Research And Implementation Of Cross-chain Consensus Algorithm Based On Distance Weighting

Blockchain has been widely used and practiced in many industries and fields,since 2008,such as finance and digital currency,social governance,authentication and data tracing.However,with the prosperity and diversification of blockchain types,it has gradually become a challenge to conduct trusted access to information between heterogeneous blockchains.Because the ledgers are relatively independent,which results in "data island",and so that the difference in block structure and consensus verification logic between heterogeneous chains makes the communication between chains even more difficult.In order to ensure cross-chain access,much of the current work is focused on chain notaries and trunk chain connectivity modes.However,these methods have the following drawbacks:1)notaries on the chain are more vulnerable to attacks due to their high degree of centralization,which causes off-chain users to lose their trust and thus exacerbates the off-chain trust crisis;2)although the relay model involves multiple parties in maintenance and supervision and enjoys a more robust trust,the participant nodes are relatively fixed,which impose a terrible dilemma that invalid nodes cannot participate in consensus formation in a timely manner,thus progressively disrupting the connectivity of the relay across heterogeneous chains and eventually reducing the rate of trusted mutual access.In this thesis,we propose a novel general framework for cross-heterogeneous blockchain communication basing on a periodical committee rotation mechanism to support information exchange of diverse transactions across multiple heterogeneous blockchain systems.Firstly,this thesis defines the concept of distance weighting between blockchains and forms a directed weighted graph.Based on this,an efficient cross-chain consensus algorithm is designed,which enables data from different ledgers to flow freely and reliably.Consensus verification of messages is carried out by distance based message validation and SPV technology.Through log formatting and routing mechanism,the message can be reliably forwarded across the chain.The exception handling mechanism is designed to enhance the reliability of consensus algorithm,so as to realize more convenient and secure log routing,consensus verification and access between heterogeneous blockchain.Secondly,in order to realize the data exchange under the cross-chain consensus,this thesis establishes a committee to connect multiple heterogeneous block chains.In order to improve the expansibility,we have designed the mechanism of safe exit and dynamic entry of committees,In order to improve the reliability of the system,an algorithm is designed to remove the down nodes periodically.In order to ensure the distribution of the system,a distributed random number generation algorithm is designed to start the next cycle.Compared with traditional methods,this thesis has a better degree of trust and a more robust running process.Finally,the prototype of the scheme is implemented,and the throughput of the cross-chain consensus algorithm and the operation efficiency of the relay committee are experimented and analyzed.Experiments show that the processing capacity of this thesis is about 20 messages per second,which is stronger than the PBFT consensus.In addition,the results also show that the proposed scheme has good performance in system stability,failure probability and fault tolerance rate of malicious nodes.