Tornado Cash Sanctioned (OFAC)
Overview
Tornado Cash is a non-custodial crypto mixer: a decentralized mixing protocol built on Ethereum using zero-knowledge proofs (zk-SNARKs). Users deposit fixed denominations into a smart contract pool and later withdraw to a different address with no on-chain link between deposit and withdrawal. The protocol was sanctioned by OFAC in August 2022, and developer Roman Storm faces criminal charges. Despite sanctions, the smart contracts remain functional on Ethereum as they are immutable.
Fee Structure
Protocol fee: none. Relayer fee: typically 0.1–0.3% for gas abstraction
The service processes transactions with a configurable delay of User-controlled (withdraw anytime), allowing users to balance speed against anonymity depth. Deposits must fall between the minimum of Fixed denominations: 0.1, 1, 10, 100 ETH and the maximum of 100 ETH per deposit.
Privacy Technology
Tornado Cash uses Non-custodial smart contract (zk-SNARK) to break the link between input and output addresses. The service supports splitting outputs across 1 (per withdrawal) with independent time delays, adding another layer of obfuscation to mixed transactions.
Pros & Cons
✓ Pros
- Fully non-custodial — funds controlled by smart contract
- Zero-knowledge proof technology
- No registration or KYC
- Immutable smart contracts still functional
- Multi-chain support (ETH, BNB, Polygon)
- Very low fees
✗ Cons
- OFAC sanctioned — legal risks for US persons
- Fixed denominations only
- Developer prosecution ongoing
- Relayer availability reduced
- Front-end interfaces frequently taken down
Our Verdict
Tornado Cash represents the gold standard in non-custodial mixing technology. Its zk-SNARK architecture eliminates the trust requirement entirely. However, the OFAC sanctions create significant legal risk — users must carefully evaluate their jurisdictional exposure before interacting with the protocol.
