Route Hijacking and DoS in Off-Chain Networks

Abstract

Off-chain transaction networks can mitigate the scalability issues of today's trustless blockchain systems such as Bitcoin. However, these peer-to-peer networks also introduce a new attack surface which is not yet fully understood. This paper identifies and analyzes a novel type of Denial-of-Service attack which is based on attracting routes, i.e., which exploits the way transactions are routed and executed along the channels of the network in order to attract nodes to route through the attacker. This attack is conceptually interesting as it highlights a fundamental design tradeoff for the defender (who determines its own routes): to become less susceptible to hijacking, a rational node has to pay higher fees to nodes that forward its payments.