Inside North Korea's Hacker Army

North Korea’s hacking prowess is almost as feared globally as its nuclear arsenal. Last May the country was responsible for an internet scourge called WannaCry, which for a few days infected and encrypted computers around the world, demanding that organizations pay ransom in Bitcoin to unlock their data. A few years before that, North Korea stole and published the private correspondence of executives at Sony Pictures Entertainment, which had produced a Seth Rogen satire of the country called The Interview.