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Block cipher (BC) is a type of symmetric cipher used to encrypt data. Despite its advantages, it faces a substantial challenge. Writing the script code for the BC scheme accurately using General-Purpose Programming Languages (GPPLs) poses a significant challenge for programmers. The aim of this paper is to present the first graphical domain-specific modeling language (DSML) for designing and implementing BC algorithms, called BCLang. It is an extension to our previous DSML that was developed for Stream cipher. Programming efficiency and expressiveness were increased by reducing grammar and runtime errors and providing a high level of abstraction. BCLang provides the fundamental components of the BC three structures, which enable the programmer to design and implement BC algorithms in a graphical manner. Two keystream generation methods, performance analysis, and tests of the National Institute of Standards and Technology (NIST) for randomness analysis were provided. The presented language was evaluated based on five subjective metrics specific to graphical DSML evaluation. The design, evaluation details, and properties are explained in depth in this paper. [ABSTRACT FROM AUTHOR]

In a cryptosystem, a cipher's security is directly dependent on a key-schedule or key-scheduling algorithm (KSA) or that is used for both encryption and decryption. The random-number-based KSA adds another layer of security and prevents hackers from performing cryptanalysis. Several previous studies have investigated the strength of a cipher's encryption process. The strength evaluation of the key-scheduling process has received less attention that can lead to weaknesses in the overall encryption process. This paper proposes a new framework consisting of cryptographic strength evaluation criteria for random number generators (RNG)-based KSAs. Our framework (CryptoQNRG) evaluates different key-schedules based on pseudorandom and quantum random number generators with a set of tests. There are test suites that compare the strength of KSAs for different block ciphers. To the best of our knowledge this is the first time that a framework is built to compare the strength of KSAs incorporating RNGs and various block ciphers. CryptoQNRG comprises of four tests: Frequency, Bit_Correlation, Bit_Interfold, and Bit_Entropy. The tests are used to explore cryptographic properties such as unpredictability, balance of bits, correlation, confusion, and diffusion in the subkeys generated by the RNG-based KSA. We have evaluated the most common KSAs with different block ciphers and a significant outcome of the proposed framework is the distinction between strong and weak RNG-based KSAs. [ABSTRACT FROM AUTHOR]

At SAC 2021, Frixons et al. proposed quantum boomerang attacks that can effectively recover the keys of block ciphers in the quantum setting. Based on their work, we further consider how to quantize the generic boomerang attacks proposed by Biham et al. at FSE 2002, so as to obtain more generic quantum boomerang attacks. Similar to Frixons et al.'s work, we only consider quantum key recovery attacks in the single-key setting. With the help of some famous quantum algorithms, this paper presents two methods to convert the attacks of Biham et al. into some new quantum key recovery attacks. In order to proof our methods, we apply our new ideas to attack Serpent-256 and ARIA-196. To sum up, for Serpent-256, we give valid 9-round and 10-round quantum key recovery attacks respectively. The quantum time complexity of 9-round and 10-round of Serpent-256 is 2 115.43 and 2 126.6 respectively. Furthermore, we show a valid quantum key attack on 6-round ARIA-196 which has a time complexity of 2 89.8 with negligible memory. The time complexity of the above quantum attacks are better than the corresponding classical attacks and quantum generic key recovery attack via Grover's algorithm. [ABSTRACT FROM AUTHOR]

The differential characteristics with high probability are critical for differential cryptanalysis. The process of searching such differential characteristics, especially the best one, is time-consuming. We believe that the modern hybrid computing systems can be used to accelerate the search process. However, to the best of our knowledge, the existing solutions are not designed for heterogeneous architectures. In this paper, we propose a parallel search algorithm for the best differential characteristic. Our method can be applied to any substitution–permutation network (SPN) block ciphers after making minor modifications. We implemented the proposed parallel search algorithm for PRESENT block cipher and also a sequential version, which based on the classic Matsui's method, for comparison. The experimental result shows that the parallel algorithm using both CPU and GPU can achieve at least 4.4x and up to 18x speed-up compared to the sequential version. [ABSTRACT FROM AUTHOR]

