AESware: Developing AES-enabled low-power multicore processors leveraging open RISC-V cores with a shared lightweight AES accelerator

Abstract

As open-source RISC-V cores continue to be released, the development of low-power multicore processors utilizing these cores is invigorating the edge/IoT device market. Nevertheless, comprehensive research on developing low-power multicore processors with integrated security features using existing open RISC-V cores remains limited. This study addresses this gap by introducing AESware, a dedicated lightweight hardware designed for energy-efficient AES (Advanced Encryption Standard) task execution, contributing to the development of AES-specific low-power RISC-V multicore processors. AESware supports variable key lengths and ensures minimal power consumption with a compact design. This standalone IP (Intellectual Property) is compatible with various open RISC-V cores, offering scalability and convenience. And importantly, we propose the most energy-efficient architecture for multicore processors equipped with AESware. Instead of assigning dedicated AESware to each core, we introduce a shared AESware architecture to maximize energy efficiency. We develop an operational algorithm for task scheduling in AESware, achieving maximum utilization and minimal latency while maintaining its lightweight nature. To evaluate our solution, we developed 24 processors into three groups: AESware-equipped, baseline, and those with an external AES accelerator per core. After FPGA (Field-Programmable Gate Array) prototyping for functional verification and power consumption analysis via 45 nm process technology synthesis, our findings revealed significant energy savings. AESware-equipped processors achieved up to 76%, 47%, and 33% energy savings at dual-, quad-, and octa-core configurations compared to baseline, respectively, and were more energy-efficient in running AES applications than those with individual accelerators.

Keywords

• Edge device
• AES
• RISC-V
• Embedded processor
• Multi-core processor architecture
• FPGA prototyping