1. Address clustering

Blockchain address clustering is a technique used to determine address ownership, helping to identify users who control multiple addresses within a blockchain network. This process is implemented for various applications, including transaction analysis, regulatory compliance, and privacy research. Traditional clustering methods for unspent transaction output (UTXO)-based blockchains rely on heuristics such as the multi-input and change address heuristics, or off-chain data (e.g., web scraping) analysis, while more advanced techniques incorporate graph-based methods or machine learning approaches to improve accuracy. However, clustering faces challenges, including false positives and negatives, the lack of expansive ground truth data, and the evolution of privacy-enhancing techniques such as CoinJoin or privacy-oriented blockchains like Monero. Additionally, scalability remains an issue as the size of blockchain networks continues to increase, requiring more computational power and hardware resources for the analysis.