A Committee-Based Byzantine Consensus Protocol for Blockchain

With the great success of Bitcoin, the blockchain, as its key underlying technology, has been paid more and more concern. However, the Proof-of-Work (PoW) mechanism used by Bitcoin requires long confirmation time and wastes more computing resource. Practical Byzantine Fault Tolerance (PBFT), as another important protocol that has been widely used, which can tolerate at most 1/3 corruptions, meanwhile confirm transactions with quick speed. In fact, it is difficult to implement and maintain it with a large-scale setting. In this paper, considering a permissioned setting, we propose a Byzantine protocol based on the committee, and elect a committee to reach the consensus on behalf of all participants. In steady state, our protocol uses PBFT to approve transactions among all members of the committee. In election state, we use an efficient election algorithm which can combine the latest consensus results with the participants' authentication information to elect a new committee. Our protocol improves on Bitcoin in confirmation time and provides safety and liveness on the condition of the amount of Byzantine participants are less than 1/3.