| 词条 | Smart contract |
| 释义 |
}} A smart contract is a computer protocol intended to digitally facilitate, verify, or enforce the negotiation or performance of a contract. Smart contracts allow the performance of credible transactions without third parties. These transactions are trackable and irreversible. Proponents of smart contracts claim that many kinds of contractual clauses may be made partially or fully self-executing, self-enforcing, or both. The aim of smart contracts is to provide security that is superior to traditional contract law and to reduce other transaction costs associated with contracting. Various cryptocurrencies have implemented types of smart contracts. HistorySmart contracts were first proposed by Nick Szabo, who coined the term.[1] With the present implementations, based on blockchains,[2] "smart contract" is mostly used more specifically in the sense of general purpose computation that takes place on a blockchain or distributed ledger. In this interpretation, used for example by the Ethereum Foundation[3] or IBM,[4] a smart contract is not necessarily related to the classical concept of a contract, but can be any kind of computer program. In 2018, a US Senate report said: "While smart contracts might sound new, the concept is rooted in basic contract law. Usually, the judicial system adjudicates contractual disputes and enforces terms, but it is also common to have another arbitration method, especially for international transactions. With smart contracts, a program enforces the contract built into the code."[5] ImplementationsByzantine fault-tolerant algorithms allowed digital security through decentralization to form smart contracts. Additionally, the programming languages with various degrees of Turing-completeness as a built-in feature of some blockchains make the creation of custom sophisticated logic possible.[3]Notable examples of implementation of smart contracts are:
Replicated titles and contract executionSzabo proposes that smart contract infrastructure can be implemented by replicated asset registries[8] and contract execution using cryptographic hash chains and Byzantine fault-tolerant replication. Askemos implemented this approach in 2002[9][10] using Scheme (later adding SQLite[11][12]) as contract script language.[13] One proposal for using bitcoin for replicated asset registration and contract execution is called "colored coins".[14] Replicated titles for potentially arbitrary forms of property, along with replicated contract execution, are implemented in different projects. {{asof|2015}}, UBS was experimenting with "smart bonds" that use the bitcoin blockchain[15]in which payment streams could hypothetically be fully automated, creating a self-paying instrument.[16] Security issuesA smart contract is "a computerized transaction protocol that executes the terms of a contract".[17] A blockchain-based smart contract is visible to all users of said blockchain. However, this leads to a situation where bugs, including security holes, are visible to all yet may not be quickly fixed.[18] Such an attack, difficult to fix quickly, was successfully executed on The DAO in June 2016, draining {{USD|50 million}} in Ether while developers attempted to come to a solution that would gain consensus.[19] The DAO program had a time delay in place before the hacker could remove the funds; a hard fork of the Ethereum software was done to claw back the funds from the attacker before the time limit expired.[20] Issues in Ethereum smart contracts, in particular, include ambiguities and easy-but-insecure constructs in its contract language Solidity, compiler bugs, Ethereum Virtual Machine bugs, attacks on the blockchain network, the immutability of bugs and that there is no central source documenting known vulnerabilities, attacks and problematic constructs.[7] See also{{Portal|Law|Business and Economics}}
References1. ^{{cite web |url=http://fortune.com/2014/01/21/bitcoin-is-not-just-digital-currency-its-napster-for-finance/ |title=Bitcoin is not just digital currency. It's Napster for finance |last=Morris |first=David Z. |date=21 January 2014 |website=Fortune |accessdate=7 November 2018}} {{Means of Exchange}}{{Cryptocurrencies|state=expanded}}2. ^{{cite web|last1=Stafford|first1=Philip|last2=Murphy|first2=Hannah|title=Has the blockchain hype finally peaked?|url=https://www.ft.com/content/5e48f9ec-b651-11e6-ba85-95d1533d9a62|website=ft.com|publisher=Financial Times|accessdate=1 June 2017}} 3. ^1 {{cite web|last1=Buterin|first1=Vitalik|title=Ethereum Whitepaper|url=https://github.com/ethereum/wiki/wiki/White-Paper/f18902f4e7fb21dc92b37e8a0963eec4b3f4793a|website=github|accessdate=1 June 2017}} 4. ^{{cite web|last1=Cachin|first1=Christian|title=Architecture of the Hyperledger Blockchain Fabric|url=https://www.zurich.ibm.com/dccl/papers/cachin_dccl.pdf|website=ibm.com}} 5. ^[https://www.jec.senate.gov/public/_cache/files/aaac3a69-e9fb-45b6-be9f-b1fd96dd738b/chapter-9-building-a-secure-future-one-blockchain-at-a-time.pdf Chapter 9: Building a Secure Future, One blockchain at a time], US Senate Joint Economic Committee, March 2018. 