Enhance security of advance encryption standard algorithm based on key-dependent S-box

Abstract

Cryptographic algorithms uniquely define the mathematical steps required to encrypt and decrypt messages in a cryptographic system. Shortly, they protect data from unauthorized access. The process of encryption is a crucial technique to ensure the protection of important electronic information and allows two parties to communicate and prevent unauthorized parties from accessing the information simultaneously. The process of encrypting information is required to be dynamic in nature to ensure protection from novel and advanced techniques used by cryptanalysts. The substitution box (S-box) is a key fundamental of contemporary symmetric cryptosystems as it provides nonlinearity to cryptosystems and enhances the security of their cryptography. This paper discusses the enhancement of the AES algorithm and describes the process, which involves the generation of dynamic S-boxes for Advance Encryption Standard (AES). The generated S-boxes are more dynamic and key-dependent which make the differential and linear cryptanalysis more difficult. NIST randomness tests and correlation coefficient were conducted on the proposed dynamic AES algorithm, their results showing that it is superior to the original AES with security verified.