The developers of Samourai Wallet have published the public beta version of Whirlpool, a Chaumian CoinJoin implementation that consists of a framework supported by various privacy-enhancing software tools.
What Is Chaumian CoinJoin?
CoinJoin is an anonymization technique first proposed by Gregory Maxwell in 2013. A “Chaumian CoinJoin” integrates chaum blind signatures — a scheme that provides a cryptographically blinded version of a receiving address. As described by ZeroLink, a bitcoin fungibility framework:
“The users connect and provide inputs (and change addresses) and a cryptographically-blinded version of the address they want their private coins to go to; the server signs the tokens and returns them. The users anonymously reconnect, unblind their output addresses, and return them to the server. The server can see that all the outputs were signed by it and so all the outputs had to come from valid participants. Later people reconnect and sign.”
This is seen as a relatively fast and cheap way to add anonymity to CoinJoin transactions. With Samourai adding this feature to its wallet, it could provide a significant and easy-to-adopt layer of privacy for mainstream bitcoin users.
As detailed by its developers, the Whirlpool framework is a fully modular CoinJoin implementation that has been developed through a “heavily modified” fork of the ZeroLink theory.
According to its official Github page, Whirlpool’s open-source software is able to “mathematically disassociate” the ownership of inputs (“sending addresses”) to outputs (“receiving addresses”) that are included in a bitcoin transaction. The disassociation between a given set of inputs and their corresponding outputs allows for greater financial privacy when making bitcoin transactions. In other words, bitcoin transfers become difficult to track because the origin (or
