LC-PBFT: A low-communication-overhead PBFT consensus scheme for wide-range applications

Practical Byzantine fault tolerance (PBFT) is suitable for large-scale network scenarios due to its ability to resist malicious nodes and high throughput. However, the complex consensus strategy and frequent communication interactions of the protocol cause N 2 communication overhead, which is difficult to implement in a large-scale environment with unstable network conditions. In order to reduce the communication cost of the PBFT blockchain system under large-scale nodes, we proposed a low-communication-overhead PBFT consensus mechanism (LC-PBFT). The scheme reduces the system communication complexity to near-linear by geographically clustering nodes and optimizing the propagation protocol. In the specific design scheme, this paper proposes a two-layer PBFT consensus model with low communication complexity and reused the leader nodes. This reuse function solves the problem of primary node centralization while bringing improvements in communication efficiency, consensus process, and view changes. In the consensus process, LC-PBFT clarifies the dynamic grouping strategy and combines the dynamic path propagation algorithm designed by IPFS to reduce the local and global communication overhead, respectively; in terms of security, the scheme uses the fault probability distribution (FPD) model to derive the security threshold and verify the security of the protocol under large-scale applications. Experimental results show that under the experimental condition of 51 nodes, the consensus efficiency of the LC-PBFT mechanism is improved by 48%–53%; in an ideal, trouble-free situation, the average throughput of the system is increased by more than three times.