If you've ever made a secure purchase with your credit card over the Internet, then you have seen cryptography, or "crypto," in action. From Stephen Levy--the author who made "hackers" a household word--comes this account of a revolution that is already affecting every citizen in the twenty-first century. Crypto tells the inside story of how a group of "crypto rebels"—nerds and visionaries turned freedom fighters—teamed up with corporate interests to beat Big Brother and ensure our privacy on the Internet. Levy's history of one of the most controversial and important topics of the digital age reads like the best futuristic fiction.