Cloning Tornado Cash Would Be Easy, but Risky

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What’s stopping anyone from redeploying the Tornado Cash contract on a new, non-sanctioned address? Technically nothing. But there are a slew of reasons – legal and technical – why it may not be in an individual’s best interest to challenge the will of the U.S. government.

On Monday, the U.S. Treasury Department’s Office of Foreign Assets Control (OFAC) took the unprecedented step of sanctioning the popular cryptocurrency transaction anonymizer. All U.S. “persons” are thus barred from interacting with this smart contract, and could face the type of penalties usually reserved for terrorist financiers or mob bosses if not in compliance.

Already there have been attempts to thwart what some see as an overzealous attempt to rein in the crypto industry. A pseudonymous crypto user is sending small ETH payments from a Tornado Cash wallet to high-profile crypto holders, making them inadvertently interact with a sanctioned entity (because crypto transactions cannot be refused) in what’s called a “dust attack.”

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Industry think tank Coin Center, among others, is questioning the constitutionality of an outright ban of an open-source project. Members of the Tornado Cash Telegram channel are sharing advice on how to access the application through identity-protecting servers including the Brave and Tor browsers.

(Tornado Cash Telegram channel)
(Tornado Cash Telegram channel)

Others have noted that because Tornado Cash’s code is open source, and because Ethereum is a permissionless blockchain, it would be trivially easy to simply reconstruct the service. If you know how to copy and paste and know how to deploy a smart contract, you could be done by dinner.

There are many justifiable reasons someone would want to interact with Tornado, which until Monday was a legal and globally-accessible service. Ethereum, like many blockchains, makes transactions visible by default – meaning that anyone who would want to shield their financial history from employers, lovers or the world would have cause to “mix” their funds.

The U.S. government claims the platform was used to launder more than $7 billion worth of crypto since it launched in 2019. But analytics company Elliptic has only identified $1.5 billion worth of crypto filtered through Tornado tied to illicit acts like ransomware or hacks.

Moreover, the $7 billion figure the U.S. Treasury cited likely represents the total value of crypto sent through the vortex. (This is hardly scientific, but Etherscan creates word-clouds of names and labels associated with blockchain addresses and the one for Tornado Cash does say “phish/hack” but also “charity,” “maker vault owner” and something called “dragonereum tokenized asset” – which seems like a pretty neat visualization of a “general purpose technology.” You may not like everything about crypto, or understand it, but not all of it is nefarious.)