This presentation analyzes the relation between the philosophical notion of privacy, its practical implementation in the domain of cryptocurrencies, and the Western regulatory financial environment. A libertarian (anarcho-capitalist, agorist) perspective is adopted. The ability of governments to extract resources from the economy depends on their ability to surveil it: property that is not seen by authorities cannot be taxed. Privacy-preserving cryptocurrencies such as Monero pose a special danger to the state because they allow buyers and sellers to interact directly without relying on regulated financial institutions, thus bolstering black (free) markets. It comes as no surprise, then, that regulators are cracking down on privacy-centric crypto projects, as shown by the Tornado Cash saga. Oddly enough, the clamp down on Tornado Cash elicited only a mild response in the cryptocurrency ecosystem. For example, the focus of proposals like Privacy Pools is on finding a practical equilibrium between the preservation of privacy and regulatory compliance without challenging the ability of the state to define the rules of the game. In order to understand why this appeasement strategy cannot work, a proper philosophical debate on the nature of privacy needs to be carried out. The main objective of this presentation is to investigate what kind of theoretical notion privacy is. Utilitarianism, privacy as a natural right, and privacy as a Kantian-Misesian a priori condition for the preservation of property rights are analyzed. Firstly, it is shown that utilitarian (relativistic) approaches do not work because they end up outsourcing the definition of privacy to the government; the powerful, not utilitarians, get to define the costs and benefits of privacy and surveillance. Secondly, the theory of privacy as a natural right is interesting because it does not depend on the arbitrary wishes of politicians and bureaucrats, but it is discarded because it is not compatible with libertarian reductionism, which correctly holds that property is the only natural right. Moreover, privacy is more of a fight than a right. Thirdly, the main proposal of this presentation is to understand privacy as a Kantian-Misesian a priori condition for the preservation of property: that privacy is required to safeguard property is an a priori truth that does not depend on empirical circumstances. This proposal is coherent with libertarian reductionism because privacy is not interpreted as a natural right; in parallel, it is superior to utilitarianism because the a priori status of privacy protects it from human arbitrariness. While the origin of a priori notions is not empirical, their use is: privacy cannot but impact how the acting man protects real-world property and interacts with fellow human beings. The Kantian-Misesian approach leads to the rejection of self-defeating appeasement strategies and to the adoption of a much more effective adversarial mindset.