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The document is a collection of written or printed data containing information. The more rapid advancement of technology, the integrity of a document should be kept. Because of the nature of an open document means the document contents can be read and modified by many parties so that the integrity of the information as a content of the document is not preserved. To maintain the integrity of the data, it needs to create a mechanism which is called a digital signature. A digital signature is a specific code which is generated from the function of producing a digital signature. One of the algorithms that used to create the digital signature is a hash function. There are many hash functions. Two of them are message digest 5 (MD5) and SHA256. Those both algorithms certainly have its advantages and disadvantages of each. The purpose of this research is to determine the algorithm which is better. The parameters which used to compare that two algorithms are the running time and complexity. The research results obtained from the complexity of the Algorithms MD5 and SHA256 is the same, i.e., ⊖ (N), but regarding the speed is obtained that MD5 is better compared to SHA256.

A novel color image encryption algorithm based on a cross 2D hyperchaotic map is proposed in this paper. The cross 2D hyperchaotic map is constructed using one nonlinear function and two chaotic maps with a cross structure. Chaotic behaviors are illustrated using bifurcation diagrams, Lyapunov exponent spectra, phase portraits, etc. In the color image encryption algorithm, the keys are generated using hash function SHA-512 and the information of the plain color image. First, the color plain image is converted to a combined bit-level matrix and permuted by the chaos-based row and column combined cycle shift scrambling method. Then, the scrambled integer matrix is diffused according to the selecting sequence which depends on the chaotic sequence. Last, decompose the diffusion matrix to get the encrypted color image. Simulation experiments and security evaluations show that the algorithm can encrypt the color image effectively and has good security to resist various kinds of attacks.

This study presents a novel quantum image encryption algorithm, using a 3D chaotic map and controlled qubit-level scrambling operations. The newly proposed 3D-BNM chaotic map effectively reduces the degradation of chaotic dynamics resulting from the finite word length effect. It facilitates the generation of highly unpredictable random sequences and enhances chaotic performance. The system’s efficacy is additionally enhanced by the inclusion of a SHA-256 hash function. Initially, classical plain images are converted into their quantum equivalents using the Novel Enhanced Quantum Representation (NEQR) model. The Generalized Quantum Arnold Transformation (GQAT) is then applied to disrupt the coordinate information of the quantum image. Subsequently, to diffuse the pixel values of the scrambled image, XOR operations are performed using pseudorandom sequences generated by the 3D-BNM chaotic map. Furthermore, to enhance the randomness and reduce the correlation among the pixels in the resulting cipher image, a controlled qubit-level scrambling operation is employed. The encryption process utilizes fundamental quantum gates such as C-NOT and CC-NOT. Both theoretical and numerical simulations validate the effectiveness of the proposed algorithm against various statistical and differential attacks. Moreover, the proposed encryption algorithm operates with low computational complexity.

At present, many encryption algorithms for color images either decompose color images into three gray images and encrypt them, respectively, or combine R, G, B channels into a two-dimensional image matrix before encryption. These methods break the internal link between the three colors and reduce the efficiency of encryption. Here, to address these shortcomings, a new hyperchaotic system two-dimension Chebyshev–Sine coupling map (2D-CSCM) is proposed to improve the security of the encryption algorithm, and the dynamic behaviors of the system are analyzed by phase diagram, bifurcation diagram, Lyapunov exponent spectra information entropy and 0–1 test. We propose a Rubik's Cube scrambling method to scramble a three-dimensional bit-level matrix of the color image directly. Then the pixel values of the scrambled image matrix are diffused by two rounds of different operations based on chaotic sequences. The parameters and initial values of the chaotic system are derived from the secret key generated by the hash function SHA-512. Simulation results and security analysis demonstrate that the proposed algorithm has high efficiency and security to resist various common attacks.

In this paper, we propose a novel image encryption algorithm based on a hybrid model of deoxyribonucleic acid (DNA) masking, a Secure Hash Algorithm SHA-2 and the Lorenz system. Our study uses DNA sequences and operations and the chaotic Lorenz system to strengthen the cryptosystem. The significant advantages of this approach are improving the information entropy which is the most important feature of randomness, resisting against various typical attacks and getting good experimental results. The theoretical analysis and experimental results show that the algorithm improves the encoding efficiency, enhances the security of the ciphertext and has a large key space and a high key sensitivity, and it is able to resist against the statistical and exhaustive attacks.

