Privacy Protocol Umbra Shuts Down Frontend to Thwart Kelp Attackers, Tornado Cash Cofounder Says Move Is Insufficient to Avoid Regulatory Scrutiny

On April 22nd, privacy protocol Umbra took its front-end website offline to make it harder for hackers to move stolen funds. Umbra noted that roughly $800,000 in stolen assets had flowed through its protocol, adding that the front-end shutdown is a "maintenance mode" measure—one that will be reversed once the team confirms it won’t disrupt recovery efforts. The move comes on the heels of a recent attack on the Kelp protocol, which resulted in losses exceeding $280 million. Suspected North Korean hackers are believed to have tried to cross-chain the stolen funds from Ethereum to Bitcoin using platforms like Umbra. But Tornado Cash co-founder Roman Storm warned that taking the front end offline alone may not shield Umbra from regulatory scrutiny. He pointed out that in his own case, authorities argued "changing the front end equals controlling the entire protocol" and that "if you can modify the user interface—including updating it to a new version on IPFS—you have full control over the protocol." In response, Umbra clarified that its protocol is designed primarily to "protect recipients’ identities, not senders’," and that all stolen funds passing through its system can be traced. The team has also been in contact with security researchers.