Trinity: A Byzantine Fault-Tolerant Distributed Publish-Subscribe System with Immutable Blockchain-based Persistence

Internet of Things (IoT), Supply Chain monitoring, and other distributed applications rely on messaging protocols for data exchange. Contemporary IoT and enterprise deployments widely use the publish-subscribe messaging model because of its resource-efficiency. However, the systems with publish-subscribe messaging model employ a centralized architecture, wherein the data from all the publishers in the application network flows via a central broker to the subscribers. Such a centralized architecture makes the publish-subscribe messaging model susceptible to Byzantine failures. For example, it provides an opportunity for the organization that owns the broker to tamper with the data. In this work, we contribute Trinity, a novel distributed publish-subscribe broker with Byzantine fault-tolerance and blockchain-based immutability. Trinity distributes the data published to one of the brokers in the network to all the brokers in the network, and stores the data in an immutable ledger through the use of blockchain technology. Through the use of consensus protocols and distributed ledger technology, Trinity can guarantee ordering, fault-tolerance, persistence and immutability across trust boundaries.Our evaluation results show that Trinity consumes minimal resources. To the best of our knowledge, Trinity is the first framework that combines the components of the blockchain technology with the publish-subscribe messaging model. Furthermore, we plan to use Trinity in a real-world use case for increasing the transparency of racial profiling.