The growth of crypto assets-related transactions is not short of phenomenal. One of the concerns of governments is their potential impact on financial and economic stability arising from illicit financial flows and reduced visibility of tax administration over crypto transactions. The United Nations Tax Committee is developing a toolkit for jurisdictions to be able to evaluate crypto asset risks. The chapter seeks to contribute to the development of this toolkit by analysing the challenges posed by the decentralized nature of crypto assets as well as the use of cryptocurrency as a medium of exchange. A survey is suggested that could be employed by governments to evaluate those challenges. The adoption of blockchain technology is continuously evolving, resulting in the formation of Decentralized Autonomous Organizations (DAOs) and Decentralized Finance (DeFi). The chapter discusses their features at length and suggests another survey to evaluate their risks as well as measures which tax administrations may consider to tackle the tax challenges arising from crypto assets, DAOs and DeFi.