Research On Hybrid Blockchain Architecture Based On DAG

Blockchain solves the problem of how to reach consensus in a network that lacks trust and is completely free and open.Blockchain technology is currently used in a variety of fields such as finance,Internet of Things,and copyright authentication.However,the consensus mechanism of Bitcoin and Ethereum greatly limits the throughput and scalability of blockchain systems,while the single-chain structure leads to the problems of selfish mining and transaction order dependency in blockchain.The distributed ledger based on(Directed Acyclic Graph,DAG),represented by IOTA and Byteball,supports concurrent execution of operations and improves the throughput and scalability of blockchain,however,there are security problems such as not supporting strong consistency,low decentralization and uncertain transaction confirmation time.In this paper,we propose a hybrid blockchain architecture(Hybrid-DAG Blockchain,H-DAG)by combining the features of single-chain blockchain and DAG distributed ledger.By improving the block structure and transaction structure and optimizing the consensus mechanism,H-DAG can maintain the high throughput of DAG while confirming the transaction order;introducing the lightweight Po W mechanism to enhance the resistance double-spending ability of the blockchain and solve the transaction order dependency problem;adopting the incentive mechanism to make the honest nodes have more motivation to participate in maintaining the network and enhance the security of the network;the blockchain state can reach strong consistency;the confirmation time of transactions can be expected.We evaluate the performance of H-DAG by comparing and analyzing multiple sets of experiments,and model and verify the resistance of H-DAG to the double-spending attack.The experimental results show that the transaction order in H-DAG is globally consistent and the confirmation time of transactions is predictable,with the 1:3 ratio of computing power of light nodes to all miners in the network and the 3:7 ratio of computing power of attacking nodes to honest nodes,the success rate of doublespending after 6 blocks is 0.027%,which is significantly lower than the 0.13% on the Bitcoin.Therefore,H-DAG improves the attack resistance and enhances the security of the blockchain while ensuring the degree of decentralization of the blockchain system.It improves the system throughput by improving the block structure.