FPGA Implementation of AES Encryption and Decryption

Advanced Encryption Standard (AES), a Federal Information Processing Standard (FIPS), is an approved cryptographic algorithm that can be used to protect electronic data. The AES can be programmed in software or built with pure hardware. However Field Programmable Gate Arrays (FPGAs) offer a quicker and more customizable solution. This paper presents the AES algorithm with regard to FPGA and the Very High Speed Integrated Circuit Hardware Description language (VHDL). ModelSim SE PLUS 5.7g software is used for simulation and optimization of the synthesizable VHDL code. Synthesizing and implementation (i.e. Translate, Map and Place and Route) of the code is carried out on Xilinx - Project Navigator, ISE 8.2i suite. All the transformations of both Encryption and Decryption are simulated using an iterative design approach in order to minimize the hardware consumption. Xilinx XC3S400 device of Spartan Family is used for hardware evaluation. This paper proposes a method to integrate the AES encrypter and the AES decrypter. This method can make it a very low-complexity architecture, especially in saving the hardware resource in implementing the AES (Inv) Sub Bytes module and (Inv) Mix columns module etc. Most designed modules can be used for both AES encryption and decryption. Besides, the architecture can still deliver a high data rate in both encryption/decryption operations. The proposed architecture is suited for hardware-critical applications, such as smart card, PDA, and mobile phone, etc.