Blockchains — particularly the cryptocurrencies they enable — rank among the most-hyped technologies of the 21st century, but their potential uses range far beyond crypto. Blockchains provide a means of securely recording data that ensures confidentiality, integrity and availability. These are essential characteristics of a modern, secure system that can provide immense value to the Department of Defense (DOD). This paper cuts through the hype around blockchains and looks at them as a foundational technology that may affect how DOD operates now and in the future.