When I meet Marlinspike at WhatsApp headquarters, he is somewhat reticent to explain his motivations, which seems typical of the man—at least in interviews with the press. Online, however, he’s not shy about his views. In the past, he has written that encryption is important because it gives anyone the ability to break the law. But in Mountain View, he is more laconic. “WhatsApp is the most popular messaging app in the world,” says Marlinspike, who is not just a coder and cryptographer but a sailor and a shipwright. “I wanted to get in touch.”