An efficient single unit T-box/T-1-box implementation for 128-bit AES on FPGA

In this paper, we present an area efficient Block RAM BRAM-based single unit design of T-box/T-1-box on a Field Programmable Gate Array FPGA for combined Advanced Encryption Standard AES encryption and decryption. Conventional FPGA designs for T-box module not only utilize several BRAMs for 16bytes parallel look-up operations but also because of asymmetric nature of AES, use separate hardware for T-1-box unit in decryption process. Alternatively in iterative architecture, BRAM in dual-port mode configuration takes eight clock cycles to access 16 look-up operations from a T-box because of its synchronous nature. Thus, resulting in an unoptimized solution not only in term of FPGA resources but also results in high latency for iterative architecture. Our proposed design uses single symmetric T-box/T-1-box table with same set of single resource-shared hardware for both the encryptor and decryptor and at the same time performs eight look-up operations from single BRAM in one clock cycle using efficient BRAM switching technique instead of using multirated clocking. Our complete 128-bit symmetric T-box/T-1-box design fits into just 2 BRAMs and 136 Slices. It occupies lowest area reported to date with 50% power saving and highest Throughput Per Slice TPS of 10.77. Copyright © 2014 John Wiley & Sons, Ltd.