As blockchain has found applications to track ownership of digital assets, it is crucial for companies to adopt more secure blockchains than the ones proven vulnerable to network attacks before moving them into production.

In this paper, we present Redbelly Blockchain (RBBC), the first secure blockchain whose throughput scales to hundreds of geo-distributed consensus participants.

To this end, we drastically revisited Byzantine Fault Tolerant (BFT) blockchains through three contributions:

(i) defining the Set Byzantine Consensus problem of agreeing on an enumerable valid subset of the union of the proposed values;

(ii) adopting a fair leaderless design to offer censorship-resistance guaranteeing the commit of correctly requested transactions;

(iii) introducing sharded verification to limit the number of signature verifications of each transaction.

We evaluate RBBC on up to 1000 VMs of 3 different types, spread across 4 continents, and under attacks. Although its performance is affected by attacks, RBBC scales in that its throughput increases to hundreds of consensus nodes and achieves 30K TPS throughput and 3-second latency on 1000 VMs, hence improving by 3x both the latency and the throughput of its closest competitor.

Redbelly was born at the University of Sydney when Prof. Vincent Gramoli set out to see if he could build a fork-proof blockchain. He could, and through a rigorous scientific development process, in partnership with CSIRO, The Redbelly Network was brought to market in 2021 with our first use-case going live in 2022.