In body area network

since physiological data transmitted between two wearable sensors are sensitive

its security of privacy has become one of the important standards for the wide application of this technology.A flexible and efficient protocol for identity authentication and key agreement is proposed.received signal strength（RSS） fingerprint signals collected by the on-body sensor in the communication process to initiate authentication

and RSS fingerprint features are combined with bilinear to complete key agreement.On the one hand

the protocol reduces the energy consumption of both communication parties and improves the security of data transmission; on the other hand

it can flexibly add sensors without pre-distributed keys.