Algorithm of G-AES

The Advanced Encryption Standard(AES) was specified in 2001 by the National Institute of Standards and Technology(NIST) and was published in Federal Information Processing Standards(FIPS) publication FIPS-PUB197 as the standard on May 26, 2002. Now AES will largely replace triple-DES for government use, and will likely become widely adopted for a variety of encryption needs. The AES algorithm has a fixed block size of 128 bits, and variable length of keys of 128, 192 and 256 bits. This paper is focused on the way to generalize the fixed block size from 128 bits to 256 bits and makes it possible to realize a new AES-like algorithm that has 256 bits fixed block size, which is named G-AES algorithm. The G-AES algorithm generalizes the fixed block size to improve the robustness and safety of the algorithm. However, it will also increase the complexity of hardware implementation. Traditionally the AES algorithm was implemented by look up tables(LUT) which store all 256 bit predefined values of S-box in a ROM. The advantage of using LUT is that it offers a shorter critical path. However, it requires a large area to implement AES encryption and decryption progress due to different tables used for different processes. And look up table is also very difficult to use for hardware realization of G-AES algorithm because it will require 65536 bytes as storage and it will also require 160 copies of the allocation of hardware resources. In this paper, the cryptographic properties of AES S-box are analyzed. Based on Galois Field, this paper makes it possible to realize the G-AES algorithm in hardware and get the conclusion that the G-AES algorithm is in the same order of magnitude with AES algorithm. Thus it can be easily used in industry in hardware implementation. The security is also discussed in the paper. We get the conclusion that the G-AES algorithm provides more safety than AES algorithm.