After spending a year in prison, Bitcoin pioneer Charlie Shrem has a new job and a new mission: Strengthening the ecosystem of blockchain assets—and, just maybe, helping build the future of the Internet. “My word is gold,” says Charlie Shrem, glass of absinthe in hand, light winking off a pinkie ring he wears that is embossed with a Bitcoin symbol. “And I make sure everyone gets paid.” Bitcoin’s first felon is in his favorite mode: full-on bluster. We’re in Sarasota, where he lives, perched...