# Time Tells All: Deanonymization of Blockchain RPC Users with Zero Transaction Fee (Extended Version)

## TL;DR

This paper introduces a novel, zero-cost deanonymization attack on blockchain RPC users that links IP addresses to blockchain pseudonyms by exploiting temporal correlations in network traffic and transaction data.

## Contribution

It presents a new attack method that does not require transaction fees or active network eavesdropping, and validates its effectiveness through large-scale measurements and real-world experiments.

## Key findings

- Achieves over 95% success rate in deanonymization
- Effective across multiple blockchain networks including Ethereum, Bitcoin, and Solana
- Relies on temporal correlation between network traffic and blockchain transactions

## Abstract

Remote Procedure Call (RPC) services have become a primary gateway for users to access public blockchains. While they offer significant convenience, RPC services also introduce critical privacy challenges that remain insufficiently examined. Existing deanonymization attacks either do not apply to blockchain RPC users or incur costs like transaction fees assuming an active network eavesdropper. In this paper, we propose a novel deanonymization attack that can link an IP address of a RPC user to this user's blockchain pseudonym. Our analysis reveals a temporal correlation between the timestamps of transaction confirmations recorded on the public ledger and those of TCP packets sent by the victim when querying transaction status. We assume a strong passive adversary with access to network infrastructure, capable of monitoring traffic at network border routers or Internet exchange points. By monitoring network traffic and analyzing public ledgers, the attacker can link the IP address of the TCP packet to the pseudonym of the transaction initiator by exploiting the temporal correlation. This deanonymization attack incurs zero transaction fee. We mathematically model and analyze the attack method, perform large-scale measurements of blockchain ledgers, and conduct real-world attacks to validate the attack. Our attack achieves a high success rate of over 95% against normal RPC users on various blockchain networks, including Ethereum, Bitcoin and Solana.