  Several types of networks that comprise unmanned aerial vehicles (UAV or
drone) are being utilized in important applications such as emergency response,
environment and infrastructure monitoring, defense and security, and commerce.
In such networks, swarms of UAVs cooperate in executing one or more missions to
achieve the application's objectives. The UAVs communicate with terrestrial
networks by connecting to fixed or mobile ground control stations (GCS). The
ability of drones to connect to online applications and offer services to
Internet users has led to the proliferation of the Internet of Drones (IoD).
However, IoD applications are highly vulnerable to many types of cyberattacks.
Hence, mechanisms must be deployed to secure the IoD operations and data.
Recently, the blockchain has been proposed as a solution to detect and prevent
malicious attacks on the UAV network (UAVN). Due to the UAV's limited
resources, it becomes a challenge to integrate the blockchain into the IoD. In
this paper, we propose a model that enables a drone to store the important data
that it requires during its flight within a lightweight blockchain system. In
addition, we propose a new blockchain consensus mechanism in which several
miners produce their blocks in parallel, which decreases the time needed to add
transactions securely to the blockchain and meets the requirements of
delay-sensitive applications. Our simulations prove the advantages of the
proposed model in decreasing the transaction-to-blockchain delay, the average
drone energy consumption, and the blockchain block size as compared to other
IoD blockchain systems.
