# Tornado Cash

> Source: https://fuckyc.org/services/tornado-cash/
> Website: https://tornado.cash/
> Categories: Mixers & coinjoin
> KYC: none — Ethereum-side privacy protocol — zero-knowledge mixer. No accounts; the contracts are immutable. Sanctioned by the U.S. Treasury OFAC in August 2022; that sanction has had complex legal history since.
> Status: seized
> Jurisdiction: protocol — decentralized; developers indicted in 2023
> Fiat on-ramp: no
> Payment methods: crypto
> Founded: 2019
> Open source: yes
> Custodial: no
> Last verified: 2026-01-01

## Verdict

Tornado Cash is the reference zero-knowledge mixer on Ethereum, sanctioned by U.S. Treasury in August 2022 and central to the most-cited "can immutable code be sanctioned?" legal debate of the 2020s. The contracts are still on-chain; using them as a U.S. person remains legally fraught even after the partial 2024-2025 OFAC walk-back. Listed here for historical and reference purposes. Treat as a case study, not a recommendation.

## Strengths

- Reference zero-knowledge mixer on Ethereum; widely studied design.
- Immutable smart contracts — the protocol itself cannot be turned off by the operator.

## Caveats

- Sanctioned by U.S. Treasury OFAC in August 2022 — U.S. persons are prohibited from interacting with listed addresses. A November 2024 Fifth Circuit ruling held that immutable smart contracts cannot be sanctioned as "property"; OFAC partially walked back the listing in early 2025, but the operational and legal posture remains contested.
- Roman Storm (one of the developers) was tried in the U.S. in 2024 on money-laundering charges related to the protocol; the case has shaped how mixer developers think about legal exposure.
- On Ethereum-side address screening, most regulated exchanges flag any address that has ever interacted with Tornado contracts.
- Listed for historical reference. Real-world use carries non-trivial legal and operational risk depending on jurisdiction.
- Facts need re-verification by operator (last seeded 2026-01).

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## What Tornado Cash is

A set of immutable Ethereum smart contracts implementing a zero-knowledge mixer. Deposits go into one of fixed-size pools (0.1 / 1 / 10 / 100 ETH); withdrawals can be made later from a different address by proving knowledge of the deposit secret, with the link between deposit and withdrawal cryptographically hidden.

## Threat-model fit

Historical and regulatory reference. The legal and operational risk profile in 2026 is the defining property — the protocol itself works as designed, but interacting with it as a U.S. person or anyone routed through a regulated venue is fraught.

## Sources

- [Tornado Cash documentation (archived)](https://docs.tornado.cash/) — accessed 2026-01-01
- [U.S. Treasury — Tornado Cash sanctions press release (August 2022)](https://home.treasury.gov/news/press-releases/jy0916) — accessed 2026-01-01
- [Wikipedia — Tornado Cash](https://en.wikipedia.org/wiki/Tornado_Cash) — accessed 2026-01-01