CoinJoin is a method of anonymizing bitcoins that developer Gregory Maxwell came up with in an effort to help bitcoin users remain anonymous. The idea is simple: when two users both want to make a transaction, if they make the transactions together, their information remains private or at least very hard to discern.
On yesterday’s 10th anniversary of the Bitcoin protocol as an idea (whereas the blockchain did not actually launch until January 2009), a CoinJoin worth over $200,000 took place. The join involved many participants, with the largest transaction in the bunch being nearly half the total volume transacted — 14.8 BTC moved to address bc1qqcrmkvp97ryyvfu3crp6883v5caunq6v2960sc.
The transaction was initiated by Wasabi Wallet developer Adam Ficsor and announced on his Twitter page.
The largest CoinJoin in the history of Bitcoin has just been created. Exactly 10 years after its whitepaper. Beautiful!https://t.co/DaTXrey12h
— nopara73 (@nopara73) October 31, 2018
The Wasabi Wallet project is a desktop bitcoin wallet project which focuses on enhancing the privacy of BTC transactions through the use of CoinJoin and other methodologies. It is owned by a company called zkSNACKs — not to be confused with ZEC’s zkSNARKs.
It intends to improve fungibility of bitcoin. Fungibility is the concept that every bitcoin is interchangeable regardless of who has held it or what purpose it has been used for. A lack of fungibility is a dangerous economic precedent, and technologically it is avoidable. CoinJoins are a method of improving fungibility by allowing “tainted” coins into “legitimate” transactions — note that both of these concepts, “clean/dirty” coins, are the problem in and of themselves that Wasabi is addressing. A good summary of their belief system might be: “a bitcoin is a bitcoin is a bitcoin.”
The best way to view the question is whether or not you would reject a $100 bill to sell your used car simply because that bill had once been used in a drug transaction. In cash transactions, this is harder to do, but with digital money, it is entirely possible, and various technologies including monero, zcash, and CoinJoin aim to prevent such a situation through privacy and anonymization of coins.
Wasabi Wallet has CoinJoin built in, as seen above. To participate in a CoinJoin one must be transacting more than 0.1 BTC. This feature is similar to monero’s mixing protocol. It appears that only other Wasabi Wallet users can participate in these CoinJoins, but nevertheless the feature is sure to increase adoption of Wasabi, which aims to launch on mobile clients in the future.