Scaling Blockchain Towards Bitcoin: Key Technologies, Constraints and Related Issues
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摘要: 比特币是一种利用区块链技术的点对点记账系统.随着比特币的发展,现有的比特币系统架构已经不能满足日益增长的交易需求,亟需扩容以寻求长期发展.比特币是以人为核心的复杂社会经济系统,比特币扩容是涉及多方利益的复杂问题,引起了业界与学术界的广泛关注.本文提出了一个比特币系统扩容问题的研究框架,包括关键技术,制约因素与衍生问题三部分,以深入探讨和研究比特币扩容问题.在该研究框架下,首先介绍链上和链下两类扩容关键技术及发展现状;其次从网络负载和节点瓶颈两方面,总结制约比特币扩容方案的宏观与微观因素;最后,探讨两类衍生问题:从系统安全性的角度,探讨比特币扩容可能引发的安全问题及解决策略;从币值、交易费与矿工收益等方面,阐述比特币扩容涉及的经济问题.Abstract: Bitcoin is a peer-to-peer ledger system based on the blockchain technology. With the development of Bitcoin, the existing Bitcoin system architecture can no longer meet the demand of the increasingly large volume of transactions, so that Bitcoin scalability becomes one of the most important problems to solve in Bitcoin-related systems today. The Bitcoin system is a complex human-centered socio-economic system, and the Bitcoin scalability problem is a complex problem involving multi-party interests, which has attracted increasing attention of both industries and academia. This paper presents a research framework for the Bitcoin scalability problem, including the key technologies, constraints and related issues, in order to help explore and study the Bitcoin scalability problem. Under the framework, we first introduce two kinds of key technologies and their current developments. Secondly, we summarize factors that restrict the Bitcoin scalability from the aspects of network load and node performance. Finally, we explore the related security issues and economic issues involved in the Bitcoin scalability.
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Key words:
- Blockchain /
- Bitcoin /
- scalability /
- segregated witness /
- lightning network
1) 本文责任编委 刘向杰 -
表 1 区块扩容方案比较
Table 1 Comparison among BIPs related to increasing block size
编号 主要内容 提出者 提出时间 状态 100 区块大小可为1 MB至32 MB之间的浮动值由矿工投票决定实际区块大小 Jeff Garzik, Tom Harding, Dagur Valberg Johannsson 2015-06-11 Removed 101 在全网75 %算力支持下在2016-01-11将区块大小限制提高到8 MB并在2036-01-06前每两年对上限值进行翻倍直到达到8 GB. Gavin Andresen 2015-06-22 Withdrawn 102 在2015-11-11将区块大小限制提高到2 MB. Jeff Garzik 2015-06-23 Draft 103 在2063年前每年将区块大小限制提高17.7 %. Pieter Wuille 2015-07-21 Draft 104 按照最近2016个区块的大小调整上限. t.khan 2017-01-13 Draft 105 按照最近2016个区块的矿工投票调整上限. BtcDrak 2015-08-21 Draft 106 1)按照最近难度区间的区块大小调整上限; 2)按照最近2个难度区间的区块大小以及交易手续费调整上限. Upal Chakraborty 2015-08-24 Draft 107 分两阶段扩容进行扩容. (阶段一) 2016~2017: 2 MB; 2018~2019: 4 MB; 2020: 6 MB; (阶段二)从2020年以后每4周按照区块大小决定是否将上限提高10 %. Washington Y. Sanchez 2015-09-11 Draft 109 在全网75 %算力支持下将区块大小限制提高到2 MB., Gavin Andresen 2016-01-28 Rejected 表 2 比特币线上扩容重要提案
Table 2 BIPs related to on-chain scaling
编号 主要内容 提出者 提出时间 状态 9 对区块中的版本字段的语义进行更改让多个软分叉方案可以并行执行.它将版本字段表示为位向量每个位可以用于跟踪独立的改变.矿工通过更新某个位的值表示对某项软分叉准备就绪.在软分叉开始$([STARTED])$后当一个难度区间内(即2 016个区块)中95 %的区块都表示支持该项软分叉则它进入锁定阶段($[LOCKED\_IN]$)否则失败($[FAILED]); $被锁定的软分叉需要再等2016个区块才能正式激活. Pieter Wuille, Peter Todd, Greg Maxwell, Rusty Russell, 2015-10-04 Final 91 该提案削弱了原SegWit激活条件(即BIP9): 1)确认窗口从2016个区块下降到336个区块; 2)激活阈值从95 %削减到80 %; 3)接受bit1和bit4两种信号发送方式在激活后拒绝没有发送bit1的区块. James Hilliard 2017-05-22 Final 148 采取UASF方案激活SegWit支持UASF的节点会在2017-08-01开始强制执行新规则不符合新规则的区块将被这些节点拒绝. Shaolin Fry 2017-03-12 Final -
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