Reuse of Public Keys Across UTXO and Account-Based Cryptocurrencies

2026-01-27

AI Summary

This study addresses the critical threat posed by cross-chain address reuse to user privacy and asset security, particularly in cryptocurrencies that mix UTXO and account-based models, where existing detection methods fall short. The authors propose a novel cross-chain clustering approach that eschews heuristic rules and instead leverages knowledge of private keys, utilizing elliptic curve cryptography to extract and compare public keys across chains. By integrating on-chain transaction data, the method systematically identifies and quantifies cross-chain key reuse for the first time across six major cryptocurrencies, including Bitcoin and Ethereum. The analysis uncovers numerous active instances of cross-chain key reuse, substantiating significant security risks and establishing a new paradigm for linking entities across heterogeneous blockchain systems.

Technology Category

• Data Mining & Knowledge Management: Anomaly/Outlier Detection
• Natural Language Processing: Machine Translation, Multilinguality, Cross-Lingual NLP
• Machine Learning: Clustering

Application Category

• Security and Privacy: Blockchains and distributed ledgers
• Web Mining and Content Analysis: Mining multimedia, multimodal, multilingual, cross-lingual Web data
• Graph Algorithms and Modeling for the Web: Representation, reconstruction, and subgraph or motif discovery in Web-related graphs

Abstract

It is well known that reusing cryptocurrency addresses undermines privacy. This also applies if the same addresses are used in different cryptocurrencies. Nevertheless, cross-chain address reuse appears to be a recurring phenomenon, especially in EVM-based designs. Previous works performed either direct address matching, or basic format conversion, to identify such cases. However, seemingly incompatible address formats e.g., in Bitcoin and Ethereum, can also be derived from the same public keys, since they rely on the same cryptographic primitives. In this paper, we therefore focus on the underlying public keys to discover reuse within, as well as across, different cryptocurrency networks, enabling us to also match incompatible address formats. Specifically, we analyze key reuse across Bitcoin, Ethereum, Litecoin, Dogecoin, Zcash and Tron. Our results reveal that cryptographic keys are extensively and actively reused across these networks, negatively impacting both privacy and security of their users. We are hence the first to expose and quantify cross-chain key reuse between UTXO and account-based cryptocurrencies. Moreover, we devise novel clustering methods across these different cryptocurrency networks that do not rely on heuristics and instead link entities by their knowledge of the underlying secret key.

Problem

• public key reuse
• cross-chain
• privacy
• cryptocurrency
• UTXO

Innovation

• cross-chain key reuse
• public key analysis
• cryptocurrency clustering
• UTXO vs account model
• privacy leakage