Enhancing the robustness of block ciphers through a graphical S-box evolution scheme for secure multimedia applications

Block ciphers are essential for the secure exchange of data and communication, as they are one of the primary components of network security systems. Modern-day block ciphers are most significantly reliant on substitution-boxes (S-boxes). In essence, the security of these cryptosystems is contingent upon the quality of the S-box that is implemented. Robustness and assurance of the security competency necessary to block ciphers are provided by the cryptographically strong S-boxes. A novel coset graph-based algebraic method was proposed to evolve a robust and efficient S-box in order to address the challenges of strong S-box generation. To begin, the vertices of coset graphs for two Galois fields and a bijective function were employed to generate an initial S-box of sufficient cryptographic strength. Afterwards, a permutation group of large order enhances the robustness of the initial S-box, ensuring its resistance against various cryptanalytic attacks. The proposed method's efficacy was verified by comparing the attributes of our S-box with those of S-boxes that have been recently investigated. Furthermore, the proposed S-box was used for image encryption. The outcome of the majority logic criterion (MLC) criteria, differential analysis, and histogram test demonstrates the suitability of the proposed S-box for secure multimedia applications in the results.