Tech evangelists have found the solution to everything from our economic woes to a cure for cancer, from an airtight defense from fake news and internet hoaxes to a way to prevent an evil AI from deciding to kill all humans. That solution? The blockchain. But just as Sawbones taught us, cure-alls cure nothing, a technology meant to fix everything is highly unlikely to succeed and the blockchain is no exception. It was invented to disrupt the global financial system, but despite its inability to succeed in this space, its fans are trying to find a problem it can actually tackle. And that prompts the question of what exactly is the blockchain and what can it really do?