High throughput and area-efficient FPGA implementation of AES for high-traffic applications

Abstract

This study presents a high throughput field-programmable gate array (FPGA) implementation of advanced encryption standard-128 (AES-128). AES is a well-known symmetric key encryption algorithm with high security against different attacks that are widely used in different applications. The main goal of this study is to design a high throughput and FPGA efficiency (FPGA-Eff) cryptosystem for high-traffic applications. To achieve high throughput, loop-unrolling, inner and outer pipelining techniques are employed. In AES, substitution bytes (Sub-Bytes) is one of the costly functions that occupy a large number of resources and has a large delay. To reduce the area of Sub-Bytes, new-affine-transformation, which is the combination of inverse isomorphic and affine transformation, is proposed and employed. Besides that, AES has been modified according to the proposed architecture. For the first nine rounds, Shift-Rows and Sub-Bytes have been exchanged, and Shift-Rows is merged with Add-Round-Key. To make an equal latency between stages, Mix-Columns is divided into two different stages. AES is implemented in counter mode on Xilinx Virtex-5 using VHDL. The proposed implementation achieves a throughput of 79.7 Gbps, FPGA-Eff of 13.3 Mbps/slice, and frequency of 622.4 MHz. Compared to the state-of-the-art work, the proposed design has improved data throughput by 8.02% and FPGA-Eff by 22.63%.