We talk about fungibility like it’s a technical property, but it’s actually the foundation of any functional currency. If every coin carries the history of its previous owners, you don’t have money—you have surveillance. The engineering required to make privacy the default, not the exception, is non-trivial. But it’s also the only approach that aligns with how money has always worked before the surveillance state arrived. The cryptography exists. The question is whether we have the conviction to prioritize it. For anyone serious about understanding why privacy can’t be compromised, this vault holds the kind of thinking that predates the noise and gets back to first principles.