Path Planning at the Edge of Payment Channel Networks

Payment Channel Networks (PCNs) improve the scalability of a cryptocurrency by increasing the number of payments that can be processed while simultaneously decreasing the latency of these payments. A PCN consists of a network of payment channels between peers. To perform a payment between peers not directly connected by a payment channel, a payment path consisting of a sequence of payment channels connecting the peers must be determined. Planning a payment path is a computationally expensive task and therefore generally infeasible for an edge device. We propose a novel method to overcome this challenge, which involves the edge device using a service provider to support this path planning task. However, sharing payment data with service providers may violate users’ privacy. To mitigate this challenge, our method integrates two privacy-preserving mechanisms. The first mechanism generalises an existing mechanism known as blinded paths and obfuscates both the start and end of the payment path. The second mechanism involves generating convincing fake requests and using these to obfuscate the genuine request. We evaluated our method against trampoline payments, a highly cited method that uses a service provider to support path planning, by simulating payment attempts on the Lightning Network which is a PCN built on the Bitcoin cryptocurrency.