Cryptanalysis of a lightweight image encryption scheme based on random shuffling and XOR operation

Abstract

The rapid exchange of visual data across open networks has made image security a critical concern, particularly in fields such as healthcare, surveillance, and remote sensing where image integrity and confidentiality are essential. While many chaotic-based encryption schemes have been proposed, their security often relies on statistical metrics without rigorous cryptanalysis, leaving them potentially vulnerable. This study presents a detailed cryptanalysis of a recently proposed lightweight medical image encryption scheme that uses Henon, Brownian motion, and Chen chaotic systems for block-based shuffling, diffusion, and XOR-based confusion. We first reconstruct an equivalent structure of the scheme and perform a chosen-plaintext attack to recover its key components, including the permutation matrix, multiplication masks, and XOR keystream. Our analysis reveals structural weaknesses that allow full key recovery without knowledge of the original secret key. Based on these findings, we propose design improvements to address the identified flaws and enhance resistance to known cryptanalytic techniques. The work underscores the importance of incorporating cryptanalysis during the design phase of image encryption algorithms to ensure robust security in real-world applications.