Medical Image Cryptosystem using Dynamic Josephus Sequence and Chaotic-hash Scrambling

Image encryption is an interesting research topic, especially in medical images. This is due to the importance of security when storing and transmitting digital images. This study proposes an image encryption procedure that combines several methods such as chaotic-hash scrambling to perform the confusion process, combined hash functions, block-based substitution, dynamic bit shifting based on Josephus sequences, and diffusion with logistic maps to obtain strong encryption against various attacks. Based on the test results implemented on medical images, standard images, and special images. The proposed encryption procedure is proven to have resistance to statistical and differential attacks which have been measured by several measuring tools such as histogram analysis, chi-square, entropy, correlation coefficient, NPCR, UACI, avalanche effect, PSNR, and SSIM. In addition, it also has enough key space to withstand brute force attacks. (c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).