High-security image encryption using Bülban chaotic map and dynamic S-boxes

In this paper, we present a novel chaos-based image encryption scheme that generates dynamic S-boxes based on the Bülban chaotic map. A symmetric encryption procedure is performed through the use of dynamically generated S-boxes, scrambling through the Fisher-Yates algorithm, and diffusion through XOR operations based on a pseudo-random sequence derived from the chaos key. The SHA-512 hash is used to generate key, ensuring sensitivity to changes in input images. The scheme shows strong resistance against statistical, differential, and occlusion attacks, with a uniform histogram and low correlation co-efficient, vast key space exceeding 2512 making brute-force attacks extremely difficult. The effectiveness of the system is validated by security analyses such as entropy, NPCR, UACI, and PSNR, as well as its resistance to noise, occlusion, known plaintext, and cipher-text only attacks.