Abstract
For decades, the security and privacy of data are among the major challenges faced by service providers dealing with public data. To cope with these challenges, most of the organizations rely on the adoption of cryptographic methods for protecting data against any illegitimate access and attacks. Modern day cryptographic ciphers utilize one or more substitution-boxes (S-boxes) that facilitate the realisation of strong security of plain data during encryption and legal decoding of it during decryption process. Security of ciphers is directly proportional to the cryptographic strength of S-boxes. This study proposes an efficient and simple method based on some modular operations for the construction of dynamic S-boxes with high nonlinearity using a heuristic evolution strategy. A large number of strong S-boxes can be easily constructed using slight variations in the parameters of the anticipated method. A specimen S-box is constructed and its critical performance analysis against standard security criteria including nonlinearity, strict avalanche criterion, bit independence criterion, differential uniformity, linear probability, and fixed points are reported as justification for the proposed technique's high cryptographic strength. Furthermore, the generated S-box is also applied to encrypt digital images to assess its cryptographic application performance. The performance and comparison study validates that the proposed S-box has better performance strength, which makes it a viable candidate for cryptographic applications in different areas of image security.