Secure key-exchange for implantable sensors using inductive coupling

The usage of implantable sensors is imperative in Body Sensor Network. The challenges associated with its security are open research problems. Implantable sensors need a set of secret keys to communicate with other sensors or entities. Secret key generation and subsequent key exchange with other sensors are significant power consuming tasks. Therefore, we propose a method based on pre-distribution of secret keys. The two major drawbacks, higher memory consumption and difficulties in the key refreshment of existing pre-distribution methods have been overcome in this paper. The key generation process has been shifted from implantable sensor to a trusted external device. The external device is paired with the sensor through inductive coupling and is used for powering the sensor and keys transfer. A variant of Diffie-Hellman key agreement with physiological values is used to facilitate secure transfer of keys. Formal security definitions of the proposed method have been presented.