Two-Stage High-Efficiency Encryption Key Update Scheme for LoRaWAN Based IoT Environment

Secure data communication is an essential requirement for an Internet of Things (IoT) system. Especially in Industrial Internet of Things (IIoT) and Internet of Medical Things (IoMT) systems, when important data are hacked, it may induce property loss or life hazard. Even though many IoT-related communication protocols are equipped with secure policies, they still have some security weaknesses in their IoT systems. LoRaWAN is one of the low power wide-area network protocols, and it adopts Advanced Encryption Standard (AES) to provide message integrity and confidentiality. However, LoRaWAN's encryption key update scheme can be further improved. In this paper, a Two-stage High-efficiency LoRaWAN encryption key Update Scheme (THUS for short) is proposed to update LoRaWAN's root keys and session keys in a secure and efficient way. The THUS consists of two stages, i.e., the Root Key Update (RKU) stage and the Session Key Update (SKU) stage, and with different update frequencies, the RKU and SKU provide higher security level than the normal LoRaWAN specification does. A modified AES encryption/decryption process is also utilized in the THUS for enhancing the security of the THUS. The security analyses demonstrate that the THUS not only protects important parameter during key update stages, but also satisfies confidentiality, integrity, and mutual authentication. Moreover, The THUS can further resist replay and eavesdropping attacks.