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Medical image encryption is important for maintaining the confidentiality of sensitive medical data and protecting patient privacy. Contemporary healthcare systems store significant patient data in text and graphic form. This research proposes a New 5D hyperchaotic system combined with a customised U-Net architecture. Chaotic maps have become an increasingly popular method for encryption because of their remarkable characteristics, including statistical randomness and sensitivity to initial conditions. The significant region is segmented from the medical images using the U-Net network, and its statistics are utilised as initial conditions to generate the new random sequence. Initially, zig-zag scrambling confuses the pixel position of a medical image and applies further permutation with a new 5D hyperchaotic sequence. Two stages of diffusion are used, such as dynamic DNA flip and dynamic DNA XOR, to enhance the encryption algorithm’s security against various attacks. The randomness of the New 5D hyperchaotic system is verified using the NIST SP800-22 statistical test, calculating the Lyapunov exponent and plotting the attractor diagram of the chaotic sequence. The algorithm validates with statistical measures such as PSNR, MSE, NPCR, UACI, entropy, and Chi-square values. Evaluation is performed for test images yields average horizontal, vertical, and diagonal correlation coefficients of –0.0018, –0.0002, and 0.0007, respectively, Shannon entropy of 7.9971, Kolmogorov Entropy value of 2.9469, NPCR of 99.61%, UACI of 33.49%, Chi-square “PASS” at both the 5% (293.2478) and 1% (310.4574) significance levels, key space is 2 500 and an average encryption time of approximately 2.93 s per 256 × 256 image on a standard desktop CPU. The performance comparisons use various encryption methods and demonstrate that the proposed method ensures secure reliability against various challenges.

Image encryption has been an attractive research filed in recent years. In this paper, we propose a novel hyperchaotic encryption algorithm for color image utilizing DNA dynamic encoding and self-adapting permutation. Firstly, A new 4-dimensional hyperchaotic system is designed, and the detailed dynamic analysis shows that the system has strong pseudo-randomness and a large range of chaotic parameters. Secondly, based on the new 4-D hyperchaotic system, we devise the methods of DNA dynamic encoding, DNA dynamic calculation and DNA dynamic decoding in the image encryption algorithm, and the sequences generated by the hyperchaotic control these coding rules dynamically to make the results of operation more unpredictable. Moreover, the initial keystream is designed dependent upon the plaintext image, and the method of plaintext-related self-adapting permutation is proposed at the bit level and DNA level of the image respectively, which enhances the sensitivity of the algorithm to plaintext image and key. The theoretical analysis and numerical simulation show that the image algorithm has good security and can resist various attacks.

In recent years, chaotic image encryption based on color images has been widely studied. However, in most articles, chaotic sequences generated by one chaotic system is used, and the obtained chaotic sequences will have the problem of correlation. At the same time, when using DNA technology for image encryption, the DNA operation rules are independent of the key type. In this paper, two hyperchaotic systems and new DNA operation rules are proposed for image encryption. Firstly, the improved Arnold scrambling algorithm is adopted in the scrambling process, which enhances the complexity of the scheme. Secondly, in the diffusion process, dynamic DNA coding and dynamic DNA operation addition, subtraction, XOR and mutation rules are implemented, and these rules are also related to the key type. Such operation rules are more complex and increase the complexity of the encryption process. Finally, the security performance such as comparing improved Arnold scrambling with traditional Arnold algorithm, histogram, key space, correlation, information entropy, differential attack and robustness is analyzed in detail to verify that the proposed algorithm is valid. Compared with the existing advanced algorithms, the experimental results show that the scheme has good performance and improves the security of image encryption and transmission.

In the digital information age, although digital images are widely used, the security issues associated with them have become increasingly severe. Consequently, ensuring secure image transmission has become a critical challenge in contemporary information security research. Chaotic systems are characterized by non-periodic behavior, strong dependence on initial conditions, and other favorable characteristics, and have been widely employed in the scrambling and diffusion processes of image encryption. Compared to classical chaotic maps, a quantum Logistic map exhibits better randomness and stronger sensitivity to initial values, effectively overcoming the attractor problem inherent in classical Logistic maps, thereby significantly enhancing the robustness of encryption methodologies. This article focuses on a innovative integration of a quantum Logistic map, hyper-chaotic Lorenz map, and DNA dynamic encoding technology, to design and implement a highly secure and efficient image encryption scheme. First, high-quality random number sequences are produced utilizing the quantum Logistic map, which is then employed to perform a scrambling operation on the image. Next, by integrating the chaotic sequences yielded from the hyper-chaotic Lorenz map with DNA dynamic encoding and operation rules, we implement a diffusion process, thereby increasing the strength of the image encryption. Experimental simulation results and multiple security analyses demonstrated that our encryption methodology achieved excellent encryption performance, effectively resisting a variety of attack strategies, and it holds significant potential for research on protecting image information through encryption.

Some image encryption algorithms are difficult to resist the chosen-plaintext attack against special images, in order to solve this problem and improve the security of the algorithm, this paper proposes a novel image encryption scheme based on the chaotic system, random number embedding and DNA-level self-adaptive permutation and diffusion. The architecture of preprocessing, permutation and diffusion is adopted. Firstly, an image preprocessing based on random number embedding (IPRNE) is presented, specifically, embed random numbers into the plain image, and then perform partition XOR operation on random numbers and their surrounding pixels to preprocess plain image. The random numbers are generated by a 4D memristive hyperchaotic system, and their embedding positions are controlled by the pixel sums of plain images. Secondly, the obtained image is encoded into a DNA matrix by use of a DNA encoding rule, and then a DNA-level self-adaptive permutation and diffusion processes are successively performed on it. Further, after decoding the diffused matrix, the cipher image is obtained. Besides, the feature information of DNA sequences of plain image is applied for disturbing the permutation and diffusion phases, which may be extracted automatically in the decryption process, and thus additional transmission and storage are avoided. Moreover, the plain image information and hyperchaotic system are integrated to design the DNA encoding /decoding rule for the plain image and mask matrix, and this can enhance the ability of the algorithm to resist chosen-plaintext attack. Experimental results and security analyses demonstrate that the proposed encryption is secure and effective, and it can be applied for image secure communication.

