Bitcoin became a buzzword overnight. It pops up in headlines and fuels endless media debate. Cryptocurrency and the “blockchain” technology behind it holds the promise of a financial system without middlemen—it could put that system in the control of the people who use it and safeguard them from a 2008-type crash. More than a digital form of currency, this technology could integrate billions of hitherto excluded people into the global economy, restore individuals’ control over their private data and identities, and change the way organizations and business relationships are governed.