Developers of Ethereum Privacy Tool Tornado Cash Smash Their Keys

Ethereum’s premier coin mixing service is now permissionless.

Tornado Cash, a privacy tool for obfuscating the history of Ether (ETH) transactions, completed a cryptographic process known as a trusted setup ceremony on May 10 followed by a contract update on Monday to create perpetually self-executing code.

“With a record 1,114 contributions this was by far the largest Trusted Setup Ceremony to date,” Tornado Cash wrote in a May 13 blog post. “By comparison, all other trusted setup ceremonies had less than 200 participants.”

The ceremony, relying on a cryptographic method known as multi-party computation (MPC), makes Tornado Cash “completely trustless and unstoppable,” co-founder Roman Storm said in an interview with CoinDesk.

Read more: MPC Explained: The Bold New Vision for Securing Crypto Money

Tornado Cash v1 first launched in August 2019, but remained an audited “experimental software” because the developers retained control over user funds through a multi-sig wallet.

With v2, all that is gone. The MPC and Monday’s contract update effectively break up the developer key by creating a crowdsourced smart contract without a private key.

Private transactions

Techwise, Tornado Cash leans on zero-knowledge proofs (ZKP), or mathematical evidence that a transaction occurred without revealing the information within the payment itself.

Tornado Cash joins two other ZKP-based Ethereum systems, Aztec and EY’s Nightfall. As reported by CoinDesk, privacy protocol Aztec launched a network on Ethereum for digital assets, beginning with dai, while EY also released a business-focused privacy solution for Ethereum transactions in October 2018.

Read more: Zcash Alliance Aims to Bring Privacy Tech to Bitcoin, Cosmos and Ethereum

Tornado Cash is more readily compared to existing coin mixers on Bitcoin (BTC) because of its retail focus. CoinJoin developers Samourai and Wasabi have brought mixing to retail bitcoin investors, with Samourai available on Google Play as of…

Read More