Research On Distributed Consensus Algorithm Based On DAG

Distributed ledger technology has been applied to various fields of social development and human life.Blockchain distributed ledger technology has the characteristics of high security,low scalability and high energy consumption,so it is difficult to be applied in the fields of Internet of things with low energy consumption and high throughput.The directed acyclic graph distributed Ledger has the advantages of high scalability and low energy consumption,which is very suitable for application in the field of the Internet of things.However,its tip selection algorithm either cannot guarantee security,or causes a large number of transactions to be left.Therefore,improving the tip selection algorithm is the core problem of this paper.This paper compares several typical tip selection algorithms,and improves the flexibility of the selection algorithm and the adaptability of the ledger to the changes of network scale by combining a variety of algorithms;This paper uses coordinator to suppress lazy nodes.It ensures the throughput of the distributed network and the certainty of authentication.The main work is as follows:Distributed ledger has been applied to various areas of social development and human life,such as digital currency,food traceability,track tracking,and data monitoring.Blockchain distributed ledger technology represented by Bitcoin and Ethereum has high security performance due to the use of workload proof algorithm,but it also leads to the bottleneck of these distributed ledgers in transaction throughput.It is difficult to apply blockchain to the field of Internet of things requiring low energy consumption.Therefore,this paper focuses on another distributed ledger technology-directed acyclic graph distributed ledger.The directed acyclic graph ledger gets rid of the chain structure of the blockchain ledger and adopts the structure of directed acyclic graph to store data,which makes it possible for the wireless growth of throughput.At the same time,the technology does not rely on the miner mechanism,there is no fee and the algorithm has low energy consumption.It is very suitable for application in the field of Iot.This paper compares the implementation of several directed acyclic graph distributed ledger technologies in the current market in energy consumption,security,throughput and other aspects,and finally makes an in-depth study around IOTA technology.The main research and results of this paper are as follows:(1)The concept of sharpness and the dynamic approximation tip selection algorithm are proposed.The improved algorithm can flexibly select different selection strategies according to the change of sub-tangle sharpness.When the sub-tangle tip sharpness is low,the weighted random walk is used,and when the sub-tangle sharpness is high,the neutral selection algorithm is used.This algorithm can significantly reduce the number of legacy transactions in the network.At the same time,the threshold value of sharpness is analyzed and calculated.(2)A method combining coordinate transaction and coordinator is proposed to suppress the generation of lazy nodes.Regulators can issue "coordinate" transactions signed by certificates.Coordinate transactions contain information such as the height of the third-party certificate signature,which can help ordinary users identify lazy transactions.When the network scale is expanded,lazy nodes can be suppressed through the snapshot mechanism.(3)An agricultural greenhouse data monitoring system is designed and implemented,which uses IOTA as the network layer of the Internet of things,and stores the sensor data in the greenhouse on the tangle.The data monitoring platform can obtain complete sensor data through the compete-IOTA nodes.