Tornado Cash

Tornado Cash is best known as a crypto mixing service, the kind people used to obscure transaction trails on Ethereum. By our assessment, that gives it a very specific technical purpose and a very serious public reputation, because privacy tools in crypto live right on the edge of legitimate secrecy and illegal concealment. The tool’s strength is obvious: it breaks easy tracing, which is exactly why it appealed to users who wanted transaction privacy. The weakness is just as obvious: that same feature made it controversial and drew heavy official scrutiny. In practice it is not a casual consumer coin at all, but a protocol whose usefulness is tied to how much privacy one wants and how much risk one is willing to carry.