Alex Stamos, 36
Stamos isn’t known for his restraint: Earlier this year, he publicly challenged Michael S. Rogers, the head of the United States National Security Agency and Cyber Command, at a security conference, for suggesting tech companies provide access to users’ encrypted data. At the time Stamos was Yahoo’s information security chief, and had been leading an email encryption project in partnership with Google—so the dust-up was personal. In June, Stamos jumped ship for Facebook where he now serves as security chief. (Uber had poached his predecessor in the role.) Among other projects, he’s now working out the kinks in the social network’s plan to drone-deliver the Internet to all regions of the globe—securely.