Edinburgh Napier University

  Securing digital image data is a key concern in today’s information-driven society. Effective encryption techniques are required to protect sensitive image data, with the Substitution-box (S-box) often playing a pivotal role in many symmetric encryption systems. This study introduces an innovative approach to creating S-boxes for encryption algorithms. The proposed S-boxes are tested for validity and non-linearity by incorporating them into an image encryption scheme. The nonlinearity measure of the proposed S-boxes is 112. These qualities significantly enhance its resistance to common cryptographic attacks, ensuring high image data security. Furthermore, to assess the robustness of the S-boxes, an encryption system has also been proposed and the proposed S-boxes have been integrated into the designed encryption system. To validate the eectiveness of the proposed encryption system, a comprehensive security analysis including brute force attack and histogram analysis has been performed. In addition, to determine the level of security during the transmission and storage of digital content, the encryption system’s Number of Pixel Change Rate (NPCR), and Unified Averaged Changed Intensity (UACI) are calculated. The results indicate a 99.71% NPCR and 33.51% UACI. These results demonstrate that the proposed S-boxes offer a significant level of security for digital content throughout its transmission and storage.