Privacy-focused Bitcoin software wallet Wasabi is getting a major protocol overhaul.
The Wasabi team is working on a new protocol design, dubbed WabiSabi, in a bid to improve the user experience and privacy guarantees of the wallet’s CoinJoin transactions. The major design change would allow users to coinjoin with different values than their peers, a first for the privacy-minded technology that could lead to new (and more flexible) use cases. Wasabi has been conceptualizing the design in a research group since the beginning of 2020 and has hired team members to work on the implementation.
Out with the old
Currently, Wasabi’s CoinJoin – a mixing protocol that, when used correctly, can obscure a bitcoin’s transaction history – relies on the ZeroLink protocol and blind signatures for mixing. Under this scheme, users must spend a set minimum amount of bitcoin with other users in a mixing pool for the CoinJoin to work successfully; these like amounts are shuffled together in a pool, after which each user receives the same amount of bitcoin back in a way that doesn’t reveal their original input.
For this to work effectively, each user in a CoinJoin transaction must send a minimum amount of bitcoin to the mixing pool (e.g., 0.1, 0.01, etc) so as to ensure that they receive the same output as other users when the CoinJoin is complete. If recipients don’t receive the same amount of Bitcoin at the end of a join as other users in the mix, the transactions could be easily deanonymized by blockchain surveillance.