When I reached Marco Santori by phone on a recent afternoon, he was walking around Manhattan’s SoHo district, and he sounded tired. “I’m beat,” Santori said, adding that it had been a long week. It was only Tuesday.

But Santori, arguably the best-known lawyer in the world of cryptocurrency, is a busy guy. He travels widely to industry events, and is a constant presence on Twitter. After departing Cooley’s fintech practice group in February, he became president and chief legal officer of the leading digital currency wallet company, simply called Blockchain. It takes its name from the technology that underpins bitcoin and other cryptocurrencies like Ethereum; although founded in 2013, the term “blockchain” became a cultural buzzword only last year.