AToM: Active Topology Monitoring for the Bitcoin Peer-to-Peer Network

TL;DR

This paper introduces AToM, a protocol for reliably inferring and monitoring Bitcoin network topology, demonstrating high accuracy and low network impact, thereby enabling better analysis and security of the network.

Contribution

It proposes a novel protocol for topology inference in Bitcoin P2P networks, addressing the limitations of obfuscation and enabling improved network analysis.

Findings

Topology obfuscation is ineffective against side-channel attacks.

The protocol achieves over 90% precision and recall in topology inference.

The system has minimal impact on network performance.

Abstract

Over the past decade, the Bitcoin P2P network protocol has become a reference model for all modern cryptocurrencies. While nodes in this network are known, the connections among them are kept hidden, as it is commonly believed that this helps protect from deanonymization and low-level attacks. However, adversaries can bypass this limitation by inferring connections through side channels. At the same time, the lack of topology information hinders the analysis of the network, which is essential to improve efficiency and security. In this paper, we thoroughly review network-level attacks and empirically show that topology obfuscation is not an effective countermeasure. We then argue that the benefits of an open topology potentially outweigh its risks, and propose a protocol to reliably infer and monitor connections among reachable nodes of the Bitcoin network. We formally analyze our protocol and experimentally evaluate its accuracy in both trusted and untrusted settings. Results show our system has a low impact on the network, and has precision and recall are over 90% with up to 20% of malicious nodes in the network.