Collision Resistance Research Articles

Controllable software licensing system for sub-licensing

The digital rights management is mainly about license management. Take software licensing as an example. A software license can be assigned to a user, a group of users, or an organization. To protect the copyright against software piracy, a software license is usually bound to the IP of the device or the identity of user. When a user wants to use a software product lawfully on multiple devices he owns, he has to purchase multiple licenses. We consider a scenario of software licensing where upon receiving a software license, the user can legally create a bounded number of licenses for his own devices. Our system is based on a novel chameleon function which is featured with n-time trapdoors. By using this feature, we can construct a secure software licensing system, called “controllable n-time software licensing system”. We formally prove that our software licenses are unforgeable, thanks to the collision resistance and indistinguishability feature of the proposed chameleon hash. We also provide the experimental results to demonstrate the computational efficiency of our system.

Quantum hashing via single-photon states with orbital angular momentum

Quantum hashing is a promising generalization of the cryptographic hashing concept on the quantum domain. In this paper, we construct a quantum hash via a sequence of single-photon states and perform a proof-of-principle experiment using orbital angular momentum (OAM) encoding. We experimentally verify the collision resistance of the quantum hash function depending on the number of qubits in use. Based on these results, we conclude that theoretical estimates are confirmed for different bases of OAM states and the proposed technique can be useful in computational and cryptographic scenarios. The possibility of multiplexing different OAM bases can make this approach even more efficient.

Simplified ciphertext-policy attribute-based encryption scheme with attribute level collusion resistance for cloud storage

The core objective of our paper is that to overcome the challenges of secure data sharing problem in cloud where users can access data if they acquire a certain set of attributes or credentials. At present, there is only one way for implementing such procedures is by employing a reliable server to mediate access control, store the data. The service providers have whole control over cloud applications, client’s data and hardware. However, if the data stored in the cloud server is conceded, then the data confidentiality will be compromised. With simplified CP-ABE data is confidential even though storage server is un trusted. Hence privacy of cloud data is enhanced by proposing a methodology that uses a privacy policy, encrypts the data based upon various group of attributes related to the user. The decryption of the data can be done only when his/her attributes match with the privacy policy. Simplified CP-ABE makes it easier to secure, broadcast and control the access of sensitive information, specifically across the cloud’s server and decrease collision resistance.

The design of keyed hash function based on CNN-MD structure

In this paper, we propose a new chaotic neural network called the Merkle–Damgaard (CNN-MD) iterative structure, which we designed from the perspective of resisting attacks, such as length extension, second original image, Joux multiple collision, and intermediate encounter attacks. A new chaotic hash function based on the CNN-MD is presented. First, CNN is used as the compression function of CNN-MD, which ensures both the unidirectionality of data compression and the sensitivity of the hash value. Furthermore, the multi-input single-output construction of the CNN can achieve highly efficient data compression. In addition, in the process of group encryption of data, we use the value padding of coupled lattice mapping to improve the alignment of the plaintext of the MD algorithm. This new alignment can enhance the hash function’s collision resistance and the CNN-MD sensitivity. Experimental and theoretical analyses show that our proposed hashing algorithm can resist attacks, such as second original image, brute force, and multiple collision attacks, better than MD5, SHA-1, and SHA-2 algorithms. In terms of speed, our proposed hashing algorithm can successfully handle existing commercial scenarios better than MD5, SHA-1, SHA-3, and other methods. Therefore, the hash algorithm proposed in this study can be applied to existing e-commerce scenarios.

The effect of anomalous resistivity on fast electrothermal instability

This manuscript presents a new theoretical contribution toward the growth rate of the “fast” form of electrothermal instability (ETI) in the presence of anomalous resistivity (AR). Current-driven ETI is present in all pulsed-power platforms, and has been shown to seed the disruptive magneto Rayleigh–Taylor instability. Fluid simulations of low-density, current-carrying plasmas are often subject to nonphysical runaway Ohmic heating due to an under predicted resistivity when using purely collisional resistivity models. AR models provide mechanisms to increase the resistivity as the drift speed increases through increased current density. The derivation of a new, generalized growth rate is presented for the ETI, which includes a resistivity that is dependent on current density, and marks the key contributions of this work. This new growth rate is then compared to the growth rate without AR. Although the striation form of the ETI growth rate is unaffected by the inclusion of AR, the filamentation form of the ETI growth rate depends on the AR. Hence, the new growth rate is verified through 1D simulations of the filamentation form of ETI. The impact of AR can be significant: up to twelve orders of magnitude on the temporally varying local growth rate for a certain choice of parameters. For experimentally relevant conditions based on kinetic simulations, the growth rate can be increased by up to four orders of magnitude if the AR is dominated by the lower-hybrid drift instability.

