The use of Unmanned Aerial Vehicles (UAVs) or drones has been increased drastically not only in military but also in logistics, precision agriculture and media production. Similarly, their ubiquity also made them be targeted by more cyberattacks, therefore solid security is a must to ensure safe and reliable operation. In this paper, drone security services, issues and solutions are presented. Based on an initial analysis of the drone system's architecture, we pinpoint critical vulnerabilities. Next, we discuss a few common types of cyberattacks and relevant countermeasures. These protocols are motivated by the point of views of different solution from traditional lightweight authentication protocols for IOT devices to more sophisticated protocols utilizing Elliptic Curve Cryptography (ECC) or Blockchain-based trust management scheme, as well as an adaptive protocol employing game theory and machine learning techniques. Our findings suggest an intrinsic tradeoff: enhancing security is generally associated with degraded performance/increased computation overhead/energy consumption, and thus a mission-specific, layered security solution, instead of a generic one-fits-all solution, is to be recommended for the most efficient use of resources. In the paper, we have highlighted what are, in our opinion, urgent problems to be addressed in the future such as defending drone swarms, responding to AI-enabled attacks, integrating post-quantum cryptography, and introducing hardware-level security.