This chapter highlights the primary legal concerns that apply to all jurisdictions grappling with cryptocurrencies, specifically those concerns which pertain to various types of criminality, including hacks and thefts, frauds and scams, money laundering and tax evasion, and terrorist financing and rogue actors. It considers the differing legal treatments of cryptocurrencies along a spectrum (most-to-least tolerant) and assign various jurisdictions along that spectrum accordingly. The chapter discusses international efforts to harmonize cryptocurrency regulation and oversight and offers some prognostications about the future of cryptocurrency legality. Money laundering is a very serious and systemic concern regarding cryptocurrency, as it can be easily used to engage in transactions that would sidestep the traditional financial system with comparative ease. For this reason, it is frequently described as “a convenient tool for money laundering”. Countries have responded to the emergence of cryptocurrency in a variety of ways, from extreme positivity to outright hostility.