What is OFAC?

The Office of Foreign Assets Control (OFAC) is a division of the United States Treasury Department that administers and enforces economic and trade sanctions. It publishes the Specially Designated Nationals and Blocked Persons (SDN) list — commonly called the OFAC list — containing individuals, entities, and assets that US persons are prohibited from dealing with.

Although OFAC is a US government body, its reach extends far beyond American soil. Because the US dollar dominates international trade and the US financial system is central to global commerce, OFAC sanctions have effectively global reach. Any institution that processes US dollar transactions — which includes virtually every major bank and financial institution in the world — must comply with OFAC regulations or risk being cut off from the US financial system.

Why OFAC started targeting cryptocurrency addresses

For years, OFAC focused on traditional financial assets. But as cryptocurrency became an increasingly significant vehicle for sanctions evasion, money laundering, and financing of designated organisations, OFAC expanded its remit to include cryptocurrency wallet addresses.

The first major cryptocurrency designation came in 2018, when OFAC designated two Iranian individuals along with their Bitcoin addresses. Since then, OFAC has designated hundreds of cryptocurrency addresses, including entire smart contracts.

The most significant cryptocurrency-related OFAC action was the designation of Tornado Cash in August 2022 — the first time OFAC had ever designated a smart contract rather than a person or entity. Tornado Cash is an Ethereum mixing protocol, and OFAC designated it on the basis that it was being used to launder cryptocurrency by North Korean state-sponsored hacking groups, most notably Lazarus Group.

Key implication of the Tornado Cash designation: Simply interacting with a designated smart contract — even passively receiving funds that passed through it — creates potential sanctions exposure. This is why OFAC screening of all addresses in a cryptocurrency transaction trail is essential.

What is on the OFAC SDN list for cryptocurrency?

The OFAC SDN list contains cryptocurrency addresses associated with:

  • State-sponsored hacking groups — including Lazarus Group (North Korea), which has stolen billions in cryptocurrency from exchanges and DeFi protocols
  • Ransomware operators — including groups responsible for attacks on critical infrastructure
  • Darknet markets — including Hydra Market, the world's largest darknet marketplace at the time of its seizure in 2022
  • Mixing services — including Tornado Cash and SUEX, a cryptocurrency exchange designated for facilitating ransomware payments
  • Sanctions evaders — individuals and entities using cryptocurrency to circumvent US sanctions on Iran, Russia, Venezuela, and other designated countries

What does an OFAC match in a blockchain trace mean?

When a blockchain trace identifies that funds passed through or currently reside in an OFAC-designated address, the implications vary depending on your position:

If you are a fraud victim: An OFAC match significantly strengthens your case. It demonstrates that your funds were handled by a sanctioned entity, which may support law enforcement action and can assist a solicitor in obtaining urgent court orders.

If you are a business: Receiving funds from or sending funds to an OFAC-designated address — even unknowingly — can constitute a sanctions violation. Voluntary self-disclosure to OFAC, coordinated through legal counsel, is strongly advisable.

If you are an exchange or financial institution: You have a legal obligation to screen transactions against the OFAC list in real time. Failure to do so can result in severe civil and criminal penalties.

OFAC and UK sanctions

The UK operates its own sanctions regime through the Office of Financial Sanctions Implementation (OFSI), part of HM Treasury. Following Brexit, the UK's sanctions list is no longer automatically aligned with OFAC's, though there is significant overlap.

UK businesses must comply with UK sanctions law, not US law — unless they have US connections or process US dollar transactions. However, given that OFAC's list is more comprehensive and more frequently updated, many UK compliance teams screen against both lists as a matter of best practice.

How to check an address against the OFAC SDN list

  • Download the SDN list from ofac.treasury.gov (updated frequently)
  • The list contains digital currency addresses under identifier type "Digital Currency Address"
  • Professional blockchain forensics tools screen every traced address automatically
  • OFAC also provides an online search tool at sanctionssearch.ofac.treas.gov

The practical takeaway

For anyone involved in cryptocurrency — whether as an individual, a business, or an investigator — OFAC screening should be a standard step. It takes seconds with the right tools, and an OFAC match is one of the most significant findings a blockchain trace can produce.

Every investigation conducted by Kestrel Forensics includes a full OFAC SDN list screening of every address in the trace, with any matches clearly flagged in the evidence record and investigation report.