Author: Sergei Tikhomirov 2021-03-28 15:56:46
Published on: 2021-03-28T15:56:46+00:00
A group of researchers have shared their novel work on channel balance probing for the Lightning Network (LN). They account for parallel channels in the context of probing, measure the efficiency of a probing attack in a simulator, propose and evaluate various countermeasures, and discuss the trade-offs they introduce. Channel probing has been explored previously, but in its simplest form, probing works as follows: An attacker sends payments with random hashes (aka probes), which fail either due to insufficient balance or incorrect hash. The attacker then learns the target channel balance with arbitrary precision by doing binary search over possible balances. The LN allows a pair of nodes to share multiple (parallel) channels. Non-strict forwarding hinders probing, as the attacker doesn't always know which channel the probes actually go through. In this paper, the authors model parallel channels from the prober's point of view, using a notion of a hop - a pair of nodes sharing one or multiple channels - and separate channel-level balance bounds from hop-level bounds. They discuss multiple countermeasures such as deliberately failing payments, spoofing errors, and introducing delays. They use an information-theoretical uncertainty metric to measure the prober's effectiveness. They simulate network delays based on real-world measurements and prior work. They hope that this work helps advance the discussion in the LN community about the optimal ways to address the trade-offs between privacy, security, and efficiency. The researchers' blog post and paper provide more details on their findings.
Updated on: 2023-06-01T18:40:48.123014+00:00