BeauForT: Robust Byzantine Fault Tolerance for Client-Centric Mobile Web Applications

In recent years, part of the web is shifting to a client-centric, decentralized model where web clients become the leading execution environment for application logic and data storage. However, current solutions to build decentralized web applications with multiple distrusting parties often involve a decentralized backend of servers running a BFT protocol between them. Existing consensus protocols using either all-to-all communication, or leader-based gossip suffer from performance degradation in unstable network conditions. In this paper, we present BeauForT, a purely browser-based platform for decentralized BFT consensus in client-centric, community-driven applications. We propose a novel, optimistic, leaderless, gossip-based consensus protocol, tolerating Byzantine replicas, combined with a robust and efficient state-based synchronization protocol. This protocol makes BeauForT well suited for the decentralized client-centric web and its dynamic nature with many network disruptions or node failures.