Information security has immense importance in today's world of digital communication. Sharing information between intended parties while keeping it secret from any outsider is a challenging task. Cryptography provides the security of information by keeping the information secret among only the communicating parties. In this paper, a new cryptographic algorithm is propounded, which is a block cipher algorithm. A positive integer, n, two n × 256 tables of ASCII characters, and a string, Mapper, are used as shared private keys in the proposed method. Every row of the key tables and Mapper contains a random permutation of all the ASCII characters. In the beginning of encryption of a block, an Exclusive Or (XOR) operation is done between the block and a random array of integers. Then, a 3-round substitution operation is done using the key tables and Mapper. We found that the encryption and the decryption speed of the proposed algorithm is faster than the encryption–decryption speed of Advanced Encryption Standard (AES) and Data Encryption Standard (DES). The strength of the proposed cipher was analyzed in the light of some popular attacks, and we found that the system is strong enough against those attacks. We hope that if integrated with the modern cryptography protocols, this method will enhance modern digital communication security. [ABSTRACT FROM AUTHOR]

Due to the powerful computing capability of quantum computers, cryptographic researchers have applied quantum algorithms to cryptanalysis and obtained many interesting results in recent years. In this paper, we study related-key attack in the quantum setting and propose a specific related-key attack, which can recover the key of block ciphers efficiently as long as the attacked block ciphers satisfy certain condition. The attack algorithm employs the Bernstein–Vazirani algorithm as a subroutine and requires the attacker to query the encryption oracle with quantum superpositions. We give a condition under which the attack will succeed and prove that any block cipher either satisfies the condition or has a distinguishing attack. As a specific example of its application, we use the attack algorithm to extract the private key of the Even–Mansour cipher. The results of this study show the power of related-key attack when combined with quantum algorithms and provide guidance for the design of quantum-secure block ciphers. [ABSTRACT FROM AUTHOR]

In CRYPTO 2019, Gohr successfully applied deep learning to differential cryptanalysis against the NSA block cipher Speck32/64, achieving higher accuracy than traditional differential distinguishers. Until now, the improvement of neural differential distinguishers is a mainstream research direction in neural-aided cryptanalysis. But the current development of training data formats for neural distinguishers forms barriers: (1) The source of data features is limited to linear combinations of ciphertexts, which does not provide more learnable features to the training samples for improving the neural distinguishers. (2) Lacking breakthroughs in constructing data format for network training from the deep learning perspective. In this paper, considering both the domain knowledge about deep learning and information on differential cryptanalysis, we use the output features of the penultimate round to proposing a two-dimensional and non-realistic input data generation method of neural differential distinguishers. Then, we validate that the proposed new input data format has excellent features through experiments and theoretical analysis. Moreover, combining the idea of multiple ciphertext pairs, we generate two specific models for data input construction: MRMSP(Multiple Rounds Multiple Splicing Pairs) and MRMSD(Multiple Rounds Multiple Splicing Differences) and then build new neural distinguishers against Speck and Simon family, which effectively improve the performance compared with the previous works. To the best of our knowledge, our neural distinguishers achieve the longest rounds and the higher accuracy for NSA block ciphers Speck and Simon. [ABSTRACT FROM AUTHOR]

In the paper we present an involutional block cipher PP-1, which is a scalable SPN. The cipher has very low memory requirements and uses only simple and fast arithmetic operations. The paper discusses in detail the PP-1 cipher design, including the S-box construction, the permutation and the round key scheduling. The quality of the PP-1 cipher is evaluated with respect to differential and linear cryptanalysis. Its quality is compared to the quality of a comparative algorithm with the same block length, as well as to the quality of the class of balanced Feistel ciphers, and in particular to DES quality. [ABSTRACT FROM AUTHOR]

Abstract: To attack block cipher systems, it is inevitable to handle the bit-substitutions, such as S-box, cycle left shift, and expansion substitutions. In this paper, a DNA sticker algorithm for bit-substitution such as cycle left shift is proposed. The proposed algorithm requires two equal long memory strands. The first memory strand stores the original binary string, while the second memory strand stores the resulting binary string. With the proposed algorithm, cycle left shift is performed on a mass of equal long binary strings, and the computation complexity of the cycle left shift is for all -bit binary strings. Furthermore, this work indicates that block cipher systems with a 64-bit key are perhaps insecure. This paper presents clear evidence of the ability of DNA computing to perform intractable computation problems. [Copyright &y& Elsevier]