6. ^{{Citation|title=7th International Conference on Principles of Security and Trust (POST)|year=2018|last1=Atzei|last2=Bartoletti|last3=Cimoli|last4=Lande|last5=Zunino|first1=Nicola|first2=Massimo|first3=Tiziana|first4=Stefano|first5=Roberto|contribution=SoK: unraveling Bitcoin smart contracts|contribution-url=https://eprint.iacr.org/2018/192.pdf|chapter-format=PDF|publisher=European Joint Conferences on Theory and Practice of Software}} 7. ^1 {{Citation|title=6th International Conference on Principles of Security and Trust (POST)|year=2017|last1=Atzei|last2=Bartoletti|last3=Cimoli|first1=Nicola|first2=Massimo|first3=Tiziana|contribution=A survey of attacks on Ethereum smart contracts|contribution-url=http://eprint.iacr.org/2016/1007.pdf|chapter-format=PDF|publisher=European Joint Conferences on Theory and Practice of Software}} 8. ^{{cite web | url=http://szabo.best.vwh.net/securetitle.html | author=Nick Szabo | title=Secure Property Titles with Owner Authority | year=2005 | accessdate=January 12, 2014 | deadurl=yes | archiveurl=https://web.archive.org/web/20140115142013/http://szabo.best.vwh.net/securetitle.html | archivedate=January 15, 2014 | df= }} 9. ^{{cite web | url=http://citeseerx.ist.psu.edu/viewdoc/download;?doi=10.1.1.11.5050&rep=rep1&type=pdf | year=2002 | author=Jörg F. Wittenberger | title=Askemos a distributed settlement |booktitle = Proceedings of International Conference on Advances in Infrastructure for e-Business, e-Education, e-Science, and e-Medicine on the Internet (SSGRR), L’Aquila }} 10. ^{{cite web | url=http://www.isl.cs.waseda.ac.jp/~sugawara/pdf/kurihara-SSGRR2002.pdf | title=Proceedings of International Conference on Advances in Infrastructure for e-Business, e-Education, e-Science, and e-Medicine on the Internet}} 11. ^{{cite journal | url=https://monami.hs-mittweida.de/frontdoor/index/index/docId/476 | title=Erstellung eines Archivierungskonzepts für die Speicherung rückverfolgbarer Datenbestände im Askemos-System | year=2009 | author=Martin Möbius}} 12. ^{{cite journal | url=https://core.ac.uk/display/33987564 | title=Entwicklung einer Datenbankschnittstelle als Grundlage für Shop-Systeme unter dem Betriebssystem Askemos | year=2010 | author=Tom-Steve Watzke}} 13. ^{{cite web | url=http://askemos.org/A0e80fdd97a7b6e7af87c5d294f39a96c | title=Beweiswürdigung elektronischer Dokumente im Zivilprozess unter vergleichender Betrachtung von qualifizierten elektronischen Signaturen nach dem Signaturgesetz und dem Askemos-Verfahren | author=RA Markus Heinker | year=2007}} 14. ^{{cite web | url=https://www.newscientist.com/article/dn24620-bitcoin-moves-beyond-mere-money.html | publisher=New Scientist | author= Hal Hodson| title=Bitcoin moves beyond mere money | date=20 November 2013 | accessdate=12 January 2014 }} 15. ^{{cite news |last=Ross|first=Rory |url=http://europe.newsweek.com/smart-money-blockchains-are-future-internet-329278 |title=Smart Money: Blockchains Are the Future of the Internet |work=Newsweek |date=2015-09-12 |accessdate=2016-05-27 }} 16. ^{{cite news |last=Wigan|first=David |url=http://www.ifrasia.com/bitcoin-technology-will-disrupt-derivatives-says-banker/21202956.article |title=Bitcoin technology will disrupt derivatives, says banker |work=IFR Asia |date=2015-06-11 |accessdate=2016-05-27 }} 17. ^{{cite book|title=The Blockchain Revolution: How the Technology Behind Bitcoin is Changing Money, Business, and the World|last1=Tapscott|first1=Don|last2=Tapscott|first2=Alex|date=May 2016|isbn=978-0670069972|pages=72, 83, 101, 127|authorlink=Don Tapscott}} 18. ^{{cite web|url=http://spectrum.ieee.org/tech-talk/computing/networks/ethereums-150-million-dollar-dao-opens-for-business-just-as-researchers-call-for-a-moratorium|title=Ethereum's $150-Million Blockchain-Powered Fund Opens Just as Researchers Call For a Halt|first=M.|last=Peck|date=28 May 2016|work=IEEE Spectrum|publisher=Institute of Electrical and Electronics Engineers}} 19. ^{{cite web|url=http://iqdupont.com/assets/documents/DUPONT-2017-Preprint-Algorithmic-Governance.pdf|title=Experiments in Algorithmic Governance: A history and ethnography of "The DAO", a failed Decentralized Autonomous Organization|last=DuPont|first=Quinn|date=2017|archive-url=https://web.archive.org/web/20170730133911/http://iqdupont.com/assets/documents/DUPONT%2D2017%2DPreprint%2DAlgorithmic%2DGovernance.pdf|archive-date=2017-07-30|dead-url=yes|accessdate=29 July 2017|website=}} 20. ^{{Cite news|url=https://www.bloomberg.com/news/articles/2016-08-25/this-is-your-company-on-blockchain|title=This Is Your Company on Blockchain|last=Coy|first=Peter|date=25 August 2016|work=|last2=Kharif|first2=Olga|newspaper=Bloomberg Businessweek|access-date=2016-12-05|via=}} 5 : Blockchains|Computer law|Contract law|Cryptocurrencies|Internet of things |
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