Image cryptosystem based on hyper-chaos and optimized typhoon wind field model

In this work, a novel digital image cryptosystem is designed, and particularly the optimized Jelesnianski typhoon wind field model (OTWFM) is used in this proposed image cryptosystem to make the encryption system possess stronger robustness. Specifically, the plaintext image is first reshaped into one-dimensional data using the clockwise vortex method. Subsequently, a chaotic pseudo-random sequence is constructed and quantised through a hyperchaotic mapping—the initial conditions of which are determined by generated adaptive parameters, thereby enhancing the cryptosystem’s sensitivity to plaintext. Subsequently, an optimised wind field model is constructed. During the obfuscation phase, the Jelesnianski moving wind field coefficients generated by OTWFM are employed to scramble the image sequence, disrupting the spatial positions of pixels. In the diffusion phase, a single-round diffusion mechanism combining the wind field sequence with dynamic indexing is proposed. This ensures that the encrypted value of each pixel dynamically correlates with the encrypted result of the preceding pixel, thereby significantly enhancing plaintext sensitivity. The proposed image cryptosystem can not only effectively resist the cryptanalysis-based attacks such as statistical, differential, occlusion and noise attacks, but also enhance the ability to defend against chosen/known plain-text attacks etc. Performance analysis and experimental results demonstrate that the proposed image cryptosystem is an efficient system and has a great security.