It’s been more than 15 years since the digital currency bitcoin was launched, going from a fringe phenomenon in the dark corners of the internet to an asset traded on Wall Street. But the identity of bitcoin’s creator, known by the pseudonym Satoshi Nakamoto, has remained a mystery wrapped in a cryptographic enigma. Now, investigative filmmaker Cullen Hoback may have cracked the case. His last HBO series “Into the Storm” uncovered the origins of the QAnon conspiracy theory. In his new documentary, “Money Electric: The Bitcoin Mystery,” Hoback sets out to answer the elusive question: Who is Satoshi Nakamoto? To prevent any spoilers, we’ll keep his conclusions secret.