Author: Chris Belcher 2019-07-30 21:39:14
Published on: 2019-07-30T21:39:14+00:00
The discussion on the Bitcoin-dev mailing list about deanonymizing the joins in JoinMarket continued with a reply from a member named Dmitry Petukhov. They raised a concern that if the attacker provides "maker outsourcing," they can capture a significant portion of the maker-outsourcing/UTXO-rent market and receive some profit from the convenience fee while deanonymizing the joins. However, it is not possible for an attacker to rent out UTXO proofs and change the privacy properties due to the quadratic term in the fidelity bond formula. JoinMarket takers always use multiple makers, so there is no chance for a single maker to deanonymize a coinjoin just because the takers have chosen them a lot. A sybil attacker who wants to run multiple makers for the purpose of deanonymization would take a substantial quadratic hit in their effectiveness. This is explained in the other document "Financial mathematics of JoinMarket fidelity bonds" by a member named Chris Belcher. Belcher also mentioned that sacrificing coins in order to compete with the single maker who could make loads of money in coinjoin fees should encourage other makers to do the same and capture some of that fee income. It is important to note that pseudonymous entities cannot be sure how much of the market the attacker controls.
Updated on: 2023-06-13T20:24:14.689177+00:00