Congestion Attacks On Lightning Network.pdf

- Attack Type: Congestion Attacks in Payment Channel Networks
- Authors: Ayelet Mizrahi and Aviv Zohar, The Hebrew University of Jerusalem
- Attack Method: Exploits payment channel networks' limitations to paralyze channels, locking funds and disrupting payments. The attack involves overloading channels with unresolved requests until their expiration time, locking the channel for new payments.
- Attack Variations: Three versions are considered - blocking high-liquidity channels, disconnecting node pairs, or isolating individual nodes.
- Evaluation: The attack's costs are assessed on Bitcoin's Lightning Network, with changes in network parameters affecting attack costs. Recent modifications in Lightning implementations' default parameters are also considered.
- Contributions: The paper presents two attacks (network-wide DoS and node isolation), provides relevant Lightning Network statistics, evaluates attack resources and harm, confirms attack feasibility with proof-of-concept experiments, and suggests mitigation techniques.
- Attack Vulnerability: Based on three fundamental properties of off-chain payment networks - trustless payments, long expiration times, and payment privacy.
- Mitigation: Increasing HTLC limits is not effective; the attacker can create more payment requests. The paper suggests short-term mitigation approaches to make the attack more difficult and reduce its efficiency.