If you have read about bitcoin in the press and have some familiarity with academic research in the field of cryptography, you might reasonably come away with the following impression: Several decades' worth of research on digital cash, beginning with David Chaum,10,12 did not lead to commercial success because it required a centralized, bank-like server controlling the system, and no banks wanted to sign on. Along came bitcoin, a radically different proposal for a decentralized cryptocurrency that did not need the banks, and digital cash finally succeeded. Its inventor, the mysterious Satoshi Nakamoto, was an academic outsider, and bitcoin bears no resemblance to earlier academic proposals.

This article challenges that view by showing nearly all of the technical components of bitcoin originated in the academic literature of the 1980s and 1990s (see Figure 1). This is not to diminish Nakamoto's achievement but to point out he stood on the shoulders of giants. Indeed, by tracing the origins of the ideas in bitcoin, we can zero in on Nakamoto's true leap of insight—the specific, complex way in which the underlying components are put together. This helps explain why bitcoin took so long to be invented. Readers already familiar with how bitcoin works may gain a deeper understanding from this historical presentation. (For an introduction, see Bitcoin and Cryptocurrency Technologies) Bitcoin's intellectual history also serves as a case study demonstrating the relationships among academia, outside researchers, and practitioners, and offers lessons on how these groups can benefit from one another.