True digital currencies were more common in science fiction than in reality until quite recently. The big stumbling block for electronic money that doesn't have a physical form is the issue of ownership. How can you truly possess something of intrinsic value that can be effectively copied ad nauseam? In 2008, a paper published under a pseudonym, Satoshi Nakamoto, introduced the world to the digital currency bitcoin , a groundbreaking development in its own right. But more important, however, was the underlying algorithm that made the cryptocurrency work. Distributed ledger technology is the truly revolutionary development that enables cryptocurrencies to function. The technology that anchors bitcoin, known as the blockchain, was the truly revolutionary development.