Collision Resistance of a Lightweight Center Pillar Made of AA7075-T6

Collision Resistance of a Lightweight Center Pillar Made of AA7075-T6

Research on low-speed collision performance of Collision resistance of different materials

In order to explore the impact of lightweight materials and structures on the performance of anti-collision beams, this paper selects aluminum alloy and carbon fiber as the research objects, and analyzes the difference in low-speed impact performance of open and closed anti-collision beams for these two materials. Based on the structure of carbon fiber materials, the mechanical properties of carbon fiber materials are analyzed. At the same time, a low-speed collision model is established using numerical simulation to study the maximum intrusion amount, intrusion acceleration and intrusion force changes with time during the collision of aluminum alloy and carbon fiber anti-collision beams, And finally use experiments to verify. The research results show that the impact of the open aluminum alloy anti-collision beam and carbon fiber anti-collision beam on the fluctuation range of the collision acceleration is less than that of the closed aluminum alloy anti-collision beam; at the same time, compared with the closed aluminum alloy anti-collision beam, the open aluminum alloy anti-collision beam and carbon fiber, the maximum intrusion of the anti-collision beam is reduced by 8.2% and 18.6%; the carbon fiber anti-collision beam has the greatest force during the collision, followed by the closed anti-collision beam and the open anti-collision beam. The test results are consistent with the numerical simulation, which further illustrates the rationality of the exploration results.

Algebraic Collision Attacks on Keccak

In this paper, we analyze the collision resistance of the two smallest versions of Keccak which have a width of 200 and 400 bits respectively. We show that algebraic and linearization techniques can serve collision cryptanalysis by using some interesting properties of the linear part of the round function of Keccak. We present an attack on the Keccak versions that could be used in lightweight cryptography reduced to two rounds. For Keccak[40, 160] (resp. Keccak[72, 128] and Keccak[144, 256]) our attack has a computational complexity of 273 (resp. 252.5 and 2101.5) Keccak calls.

O3-R-CP-ABE: An Efficient and Revocable Attribute-Based Encryption Scheme in the Cloud-Assisted IoMT System

With the processes of collecting, analyzing, and transmitting the data in the Internet of Things (IoT), the Internet of Medical Things (IoMT) comprises the medical equipment and applications connected to the healthcare system and offers an entity with real time, remote measurement, and analysis of healthcare data. However, the IoMT ecosystem deals with some great challenges in terms of security, such as privacy leaking, eavesdropping, unauthorized access, delayed detection of life-threatening episodes, and so forth. All these negative effects seriously impede the implementation of the IoMT ecosystem. To overcome these obstacles, this article presents an efficient, outsourced online/offline revocable ciphertext policy attribute-based encryption scheme with the aid of cloud servers and blockchains in the IoMT ecosystem. Our proposal achieves the characteristics of fine-grained access control, fast encryption, outsourced decryption, user revocation, and ciphertext verification. It is noteworthy that based on the chameleon hash function, we construct the private key of the data user with collision resistance, semantically secure, and key-exposure free to achieve revocation. To the best of our knowledge, this is the first protocol for a revocation mechanism by means of the chameleon hash function. Through formal analysis, it is proven to be secure in a selectively replayable chosen-ciphertext attack (RCCA) game. Finally, this scheme is implemented with the Java pairing-based cryptography library, and the simulation results demonstrate that it enables high efficiency and practicality, as well as strong reliability for the IoMT ecosystem.

Usefulness of Decoherence in Quantum-Walk-Based Hash Function

We study the usefulness of the broken-line-type decoherence in quantum Hash functions based on discrete-time quantum walks on a cycle. We first observe that the time-evolution of probability distribution of quantum walks on a cycle is of high sensitivity to such broken-line-type decoherence, increasing with the number of steps in the walk. Based on this observation, we further propose a quantum Hash function based on the broken-line quantum walk on a cycle. Numerical simulation and performance analyses show that decoherence can be useful to improve the performances of quantum hash functions such as better diffusion and confusion, better collision resistance and more uniform distribution of hash values in the hash space. Moreover, our results promote the practical use of quantum-walk-based hash functions in realistic situations.

Keyed Parallel Hash Algorithm Based on Multiple Chaotic Maps (KPHA-MCM)

Hash functions are considered as the core of cryptography, which are the basic technique used for data security. Cryptographic hash functions also can be used to achieve the integrity of large data such as the data stored in a hard disk and set of financial data. So, in the era of large data and increasing capacity of data in applications, fast hash schemes with parallel operations are extremely desirable which effectively increases the computational speed. Functions of random behavior like chaotic maps are used in hash functions to generate the fixed length message digest from the original message. This paper proposes a parallel hash algorithm based on multiple chaotic functions by mixing logistic map, tent map, and sine function. In the proposed scheme the structure of coupling lattice is changed and using diamond lattice as new structure. This algorithm is flexible to generate 128, 256 or longer hash value. The simulation analysis such as hash distribution, key sensitivity, confusion and diffusion statistical properties, and collision resistance are executed. The results demonstrated that the proposed hash is an efficient, simple and fast algorithm comparing with some recent hash algorithms based on chaotic maps.

