CoinJoin. Trustless mixing. Anonymity. Bitcoin Magazine’s September 2013 cover — all black with hints of golden fingerprints — needed only four words to announce a powerful new privacy tool. At a time when industry representatives like the Bitcoin Foundation were downplaying Bitcoin’s anonymity features, regulators in New York were developing the BitLicense and Silk Road was about to be shut down, two hackers working from a former textile factory in Catalonia had begun to fight back. Amir Taaki and Pablo Martin realized the first ever CoinJoin application, and Bitcoin Magazine’s Vitalik Buterin was quick to cover[1] the development.
Just weeks prior to the publication of this fourteenth Bitcoin Magazine print edition, Bitcoin Core contributor Gregory Maxwell had posted what has come to be considered the unofficial CoinJoin announcement thread[2] on the Bitcoin Forum. The developer had already published[3] the idea in January 2013 in a more tongue-in-cheek stunt to trick blockchain analysis into thinking he was “taint rich,” asking forum users to mix their coins with his. But in his more serious August post, Maxwell introduced the name “CoinJoin,” while emphasizing the importance of tools like it.
“Traditional banking provides a fair amount of privacy by default. Your inlaws don’t see that you’re buying birth control that deprives them of grand children, your employer doesn’t learn about the non-profits you support with money from your paycheck, and thieves don’t see your latest purchases or how wealthy you are to help them target and scam you,” Maxwell wrote. “Poor privacy in Bitcoin can be a major practical disadvantage for both individuals and businesses.”
Bitcoin did have poor privacy. While Bitcoin addresses aren’t in themselves tied to real-world identities, blockchain analysis can often establish these links. A key
