Adaptive medical image encryption algorithm based on multiple chaotic mapping

TLDR

Digital medical images contain confidential patient data and are increasingly transmitted over public networks, making robust confidentiality schemes essential. The study proposes an adaptive medical image encryption algorithm that improves upon existing chaotic encryption methods. The algorithm first scrambles the image with a Logistic‑sine chaotic map, partitions it into 2×2 sub‑blocks, and then adaptively encrypts each block using a hyper‑chaotic system. Experimental analysis of key space, entropy, correlation, and plaintext sensitivity demonstrates that the algorithm overcomes single‑direction diffusion deficiencies, resists all tested attacks, and offers superior security and robustness.

Abstract

Digital images are now widely used in modern clinic diagnosis. The diagnostic images with confidential information related to patients' privacy are stored and transmitted via public networks. Secured schemes to guarantee confidentiality of patients' privacy are becoming more and more vital. This paper proposes an adaptive medical image encryption algorithm based on improved chaotic mapping in order to overcome the defects of the existing chaotic image encryption algorithm. First, the algorithm used Logistic-sine chaos mapping to scramble the plain image. Then, the scrambled image was divided into 2-by-2 sub blocks. By using the hyper-chaotic system, the sub blocks were adaptively encrypted until all the sub block encryption was completed. By analyzing the key space, the information entropy, the correlation coefficient and the plaintext sensitivity of the algorithm, experimental results show that the proposed algorithm overcomes the shortcoming of lack of diffusion in single direction encryption. It could effectively resist all kinds of attacks and has better security and robustness.