A Novel Hash Function Based on a Chaotic Sponge and DNA Sequence

Many chaos-based hash functions have convoluted designs that are not based on proper design principles, complicating the verification of security claims. We address this problem by proposing a hash function based on a chaotic sponge construction and DNA sequence. DNA sequence is used to design state transition rules of a deterministic chaotic finite-state automata (DCFSA), a chaotic structure that enhances the chaoticity of digital chaotic maps. We use a DCFSA configuration consisting of four states associated with logistic maps. Analysis shows that the DCFSA configuration is efficient and has high chaotic complexity. Both DCFSA and DNA are used to design the sponge-based hash function. An input message is transformed into a DNA sequence and divided into fixed-length blocks. Each block is absorbed into a sponge structure via DNA-XOR. The sponge state is then updated with a new DNA sequence by iterating DCFSA as a compression function. Statistical evaluations indicate that the proposed hash function has near-ideal diffusion, confusion, collision resistance and distribution properties. The proposed hash can also extend the provably secure notions of the sponge construction, specifically the indifferentiability from random oracles. Furthermore, the hash function has a high level of performance as compared to other chaos-based hash functions.

Construction and Analysis of SHA-256 Compression Function Based on Chaos S-Box

To further improve the security of SHA-256, a compression function construction scheme based on chaotic S-box is proposed. Through the reasonable design of the iteration mode and using the nonlinearity, confusion, and anti-difference of chaotic S-box, the relationship between the plaintext and the hash value becomes more complicated and unpredictable, by the diffusion of the linear transformation P-box, the dependence between the plaintext and the hash value is further improved. The compression function is applied to the SHA-256 Hash Algorithm to test and analyze the distribution, sensitivity, confusion, diffusion, and collision resistance, and compared with the original SHA-256 and the mainstream Hash Algorithms. The results show that the proposed scheme can effectively improve the collision resistance of the SHA-256 Hash Algorithm and enhance the stability of confusion and diffusion with fewer cryptographic components and lower operational consumption to provide more reliable security guarantee for its application.

Collision mechanism of unmanned aerial vehicles onto glass panels

The international standards for safety glass design have been limited to the use of a soft body impactor representing a human body to estimate the accidental collision resistance. However, UAVs have recently emerged as a new collision source due to their increasingly widespread use. An evaluation protocol for UAV collision is required to secure the safety of the glass used for structural cladding. In this paper, the collision mechanism of unmanned aerial vehicles (UAVs) onto glass panels is investigated by conducting experiments. We evaluate the impact forces of UAV collision on the glass panels and verify the numerical simulations by comparing the resultant forces from the experiments. Using the verified numerical simulation, 72 different collision conditions (changing the impact angles and velocities, respectively) are modeled, including extreme collision conditions that could be infeasible in the real experiments under manual control. Through this study, complicated collision mechanisms are clarified and elucidated. Additionally, specific collision conditions that induce maximum and minimum threats are identified, which should assist the design of future structural cladding glass systems and the UAV operation discipline in urban areas.

Onset of fast magnetic reconnection and particle energization in laboratory and space plasmas

The onset of magnetic reconnection in space, astrophysical and laboratory plasmas is reviewed discussing results from theory, numerical simulations and observations. After a brief introduction on magnetic reconnection and approach to the question of onset, we first discuss recent theoretical models and numerical simulations, followed by observations of reconnection and its effects in space and astrophysical plasmas from satellites and ground-based detectors, as well as measurements of reconnection in laboratory plasma experiments. Mechanisms allowing reconnection spanning from collisional resistivity to kinetic effects as well as partial ionization are described, providing a description valid over a wide range of plasma parameters, and therefore applicable in principle to many different astrophysical and laboratory environments. Finally, we summarize the implications of reconnection onset physics for plasma dynamics throughout the Universe and illustrate how capturing the dynamics correctly is important to understanding particle acceleration. The goal of this review is to give a view on the present status of this topic and future interesting investigations, offering a unified approach.

