On the substitution method of the AES algorithm
Luminița Scripcariu, Petre-Daniel Mătăsaru · 2013
This paper is focused on the weakness of the Advanced Encryption Standard (AES) provided by the substitution step of the algorithm, which replaces each input data byte with a fix value provided by a static substitution box (S-box) [1]. Efficiently attacks on software programs secured by AES, are concentrated on whitening the S-box, in order to compromise the encryption key and the private information [2]. We propose an algebraic substitution method which dynamically modifies the “S-box”, based on a key sequence and a mathematic function operating on the Galois Field with 8-bit elements. The algorithm will be more robust under cryptographic attacks and the security of the system will be considerably improved.