A Simultaneous Confusion-Diffusion Structure for Fast Image Encryption Based on Plaintext-Related Mechanism and Dynamic Josephus Trajectory
Ahmed Kareem Shibeeb, Salah Abdulhadi Albermany, Sadiq Abdul Aziz Mehdi · 2025
The security of image cryptosystem is fundamentally contingent upon the efficacy of the confusion and diffusion methodologies employed by the cryptosystem, as well as the dynamic behavior of chaotic systems. Nonetheless, prevailing chaos-based image cryptosystem are hindered by slow performance, inadequate resistance to a variety of attacks, a lack of correlation between the input image and the encryption key, suboptimal dynamic performance, and limited sensitivity to chaotic systems. In order to mitigate these deficiencies, this paper presents a simultaneous confusion-diffusion structure for image encryption based on a plaintext-related mechanism, which demonstrates a high correlation with the plain image using the U-Quark hash function and Collatz conjecture. Firstly, the plain image is divided into non-overlapping blocks. Secondly, the dynamic Josephus trajectory permutes the image blocks using random indices generated through a 7D hyperchaotic system. Thirdly, a parallel simultaneous confusion-diffusion structure is employed to confuse and diffuse all image pixels. The results of the experimental study imply that the recommended cryptographic approach, in relation to earlier investigations, delivers a variety of benefits concerning MSE, PSNR, entropy and correlation coefficient indicators, accomplishing an encryption time of around 0.024 seconds and a key size greater than about 10266. Furthermore, it exhibits commendable resilience against a spectrum of attacks.