Implementation and Analysis of Sensor Security Protocols in a Home Health Care System

A wireless sensor network can be used in a home health care system to monitor the elderly or patients with chronic diseases. The quality of security of the home health care system is an important requirement. If the security services or servers malfunction then the system itself may become compromised. We show that with multi--server protocols, even if one or more servers become unavailable or untrustworthy, it may still be possible for the sensor nodes to establish a good session key. We compare and contrast different multi--server protocols. We also show which protocols are more suited for our system. The protocols were implemented in TinyOS and run on mica2 motes. The time elapsed, complexity of the code, and memory requirements are analysed in detail. We show that a symmetric key implementation has advantages over an asymmetric implementation.