Dynamic rotation medical image encryption scheme based on improved Lorenz chaos

With the rapid development of AI technology and the continuous improvement of Internet technology, information technology and intelligent technology are gradually combined with medical treatment, which has given rise to the rapid rise of digital medical industry, and smart medical alliance has gradually become a hot topic in the medical field. The data and systems in medical institutions are frequently attacked by network due to their high value and vulnerability. A large number of network security attacks may damage medical services and affect patient safety. A dynamic rotation medical image encryption scheme based on improved Lorenz chaos is proposed for solving the security problems such as theft and tampering faced by digital medical images in Internet transmission. Firstly, in order to improve the key randomness and security of image encryption, we improved the classical Lorenz chaotic system. By adding new nonlinear adjustment terms and control parameters, the generated pseudo-random numbers are more unpredictable. From 0-1 test analysis, Lyapunov exponent and different analysis results, it can be seen that the improved Lorenz chaotic system has a wider range of chaotic parameters and better chaotic characteristics. We use the improved chaotic system as a key generator and apply it to the proposed image encryption scheme with dynamic rotation permutation and double diffusion. Under the premise of two kinds of scrambling modes within a block and between blocks, a pixel exchange threshold is innovatively designed to judge the feasibility and effectiveness of the exchange of pre-exchange pixels. The diffusion algorithm uses a relatively novel filter diffusion method to diffuse the scrambled image, and then uses a dynamic diffusion method to further improve the security of the ciphertext image. Through the analysis of the experimental results of a number of security tests, it can be seen that the proposed scheme is more effective in image encryption, and can effectively resist common attacks.