A concrete attack using side channel information from cache memory behaviour was proposed for the first time at ISITA 2002. The attack uses the difference between execution times associated with S-box cache-hits and cache-misses to recover the intermediate key. Recently, a theoretical estimation of the number of messages needed for the attack was proposed and it was reported that the average method obtains key information with fewer messages than maximum threshold or intermediate threshold method. Taking the structure of cipher into account, this paper provided the cache attack in which the average method is embodied, and provides improved key estimation. This paper includes the study on the attack that exploits internal collision. [ABSTRACT FROM AUTHOR]

This paper presents a detailed architecture and a reconfigurable logic based hardware design of the SCAN algorithm. This architecture can be used to encrypt high resolution images in real-time. Although the SCAN algorithm is a block cipher algorithm with arbitrarily large blocks, the present design is for 64×64 pixel blocks in order to provide real-time image encryption throughput. The architecture was initially targeted at the Xilinx XCV-1000 FPGA, for which design and performance results are presented in the paper. [ABSTRACT FROM AUTHOR]

Image encryption and decryption are essential for securing images from various types of security attacks. In this paper, we have proposed a new algorithm for RGB image encryption and decryption using diffusion method with a combination of chaotic maps. We have formulated a new algorithm for the entire possible range to choose keys for encrypting and decrypting RGB image. Computer simulation with two standard examples and results are given to analyse the capability of the proposed approach. Several important analysis like key space, key sensitivity, NPCR, UACI, MSE and PSNR analysis are performed. Results of various analysis and computer simulation confirm that the new algorithm offers high security and is suitable for practical image encryption. [ABSTRACT FROM AUTHOR]

Among instances when the data and image security in resource constrained environment (smart devices and the like) are to be taken into consideration, lightweight encryption algorithms accede in popularity and are deemed of to be of great merit. In devices as those of the sort mentioned, reducing both power consumption and gate count is always a prime concern. LEA, therefore, triumphs on merit, owing to its low consumption levels of hardware resources, which itself is a result of the adaption of simple modular addition, bitwise rotation and bitwise XOR (ARX) operation instead of the relatively more complex S-box technique. The algorithm in question supports keys of varying sizes three, to be precise: 128, 192 and 256-bit for the intent of providing three levels of image and data security. The hardware implementation of the LEA algorithm for the varying key sizes as mentioned above share significant kinship and hardware resources. This paper puts forward the proposition regarding a high speed low area unified architecture for LEA algorithm for three different sizes of key. The individual hardware implementations of the three key sizes tend to consume more hardware resources than those involved in the proposed unified architecture. The pipelined implementation of the proposed design improves operating frequency to a significant degree, with a little increase in the hardware costs. The design proposed in this paper notably supports three varying tile sizes, i.e. 256 × 256 , 128 × 128 , 64 × 64, of an input image. As resolution of an input image may not necessarily be an integer multiple of the size of tile, smaller tile sizes at the image boundary can also be handled by the same architecture. The design hereby proposed has been implemented on both UMC ASIC 0.09- μ m and XC5VLX330T FPGA platforms and achieved maximum operating frequencies of 740 MHz and 292 MHz respectively. As its increasingly evident on account of the FPGA implementation outcomes, the proposed unified architecture results in vastly improved levels of operating frequency (34%, 33% and 131%) as opposed to the individually available LEA architectures (corresponding to three different key sizes: 128, 192 and 256-bit, respectively). Proposed architecture shows 28%, 35% and 45% increment in the hardware resources with respect to available LEA architectures with single key. The incorporation of the unified key generation technique and pipeline implementation of the algorithm are the main reasons for the more hardware utilization. [ABSTRACT FROM AUTHOR]

Abstract: The key space of phase encryption algorithm using discrete random phase mask is investigated by numerical simulation in this paper. Random phase mask with finite and discrete phase levels is considered as the core component in most practical optical encryption architectures. The key space analysis is based on the design criteria of discrete random phase mask. The role of random amplitude mask and random phase mask in optical encryption system is identified from the perspective of confusion and diffusion. The properties of discrete random phase mask in a practical double random phase encoding scheme working in both amplitude encoding (AE) and phase encoding (PE) modes are comparably analyzed. The key space of random phase encryption algorithm is evaluated considering both the encryption quality and the brute-force attack resistibility. A method for enlarging the key space of phase encryption algorithm is also proposed to enhance the security of optical phase encryption techniques. [Copyright &y& Elsevier]

