Finding Possible Receivers of Lightning Transactions by Using Timing Information

Abstract

Foremost among the challenges of the Bitcoin blockchain is the scalability bottleneck. To address this issue, the Lightning Network, a payment channel network, was created. Lightning is a payment channel network that is source-routed and uses onion routing, like Tor. However, unlike Tor, the routing path is determined by optimizing a cost function, which uses public information. In this paper, a timing attack is evaluated by simulation of the Lightning Network. The goal of the attack is for an adversary that is part of a payment to determine the destination of the payment. The influence colluding adversaries have on the performance of the attack is evaluated. Three types of colluding adversaries (closest to destination, farthest from destination, average of all adversaries) are compared to a simple adversary that guesses the next hop in the payment is the destination of the payment. It is found that the adversary closest to the destination performs the best. Furthermore, shadow routing, a mitigation against these types of attacks, is evaluated against this attack. It is found that shadow routing does not have a significant impact on the performance of this attack.