COAu-IoD: A Cloud and Offline Computing-Assisted Authentication Framework for Lightweight UAV Communication in IoD

The Internet of Drones (IoD) enables efficient communications among unmanned aerial vehicles (UAV) via wireless links. Restricted by limited onboard computing resources and complicated operating environments, such a network is vulnerable to external or internal security threats. It is therefore urgent to deploy an effective authentication mechanism to isolate malicious attackers prior to UAV communications. Nevertheless, the conventional identity-based IoD authentication schemes must account for total computation and communication overhead, regardless of the effective instant of authentication messages. In this work, we consider the offline precomputation in the authentication phase before the message is available and add cloud servers as an extra component in IoD to assist limited onboard resources to share partial authentication calculation. As a result, this work proposes a new cloud- and offline-computing-assisted authentication framework, known as COAu-IoD, to provide lightweight communication between a UAV and ground station by transferring heavy computation overhead to the offline phase. We give a security model for this authentication framework and provide an efficient construction based on this framework and a known identity-based signature scheme. What is more, we give its security proof and evaluate its performance using the standard and recent state-of-the-art IoD authentication schemes. The results demonstrate that our COAu-IoD scheme achieves lower online computation and communication overhead for UAVs, at the cost of acceptable offline precomputation overhead.