Abstract
The creation of S-boxes and the study of their cryptographic strength is one of the main activities in symmetric cryptography. It is known that one of the most important transformations responsible for the cryptographic strength of a symmetric block encryption algorithm is the S-box replacement table. In this regard, in this paper, we consider a new method for obtaining 4-bit S-boxes based on the exponentiation operation in the Galois field. Currently, there are a large number of methods for checking the cryptographic strength of S-boxes, one of which is the study of a strict avalanche criterion. Therefore, the study of cryptographic strength of the S-box obtained by the new method based of a strict avalanche criterion (SAC) of a Boolean function in comparison with the results of S-boxes of popular algorithms, showed very good results.