Heuristics for Detecting CoinJoin Transactions on the Bitcoin Blockchain
Hugo Schnoering Michalis Vazirgiannis
This research delves into the intricacies of Bitcoin, a decentralized
peer-to-peer network, and its associated blockchain, which records all
transactions since its inception. While this ensures integrity and
transparency, the transparent nature of Bitcoin potentially compromises users'
privacy rights. To address this concern, users have adopted CoinJoin, a method
that amalgamates multiple transaction intents into a single, larger transaction
to bolster transactional privacy. This process complicates individual
transaction tracing and disrupts many established blockchain analysis
heuristics. Despite its significance, limited research has been conducted on
identifying CoinJoin transactions. Particularly noteworthy are varied CoinJoin
implementations such as JoinMarket, Wasabi, and Whirlpool, each presenting
distinct challenges due to their unique transaction structures. This study
delves deeply into the open-source implementations of these protocols, aiming
to develop refined heuristics for identifying their transactions on the
blockchain. Our exhaustive analysis covers transactions up to block 760,000,
offering a comprehensive insight into CoinJoin transactions and their
implications for Bitcoin blockchain analysis.