Optical Hash function based on multiple scattering media

Hash functions, which can extract message digest from input messages as output, play an important role in digital signature and authentication. Meanwhile, Hash functions are essential in many cryptographic protocols and regimes. With the research becoming more and more in depth, a series of Hash functions is proposed, such as MD series and SHA series. At the same time, the security analysis and attacks against Hash functions are carried out. The security of Hash functions is threatened. In this case, how to improve the security of the Hash functions becomes the primary concern. In this paper, an optical Hash function based on the interaction between light and multiple scattering media is proposed. Unlike most of the traditional Hash functions which are based on mathematical transformations or complex logic operations, this method innovatively takes advantage of the natural random scattering effect of multiple scattering media on coherently modulated light, and realizes the “confusion” and “diffusion” of modulated light, which satisfies the core functional requirement of the Hash function: one-way encoding/encryption with strong security. The photoelectric hybrid system designed by this method can effectively simulate the "compression function" in the Hash function. Combined with the Sobel filter with feature extraction function, the input data of arbitrary length can be compressed and encrypted into the output with a fixed length of 256-bit (Hash value). The principle of the proposed optical Hash function can be described as follows. 1) Two 8-bit images with a size of 16×16 pixels are loaded in SLM<sub>1</sub> (amplitude-only spatial modulator) and SLM<sub>2</sub> (phase-only spatial modulator) respectively. 2) The coherent wavefront is modulated by SLM<sub>1</sub> and SLM<sub>2</sub>, and then propagates on multiple scattering media. 3) A speckle pattern is recorded by CCD because of the confusion of multiple scattering media. 4) The features of the speckle pattern, which is extracted by Sobel filter, serve as the input of the next compression function. For the unpredicted and non-duplicated disorder multiple scattering media, it is tremendously difficult to determine the internal state of the multiple scattering media. Therefore, the proposed optical Hash function is considered to have a high security. A series of simulation results shows that the proposed optical Hash function has a good “avalanche effect” and “collision resistance”, and its security performance is comparable to that of the most widely used traditional Hash functions (MD5 and SHA-1).

Combined application of patchwork and partial softening to enhance the collision resistance of the center pillar

Hot press formed parts in a fully martensitic structure limit its application in the centre pillar, which requires high collision resistance. In this study, the combined effect of the patchwork and partial softening on the collision characteristics of the centre pillar, such as impulse, absorbed energy, and intrusion displacement, were investigated both experimentally and numerically. The partial softening process was used to provide ductility, while the patchwork was attached to improve the stiffness during impact loading. The energy absorption was assessed by integrating unit element deformation during impact. When patchwork and partial softening were applied to the centre pillar simultaneously, the anti-intrusion and absorbed energy were improved remarkably by 20.0% and 20.3%, respectively. The combined application of patchwork and partial softening is a feasible alternative for enhancing the collision resistance of the centre pillar with high degree of reliability.

Performance and Security Tradeoffs in Cryptographic Hash Functions

A cryptographic hash function is an important component used in many applications, such as blockchain, authentication, data integrity, and digital signature. With the rapid increase in usage of mobile devices, more attention goes towards the tradeoffs between performance and security of cryptographic hash functions on mobile devices due to their limited computational power. The researchers in this paper study the most common cryptographic hash functions and highlights the tradeoffs between their performance and security. The hash functions considered in this study are MD4, MD5, Whirlpool, and the hash functions in the SHA family. The security of these hash functions is compared based on recent attacks in terms of collision resistance, preimage attacks, and sensitivity analysis. While the performance is tested on different input block sizes, useful observations and recommendations are made based on the results of this study.

Fabrication and Testing of Novel Aluminium Composite Panel and Analysis of Composite Panel for Impact Loads in Collision Environment for Four-Wheelers Automobile

Impact loads from the crash of automobile always challenge the structural parts of the collided vehicles. Modern high – speed vehicles are subjected to high impact loads during accidents when the vehicle is accelerating at high speeds. This results in structural damage to the vehicle as well as passengers in the vehicle. In recent years, high-strength aluminum alloys have increasingly been used for building high-speed vehicles, and other types of weight-critical structures. In such structures, stiffened panels are the basic strength members. Composite panels can be used for the car body to reduce the weight of the vehicle and to increase the collision resistance. In this study, the aluminum composite panels with composite filled stiffeners are fabricated and tested experimentally under compression and impact loadings. Recycled ceramic powder, recycled steel flakes, and E - glass fiber mesh is taken as reinforcements and thermoplastic resins as matrix materials in the preparation stiffener filler composite. The composite panel specimens are fabricated and are tested experimentally under axial compression for collapse resistance.

One-Way Hash Function Based on Delay-Induced Hyperchaos

A scheme for constructing one-way Hash function based on hyperchaos induced by time delay and key-stream function iteration is proposed in this paper. In this scheme, the plaintext and secret key are used as the initial value in two hyperchaotic Chen systems; these values are evolved in a hyperchaotic way during a predefined period. The results of the evolution are quantified and iterated using key-stream function iteration to confuse and diffuse the plaintext and secret key. The cipher block chaining mode is used to generate a 128 bits Hash value for a plaintext of arbitrary length. Theoretical analysis and simulation results indicate that the proposed algorithm has satisfactory performance, such as value compression function, irreversibility, initial value sensitivity, forgery resistance and collision resistance.