Prologue 0: If

I remember the moment code began to seem interesting to me. It was the tail end of 2013, and in the excitable tech quarters of New York, London and San Francisco, a cult was forming around an obscure “cryptocurrency” called Bitcoin. We know the story well by now. The system’s pseudonymous creator, Satoshi Nakamoto, had appeared out of nowhere, dropped his ingenious plan for near-untraceable, decentralized money into the web, and then vanished, leaving only a handful of writings and 100,000 lines of computer code behind. Who would do such a thing? And why? Like a lot of mesmerized onlookers, I decided to investigate.

There didn’t seem much to go on, until a chance encounter in a coffee line at a Bitcoin meetup in the East End of London opened me to something new. The man I met was a Finnish programmer. He told me that while Satoshi had taken pains to cover his tracks, there were clues in his code if you knew how to see them. There were also antecedents: the Bitcoin mechanism was a work of genius, but its creator built on the groundwork of others, some of whom he had contacted during development. My adviser pointed me to an Englishman named Adam Back, one of a loose group of cryptographer hacktivists who came to prominence in the 1990s as self-styled “cypherpunks.” I set off on the cryptographer’s trail.

The cypherpunk agenda, when it appeared toward the end of the eighties, was at once simple and complex. Humanity’s impending lurch online would be an epochal gift to anyone with a political or economic incentive to surveil, the rebel cryptographers warned. We stood at a fork in the technological road, with the broadest path pointing to an Orwellian future of industrial scale intrusion and forfeiture of privacy, in which no facet of our lives was too intimate to be colonized by anyone with the right programming skills. To repel the bad actors massing to swarm cyberspace, citizens would need tools in the form of cryptographic software. Cypherpunks aimed to supply these tools.

Essential to online privacy would be a payment system that mimicked the anonymity of cash by making transactions hard to trace. Feverish effort went into designing such a system, but the task was daunting. Code derives its power from being digital, at rootnumeric and therefore exactly and infinitely reproduceable. How would you make digital money that could be transferred at will but not copied; whose electronic movements were registered on a ledger but without recourse to a corruptible central authority? By the end of the 1990s most Cypherpunks had abandoned the quest as Sisyphean, even if some bright ideas were floated along the way. And the travails were not wasted. Eleven years after Adam Back described a cryptographic spam-filtering algorithm called “hashcash” in 1997, it would star in Satoshi’s dazzling system. Now I learned that Back had been contacted by the Bitcoin inventor—anonymous