European Union Agency for Cybersecurity (ENISA) published a report: “Crypto Assets: Introduction to Digital Currencies and Distributed Ledger Technologies”. This report aims to increase the understanding of blockchain technologies. It aims to explain the underlying technical concepts and how they relate to each other. The goal is to explain the components and illustrate their use by pointing to deployed instances where the ideas are utilised. With this first introductory study focusing on the rise of cryptocurrencies & DLT, the European Union Agency for Cybersecurity is launching a series of information security studies in the area of crypto-assets to support policy-makers and raise awareness on the arising security and data protection.