privacy that regulators can verify (paper 2023 — Buterin, Soleimani et al.; live on Ethereum 2025 via 0xbow; Railgun's proofs of innocence are the same class). a depositor proves in zero knowledge that their withdrawal dissociates from a chosen set of tainted deposits — "my coin is provably outside the bad set" — without revealing which clean deposit is theirs. the association set makes lawfulness a statement you prove, identity stays yours
the lesson: compliance by dissociation. after the tornado cash wars, this is the bridge — regulation satisfied by proof rather than by surveillance, the anonymity set intact for everyone honest. selective disclosure applied at the level of jurisdictions: prove the property, keep the number