Research On Dynamic TBFT Mechanism Based On Threshold Signature

With the development of cryptocurrency led by bitcoin,blockchain as its underlying technology has attracted wide attention from governments and industry giants.As an important branch of the blockchain,the permission chain is characterized by its strong privacy,easier supervision and high efficiency,making it widely used in the fields of finance and banking.However,the consensus mechanism in the current permission chain has problems such as the fact that the consensus node cannot be dynamically added and the fault tolerance rate is low,which cannot meet the requirements of the current application market.In the PBFT technology used by R3 and Hyperledger,consensus nodes cannot be dynamically added to the consensus network,and the consensus system fault tolerance rate is only f =(n-1)/3.In Ripple's RPCA mechanism,in addition to the consensus node can't dynamically join the consensus network,the connectivity between RPCA consensus nodes is less than 20%or the number of honest verification nodes in the UNL list of consensus nodes is less than 80%of the total nodes,the blockchain will also occur bifurcation.After studying the above consensus mechanism,this paper combines(t,n)threshold signature with PBFT technology to propose our dynamic TBFT scheme based on threshold signature.Compared with PBFT and RPCA,the TBFT scheme offers the following advantages:1.No fork:Combining the threshold signature with the PBFT technology ensures that the consensus node can confirm the consistency of the block data,and the blockchain will not be forked.2.The consensus node only needs to maintain a pair of public and private keys:(t,n)threshold signature is applied to the design of the permission chain consensus mechanism.Consensus nodes only need to maintain a pair of public and private keys to achieve consistency confirmation of the block.After the consensus node dynamically joins the consensus network,the number of public and private keys maintained between the consensus nodes does not increase.3.Dynamic join of consensus nodes:(t,n)threshold signature is applied to the design of the permission chain consensus mechanism,under the decentralization mechanism,as long as t+1 consensus nodes in the consensus network cooperate,the dynamic join of the consensus nodes can be realized.4.High fault tolerance rate:Combining(t,n)threshold signature with PBFT technology,and using PBFT three-stage protocol broadcast mechanism,our TBFT scheme can achieve the fault tolerance rate of f'=(n-1)/2.Finally,we experimentally tested the efficiency of the TBFT scheme,and the experimental data shows that our scheme can achieve 4 seconds of transaction confirmation time and 2048 transaction throughput,meeting the performance requirements of most consensus systems.