查看更多>>摘要：Context:Decentralized autonomous organizations are a new form of smart contract-based governance.Decen-tralized autonomous organization platforms,which support the creation of such organizations,are becoming increasingly popular,such as Aragon and Colony.Selecting the best fitting platform is challenging for organi-zations,as a significant number of decision criteria,such as popularity,developer availability,governance issues and consistent documentation of such platforms,should be considered.Additionally,decision-makers at the or-ganizations are not experts in every domain,so they must continuously acquire volatile knowledge regarding such platforms.Objective:Supporting decision-makers in selecting the right decentralized autonomous organization platforms by designing an effective decision model is the main objective of this study.We aim to provide more insight into their selection process and reduce time and effort significantly by designing a decision model.Method:This study presents a decision model for the decentralized autonomous organization platform selection problem.The decision model captures knowledge regarding such platforms and concepts systematically.This model is based on an existing theoretical framework that assists software engineers with a set of multi-criteria decision-making problems in software production.Results:We conducted three industry case studies in the context of three decentralized autonomous organizations to evaluate the effectiveness and efficiency of the decision model in assisting decision-makers.The case study participants declared that the decision model provides significantly more insight into their selection process and reduces time and effort.Conclusion:We observe in the empirical evidence from the case studies that decision-makers can make more rational,efficient,and effective decisions with the decision model.Furthermore,the reusable form of the captured knowledge regarding decentralized autonomous organization platforms can be employed by other researchers in their future investigations.
查看更多>>摘要：Blockchain technology has been rapidly growing since Bitcoin was invented in 2008.The most common type of blockchain system,public(permissionless)blockchain system,has some unique features that lead to a tension with the European Union's General Data Protection Regulation(GDPR)and other similar data protection laws.In this paper,we report the results of a systematic literature review(SLR)on 114 research papers discussing and/or addressing such a tension.To the best of our knowledge,our SLR is the most comprehensive review of this tension,leading to a more in-depth and broader analysis of related research work on this important topic.Our results revealed three main types of issues:(ⅰ)difficulties in exercising data subjects'rights such as the'right to be forgotten'(RTBF)due to the immutable nature of public blockchains;(ⅱ)difficulties in identifying roles and responsibilities in the public blockchain data processing ecosystem(particularly on the identification of data controllers and data processors);and(ⅲ)ambiguities regarding the application of the relevant law(s)due to the distributed nature of blockchains.Our work also led to a better understanding of solutions for improving the GDPR compliance of public blockchain systems.It can help inform not only blockchain researchers and developers but also policymakers and law markers to consider how to reconcile the tension between public blockchain systems and data protection laws(the GDPR and beyond).
查看更多>>摘要：The Ethereum blockchain's smart contract is a programmable transaction that performs general-purpose com-putations and can be executed automatically on the blockchain.Leveraging this component,blockchain tech-nology(BT)has grown beyond the scope of cryptocurrencies and can now be applicable in various industries other than finance.In this paper,we investigated the current trends in Ethereum-based decentralized applications(DApps)to be able to categorize and analyze the DApps to measure the complexity of smart contracts behind them,their level of security and their correlation to the maintainability of the DApps.We leveraged the source code analysis,security analysis,and the developmental metadata of the DApps to infer this correlation.Based on our findings,we concluded that the maintainability of Ethereum DApps is proportional to the code size,number of functions,and,most importantly,the number of outgoing invocations and statements in the smart contracts.
查看更多>>摘要：The bunker industry has faced negative perception to their trust and credibility in recent times.This is further compounded by the need for the industry to answer new challenges to meet the requirement of the International Maritime Organization 2020.The aim of this work is to illustrate how blockchain technology may be adopted for aiding in bunker dispute resolution.To demonstrate how blockchain may aid in disputes within the bunker industry,this paper first examines the existing bunker supply process,which involves the formation of contracts under English law,the Bunker Delivery Notes,the different types of disputes that may arise during a bunker transaction and the methods of dispute resolution utilised by the industry.Furthermore,the current literature in relation to blockchain technology and blockchain smart contracts is examined.Finally,interviews and surveys within the industry have been conducted to identify the benefits and challenges in adopting blockchain technology.The research found that blockchains may benefit the bunker supply chain offering the effective resolution of bunker quality disputes.Furthermore,blockchains may also serve as a verification tool for electronic bunker delivery notes,which may aid quality and quantity bunker disputes as well as compliance with the new Inter-national Maritime Organisation 2020 requirements.As a result,despite the research having shown blockchain to be situationally dependent and having an element of legal uncertainty,blockchain does offer a solution to aid in bunker disputes and for improving the trust and credibility within the bunker industry.
Paolo BottoniClaudio Di CiccioRemo PareschiDomenico Tortola...
