Advancement: Towards Scalability and Security Problem in Payment Channel Networks

Xiaoxue Zhang
Computer Engineering PhD Student
Location
Virtual Event
Advisor
Chen Qian

Join us on Zoom: https://ucsc.zoom.us/j/95365122028?pwd=WTZncElxNko2NXNJQUxyaTk1ZWJIUT09 / Passcode: 344802

Description: Payment channel networks (PCNs), have been designed to address the scalability challenge and throughput limitation of blockchains. Routing is a core problem of PCNs. An ideal PCN routing method needs to achieve high scalability that can maintain low per-node memory and communication cost for large PCNs, high resource utilization of payment channels, and the privacy of users. However, none of the existing PCN systems consider all these requirements. We first present WebFlow, a distributed routing solution for PCNs, which only requires each user to maintain localized information and can be used for massive-scale networks with high resource utilization. WebFlow makes use of two distributed data structures: multi-hop Delaunay triangulation (MDT) originally proposed for wireless networks and our innovation called distributed Voronoi diagram. We propose new protocols to generate a virtual Euclidean space in order to apply MDT to PCNs and use the distributed Voronoi diagram to enhance routing privacy. Then, we consider the problem of Payment channel networks (PCNs), that payment channels require a separate deposit for each channel of two users. It significantly locks funds from users into particular channels without the flexibility of moving these funds across channels. Thus, the proposal study a new method, Aggregated Payment Channel Network (APCN), in which allocatable funds are fixed as a per-user basis instead of a per-channel basis. To prevent users from misbehaving such as double-spending, APCN include mechanisms that make use of hardware trusted execution environments (TEEs) to control funds, balances and payments. The distributed routing protocol in APCN only requires each user to maintain localized information and can be used for massive-scale networks with high resource utilization. Lastly, we discuss the interoperability problem in Blockchain. Considering the existence of many different Blockchains and cryptocurrencies, we try to build a PCN system that support cross-chain communication and token swap among different Blockchain users.