摘要
随着第一个去中心化加密货币系统——比特币系统自2009年上线成功运行至今,其背后的区块链技术也受到广泛关注.区块链技术独有的去中心化、去信任的特性,为构建价值互联平台提供了可能.在比特币白皮书中,区块链的概念十分模糊,而现有的一些介绍区块链的文章中,也多从抽象层次进行介绍,对于更深入的后续研究提供的帮助十分有限.本文首先将区块链技术从具体应用场景中抽象出来,提取出其五层核心架构,并就其中数据、网络、共识三层基础架构作详细说明.这三层架构包含了区块链系统中的三大核心技术:密码学、共识算法、网络.文中介绍这三种技术的研究现状,能够使读者迅速了解区块链技术的发展状况,并能根据自己的需要进行深入阅读.最后,介绍了区块链目前的应用现状和技术展望.
While the first decentralized cryptocurrency system,Bitcoin,has run successfully since it was launched in 2009,the underlying technology,blockchain,now draws increasing attention.Based on the unique decentralization and trusted features of blockchain,it is possible to build a value-connected platform.However,the Bitcoin white paper does not provide a rigorous definition of blockchain.Meanwhile,prior related work mainly introduces high level concepts in blockchain,ignoring the important technique details.To provide an in-depth introduction of blockchain,this survey first extracts the blockchain technology from specific application scenarios,breaks the blockchain architecture into five core layers,and elaborates on the data,network,and consensus layers.More specifically,we introduce state-of-the-art techniques of three main components of a blockchain system:cryptography,consensus algorithm,and network in detail.We firstly introduce basic cryptographic tools involved in blockchain systems,such as hash calculation,Merkle tree,digital signature,elliptic curve digital signature algorithm(ECDSA),ring signature algorithm,zero-knowledge proof,and anti-quantum cryptographic algorithm.We then summarize the mainstream consensus processes involved in the existing systems and refine the consensus framework.Users can choose different consensus components to build their own consensus models according to the characteristics of the application scenarios.The end of the consensus section introduces the methods for modeling consensus algorithms abstractly and the two approaches used to formally prove and analyze the essential features of consensus models.Further,we introduce the network topologies and common network protocols adopted in blockchain systems.In addition,we introduce three hot issues related to blockchain,which are privacy protection,common attack schemes and capacity expansion.The paper analyzes the existing research results on the anonymity of Bitcoin,and then introduces three options to enhance its privacy:mixed currency,ring signature and zero knowledge proof.The existing attack schemes are divided into two categories in the paper,one based on the consensus model adopted by the system,and the other based on the network.We summarize the existing blockchain expansion schemes as single-chain extensions and cross-chain extensions,and analyze the two types in detail.At last,the current application situation and technical prospects of blockchain are introduced.We introduce three phases of the development of blockchain application,namely the digital currency,smart contract and new extensions in other areas.We compared different digital currencies in terms of purpose,distribution method,consensus algorithm and other aspects.We select three typical systems,Ethereum,Hyperledger and Enterprise Operation System(EOS),as the examples to show how to build smart contracts.Blockchain has made significant impact on the innovation and evolution of various fields,especially in the areas of Internet of Things,medical and public key infrastructure.Compared with other blockchain surveys,this survey summarizes and refines the papers in the blockchain field rather than a simple combination of prior work.For example,in the introduction to the consensus module,we extract a general framework from many existing consensus models.We split the consensus instances in different systems according to the hierarchy of the framework,and extract the components that are necessary for building a consensus model.Based on this survey,readers are able to understand the development of blockchain quickly and can explore in depth according to their respective needs.
作者
蔡晓晴
邓尧
张亮
史久琛
陈全
郑文立
刘志强
龙宇
王堃
李超
过敏意
CAI Xiao-Qing;DENG Yao;ZHANG Liang;SHI Jiu-Chen;CHEN Quan;ZHENG Wen-Li;LIU Zhi-Qiang;LONG Yu;WANG Kun;LI Chao;GUO Min-Yi(Department of Computer Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240;Shanghai Institute for Advanced Communication and Data Science,Shanghai Jiao Tong University,Shanghai 200240;College of Internet of Things,Nanjing University of Posts and Telecommunications,Nanjing 210003)
出处
《计算机学报》
EI
CSCD
北大核心
2021年第1期84-131,共48页
Chinese Journal of Computers
基金
国家重点研发计划项目(2018YFB1004800)
国家“九七三”计划项目(2015CB352403)
国家自然科学基金项目(61872240,61602301,61632017,61702329,61832006,61702328)
上海市科技创新行动计划(19511101403)资助.
关键词
区块链
比特币
密码学
共识算法
P2P网络
区块链应用
blockchain
Bitcoin
cryptography
consensus algorithm
P2P network
blockchain application
作者简介
蔡晓晴,博士研究生,中国计算机学会(CCF)学生会员,主要研究方向为区块链.E-mail:cai-xq@sjtu.edu.cn;邓尧,硕士研究生,中国计算机学会(CCF)学生会员,主要研究方向为区块链;张亮,博士研究生,中国计算机学会(CCF)学生会员,主要研究方向为分布式系统、数据流、区块链;史久琛,博士研究生,中国计算机学会(CCF)学生会员,主要研究方向为分布式系统、区块链;陈全,博士,特别研究员,中国计算机学会(CCF)会员,主要研究领域为分布式计算、计算机体系结构、区块链;郑文立,博士,特别副研究员,中国计算机学会(CCF)会员,主要研究方向为分布式系统、云计算、区块链;刘志强,博士,副教授,中国计算机学会(CCF)区块链专委会委员,主要研究方向为区块链、信息安全与密码学;龙宇,博士,副教授,主要研究方向为密码学、区块链;王堃,博士,教授,中国计算机学会(CCF)会员,主要研究领域为区块链、能源互联网、边缘计算;李超,博士,特别研究员,中国计算机学会(CCF)会员,主要研究领域为面向新应用新技术的体系结构;通信作者:过敏意,博士,教授,中国计算机学会(CCF)会士,主要研究领域为并行计算、分布式系统、大数据、区块链.E-mail: guo-my@cs.sjtu.edu.cn。