68-83页
查看更多>>摘要：Smart contracts show a high potential to make supply chain management strategies epochally leap towards higher levels of productivity,not only in the functioning of production processes but also in terms of product innovation and overall economic returns.This article illustrates the principle of Income Sharing as a highly performing economic strategy for supply chains with a natural implementation in blockchain smart contracts.It proposes a blockchain-based architecture that uses smart contracts to implement various algorithmic versions of the Income Sharing principle among companies participating in a supply chain.The formation of the total income and its consequent redistribution are calculated taking into account the role of the technological platform automating these procedures,which therefore becomes a party to the inter-company business project of a supply chain in the alternative roles,as feasible in business practice,of Blockchain-as-a-Service and Blockchain-as-a-Partner.The approach is implemented on Hyperledger Fabric,the most widespread platform for private and consortium blockchains.We compare and justify this design choice with the alternative given by public blockchains,with specific attention to Ethereum.
查看更多>>摘要：User-centric data sharing is essential to encourage citizens'active participation in the digital economy.One key to smart cities,a form of the digital economy,is the promotion of public use of citizen data.Nevertheless,it is not easy to utilize data without citizens'consent.In this study,we took a technological approach to these issues.User-managed access(UMA)is a well-known framework for delegating resource access rights to others on the Internet.In UMA,authorization mechanisms are designed to be centralized so that resource owners can centrally manage access rights for various resources stored in different domains.However,the lack of transparency in the autho-rization mechanism is a barrier to its implementation in large-scale systems such as smart cities.In this study,we developed a blockchain-based cross-domain authorization architecture that enables a resource-sharing ecosystem in which organizations that wish to utilize data can freely trade with each other.The proposed architecture solves the transparency problem that conventional authorization systems have had by designing the authorization mechanism on blockchain technology.We implemented the proposed architecture as smart contracts and eval-uated its processing performance.The resultant time required for delegating access rights and accessing resources was less than 500 ms.Furthermore,we found that the fluctuation in the processing time overhead was small.Based on these results,we concluded that performance degradation with the proposed architecture is minor.
William HughesTobias MagnussonAlejandro RussoGerardo Schneider...
99-124页
查看更多>>摘要：Smart contracts are self-executing programs running in the blockchain allowing for decentralised storage and execution without a middleman.On-chain execution is expensive,with miners charging fees for distributed execution according to a cost model defined in the protocol.In particular,transactions have a high fixed cost.We present MultiCall,a transaction-batching interpreter for Ethereum that reduces the cost of smart contract executions by gathering multiple users'transactions into a batch.Our current implementation of MultiCall in-cludes the following features:the ability to emulate Ethereum calls and create transactions,both from MultiCall itself and using an identity unique to the user;the ability to cheaply pay Ether to other MultiCall users;and the ability to authorise emulated transactions on behalf of multiple users in a single transaction using hash-based authorisation rather than more expensive signatures.This improves upon a previous version of MultiCall.Our experiments show that MultiCall provides a saving between 57％and 99％of the fixed transaction cost compared with the standard approach of sending Ethereum transactions directly.Besides,we also show how to prevent an economic attack exploiting the metatransaction feature,describe a generic protocol for hash-based authorisation of metatransactions,and analyse how to minimise its off-chain computational and storage cost.
查看更多>>摘要：Presently,there are over 500 cryptocurrency exchanges worldwide and more than 19,700 different crypto-currencies.Despite the fact that cryptocurrency trading is possible via private peer-to-peer transactions,more than 90％of trading occurs on organised exchanges,which provide convenience and liquidity.However,centralised cryptocurrency exchanges are regarded as high-value targets by criminals and are often victims of cyberattacks.In this paper,we investigate the risk of cryptocurrency exchange closures and develop predictive models to forecast which markets will close down and which ones will remain active using publicly available data.Our models perform well and reach a high level of classification accuracy.Exchange trading volume,the availability of public information on exchange staff,exchange lifetime,and several cybersecurity features are identified as key attri-butes in predicting exchange closures.Nevertheless,our models do not account for all sources of risk,e.g.,po-tential fraud and mismanagement of client funds committed by the exchanges themselves,and market participants are encouraged to carefully consider where and how they store their digital assets.
查看更多>>摘要：The search for smart contract source codes has drawn research attention to fulfill developers'and researchers'needs.Yet,the existing studies are not mature enough to address smart contracts'technical properties and functionalities.This paper proposes a system to improve the naive search for smart contract codes;for example,Etherscan has one keyword search feature without regard to the contract structure.We consider clustering smart contracts based on developers'preferences,which increases the probability that the resulting source codes match developers'needs.Our experimental results show a significant improvement in the complexity of the retrieved source codes of smart contracts compared with the baseline scenario using blockchain search engines(e.g.,Etherscan).Our solution reduces the number of retrieved smart contract codes the developer has to check if the codes match her/his needs by 94％,88％,82％,or 98％,depending on the user's search preferences.
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