Lightweight and Low-Latency AES Accelerator Using Shared SRAM

Abstract

In this study, we propose a lightweight and low-latency advanced encryption standard (AES) accelerator. Instead of being connected to the bus through its own slave wrapper, the proposed AES accelerator is located within the slave wrapper of the static random-access memory (SRAM) and is directly attached to the SRAM. Hence, the AES accelerator can directly access data in the SRAM and share SRAM space for storing expanded keys, resulting in no time for transferring input and output data, no resource usage for storing keys, and no power wastage for repeated key expansion. The proposed AES accelerator has a latency of 53 clock cycles per encryption/decryption process and has a gate count of 2912 when synthesized using 28 nm process technology. The latency is similar to that of another AES accelerator with the same 32-bit data path; however, the size of the proposed accelerator is 46.0% smaller. Furthermore, compared with other AES accelerators with 8-bit data path, the proposed AES accelerator has a 3.0–22.0 times smaller latency with a slightly larger area.