Matthew Green, professor at Johns Hopkins University, along with the support of the organization Electronic Frontier Foundation (EFF), made it known through a statement the initiative for the return of access public to project code Tornado cash, whose repositories were removed in early August by GitHub after the service was placed on the US Office of Foreign Assets Control (OFAC) sanctions lists.
The Tornado Cash Project developed a technology to create decentralized services to anonymize cryptocurrency transactions, which significantly complicates the tracing of transfer chains and makes it difficult to determine the connection between the sender and recipient of the transfer on networks with publicly available transactions.
The technology is based on dividing the transfer into many small parts, in several stages mix these parts with parts of the transfers of other participants and transfer the required amount to the recipient in the form of a series of small transfers from different random directions.
The largest anonymizer based on Tornado Cash was implemented on the basis of the Ethereum network and processed more than 151 transfers 12 users for a total of $000 billion before closing.
The service was recognized as a threat to the national security of the United States and was included in the sanctions list, which prohibits financial transactions to United States citizens and companies. The main reason for the ban was the use of Tornado Cash to launder criminally earned funds, including $455 million stolen by the Lazarus group that was laundered through this service.
After adding Tornado Cash and its associated cryptocurrency wallets to the sanctions lists, GitHub has blocked all developer accounts on the project and removed their repositories. Under the blow included experimental systems based on Tornado Cash, which were not used in working implementations. It is not yet clear if the restriction of access to the code was part of the goals of the sanction or the removal was carried out without direct pressure on the GitHub initiative to minimize the risks.
The position of the EFF is that the prohibition applies to the use of labor services for money laundering., but the technology of anonymizing transactions itself is just a method of ensuring confidentiality, which can be used not only for criminal purposes.
In previous litigation, the source code was recognized as being subject to the First Amendment to the United States Constitution, which guarantees freedom of expression. The code itself with the implementation of the technology, and not the finished product suitable for implementation for criminal purposes, cannot be considered an object of prohibition, therefore, EFF believes that republishing previously removed code is legal and should not be blocked by GitHub.
Professor Matthew Green is known for his research on cryptography and privacy, including being one of the creators of the anonymous cryptocurrency Zerocoin and a member of the team that discovered a backdoor in the Dual EC DRBG pseudo-random number generator developed by the US National Security Agency. Matthew's main activities include studying and improving privacy technologies, as well as teaching students about such technologies (Matthew teaches computer science, applied cryptography, and anonymous cryptocurrency courses at Johns Hopkins University).
Anonymizers like Tornado Cash are an example of a successful implementation of privacy technologies, and Matthew believes his code should remain available for technology study and development.
Also, the loss of the reference repository will lead to confusion and uncertainty about which forks can be trusted (attackers may start distributing forks with malicious changes).
The removed repositories are recreated by Matthew under the new repository organization on GitHub to emphasize that such code is valuable to researchers and students, as well as to test the hypothesis that GitHub removed the repositories in compliance with the writ of execution and the penalties were applied. used until the prohibition of the publication of the code.
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