Key Agreement between User and Drone with Forward Unlinkability in Internet of Drones

Many applications are equipped to utilize drones to provide various services to users in Internet of Drones (IoD) environments. In such applications, it is necessary to make a session key between a drone and a user to establish an authenticated and secure channel. It is also desirable to provide strong anonymity to increase user(drone) privacy. To provide robust anonymity, a protocol has to provide both pseudonymity and unlinkability. If a protocol provides only pseudonymity without unlinkability, user(drone) privacy could be breached by analyzing communication frequency or user(drone) movement. On the other hand, we consider drone capture attacks in the IoD, because if a drone is captured, the secret information of the drone could be revealed. To minimize the damage against the capturing attacks, a key exchange should provide the forward unlinkability as well as forward secrecy. Forward unlinkability means that even though the secret information of the drone is revealed, the unlinkability is guaranteed. In the paper, we suggest the first key agreement protocols providing both pseudonymity and forward unlinkability, whereas previous key agreement protocols provide only pseudonymity and unlinkability.