A Study Of De-Anonymization Techniques For Mixed-Currency Service

Tornado.Cash,as the most popular decentralized mixing service platform on Ethereum,achieves untraceability through address obfuscation mechanisms.However,Tornado.Cash,originally designed for privacy protection,has unfortunately become the tool for money laundering.Therefore,we aim to enhance the health of the blockchain ecosystem by studying the de-anonymization techniques of Tornado.Cash.While its security has been validated over time from a technical perspective,inappropriate behaviors can still lead to privacy leakage.Specifically,we addresses two major challenges in researching mixing services:(1)establishing heuristics for linking deposit and withdrawal accounts and(2)obtaining ground truth for evaluating the account linkability.Based on these challenges,we propose innovative techniques for account linkability from two dimensions:user account transactions and account profiling,and leveraging existing research to address the evaluation problem.The main contributions are as follows:1.Propose the account linkability technology based on user account transactions.This paper classifies asset transfers on the blockchain into three types:normal transfers,cross-chain transfers,and token transfers.For each type,specific heuristics for account linkability are proposed.Experimental results demonstrate that this technique improves the de-anonymization effectiveness by 5.5%compared with the existing research.2.Propose account linkability techniques based on user account profiling.This technique is mainly based on users’ behavioral perference on the blockchain,such as decentralized applications used,crypto assets owned,and account reuse,to determine whether there is an linkability between mixed coin accounts.By analyzing users preference,it achieves the 15.6%de-anonymization effect on the asset pool of Tornado.Cash.This idea establishes a structured approach to account linkability and helps users gain deeper insights into user behavior in decentralized networks.3.Build a mixing account linkability analysis system.Due to sanctions imposed on Tornado.Cash,its portal website has been shut down,which makes it impossible to access any statistical information.Therefore,this system provides functionality for querying mixing transaction data and implements the main feature of account linkability based on the techniques proposed in the paper.This greatly help regulatory agencies to trace the flow of illicit funds.