GossipSub: Attack-Resilient Message Propagation in the Filecoin and\n ETH2.0 Networks

Abstract

Permissionless blockchain environments necessitate the use of a fast and\nattack-resilient message propagation protocol for Block and Transaction\nmessages to keep nodes synchronised and avoid forks. We present GossipSub, a\ngossip-based pubsub protocol, which, in contrast to past pubsub protocols,\nincorporates resilience against a wide spectrum of attacks.\n Firstly, GossipSub's mesh construction implements an eager push model keeps\nthe fan-out of the pubsub delivery low and balances excessive bandwidth\nconsumption and fast message propagation throughout the mesh. Secondly, through\ngossip dissemination, GossipSub realises a lazy-pull model to reach nodes\nfar-away or outside the mesh. Thirdly, through constant observation, nodes\nmaintain a score profile for the peers they are connected to, allowing them to\nchoose the most well-behaved nodes to include in the mesh. Finally, and most\nimportantly, a number of tailor-made mitigation strategies designed\nspecifically for these three components make GossipSub resilient against the\nmost challenging Sybil-based attacks. We test GossipSub in a testbed\nenvironment involving more than 5000 VM nodes deployed on AWS and show that it\nstays immune to all considered attacks. GossipSub is currently being integrated\nas the main messaging layer protocol in the Filecoin and the Ethereum 2.0\n(ETH2.0) blockchains.\n