined chaotic system

S-box is the only nonlinear cryptographic component that determines the security of the block cipher. The higher the security of the S-box, the higher the security of the block cipher. Therefore, this paper proposes an S-box multi-objective optimization algorithm based on the combined chaotic system. Firstly, designing an integrated chaotic system based on a fractional index and its dynamic behavior is studied; it shows incredibly high-performance stability and chaotic parameter range coverage in the entire parameter space. A novel chaotic S-box construction algorithm is proposed based on the combined chaotic system. It introduces a linear congruential pseudo-random number generator to extend the sequence period and scramble the chaotic S-box through Henon mapping to improve the nonlinearity of the s-box. Finally, introducing a teaching and learning multi-objective optimization model and the performance evaluation criteria of the S-box are incorporated into the design of the objective function; this design enables the resulting S-box to perform well under multiple performance indicators, and then the approximate optimal S-box in the population is obtained. Through the performance test of the approximate optimal S-box, the comparative analysis shows that the S-box has good cryptographic performance, can resist linear analysis and differential analysis, and has a good application prospect in lightweight cipher.

Implementation of novel cryptographic technique for enhancing the cipher security for Resilient Infrastructure

Cryptography is a well-known technology for providing confidential data transfer via asymmetric or symmetric algorithms with public or private keys. Secure data transmission over networks using unreliable, untrusted channels is made achievable by cryptography. As a result of the quick digital transition, network traffic is rapidly rising, and consumers remain constantly connected and accessible online. Extortions, including transforming, spoofing, and tracking data through unauthorised access, are quite widespread over the internet. Many more cryptographic algorithms already exist, but they need to be consistently improved and optimized for better performance within the constraints imposed by new technology and a wide variety of application domains. To overcome these limitations, we suggest a novel FishyCurve Cipher technique by combining an elliptic curve-based algorithm (ECA) with a Threefish cipher algorithm (TCA) to improve cipher security and performance, the data will be encrypted using TFCA, and the key will be secured by the EC technique. To verify data integrity, a digital signature algorithm (DSA) is employed. To evaluate the effectiveness of the proposed FishyCurve Cipher technique, comprehensive experimental tests have been conducted. The results clearly demonstrate its superiority in terms of cipher security when compared to traditional encryption algorithms. Its outstanding resilience against a wide range of attacks makes it a strong method of securing resilience infrastructure from malicious actors who seek to compromise data confidentiality and integrity.

Encryption of Medical Image Based on Cascaded Design of AES Block Algorithm and Chaotic Map

Security concerns in the transfer of medical images have drawn a lot of attention to the topic of medical picture encryption as of late. Furthermore, recent events have brought attention to the fact that medical photographs are constantly being produced and circulated online, necessitating safeguards against their inappropriate use. To improve the design of the AES algorithm standard for medical picture encryption, this research presents several new criteria. It was created so that needs for higher levels of safety and higher levels of performance could be met. First, the pixels in the image are diffused to randomly mix them up and disperse them all over the screen. Rather than using rounds, the suggested technique utilizes a cascaded-looking composition of F-functions in a quadrate architecture. The proposed F-function architecture is a three-input, three-output Type-3 AES-Feistel network with additional integer parameters representing the subkeys in use. The suggested system makes use of the AES block cipher as a function on a Type-3 AES-Feistel network. Blocks in the proposed system are 896 bits in length, whereas keys are 128 bits. The production of subkeys is encrypted using a chain of E8- algorithms. The necessary subkeys are then generated with a recursion. The results are reviewed to verify that the new layout improves the security of the AES block cipher when used to encrypt medical images in a computer system.

Cipher Craft: Design and Analysis of Advanced Cryptographic Techniques for Secure Communication Systems

The name “cryptography” comes from a Greek word that refers to the art of securing data by organizing it in a disorganized and unintelligible way. It combines software engineering with math. The explosive expansion of the Internet has led to a greater awareness of intriguing uncertainty concerns. Although security is the biggest concern when it comes to the internet, many apps have been developed and designed without taking confidentiality, authentication, and protection—the three essential components of data security—into account. Knowing these kinds of security problems and challenges is going to be more important as our daily activities rely more and more on data networks. Cryptography is necessary to prevent some unwanted customers or persons from gaining access to the data. This study presents a novel hybrid security cipher that combines the three most significant ciphers, such as the Caesar, Rail Fence and Vigenère ciphers. When compared to traditional ciphers, this hybrid encryption cipher offers more security.