In this paper, a universal two-dimensional (2D) enhanced cosine coupled model (2D-ECCM) is first designed, which can construct new 2D chaotic systems using most of the existing two one-dimensional (1D) maps as the seed maps. And a novel 2D Logistic-sine coupled map (2D-NLSCM) and a new 2D cubic-tent coupled map (2D-NCTCM) are generated by using the 2D-ECCM, and their chaotic features are analyzed by bifurcation diagram, trajectory, Lyapunov exponent spectrum, etc. Performance analyses show that two new maps have better chaotic behaviors than some state-of-the-art 2D chaos. Then, using the 2D-NLSCM, an image adaptive encryption algorithm is further designed. We propose an adaptive scrambling method to scramble image pixels directly by combining the target image information, and a bidirectional-sequential diffusion method for image pixels diffusion. The image adaptive scrambling can change the pixel values while effectively scrambling the pixel positions. And the bidirectional-sequential diffusion can be achieved to diffuse a minor change of a pixel value in the original image to all pixels of the encryption image. Therefore, the proposed algorithm is closely related to the target image in the encryption process. Moreover, the key of the proposed encryption algorithm is updated through the hash function SHA-512, which further increases the security of the algorithm. Ultimately, simulation experiment shows that the designed encryption algorithm has superior encryption efficiency. Performance analysis results indicate that the designed encryption algorithm, with average information entropy of 7.9988 and average chi-square of 238.3495, can withstand a series of common cryptanalytic attacks.

There are many emerging areas in which highly constrained devices are interconnected and communicated to accomplish some tasks. Nowadays, Internet of Things (IoT) enables many low resources and constrained devices to communicate, compute process and make decision in the communication network. In the heterogeneous environments for IoT, there are many challenges and issues like power consumption of devices, limited battery, memory space, performance cost, and security in the Information Communication Technology (ICT) network. In this paper, we discuss a state-of-art of lightweight cryptographic primitives which include lightweight block ciphers, hash function, stream ciphers, high performance system, and low resources device for IoT environment in details. We analyze many lightweight cryptographic algorithms based on their key size, block size, number of rounds, and structures. In addition, we discuss the security architecture in IoT for constrained device environment, and focus on research challenges, issues and solutions. Finally, a proposed security scheme with a service scenario for an improvement of resource constrained IoT environment and open issues are discussed.

In this paper, a new four-dimensional chaotic system is constructed. Then, the dynamics of the phase diagram, Lyapunov exponent, bifurcation, and complexity of the system are investigated, and the simulation circuit of the system is designed and the trajectory simulation of the system is implemented using a field programmable gate array. National Institute of Standards and Technology tests have verified the randomness of the output of the chaotic sequence by the system. Finally, a new color image encryption algorithm is designed based on this system. In the proposed algorithm, the plaintext information is used to generate the initial value of the system through a hashing algorithm, and the plaintext information is applied to the algorithm, reflecting the idea of algorithmic adaption. The bit-plane decomposition row dislocation breaks the strong correlation between pixels, and finally, the DNA encoding is combined with the diffusion method to complete the complete encryption process. Multiple security analysis methods show that the scheme has a good encryption effect.

To enhance the security of single-chaotic systems, we propose a novel image encryption cryptosystem based on true random numbers and chaotic systems. First, we select any one of several chaotic systems. Next, the hash function is used to calculate the initial value of the chaotic system using a plaintext image. Then, we obtain a solution of this chaotic system and use the k-medoids clustering machine-learning algorithm and chaotic sequence to scramble the original image. Finally, new random numbers obtained using a chaotic signal and true random numbers are used to perform the exclusive-OR operator on the scrambled results. To illustrate the effectiveness of our method, a one-dimensional (1D) logistic chaotic system is selected for image encryption. The simulation results show that compared with the existing models, such as image encryption based on chaos and image encryption based on the advanced encryption standar (AES), our method is simpler with a higher security and resists different classical attacks.

The purpose of this research is to determine the pattern of hijacking cases in Samarinda by using association rules and comparing apriori and hash-based. The data used for this research are secondary data from POLRESTA Samarinda which is processed using association rules algorithm with apriori and hash-based with minimum support of 10% and minimum confidence of 70%. The result of this research, in apriori, the pattern is often formed as many as 4 5-itemset combination while the hash-based obtained pattern that often formed by 3 3-itemset combination. In 2-itemset that is if the victim is female and young, then have a possibility of 46.67% chance of experiencing minor injuries with confidence of 90.9%, in 3-itemset if the victim is in location 1 and young, then have a possibility 53.33% chance of experiencing minor injuries with confidence of 88.89%, in 4-itemset if the victim in location 2, female and young then have a possibility 40% chance of experiencing minor injuries with confidence of 100%, in 5-itemset if the victim in location two, quite, female and young then have a possibility 26.67% chance of experiencing minor injuries with confidence of 100%.