DCCP: a dependable committee consensus protocol for permissionless blockchain

The consensus protocol is the core of blockchain systems. The existing hybrid committee-based consensus protocol is one of the important ways to improve the permissionless blockchain system. But the presence of malicious nodes, it can interfere with the normal operation of the committee. However, there is a deficiency in the existing mechanism to ensure the efficient and secure operation of the committee. Therefore, a reliable committee consensus protocol (DCCP) for permissionless blockchain is proposed. The protocol guarantees the operation of the committee in three ways. First, a reliability evaluation model is designed based on the performance of committee members. Second, a reliable node selection strategy is proposed by combining the mining process and node reliability value. Third, a malicious node replacement mechanism is proposed to optimize the committee operation. Finally, a delayed reward mechanism is designed in order to encourage node participation. The experiment shows that the DCCP protocol can effectively inhibit the entry of malicious nodes and can improve the throughput by 12% in the presence of malicious nodes, with high throughput and security.