Background/Objectives: Drones were originally developed for military use, and as their technology evolves, they can be said to be the new industrial sector of the 4th Industrial Revolution, which has unlimited possibilities. Methods/Statistical analysis: The first was a hot air balloon, which was actually used in the Battle of Austria in 1849 and subsequently as an important combat weapon in World Wars I and II. On the top of that, drone is unmanned, remote-controlled flight systems. Findings: It's widely used as an entertainment tool, but actually it's not only used for military purposes such as reconnaissance and surveillance, but also for transportation like Amazon Prime Air. Drones are vulnerable to hacking like GPS spoofing, control extortion, and jamming because they're wirelessly controlled. There are these various anti-drones technologies and there are grave risks to drone security. Improvements/Applications: Therefore, it is necessary to protect privacy from unwanted drone to use anti-drones technology.