ETH Mixer Tornado Cash Reveals Blocking OFAC Sanctioned Ethereum Addresses via Chainalysis Oracle Contract

According to the project’s official Twitter account, Tornado Cash, the ethereum mixing service that allows participants to shuffle ether, is blocking flagged ethereum addresses listed on the Office of Foreign Assets Control’s (OFAC) Specially Designated Nationals And Blocked Persons list (SDN). The decision follows the recent OFAC update, that lists the Ronin exploiter’s ethereum address, and further notes that the ether wallet is allegedly associated with the infamous North Korean hackers, Lazarus Group.

Tornado Cash announced on April 15, 2022, that the project is leveraging a Chainalysis oracle to block OFAC sanctioned wallets. “Tornado Cash uses [a] Chainalysis oracle contract to block OFAC sanctioned addresses from accessing the dapp,” the official Twitter account said on Friday. “Maintaining financial privacy is essential to preserving our freedom, however, it should not come at the cost of non-compliance,” the Tornado Cash Twitter account added.

The decision comes after the U.S. Treasury and OFAC published an update concerning the Ronin bridge hacker’s ethereum wallet. The ethereum address that was used by the Ronin bridge exploiter is now sanctioned and U.S.-based companies and citizens are banned from transacting with the address. According to the OFAC update, the address is associated with the North Korean hacking organization known as Lazarus Group. Following the decision, Tornado Cash got a lot of criticism for the move.

“So let me get this straight,” one individual tweeted, “if my address is on the OFAC sanctioned addresses list, I just need to transfer it to another address and then I can begin my money laundering.”

The news also follows the controversy surrounding the claims that the blockchain surveillance and intelligence company, Chainalysis, deanonymized Wasabi-based Coinjoin transactions. After the deanonymizing claims, Wasabi told the public a blacklist would prevent some UTXOs (unspent transaction outputs) from registering to Coinjoin transfers. The founder and creator of Wasabi wallet, Adam Ficsor, told the public: “Blacklisting arrived to Coinjoins. IMO it is a major setback to Bitcoin’s fungibility.”



Meanwhile, the changes Tornado Cash added may be bypassed by not only simply switching to other ether addresses, but also by leveraging the contract without using the Tornado Cash protocol’s frontend. “Don’t worry guys, your favorite hackers will still be able to wash the money they have stolen from you using the smart contract directly,” one individual replied to the Tornado Cash Twitter statement. “This just affects the website frontend, contract is permissionless.”

What do you think about the statements the Tornado Cash team made on Friday about blocking OFAC sanctioned ethereum addresses? Let us know what you think about this subject in the comments section below.