It is one of the great mysteries of the digital age.

The hunt for Satoshi Nakamoto, the elusive creator of Bitcoin, has captivated even those who think the virtual currency is some sort of online Ponzi scheme. A legend has emerged from a jumble of facts: Someone using the name Satoshi Nakamoto released the software for Bitcoin in early 2009 and communicated with the nascent currency’s users via email — but never by phone or in person. Then, in 2011, just as the technology began to attract wider attention, the emails stopped. Suddenly, Satoshi was gone, but the stories grew larger.

Over the last year, as I worked on a book about the history of Bitcoin, it was hard to avoid being drawn in by the almost mystical riddle of Satoshi Nakamoto’s identity. Just as I began my research, Newsweek made a splash with a cover article in March 2014 claiming that Satoshi was an unemployed engineer in his 60s who lived in suburban Los Angeles. Within a day of publication, however, most people knowledgeable about Bitcoin had concluded that the magazine had the wrong man.

Many in the Bitcoin community told me that, in deference to the Bitcoin creator’s clear desire for privacy, they didn’t want to see the wizard unmasked. But even among those who said this, few could resist debating the clues the founder left behind. As I had these conversations with the programmers and entrepreneurs who are most deeply involved in Bitcoin, I encountered a quiet but widely held belief that much of the most convincing evidence pointed to a reclusive American man of Hungarian descent named Nick Szabo.

Mr. Szabo is nearly as much of a mystery as Satoshi. But in the course of my reporting I kept turning up new hints that drew me further into the chase, and I even stumbled into a rare encounter with Mr. Szabo at a private gathering of top Bitcoin programmers and entrepreneurs.