An Experimental Evaluation of BFT Protocols for Blockchains

Abstract

Byzantine Fault Tolerant (BFT) protocols have been used in blockchains due to their high performance and fast block acceptance. However, their weakness is a lack of scalability to support a large number of nodes in the network due to message demanding broadcasts. There have been recent improvements to the classic Practical Byzantine Fault Tolerant (PBFT) protocol. Evaluating the performance and reliability of the different BFT based protocols in the context of blockchains will give users a better picture of the behaviour and scalability of these protocols under different circumstances. For this purpose, we implemented and evaluated the performance of different BFT based protocols for blockchains under normal conditions as well as when byzantine failures are encountered in the network. Furthermore, we also calculated the reliability of each protocol under the desired throughput.