A new method of image encryption using advanced encryption Standard (AES) for network security

With the rapid increase in the use of technology, images have become a major source of sharing personal, confidential and official information and there is a dire need to protect this secret data. Image encryption plays major role in the security of images and there are many techniques developed for this purpose. Chaos based image encryption has now become most applicable and beneficial technique for image encryption. The purpose of this paper is to highlight a new method of image encryption with the use of advanced encryption standard (AES) and chaotic maps. This technique is composed of substitution and permutation phases. AES is found to be most secure cipher until now against different kinds of attacks. The round keys are generated by AES using key expansion algorithm. The sensitivity of this technique is that it is dependent on initial values and input image. S-boxes in AES introduce non-linearity, confusion, and an avalanche effect, enhancing security and resistance to cryptographic attacks by substituting bytes in the encryption process. The combination of AES and chaotic maps in encryption schemes provides a two-tiered approach to enhance security. AES offers a strong and well-established encryption method, while chaotic maps introduce randomness and complexity, making it more difficult for attackers to decipher encrypted data. This combination is often used to achieve a higher level of encryption security in various applications, including data transmission and storage. Different kinds of analysis and tests are performed on the technique which includes information entropy, number of pixel change rate (NPCR), and peak signal-to-noise ratio (PSNR), unified average changing intensity (UACI) and histogram correlation of adjacent pixels. The results of these tests show that this technique is secure and resistant towards attacks.

A General Correlation Evaluation Model on LFSR-Based Stream Ciphers

In this paper, a general model for evaluating the correlations of correlation attack distinguishers for an LFSR-based stream cipher is given by the Walsh spectrum theory of composite functions. We transform equivalently the linear approximations with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> consecutive keystream words into that of a composite function consisting of several simple functions, which enables cryptanalysts to derive linear approximations of any LFSR-based stream cipher by this model and to search for linear trails with high absolute correlations. This model suits any LFSR-based stream cipher, does not need the implicit independence assumption widely used in previous cryptanalysis, and can theoretically ensure that the correlation obtained is the accurate correlation of a correlation attack distinguisher. In addition, we prove that it is enough to consider the distinguishers where the masks of all LFSR elements are zero except for those of a maximal linearly independent system of LFSR elements involved in the update function and output function. As applications, the approximation processes for the correlation attack distinguishers of SNOW-V, SNOW2.0, ZUC, and Grain-128 are exhibited respectively by this method. Moreover, by the proposed method we can perform a full coverage search for binary linear approximations of them. For SNOW-V, we prove that the approximation given by our model is equivalent to that by Shi et al. at EUROCRYPT 2022, and is simpler and more intuitive. For SNOW2.0, we find more linear approximations with the best correlation. For ZUC, for the first time we get the accurate correlations of a series of linear approximations including the known results, and give the supremum of the absolute correlations for a larger set of linear approximations. For Grain-128, utilizing our method, we rediscover the best known correlation as well, which provides more support for the validity of our general model. Our work can give some evidence for the provable security of LFSR-based stream ciphers against correlation attack to some extent, and may provide the key clues in the analysis of complex stream ciphers.

Unconditionally Secure Ciphers with a Short Key for a Source with Unknown Statistics.

We consider the problem of constructing an unconditionally secure cipher with a short key for the case where the probability distribution of encrypted messages is unknown. Note that unconditional security means that an adversary with no computational constraints can only obtain a negligible amount of information ("leakage") about an encrypted message (without knowing the key). Here, we consider the case of a priori (partially) unknown message source statistics. More specifically, the message source probability distribution belongs to a given family of distributions. We propose an unconditionally secure cipher for this case. As an example, one can consider constructing a single cipher for texts written in any of the languages of the European Union. That is, the message to be encrypted could be written in any of these languages.

Revisiting the Software-Efficient Stream Ciphers RCR-64 and RCR-32

Abstract The synchronous stream ciphers RCR-64 and RCR-32 designed by Sekar, Paul and Preneel are strengthened variants of the ciphers TPy and TPypy (designed by Biham and Seberry), respectively. The RCR ciphers have remained unbroken since they were published in 2007. In this paper, we present arguments that not only support the designers’ security claims but suggest, in general, that the ciphers are secure against several classes of cryptanalytic attacks. We find that the ciphers are best used with 256-bit keys and 384-bit IVs. We also suggest ways to protect software implementations of the RCR ciphers against (cache-)timing and processor flag attacks. Our performance evaluation suggests that the protected implementation of the RCR-64 encrypts long messages at speeds comparable to some of the fastest stream ciphers available today. Consequently, we find that the RCR ciphers may be well suited for PC-based applications in general and streaming audio / video applications in particular. This is the first paper to present a detailed study on the security and performance of the RCR ciphers.