A Fault-Tolerant and Secure Architecture for Key Management in LoRaWAN Based on Permissioned Blockchain

Low-Power Wide-Area Network (LPWAN) is a new type of wireless technology that offers long range communication for devices in the Internet of Things (IoT) and LoRaWAN is one of the main technologies currently available to enable LPWAN environments. In the LoRaWAN architecture, the Join Server is a key component and is responsible for security tasks, such as authentication and key management. However, the Join Server acts as a Single Point of Failure (SPOF) since all encryption keys are stored centrally. Then, this paper presents a secure and fault-tolerant architecture to increase the levels of security and availability in LoRaWAN. A permissioned blockchain and smart contracts are used to replace the Join Server and solve the SPOF problem. A working prototype was created using open-source tools in order to evaluate the feasibility of the proposed architecture. Additionally, the performance of a blockchain network was analyzed in a cloud environment under multiple workloads and fault-tolerance experiments were performed to evaluate the impact of network failures. The results show a trade-off between availability and performance when choosing the number of blockchain peers in small scenarios. However, this behavior is reversed in large scenarios where the performance of multiple peers is best suited.