(Bloomberg) -- After the US Treasury Department said it had barred American companies and individuals from using a so-called crypto mixer known as Tornado Cash, fans of the service rallied in support of the founders of the popular protocol. Tornado Cash allowed users to obfuscate their crypto transactions; the Treasury alleged that North Korean hackers and other entities had relied on it to launder illicit gains totaling more than $7 billion.

But within hours, those fans (and critics) were reacting to something else: the erasure of accounts and websites linked to Tornado Cash from the internet. 

A GitHub account that previously hosted code related to Tornado Cash returned a “page not found” error, as did the website linked to the project. Emails to the Tornado Cash founders bounced back with the message, “The email account that you tried to reach is disabled.” GitHub, owned by Microsoft, is a way for developers to collaborate on software projects.  

Read more: Crypto Mixer Tornado Cash Sanctioned by US Treasury Department

In an emailed statement, a GitHub spokesperson said that trade laws require GitHub to “restrict users and customers identified as Specially Designated Nationals (SDNs) or other denied or blocked parties, or that may be using GitHub on behalf of blocked parties.”

“We examine government sanctions thoroughly to be certain that users and customers are not impacted beyond what is required by law,” they added.

Google, which was listed as the domain registrar for the Tornado Cash website, did not return a request for comment. 

Tornado Cash co-founder Roman Semenov tweeted that his GitHub account had been suspended. “Is writing an open source code illegal now?” he asked in the tweet about the suspension. Other influential crypto personalities echoed that sentiment. “If software isn’t safe then speech isn’t,” Ryan Sean Adams, who writes a newsletter about crypto with tens of thousands of paid subscribers, said in a tweet posted after the suspensions. 

Other users posted links they described as mirrors of the code originally hosted on GitHub, and to backup versions of the Tornado Cash website itself. Tom Robinson, co-founder of blockchain analytics firm Elliptic, said the suspensions wouldn’t stop the mixer from operating. “The Tornado Cash smart contacts have been deployed on blockchain such as Ethereum and anyone with a wallet is free to use them,” he told Bloomberg News in an emailed statement.

Part of the appeal of cryptocurrency to its users is the supposed ability to evade government censorship and restrictions. This resilience has been tested by bans in countries like China, by the crackdown on ransomware funded by crypto, and by recent sanctions related to Russia. Following Russia’s invasion of Ukraine in February, the US and its allies worked to cut off crypto as a sanctions workaround in response to warnings from regulators and officials. 

Read more: Russian Crypto Trading Falls Even as Doubts Persist on Sanctions

(Adds comment from GitHub)

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