Ten Myths About Blockchain Consensus

Blockchain and distributed ledger technologies have become key to develop secure decentralized applications. Their potential applications span various industries and their use-cases have already demonstrated the potential of such applications. Interestingly, these technologies rely on a large body of complex research topics like the Byzantine consensus problem. Although such problem was defined four decades ago, its subtle ramifications are largely misunderstood by many blockchain developers, let alone application programmers who build upon these blockchains. These misconceptions are dramatic as they prevent these applications from working efficiently and they make them vulnerable to attacks. This chapter debunks the major myths about blockchain consensus. First, it lists ten myths about blockchain consensus that are appearing frequently in the blockchain community. Second, it presents clarifications that debunk these myths to help build safer and more efficient blockchain and distributed ledger systems. These misconceptions are illustrated with the evaluation of three distributed ledgers, Hyperledger Fabric, Red Belly Blockchain, and R3 Corda, as well as three important consensus algorithms, BFT-SMaRt, Democratic BFT, and HotStuff.