Security Analysis of Sharding in Blockchain with PBFT Consensus

Abstract

Blockchain sharding technology randomly divides all nodes in the blockchain system into multiple shardings. This design aims to solve the scalable problem when there are too many access nodes in the blockchain network, by significantly reducing the complexity of reaching consensus and improving the throughput and efficiency of transactions in the blockchain system. However, if too many malicious nodes are allocated or the number of nodes is not enough, it may bring security risks to sharding. This paper analyzes the sharding security of blockchain systems with PBFT consensus under non-cross sharding transaction and cross sharding transaction. Simulation results show that both the number of nodes in a sharding and the number of malicious nodes affect the sharding security. In the case of cross-sharding, we can increase the number of cross-sharding validation nodes to improve the success rate of consensus.