Flexible Authentication Protocol with Key Reconstruction in WBAN Environments

Wireless body area network (WBAN) plays an important part in mobile healthcare. WBAN can be imagined as a small wireless local area network around our body. In WBAN, there exist three roles: sensors, gateway, and healthcare center. However, the communication distance between sensors and gateway is only 1-2 meters. If the gateway is lost or leaves the range of WBAN consisting of the sensors, the sensed data will not be aggregated and forwarded. Furthermore, the original gateway holds the long-term key shared with the healthcare center, but the user's devices which may serve as the backup gateway do not hold the long-term key. In order to deal with the problems, we propose a key reconstruction protocol for WBAN. In the proposed protocol, the original gateway enables the backup gateway to reconstruct a temporary token, and the backup gateway will use the temporary token to establish a secure channel with the healthcare center without using the long-term key of the original gateway.