Abstract

Because the operations of AES are based on two different Galois Fields, GF(2) and GF(28), this brings a lot of difficulties and complexities to the cryptanalysis of AES. Therefore, BES, which stands for Big Encryption System, is introduced. By enlarging the message space and key space, BES can replicate the actions of AES by just using simple operations only on GF (2 8), thereby enabling an easy and equivalent approach to analyze AES. In order to give more practical support to the cryptanalysis of the AES, the BES implementation is strongly encouraged. This thesis discusses the issues related to the BES implementation. Firstly, a detailed exploration of the implementation of BES encryption is addressed. Then the inverse BES cipher is proposed with full respect to the design principles of BES. Finally, a testing analysis of the BES implementation is given.