Nicholas Allegra lives with his parents in Chappaqua, New York. The tall, shaggy-haired and bespectacled 19-year old has been on leave from Brown University since last winter, looking for an internship. And in the meantime, he’s been spending his days on a hobby that periodically sends shockwaves through the computer security world: seeking out cracks in the source code of Apple’s iPhone, a device with more software restrictions than practically any computer on the market, and exploiting them to utterly obliterate its defenses against hackers.