QPBFT: Practical Byzantine Fault Tolerance Consensus Algorithm Based on Quantified-Role

Abstract

Practical Byzantine Fault Tolerance (PBFT) is an optional consensus protocol for consortium blockchains scenarios where strong consistency is required. However, it also inevitably incurs high energy consumption, low efficiency and poor scalability. What is more, the reliability of the consensus node cannot be guaranteed by itself. For addressing these problems, this paper proposes practical byzantine consensus algorithm based on quantified-role (QPBFT), which can achieve the following advantages: (1) Improving the security and reliability of the blockchain. The reliability attributes of nodes are quantified based on analytic hierarchy process (AHP), those nodes with high reliability evaluation scores are more likely to participate in block production by introduction of the quantified-role, which can ensure the reliability of blockchain network; (2) Realizing high efficiency and low energy consumption. Voting mechanism is adopted to simplify and optimize the PBFT consensus process; (3) Implementing adaptation to dynamic network environments. Management nodes, voting nodes, candidate nodes, and ordinary nodes are dynamically adjusted according to node reliability evaluation score for optimizing consensus performance. The paper demonstrates the security feature including reliability and fault tolerance. Meanwhile, simulation experiments are conducted to validate the higher efficiency and less resource consumption of QPBFT compared with PBFT.