Crypto Mixers, Privacy Tools Gain Legitimacy as Regulators Shift Focus

The growing use of public blockchains has raised concerns about user privacy, particularly with regards to commercial confidentiality and individual protection from targeted attacks.

Crypto mixers, also known as tumblers, pool deposits from many users, shuffle them, and return equivalent amounts to fresh addresses. This breaks the obvious 'who paid whom' link on-chain while preserving the underlying asset.

The U.S. Treasury's Office of Foreign Assets Control (OFAC) had previously sanctioned Tornado Cash, a decentralized Ethereum mixer using zk-SNARKs, citing its alleged use by North Korea's Lazarus Group. However, in 2025, the Fifth Circuit Court of Appeals ruled that immutable smart contracts are not 'property' under the International Emergency Economic Powers Act, leading to OFAC removing Tornado Cash from its sanctions list.

Zero-knowledge proofs are also being used to add privacy to existing chains rather than creating a separate asset. Zcash's shielded transactions and viewing keys allow users to reveal transaction details to an auditor or exchange while keeping the transaction private on-chain.