A novel lightweight authentication protocol for WBAN based on Stern–Brocot tree

Wireless body area network (WBAN) is important in monitoring patients’ physiological data in real time and making prompt communication with medical centers. Given the importance and privacy of medical data and disease symptoms, establishing secure and reliable connection is critical. However, the resource constraints of sensor nodes make it difficult to support computationally intensive security protocols, necessitating a delicate balance between privacy security and resource efficiency. To address this challenge, a lightweight authentication and key agreement protocol SB_Auth is proposed. The protocol designs the sensor node authentication process based on the Stern–Brocot tree, instead of using complex encryption algorithms. Formal security analysis based on BAN logic validates the robustness and security of the protocol, while non-formal security assessment further demonstrates the protocol’s resilience to various attacks and upholds security, privacy, anonymity and forward confidentiality. Compared with other protocols, SB_Auth keeps the least computation and communication cost on the sensor node side.