Anonymous. WikiLeaks. The Syrian Electronic Army. Edward Snowden. Bitcoin. The Arab Spring. Five years ago, these terms were meaningless to the vast majority of people in the world. Today, they and many like them dominate the news and keep policymakers, security experts, and military and intelligence officials up at night. These groups and individuals are enabled and empowered by digital technology to confound and provoke the state in a way not possible before the Internet revolution. They are representative of a wide range of 21st century global actors and a new form of 21st century power: disruptive power.