Once they had logged where and when the spoofing incidents occurred, researchers cross-referenced this information with the travel schedule of the Russian President, Vladimir Putin. On a fall afternoon in 2017, six minutes before Putin gave a speech in the coastal town of Bolshoy Kamen, a nearby ship’s G.P.S. coordinates showed it jumping to the airport in Vladivostok. In 2018, when Putin attended the official opening of a bridge across the Kerch Strait, at least twenty-four ships in the area reported their location as Anapa Airport, sixty-five kilometres away. What was going on? It seemed increasingly likely that the President’s security detail was travelling with a portable software-defined spoofer, in the hope of protecting Putin from drone attacks.