Compact and efficient encryption/decryption module for FPGA implementation of the AES Rijndael very well suited for small embedded applications

Abstract

Hardware implementations of the advanced encryption standard (AES) Rijndael algorithm have recently been the object of an intensive evaluation. Several papers describe efficient architectures for ASICs and FPGAs. In this context, the highest effort was devoted to high throughput (up to 20 Gbps) encryption-only designs, fewer works studied low area encryption-only architectures and only a few papers have investigated low area encryption/decryption structures. However, in practice, only a few applications need throughput up to 20 Gbps while flexible and low cost encryption/decryption solutions are needed to protect sensible data, especially for embedded hardware applications. We purpose an efficient solution to combine Rijndael encryption and decryption in one FPGA design, with a strong focus on low area constraints. The proposed design fits into the smallest Xilinx FPGAs, deals with data streams of 208 Mbps, uses 163 slices and 3 RAM blocks and improves by 68% the best-known similar designs in terms of ratio Throughput/Area. We also propose implementations in other FPGA Families (Xilinx Virtex-II) and comparisons with similar DES, triple-DES and AES implementations.