Office of Foreign Assets Control (OFAC)

The Office of Foreign Assets Control, or OFAC, is the US Treasury agency that administers economic sanctions, maintaining the Specially Designated Nationals list with which US persons and companies are forbidden to transact. In November 2018 it added Bitcoin addresses to the list for the first time, attaching two addresses linked to Iranian ransomware facilitators.

Why it matters

OFAC's reach defines much of the compliance perimeter around bitcoin. Exchanges screen deposits and withdrawals against listed addresses, chain-analysis firms trace flows from sanctioned entities, and the August 2022 sanctioning of the Ethereum mixer Tornado Cash tested whether immutable software, rather than a person or company, could itself be designated. A federal appeals court ruled in 2024 that the protocol's immutable smart contracts were not sanctionable property, and the designation was lifted in 2025.

For miners and nodes the question is sharper: a few mining pools have at times excluded transactions involving sanctioned addresses, raising the issue of whether bitcoin's neutrality survives contact with state power.

In the gold vs bitcoin debate

Sanctions expose the censorship-resistance argument at its most concrete. Gold held abroad can be frozen, as when the Bank of England declined to release Venezuela's gold in 2019. Bitcoin's base layer has never blocked a sanctioned transaction, though every regulated ramp around it complies. The open question is whether chokepoint regulation suffices to control an asset whose settlement layer answers to no jurisdiction.