An 8-Bit ROM-Free AES Design for Low-Cost Applications

We have presented a memory-less design of the advanced encryption standard (AES) with 8-bit data path for applications of wireless communications. The design uses the minimal 160 clock cycles to process a 128-bit data block. For achieving the requirements of low area cost and high performance, new design methods are used to optimize the MixColumns (MC) and Inverse MixColumns (IMC) and ShiftRows (SR) and Inverse ShiftRows (ISR) transformations. Our methods can efficiently reduce the required clock cycles, critical path delays, and area costs of these transformations compared with previous designs. In chip realization, our design with both encryption and decryption abilities has a 29% area increase but achieves 4.85 times improvement in throughput/area compared with the best 8-bit AES design reported before. For encryption only, our AES occupies 3.5 k gates with the critical delay of 12.5 ns and achieves a throughput of 64 Mbps which is the best design compared with previous encryption-only designs.