OFAC sanctions list

In plainer words

OFAC is an agency under the US Treasury (the Office of Foreign Assets Control). It maintains a sanctions list (often called the SDN list) of sanctioned individuals, entities, countries — and, increasingly, crypto wallet addresses. Paying an address on the list can break the law outright, whether you meant to or were tricked. A famous case is the mixer Tornado Cash being sanctioned by OFAC: afterward, anyone interacting with its contracts risks crossing the line. For agent payments this is a hard constraint: an agent won't check whether a payee is on the sanctions list, but once the money's out, the liability has landed. So "check against OFAC before paying" is the most basic, least-skippable step in AML screening. OceanAlt's free address check does this first — and the list must be kept current, which is one reason our data source must keep growing.