Editor's Note: Criminals have long benefited from new technologies, and the current era of digitalization has been no exception. In the first two parts of this series on crime and technology we explored how criminals have adopted new technologies to communicate and coordinate activities , as well as establish new marketplaces online . Both have facilitated the expansion of traditional criminal activity, such as drug sales, as well as the emergence of entirely new criminal activities, such as hacker-for-hire services. In the third and final article of this series, we will explore how criminals have adopted new financial instruments to facilitate old and new criminal activities. As with new forms of communications and marketplaces, new financial tools present both opportunities and vulnerabilities to the criminals who adopt them. A cryptocurrency is a financial instrument that exists solely in digital form.