Affine Equivalence in S-boxes

Nowadays, Linear redundancy has been identified in all S- boxes generated from finite field inversion and power mappings. That means it may be used in a new cryptanalytic attack in the future. In our study, we have developed an application to show that all output functions of an S-box are equivalent under an affine transformation of the input bits. To realize this application, we have used 4-bit input and 4-bit output S-box which has similar design technique with AES S- box. This application shows that S-boxes generated with the same tecnique of AES S-box has a vulnerability.