The trial of Roman Storm, co-founder of Tornado Cash, has brought the issue of "control" over cryptocurrency platforms to the forefront. Prosecutors are arguing that Storm had the ability to control the flow of illicit funds through the platform, while the defense maintains that Tornado Cash is a decentralized protocol beyond his control.

The U.S. government alleges that Storm conspired to launder money, violated sanctions, and operated an unlicensed money-transmitting business through his involvement with Tornado Cash. Tornado Cash is an open-source protocol that allows users to conceal their blockchain transactions. Prosecutors claim that Storm knowingly facilitated money laundering. They argue that he "chose to remove the switch that could have controlled the washing machine," referring to Tornado Cash as a "giant washing machine for dirty money". Assistant U.S. Attorney Kevin Mosley stated that Storm "had the keys to the front door" and was "doing business with criminals," allegedly laundering $600 million for North Korea. The prosecution presented a T-shirt worn by Storm at a tech conference, featuring a washing machine and the Tornado Cash logo, as evidence of his intent to market the platform for money laundering.

The defense counters that Storm merely wrote and published open-source code and that Tornado Cash is a privacy protocol freely available to everyone. They argue that he didn't run a business, offer a service, or manage customers. Storm's legal team is led by Brian Klein and David Patton, who have experience in high-profile crypto cases. They argue that Storm cannot be held responsible for how Tornado Cash was used because the protocol is decentralized and beyond his control. In May 2020, Tornado Cash developers began relinquishing control and moved toward a fully decentralized system. The defense also accused prosecutors of misrepresenting key Telegram evidence, claiming the government only disclosed critical metadata showing a reporter's message was forwarded by Storm, not authored.

IRS Criminal Investigation Special Agent Stephan George testified that Storm "[had] control" over funds after an account connected to Binance sent crypto to Tornado Cash smart contract addresses, based on communications between the co-founders. The prosecution's case hinges on the argument that Storm's interactions with Tornado Cash's smart contracts deviated from standard user behavior, suggesting intentional oversight or intervention. According to court documents, these deviations could indicate a “backdoor” to monitor or redirect funds, effectively granting Storm operational control over the platform's functions. The IRS emphasized that while Tornado Cash is technically trustless, Storm's role in deploying and managing its architecture could link him to criminal facilitation.

Storm's defense has contested the credibility of this evidence, questioning the qualifications of IRS witnesses like George to interpret complex cryptocurrency transactions. Defense attorneys argue that George's accounting expertise does not extend to blockchain forensics, undermining the reliability of his testimony. They also highlighted inconsistencies in the prosecution's claims, citing Hanfeng Lin, a victim of a crypto romance scam, to assert that disputed funds were never routed through Tornado Cash, challenging the prosecution's narrative of direct involvement in illicit activity. Storm's lawyers suggested that they may move for a mistrial after research suggested none of the funds went to the crypto mixing service.

The trial raises critical questions about the responsibility of developers in the cryptocurrency space and whether writing and publishing open-source code can be considered criminal conduct if that code is later used for illicit purposes. The outcome of the trial could have significant implications for the future of decentralized finance and the regulation of cryptocurrency.