The year I stepped into the closet of Snowden’s classified secrets, the zero-day market had become a full-fledged gold rush. But there was little incentive to regulate a market in which the United States government was still its biggest customer. That year, having ironically spawned the zero-day market and launched the world into the era of cyberwar, Keith Alexander, Stuxnet’s architect, was asked what kept him up at night. “My greatest worry,” Alexander told a reporter, was the growing likelihood of zero-day exploits falling into the wrong hands.
