A hybrid approach of substitution and permutation techniques for modern image-cryptosystem

Abstract In this paper, we implemented an image encryption algorithm using a hybrid approach that combines substitution and permutation techniques. The hybrid approach starts by creating the initial S-Box from the irreducible polynomial over the Galois field, followed by the permutation operation to obtain the final S-Box; this is the first step of the encryption process. Subsequently, we conducted numerous analyses on the S-Box, examining its bijectivity, non-linearity, strict avalanche criteria, differential analysis, and fixed points to evaluate its performance. Our findings were commendable when compared to existing literature. Next, we utilized our unique chaotic map and cellular automata, which are both effective pseudo random number generators for cryptographic properties, in conjunction with S-Box to enhance the security and complexity of the encryption algorithm. Finally, we subject our encryption algorithm to various security analyses and compare its performance with existing literature. The results indicate that the proposed algorithm performs well in terms of security and complexity, and its low computational resource makes it suitable for real-time cryptographic applications. This contribution will be an added advantage in the development of image encryption standards.