ZeroLink, the product of the combined efforts between developers from SamouraiWallet and HiddenWallet, promises to make using Bitcoin fully anonymous, something that has never been achieved before.
Zerolink is not only an excellent anonymity technique; it’s a whole process that’s called the Wallet Privacy Framework.
The Wallet Privacy Framework consists of a pre-mix and post-mix wallet, as well as a mixing technique. Three layers of anonymization are implemented to ensure that users are not deanonymized through tactics such as network analysis.
Pre-mix wallets can be easily added to Bitcoin wallets, but post-mix wallets have a bit more requirements for privacy such as coin selection, private transaction, and balance retrieval, as well as transaction input/output indexing and broadcasting.
Together, the two wallets create the framework. Coins are moved between the two wallets via mixing and common mixing techniques such as CoinShuffle, CoinShuffle++ or TumbleBit can be used here.
However, ZeroLink encompasses its own mixing technique called Chaumian CoinJoin. CoinJoin is not a new concept, first being described by Gregory Maxwell on BitcoinTalk in 2013. A mixing round is complete within seconds, and the cost is low enough to make it financially feasible.
The only reason an implementation using Maxwell’s technique has never been done before was due to the feasibility of DoS protection; with low fees, it was economically viable to disrupt mixing. Since Bitcoin fees have gone up dramatically from 2013 and on average are higher than $1 for a transaction, it is economically impractical for anyone to disrupt mixing rounds.
If Zerolink is deployed and becomes mainstream, it would put a lot of privacy-centric altcoins under a lot of pressure to innovate, such as Monero and Dash. Zerolink would solve concerns surrounding Bitcoin regarding fungibility as well, killing two birds with one stone.
Stratis’ BreezeWallet, which released announced the imminent release of its TumbleBit wallet recently, has also expressed interest in the project, and are actively monitoring the progress of Zerolink. ZeroLink will be put into production by SamouraiWallet according to Adam Ficsor, which will be a welcome move, as Bitcoin now focuses on improving fungibility following the lock-in of SegWit and Bitcoin Cash split.