An OFAC sanctions check screens a wallet's counterparties against the Treasury SDN list of designated crypto addresses; Plastron runs this check free against weekly-updated OFAC data as an informational signal, not legal advice.

The Office of Foreign Assets Control maintains the Specially Designated Nationals list — a comprehensive sanctions database covering individuals, entities, and since 2022, smart contract addresses. The crypto-related SDN entries cover North Korean, Iranian, Russian, Venezuelan, and other OFAC-designated parties who have used cryptocurrency to evade sanctions. Transactions involving SDN-listed addresses by US persons or on US-nexus platforms are prohibited, regardless of whether the US person knew about the designation. This strict liability standard is what makes OFAC compliance particularly important for crypto users: you can inadvertently transact with a sanctioned address through a DEX swap, a liquidity pool, or a wallet that received funds from a designated entity, and the compliance exposure is real regardless of your intent. Every regulated exchange — and most unregulated ones that want to remain in good standing globally — screens deposits against the OFAC SDN list. Direct hits result in immediate account freezes. Indirect exposure through counterparties results in enhanced due diligence requests and potential holds. Plastron updates its OFAC database weekly via the US Treasury SDN XML feed and checks your wallet against the full list on every scan. A clean OFAC result is the most important factor in avoiding a compliance freeze at a major exchange.