Optimized byzantine fault tolerant algorithm for improving performance and security with trust values

Blockchain is considered to be a promising technology due to its decentralization, open, and non tamperation. Nevertheless, the current blockchain system cannot replace traditional financial institutions because its performance and security indicators in the consensus algorithm are not perfect. As one of the emerging capacity expansion technologies, sharding technology improves throughput by grouping users and processing transactions in parallel. This paper proposes an improved Byzantine Fault Tolerance algorithm TV-BRAFT. TV-BRAFT calculates a trust value for each user through an incentive mechanism. The sharding scheme based on the trust value is adopted to reduce the probability of malicious nodes being allocated to the same partition, thus improving the security of the system. In the consensus, the system selects users with qualified trust values to form a verification group to supervise the consensus process and avoid submitting error transactions to the blockchain. In order to prove that the TV-BRAFT can resist Byzantine attacks, a recursive formula is used to prove the security of sharding and the security of consensus within one shard. Finally, the simulation results show that the TV-BRAFT not only guarantees the fairness of incentives but is also better than the Raft and PBFT algorithms in efficiency and throughput.