基于有向无环图的区块链技术综述

区块链技术已广泛应用于金融、公共服务、物联网、网络安全、供应链等多个领域，但传统单链结构的区块链在吞吐量、交易确认速度和可扩展性方面存在不足，导致其在一些短时高并发量数据场景中难以落地应用。基于有向无环图（DAG）的区块链技术因其具有交易并发确认功能、吞吐量高、可扩展性强等优势受到研究者广泛关注。通过分析研究现有DAG区块链的发展和演化过程、评估方法、优化方向以及应用场景，探索DAG区块链在落地应用中的可行性。阐述主流DAG区块链的研究现状，比较传统区块链与DAG区块链的优势与不足，并分析现有区块链属性评估方法，总结DAG区块链评估结果。在此基础上，从交易确认速度、系统吞吐量、系统安全性、存储结构等方面对比现有DAG区块链的优化方法，介绍DAG区块链在数据管理、基于边缘计算和联邦学习的数据共享以及面向访问控制和隐私保护的数据安全等场景中的应用情况，并指出当前研究中存在的主要问题和挑战，对未来的研究方向进行展望。

Survey of Directed Acyclic Graph Based Blockchain Technology

Blockchain technology has been widely used in finance, public services, the Internet of Things(IoT), network security, supply chains, and other fields.However, the traditional blockchain with a single chain structure has some deficiencies in throughput, transaction confirmation speed, and scalability, which makes it difficult to apply it in some short-term and high concurrency data scenarios.In this paper, the Directed Acyclic Graph(DAG) based blockchain technology has attracted extensive attention and studied by scholars because of its advantages, such as concurrent transaction confirmation, high throughput, and strong scalability.By analyzing and studying the development and evolution, evaluation methods, optimization direction, and application scenarios of the existing DAG based blockchains, this paper explores the feasibility of DAG based blockchains in landing applications.Through the development of a mainstream DAG based blockchain, it compares the advantages and disadvantages of traditional blockchains and DAG based blockchains, analyzes the existing blockchain attribute evaluation methods, and summarizes the current DAG based blockchain evaluation results.On this basis, this paper summarizes the optimization methods of the existing DAG based blockchain from the aspects of transaction confirmation speed, system throughput, system security, and storage structure, and summarizes the application of a DAG based blockchain in data management, data sharing based on edge computing and federated learning, and data security for access control and privacy protection.Finally, it points out the main problems and challenges in the current studies, and provides further research directions.