Block cipher encryption algorithms generally process on word structures of fixed length such as 8 or 16-bits. IDEA is one of the most widely used block ciphers and operates on 16-bit words. Square analysis is a method that exploits the word structure of block ciphers. Some square distinguishers of IDEA are given in previous studies. The best attacks against IDEA use square-like techniques. In this paper, we focus on the square properties of the IDEA block cipher. We consider all fixed word combinations of the plaintext to investigate the structural behavior of the algorithm. We observe that the cipher can be distinguished from a random permutation by fixing one, two or three subblocks of the cipher for 2 and 3 rounds. We find out novel 3-round distinguishers that require 216 chosen plaintexts. Furthermore, this approach enables us to propose the first four and five round square distinguishers of IDEA. [ABSTRACT FROM AUTHOR]

Several emerging areas like the Internet of Things, sensor networks, healthcare and distributed networks feature resource-constrained devices that share secure and privacy-preserving data to accomplish some goal. The majority of standard cryptographic algorithms do not fit with these constrained devices due to heavy cryptographic components. In this paper, a new block cipher, BRISK, is proposed with a block size of 32-bit. The cipher design is straightforward due to simple round operations, and these operations can be efficiently run in hardware and suitable for software. Another major concept used with this cipher is dynamism during encryption for each session; that is, instead of using the same encryption algorithm, participants use different ciphers for each session. Professor Lars R. Knudsen initially proposed dynamic encryption in 2015, where the sender picks a cipher from a large pool of ciphers to encrypt the data and send it along with the encrypted message. The receiver does not know about the encryption technique used before receiving the cipher along with the message. However, in the proposed algorithm, instead of choosing a new cipher, the process uses the same cipher for each session, but varies the cipher specifications from a given small pool, e.g., the number of rounds, cipher components, etc. Therefore, the dynamism concept is used here in a different way. [ABSTRACT FROM AUTHOR]

In this paper, we present two alternative architectures and FPGA implementations of the 64-bit NESSIE proposal, MISTY1 block cipher. The first architecture is suitable for applications with high-performance requirements. A throughput of up to 12.6 Gbps can be achieved at a clock frequency of 168 MHz. The main characteristic of this architecture is that uses RAM blocks embedded in modern FPGA devices in order to implement the S-boxes defined in the block cipher algorithm. The second architecture can be used in implementing applications on area-constrained systems. It utilizes feedback logic and inner pipeline with negative edge-triggered register. This technique shortens the critical path, without increasing the latency of the MISTY1 algorithm execution. Compared with an implementation without inner pipeline, performance improvement of 97% is achieved. The measured throughput of the second architecture implementation is 561 Mbps at 79 MHz. [ABSTRACT FROM AUTHOR]

Public-key cryptography has been widely accepted as the method in which data is encrypted, using algorithms such as the widely known and popularly used RSA algorithm. However, management of the public-key and its storage is an on-going issue. To avoid these problems the symmetric-key approach can be taken, where there is only one key and it must be kept secret. Presented in this paper is a new cipher based on symmetric-key cryptography, called the NASA/Kennedy Cipher (N/KC), and further designed as a block cipher using 128-bit blocks. The minimum key size is set at 128 bits with a maximum allowable of 2048 bits, modulus 2. The main focus of this work is encryption of image data for the purpose of protecting intellectual properties. However, empirical results are presented on N/KC's ability of encrypting and decrypting text data in the form of vectors and documents as well. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 178–188, 2005 [ABSTRACT FROM AUTHOR]

This paper proposes a new secret-key block cipher algorithm called MKC1. MKC1 is a Feistel-type block cipher with variable block length, key length, and number of rounds. The merits of this algorithm are that numerous structures can be formed by selecting the encryption functions and that cellular automata, which can ensure an immense number of structures, and power functions over a finite field, which have strong resistance to differential and linear attacks, are used for the encryption functions. These features increase MKC1's resistance to exhaustive key searches and analytical cryptanalysis. In addition, rules that are relatively powerful as encryption functions among the total of 256 rules for one-dimensional, two-state, neighborhood-three cellular automata were found to practically correspond to Class 3 of Wolfram's classification scheme. The results of computer experiments indicate that MKC1 is several times faster than DES. The industrial value of this algorithm was confirmed, by implementing it in an automatic electronic ticket system using a contactless IC card. [ABSTRACT FROM AUTHOR]