Discharged Payment Channels: Quantifying the Lightning Network's Resilience to Topology-Based Attacks
This work addresses security vulnerabilities in the widely used Lightning Network, which is crucial for cryptocurrency users and developers, though it is incremental as it builds on existing network analysis methods.
The paper analyzes the Lightning Network's payment channel topology to assess its resilience against random failures and targeted attacks, such as channel exhaustion and node isolation, finding that it is susceptible to these attacks and that attackers should use centrality-based or highest ranked minimum cut strategies depending on their resources.
The Lightning Network is the most widely used payment channel network (PCN) to date, making it an attractive attack surface for adversaries. In this paper, we analyze the Lightning Network's PCN topology and investigate its resilience towards random failures and targeted attacks. In particular, we introduce the notions of channel exhaustion and node isolation attacks and show that the Lightning Network is susceptible to these attacks. In a preliminary analysis, we confirm that the Lightning Network can be classified as a small-world and scale-free network. Based on these findings, we develop a series of strategies for targeted attacks and introduce metrics that allow us to quantify the adversary's advantage. Our results indicate that an attacker who is able to remove a certain number of nodes should follow a centrality-based strategy, while a resource-limited attacker who aims for high efficiency should employ a highest ranked minimum cut strategy.