Glossary
Tornado Cash
An Ethereum privacy mixer using zero-knowledge proofs to break the on-chain link between deposit and withdrawal. Sanctioned by OFAC in August 2022.
Tornado Cash is a fixed-denomination Ethereum mixer: users deposit a denominated amount (0.1, 1, 10, 100 ETH) into a pool, and later withdraw it to a fresh address by submitting a zero-knowledge proof that they made one of the prior deposits — without revealing which.
In August 2022 the US OFAC sanctioned the protocol's smart-contract addresses, the first time a sanctions designation targeted code rather than people or entities. The case is still being litigated and is the canonical reference for the ongoing privacy-vs-compliance debate in crypto.