To address the high redundancy and weak security inherent in satellite image transmission, this paper proposes an image encryption algorithm founded on a novel five-dimensional fractional-order cosine memristive Hopfield neural network (5D-FOCMHNN). The constructed hyperchaotic system exhibits long-term memory and multistability, capable of generating reconfigurable multi-scroll attractors. A multivariate bit-level scrambling strategy effectively disrupts pixel correlations using neuron state sequences. Furthermore, the system’s chaotic output dynamically governs DNA encoding rules, while a bidirectional diffusion mechanism ensures strong randomization and resistance to differential attacks. Comprehensive experiments demonstrate that the 5D-FOCMHNN-based scheme provides a key space of 2256, has an information entropy approaching the ideal value of 8, and exhibits robust resilience against cropping, noise, and statistical cryptanalysis, thereby providing a highly secure solution for satellite image transmission.

This paper proposes a six-dimensional hyperchaotic system based on the Cellular Neural Networks (CNN) theory. Numerical analysis of the Lyapunov exponential spectrum, bifurcation diagrams, and complexity methods reveals that the system has multiple coexisting attractors and high initial sensitivity, verifying its rich dynamics and making it highly valuable in secure communications. The circuit of the system was then designed and implemented using the Multisim circuit simulation software, and the experimental results agreed with the numerical simulation results, verifying the realistic feasibility of the system. Finally, a color image chunking encryption algorithm is designed with the DNA algorithm, using the chaotic sequence generated by the six-dimensional CNN as the secret key source and the Logistic chaos mapping to generate the private key again to achieve double encryption. Since the legend of the algorithm is generated from the plaintext image, the effect of “one image, one secret” can be realized. The results show that the encryption algorithm has a good effect, high dislocation of the encrypted image, low correlation between neighboring pixels, increased sensitivity to the key, and high complexity and security.

In this digital world, encryption plays an important role in various domains. Securing the information is the main goal when transfer of information takes place. Image encryption is a very important part of this as it applies to various domains like medical, multimedia, defence etc. A new method for image encryption is proposed here taking into account the \"confusion-diffusion\" structure. While working with secure data, requirements like fast computation, compression and processing are important issues. Deoxyribonucleic Acid (DNA) encoding has the capability to cope up with this requirement. In this paper a new algorithm is proposed based on composite chaos map for pixel scrambling and hence image encryption. First the algorithm takes the image and XORs with a composite chaotic map which further goes into dynamic DNA encoding followed by pixel scrambling which results in the image being very random thus it becomes less prone to attacks. The method discussed performs efficiently as shown in the experimental results.

Due to the truncation effects inherent in implementing chaotic systems on digital circuits, the limited precision reduces the sensitivity to initial conditions in chaotic systems. This ultimately leads to the overlap of adjacent trajectories, causing the system to transition from a chaotic state to either a periodic state or fixed point state. The Lyapunov exponent is a quantitative measure of chaotic characteristics, quantifying the mean degree of convergence and divergence among the various trajectories of a chaotic system. This paper introduces a construction algorithm for a N -dimensional non-degenerate chaotic system based on singular value estimation (NC-CSVE) from the perspective of controlling the Jacobian matrix of system, achieving indirect control of the Lyapunov exponents (LEs). Experimental analyses using lyapunov spectrum, joint entropy, sample entropy, and NIST tests indicate that compared to existing non-degenerate chaos construction methods, the system constructed by our method demonstrates superior performance in terms of chaotic dynamic characteristics, algorithm complexity, and construction time expenditure, meeting the needs of practical application scenarios. Additionally, to validate the feasibility and reliability of the proposed construction algorithm in practical applications, this paper introduces a new dynamic DNA color image encryption algorithm based on NC-CSVE. The encryption techniques include three-dimensional six-direction bit diffusion (TDSBD), bit-plane global shift and local rotation scrambling (B-GSLR), DNA calculation rule extension (DNA-CRE) and DNA dynamic mutation (DNA-DM), achieving fast encryption of color images. The results of the statistical tests indicate that the algorithm demonstrates higher efficiency and excellent resistance to attacks. The encrypted images approach ideal values in terms of information entropy, histograms and pixel correlation, confirming the effectiveness and reliability of the algorithm.

Nonlinear dynamic systems and chaotic systems have been quite exhaustively researched in the domain of cryptography. However, the possibility of using fractional chaotic systems in the cryptosystem design has been much less explored while it bears advantages such as enlarged keyspace and better resistance to attack compared to classical nonlinear systems. This paper, therefore, proposes a novel structure for the pseudo-random number generator based on 3 different fractional chaotic systems, namely fractional Chen system, Lu system, and fractional generalized double-humped logistic map. Then, the outputs of this fractional chaotic pseudo-random number generator are used as a keystream for an image encryption scheme. The confusion layer of the scheme is conducted by a dynamic DNA encoding and decoding method combined with a 2D cat map for the permutation in the DNA bases level. The diffusion layer is performed through the adoption of a 32 bits discrete logistic map. The performance and security analyses have been conducted for the above-designed cryptosystem, proving that the proposed cryptosystem is practical and efficient, and can be successfully implemented in image encryption.