A COMPACT MEMORY-FREE ARCHITECTURE FOR THE AES ALGORITHM USING RESOURCE SHARING METHODS

Abstract

This paper presents a resource-shared 8-bit (RS8) architecture for the AES algorithm, which aims at compacting the hardware architecture and allows hardware resources to be shared efficiently between encryption and decryption without using a memory. The RS8 architecture only requires one combined S-box/S-1-box for encryption, decryption and key expansion. The RS8 architecture implements the multiplicative inverse in the composite field GF((24)2) with resource sharing methods. In addition, the number of XOR gates used by the proposed combined MixColumns/InvMixColumns module is less than half that of the conventional 32-bit architecture. When comparing the RS8 architecture with the conventional 32-bit architecture on a Xilinx Spartan2 FPGA, the number of total equivalent slices is reduced by 51%. Additionally, the highest operation frequency of the RS8 architecture is 66 MHz, and the throughput is 24 Mbps. Therefore, the performance of the RS8 architecture is sufficient for low-area applications such as wireless network devices and radio frequency identification (RFID).