Security Analysis and Improvement of Key Exchange Protocol in LoRaWAN Network

While using very low-power and inexpensive transmitters, LoRaWAN networks exhibit very high sensitivity and excellent reliability over very long ranges. Although these networks benefit from higher security performance compared to other low-power wide-area communication protocols, some aspects of their security can be greatly improved. Namely, the key exchange protocol was considered as one of the weakest links in the security of LoRaWAN networks. This issue was addressed at the second edition of the LoRaWAN protocol. However, the improvement was achieved at the cost of using much more complicated algorithms. Even then, some of the security issues of the protocol such as vulnerability against node capture attack and forward secrecy remained the same. In this paper, we demonstrate the limitations of new LoRaWAN key exchange protocols using Scyther and ProVerif security analysis tools. Then we propose a novel scheme that while requiring much less complex computations, offers a more robust security for LoRaWAN networks. We use the aforementioned tools to verify that the proposed method considerably improves the resilience of LoRaWAN against known attacks.