the telegraph, telephone, radio, and especially the computer have put everyone on the globe within earshot—at the price of our privacy. It may feel like we’re performing an intimate act when, sequestered in our rooms and cubicles, we casually use our cell phones and computers to transmit our thoughts, confidences, business plans, and even our money. But clever eavesdroppers, and sometimes even not-so-clever ones, can hear it all. We think we’re whispering, but we’re really broadcasting.
A potential antidote exists: cryptography, the use of secret codes and ciphers to scramble information so that it’s worthless to anyone but the intended recipients. And it’s through the magic of cryptography that many communications conventions of the real world—such as signatures, contracts, receipts, and even poker games—will find their way to the ubiquitous electronic commons. But as recently as the early 1970s, a deafening silence prevailed over this amazing technology. Governments, particularly that of the United States, managed to stifle open discussion on any aspect of the subject that ventured beyond schoolboy science. Anyone who pursued the fundamental issues about crypto, or, worse, attempted to create new codes or crack old ones, was doomed to a solitary quest that typically led to closed doors, suddenly terminated phone connections, or even subtle warnings to think about something else.
The crypto embargo had a sound rationale: the very essence of cryptography is obscurity, and the exposure that comes from the dimmest ray of sunlight illuminating the working of a government cipher could result in catastrophic damage. An outsider who knew how our encryption worked could make his or her own codes; a foe who learned what codes we could break would shun those codes thereafter.
But what if governments were not the only potential beneficiaries of cryptography? What if the people themselves needed it, to protect their communications and personal data from any and all intruders, including the government itself? Isn’t everybody entitled to privacy? Doesn’t the advent of computer communications mean that everyone should have access to the sophisticated tools that allow the exchange of words with lawyers and lovers, coworkers and customers, physicians and priests with the same confidence granted face-to-face conversations behind closed doors?
This book tells the story of the people who asked those questions and created a revolution in the field that is destined to change all our lives. It is also the story of those who did their best to make the questions go away. The former were nobodies: computer hackers, academics, and policy wonks. The latter were the most powerful people in the world: spies, and generals, and presidents. Guess who won.