A father of four turned an awkward family lesson into Greenlight. A decade later, Timothy Sheehan is still designing places where children can make small money decisions before adulthood sends the bill.
Adam Back's hashcash sits inside the Bitcoin whitepaper. A decade later, the company he co-founded is trying to build the rails everyone else runs on - sidechains, Lightning nodes, hardware wallets, and a satellite that beams the blockchain to Earth.