REALISE-IoT: RISC-V-Based Efficient and Lightweight Public-Key System for IoT Applications

LoRa is a promising choice for deploying an IoT network due to its lightweight feature and the extensive support by LoRa Alliance. However, as a fundamental part of LoRa, the typical LoRaWAN protocol confronts severe security challenges because it insecurely utilizes AES-128 to support the low-cost feature. In this article, we propose a systematic solution that is compatible with LoRaWAN for IoT applications. We extend the standard LoRaWAN protocol with public-key infrastructures. Public-key features like key exchange and authentication are supported by lightweight hardware implementations of SHA-2, ECDH, EdDSA, and TRNG. A lightweight RISC-V processor with a security coprocessor is implemented and verified using FPGA technology. The security protocol and the prototype hardware system are validated and evaluated on practical applications from our industrial partner. The prototyped development board consumes a static power of 0.116 W and a dynamic power of 0.206 W. The proposed system can achieve a 5.6x - 144.7x speed up and reduce memory usage by 2.4x - 12.3x for security computations.