Research And Implementation Of Blockchain Consensus Algorithm Based On Satellite Network

Blockchain technology has attracted much attention from academia and industry since the success of Bitcoin.Due to its special chained data structure,consensus algorithm and incentive mechanism,blockchain has some unique features like being tamper-resistant and trustfree.Still,low throughput remains to be the biggest obstacle to the large-scale application of blockchain,which explains why improving the throughput of blockchain systems has always been the focus of researches.Most existing optimization schemes have been considering things in the scope of consensus algorithm but ignored the impact of the underlying broadcast network on the throughput.Considering the indispensable maintenance of data consistency,it is essential that a considerable amount of data should be broadcasted in the blockchain system.Consequently,the performance of the underlying broadcast network would greatly matter for the performance of the whole system,and this is the perspective where this paper sees from in aim of improving the system.In order to optimize the underlying broadcast network,this paper adds a satellite node to the current network structure,and uses the satellite broadcasting to replace the current Internet broadcasting.Compared with Internet broadcasting,satellite broadcasting does not require the participation of nodes in the broadcasting process,which can avoid the Byzantine attack by malicious nodes during data broadcasting.In addition,since all data is broadcast serially by the satellite,the order in which the ground nodes receive the data can normally be considered to be exactly same.Besides,the introduction of satellites changes the network structure into a satellite-centric star topology,which can avoid traffic redundancy during data broadcasting.It is worth noting that the decentralization of the blockchain system will not be compromised because the satellite is only responsible for data broadcasting and does not participate in consensus.This paper is divided into the following three main parts: an analysis of the underlying broadcast network,the design of consensus algorithm based on the single satellite network and the design of consensus algorithm based on the multi-satellite network.In the first part,we,taking the Bitcoin system as the research object,analyzed the topology and data broadcast mode of the underlying broadcast network and found out two defects.In addition,we collected a lot of real data about the underlying network of Bitcoin from thirdparty websites and used those data to construct two Bitcoin simulation environments,where five tests were designed to explore the impact of the defects on the system.In the second part,we firstly introduced a geostationary satellite into the underlying broadcast network as an auxiliary communication node to optimize the network structure.By replacing the broadcasting algorithm with satellite broadcasting in the blockchain system,malicious nodes can be prevented from using the broadcasting algorithm to create data inconsistencies.Then,we proposed a consensus algorithm based on single-satellite network.In this algorithm,the advantages of the satellite network were used to improve system throughput.Next we proposed a recovery mechanism to deal with the short-term interruption of satellite channels caused by special astronomical phenomena.Finally,we tested the performance and effect of the above algorithm through experiments.In the third part,we carried on the preliminary design of the algorithm based on multisatellite network to realize a full coverage of the whole globe as an advancement of the singlesatellite network.Through the global clock characteristic of the multi-satellite network,the algorithm tackled the nodes' data receival disorder,which was caused by inter-satellite routing in multi-satellite network.In addition,we used the satellite signature and inquiry mechanism to terminate possible data loss in the network,that is,the node's failure to receive part of the broadcast data.