A new source of randomness was introduced in Wasabi v2.0.6 to improve the privacy of the coinjoin feature. In earlier versions, clients would always attempt to register for the next coinjoin as soon as the previous one finished. Now, clients randomly pause and wait in between coinjoin rounds, which increases confusion for anyone attempting to track funds based on the timing of their movements.
The way this randomness was implemented does not behave like a fair dice, instead, it gives users artificial luck. Random skips occur more frequently while fees are high, and skipping is less likely when fees are low.
How long your wallet waits when skipping rounds is influenced by the coinjoin strategy you choose. There is a different chance to participate in a coinjoin round depending on whether you select “minimize costs”, “maximize speed”, or “maximize privacy”.
The Participation Calculation
The median fee rate of the previous day, week, and month determines the chance of skipping a coinjoin round. This chart shows what percentage of rounds your client will join under each possible combination of fee conditions for each coinjoin strategy profile.
Since the minimize costs strategy uses “weeks” as the coinjoin time preference, there is zero chance of participating whenever fees are higher than the median of the previous day or week. Whenever fees are at the absolute cheapest levels, clients will never choose to gamble away that opportunity and will join 100% of coinjoin rounds.
An additional privacy benefit from random skips is that it staggers the crowd of remixers. Since some users stall in between coinjoins, it increases the likelihood of coinjoining with more unique users as opposed to coinjoining with the same participants of the previous round again.
The subtle privacy fortifications implemented in the Wasabi v2.0.6 release minimize the UX trade-offs with cost or speed that are associated with coinjoins. If you haven’t tried the newest version, don’t skip the upgrade, let the upgrade do the skipping for you!
