区块链起源于中本聪的比特币，作为比特币的底层技术，本质上是一个去中心化的数据库。 是指通过去中心化和去信任的方式集体维护一个可靠数据库的技术方案。 区块链技术是一种不依赖第三方、通过自身分布式节点进行网络数据的存储、验证、传递和交流的一种技术方案。
上一篇给大家分享了学术范里的区块链面临的挑战与机遇、研究技术进展与未来的发展趋势。此篇分享区块链在隐私保护和比特币方面的应用。
文献均来自学术范Blockchain-研究方向详细 - 学术范 (xueshufan.com)
参考翻译：学术范自带翻译（边浏览边翻译这个功能对英语渣渣太太友好了！）
1.Hawk: The Blockchain Model of Cryptography and Privacy-Preserving Smart Contracts
会议论文2016IEEE S&P 2016
Ahmed E. Kosba 1 /Andrew Miller 1 /Elaine Shi 2 /Zikai Wen 2 /Charalampos Papamanthou 1
1University of Maryland, College Park2Cornell University
Emerging smart contract systems over decentralized cryptocurrencies allow mutually distrustful parties to transact safely without trusted third parties. In the event of contractual breaches or aborts, the decentralized blockchain ensures that honest parties obtain commensurate compensation. Existing systems, however, lack transactional privacy. All transactions, including flow of money between pseudonyms and amount transacted, are exposed on the blockchain. We present Hawk, a decentralized smart contract system that does not store financial transactions in the clear on the blockchain, thus retaining transactional privacy from the public's view. A Hawk programmer can write a private smart contract in an intuitive manner without having to implement cryptography, and our compiler automatically generates an efficient cryptographic protocol where contractual parties interact with the blockchain, using cryptographic primitives such as zero-knowledge proofs. To formally define and reason about the security of our protocols, we are the first to formalize the blockchain model of cryptography. The formal modeling is of independent interest. We advocate the community to adopt such a formal model when designing applications atop decentralized blockchains.
2.IoT security: Review, blockchain solutions, and open challenges
期刊论文2017Future Generation Computer Systems
Minhaj Ahmad Khan 1 /Khaled Salah 2
1Bahauddin Zakariya University2Khalifa University
With the advent of smart homes, smart cities, and smart everything, the Internet of Things (IoT) has emerged as an area of incredible impact, potential, and growth, with Cisco Inc. predicting to have 50 billion connected devices by 2020. However, most of these IoT devices are easy to hack and compromise. Typically, these IoT devices are limited in compute, storage, and network capacity, and therefore they are more vulnerable to attacks than other endpoint devices such as smartphones, tablets, or computers. In this paper, we present and survey major security issues for IoT. We review and categorize popular security issues with regard to the IoT layered architecture, in addition to protocols used for networking, communication, and management. We outline security requirements for IoT along with the existing attacks, threats, and state-of-the-art solutions. Furthermore, we tabulate and map IoT security problems against existing solutions found in the literature. More importantly, we discuss, how blockchain, which is the underlying technology for bitcoin, can be a key enabler to solve many IoT security problems. The paper also identifies open research problems and challenges for IoT security.
3. Making Smart Contracts Smarter
会议论文2016ACM CCS 2016
Loi Luu 1 /Duc-Hiep Chu 1 /Hrishi Olickel 2 /Prateek Saxena 1 /Aquinas Hobor 1
1National University of Singapore2Yale-NUS College
Cryptocurrencies record transactions in a decentralized data structure called a blockchain. Two of the most popular cryptocurrencies, Bitcoin and Ethereum, support the feature to encode rules or scripts for processing transactions. This feature has evolved to give practical shape to the ideas of smart contracts, or full-fledged programs that are run on blockchains. Recently, Ethereum's smart contract system has seen steady adoption, supporting tens of thousands of contracts, holding millions dollars worth of virtual coins. In this paper, we investigate the security of running smart contracts based on Ethereum in an open distributed network like those of cryptocurrencies. We introduce several new security problems in which an adversary can manipulate smart contract execution to gain profit. These bugs suggest subtle gaps in the understanding of the distributed semantics of the underlying platform. As a refinement, we propose ways to enhance the operational semantics of Ethereum to make contracts less vulnerable. For developers writing contracts for the existing Ethereum system, we build a symbolic execution tool called Oyente to find potential security bugs. Among 19, 336 existing Ethereum contracts, Oyente flags 8, 833 of them as vulnerable, including the TheDAO bug which led to a 60 million US dollar loss in June 2016. We also discuss the severity of other attacks for several case studies which have source code available and confirm the attacks (which target only our accounts) in the main Ethereum network.
4.Majority Is Not Enough: Bitcoin Mining Is Vulnerable
会议论文2014FC 2014
Ittay Eyal 1 /Emin Gün Sirer 1
The Bitcoin cryptocurrency records its transactions in a public log called the blockchain. Its security rests critically on the distributed protocol that maintains the blockchain, run by participants called miners. Conventional wisdom asserts that the mining protocol is incentive-compatible and secure against colluding minority groups, that is, it incentivizes miners to follow the protocol as prescribed.
