FPGA-Based Secured and Efficient Lightweight IoT Edge Devices with Customized RISC-V

In recent years, the IoT edge computing paradigm has been used in various domains such as environmental management, smart office and home, video surveillance, etc. However, most systems rely on processor-based embedded boards like Raspberry Pi or Micro that require high power consumption but lack security. This paper presents our FPGA-based secured and lightweight architecture and implementation for IoT edge devices. The proposed approach is based on the RISC-V architecture with our customization to allow data to be encrypted and decrypted securely with the SHA-256 algorithm. The secured algorithm is designed and then implemented by Verilog as an extension instruction of the RISC-V processor to accelerate encryption performance. Our proposed system is built with Gowin and Xilinx FPGA to compare performance with Micro:bit and Raspberry Pi embedded systems. For testing customized RISC-V processors, the Dhrystone benchmark is used. The experimental results show that our system achieves speed-ups by up to 13.8x compared to Mirco:bit. Although our system requires more execution time than Raspberry Pi 4, it is up to 3.10× energy-efficient than the Raspberry platform. When evaluated with the Dhrystone benchmark, our proposed customized RISC-V processor obtains the value DMIPS/MHz of 1.32, better than ARM Cortex 3 running at 18.5 MHz.