Consensus-forming method in network, and node for configuring network

摘要

A consensus building method suitable when f Byzantine failure nodes (f is an integer equal to or larger than 1 and smaller than N/3) are assumed in a network having N nodes (N is an integer equal to or larger than 1) participating in consensus building, comprising the steps of: receiving a first message from other node which communicates that the other node determined a message including data subject to consensus building valid as a proposal, when the number of received first messages reach a predetermined value Q, transmitting a second message to each node which communicates that it is accepting the proposal, and when the number of received first messages do not reach the predetermined value Q, transmitting a third message to each node which communicates that it is dismissing the proposal, when the number of received second messages reach a predetermined value Q, transmitting a fourth message to each note which communicates that it is treating the proposal as agreed in the network, and when the number of received third messages reach a predetermined value Q, transmitting a fifth message for proceeding to a next round (a unit of consensus building process is called “round”.) to each node, wherein the predetermined value Q is an integer equal to or larger than (f+N+1)/2 when a value of f is known, and wherein when the number of received first message reaches a predetermined value Q, a lock is set to limit behaviors thereafter.