OFAC screening for blockchain companies

Blockchain companies face sanctions obligations at the protocol, front-end, wallet, and enterprise layers.

TL;DR

TL;DR: Blockchain companies should screen at every layer where value moves, from protocol wallets to front-end flows, because OFAC applies strict liability throughout.

Protocol and front-end layers

At the protocol layer, OFAC obligations attach to wallets that interact with a sanctioned party. The 50 Percent Rule and the Tornado Cash designation show that OFAC treats smart contracts and code as within scope, not only the operators. At the front-end layer, a dapp that lets users transact should screen the counterparty before any payment is initiated.

Wallet and enterprise layers

The wallet layer is the most direct control. A wallet can check an address against the 947 OFAC-listed crypto wallets before signing. At the enterprise layer, exchanges and custodians run full screening programs with audit logs, alerts, and periodic reviews, because their volume and their regulatory exposure are both higher.

A layered control

The layered approach shares one primitive: a screening call that returns ALLOW or BLOCK in under 100 ms. Because the data, 19,218 SDN names plus the wallet list, syncs hourly, each layer can stay current without duplicating effort.

Screening at the dapp layer

For a dapp, the front end is the cheapest place to enforce a block. A wallet connection can be checked against the 947 OFAC-listed crypto wallets before any transaction is signed, and the result logged. This does not replace protocol-level design choices, but it stops the most common interaction before it happens.