Edward Frenkel, professor of mathematics at the University of California-Berkely, and Australian video journalist Brady Haran discuss exactly how the NSA hacked into our e-mails and social media, creating a worldwide surveillance scandal for the Obama Administration. Although the conversation gets a bit esoteric at times, Frenkel explains how the feds used modular, or clock, arithmetic, and equations with two variables to get their info in this edition of Numberphile.