In recent years, various chaos-based image encryption algorithms have been proposed to meet the growing demand for real-time secure image transmission. However, chaotic system that is the core component of chaos-based cryptosystem usually degrades under finite computing precision, causing many security issues. In this paper, a novel cryptosystem with analog-digital hybrid chaotic model is proposed. Firstly, the analog Chen chaotic system and the digital Logistic map are adopted to depict the capability of the hybrid model, in which analog system is used to perturb digital system. Dynamic analyses demonstrate that the hybrid method has better complexity, larger chaotic parameter range and good ability to counteract dynamical degradation. The chaos-based key streams generated by the perturbed Logistic map are more suitable for image encryption. Secondly, a parameter selection mechanism is introduced to increase security. The state variables of Chen chaotic system and cipher image are involved in parameter selection process to dynamically change the parameter of the perturbed Logistic map. The involvement of cipher image makes the key streams relevant to plain image and can resist known/chosen-plaintext attacks. Performance, security and comparison analyses indicate that this cryptosystem has high security, low time complexity, and ability to resist common attacks.
相似文献Based on the deoxyribonucleic acid (DNA) sequence operations and chaotic systems, a novel improved color image encryption algorithm is presented with one-time-pad. Three DNA matrices are obtained by DNA encoding the plain-image firstly. To enhance the proposed algorithm’s robustness of resisting known-plaintext and chosen-plaintext attacks, the key streams, which are used to scramble the positions of the three DNA matrices, are generated from 3D skew tent map (3D-STM) by using the secret keys and the hamming distances between the DNA matrices. Then, we perform the DNA XOR, addition and subtraction operations on the DNA matrices and the key streams to get the cipher-image. At this stage, we also update the initial values of the coupled map lattice (CML) by the circle distance of DNA matrices obtained from the previous step to further enhance the proposed algorithm’s ability of resisting plaintext attack. Finally, we get the encrypted color image by decoding DNA matrices. The simulation and security analysis show that the proposed algorithm has an extraordinary ability to resist plaintext attack, differential attack and statistical attack, etc.
相似文献With the expansion and prevalence of financial certification, problems of financial security have been springing up. How to ensure the security of financial information and protect our privacy is an issue of particular concern. In order to reduce the influence of chaotic periodicity on cipher-text, an image dynamic encryption algorithm based on hybrid chaotic system and deep network is proposed in this paper. Firstly, the hybrid chaotic system is constructed to combine many mapping functions by using the nonlinear combination mechanism, and the chaotic sequence is outputted to generate the initial value of hybrid chaotic system by using the pixel value. Then the plain-text pixel values are adopted to generate the initial value of the hybrid system for improving the anti-plain attack ability of the algorithm; Artificial neural network is used to process chaotic sequences, and effectively eliminate chaotic periodicity; The classification and encryption of permutation image are realized by constructing quantization method and hetero-diffusion technology. The experimental results show that our proposed encryption technology has higher security and stronger ability to resist plain-text attack compared with the existing image encryption algorithms, which adapts to enhance the security of the financial system.
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