The potentiality of Blockchain technology is widespread and applied to diverse fields. Blockchain is a distributed ledger of transactions that store immutable records in chronological order in an append-only mode. Hence, humongous data is stored on the blockchain and will continuously expand over time. Blockchain has been rapidly adopted by many businesses for storing the provenance data because of its salient features like immutability, robustness and tamperproof. Blockchain stores data provenance as transactions that are collected from sources like a centralized cloud or decentralized cloud that helps in identifying cybercrimes. This paper emphasizes on the different approaches of querying the data provenance transactions stored in Ethereum Blockchain based on various search parameters using REST API web services. The approach not only queries based on the first-class data elements like blocks, transactions, account address and contract address but also queries based on the provenance data stored on the Ethereum Blockchain explained with a use case LegalProv.
A decentralized private Blockchain implementation for academic document storage and document verification can add self-sovereignty to the process. It can dramatically minimize the time and cost of verification at various layers of verification. Blockchain would remove all the layers at all and it will provide immediate auditing of any document. So, the request and response will be truly real time in our case.Apart from speeding up the verification process, it will also increase the security of personal education data and will check all kind of misuse also. Putting documents on Blockchain would increase the security, because all the data would only be accessible by private key and proper authentication to that private key.We are proposing a private Blockchain that would be managed by some private vendors and only those vendors will take part in consensus. So, we are using proof of stake consensus in our case. We are using private IPFS database server for storing our documents over Blockchain. We are considering Ethereum Blockchain ecosystem in our case. Alternatively we can also use Hyperledger Fabric for implementation but that discussion is out of the scope for current document.
Visualization is a widely used in different fields of studies such as supply chain management when there is a need to communicate information to general users. However, there are multiple limitations and problems with visualizing information within traditional systems. In traditional systems, data is in control of one single authority; so data is mutable and there is no guarantee that system administer does not change the data to achieve a desired result. Besides, such systems are not transparent and users do not have any access to the data flow. In this thesis, the main goal was to visualize information that has been saved on top of a new technology named blockchain to overcome the aforementioned problems. All the records in the system are saved on the blockchain and data is pulled out from blockchain to be used in visualization. To have a better insight, a review has been done on relevant studies about blockchain, supply chain and visualization. After identifying the gap in literature review, an architecture was proposed that was used in the implementation. The implementation contains, a system on top of ethereum blockchain and front-end which allows users to interact with the system. In the system, all the information about products and all the transactions that ever happened in the system, are recorded on the blockchain. Then, data was retrieved from the blockchain and used to visualize provenance of products on Google Map API. After implementing the system, the performance was evaluated to make sure that it can handle different situations where various number of clients sending request to the system simultaneously. The performance was as expected in which system responds longer when number of clients sending requests were growing. \nThe proposed solution fill the gap that was identified in the literature review. By adding provenance visualization users can explore previous owners and locations of a product in a trustable manner. Future research can focus on analysis of data which will allow organizations to make informed decisions on choosing popular products to sell.
Hamza Baqa, Nguyen B. Truong, Noël Crespi, Gyu Myoung Lee · 5 authors
The emerging Blockchain (BC) and Distributed Ledger technologies have come to impact a variety of domains, from capital market sectors to digital asset management in the Internet of Things (IoT). As a result, more and more BC-based decentralized applications for numerous cross-domain services have been developed. These applications implement specialized decentralized computer programs called Smart Contracts (SCs) which are deployed into BC frameworks. Although these SCs are open ato public, it is challenging to discover and utilize such SCs for a wide range of usages from both systems and end-users because such SCs are already compiled in form of byte-codes without any associated meta-data. This motivates us to propose a solution called Semantic SC (SSC) which integrates RESTful semantic web technologies in SCs, deployed on the Ethereum Blockchain platform, for indexing, browsing and annotating such SCs. The solution also exposes the relevant distributed ledgers as Linked Data for enhancing the discovery capability. To achieve this goal, the OWL-S service ontology is extended by incorporating some domain specific terminologies, which are used in the development of the proposed SSCs. As a result, SSC can be utilized to enrich queries for a domain-specific terms across multiple distributed ledgers, which greatly increases the discovery capability of decentralized IoT applications and services. Contribution in standardization is also discussed. We believe that our research work takes the first steps towards connecting BC-based decentralized services with semantic web services in order to provide better IoT ecosystems.
Background: Millions of smart contracts have been deployed to Ethereum for providing various applications. Recent studies discovered many severe security and performance issues in smart contracts by applying static program analysis techniques to them. Given a smart contract, the majority of these analysis techniques need to first construct its control flow graph, which connects basic blocks through control flow transfers (CFTs), before conducting further analysis. Aims: The objective of this work is to understand the capabilities of static program analysis techniques to identify CFTs, and to investigate how static program analysis techniques can be improved if the CFTs are complemented. Method: We perform a comprehensive empirical study on six widely-used tools for smart contract analysis by using all deployed smart contracts to understand their capabilities to recognize CFTs. We capture all execution traces of all smart contracts to evaluate the number of CFTs covered by traces that are not found by those tools. We enhance a state-of-the-art tool, OYENTE for discovering vulnerabilities in smart contracts with the CFTs covered by traces to investigate how the tool is improved. Results: These studied tools fail to identify all CFTs due to several reasons, e.g., incomplete code patterns. Execution traces effectively complement these tool in recognizing CFTs. By including the CFTs covered by traces, the false negative rate of OYENTE can be reduced by up to 30%. Conclusions: Our study underlines the ineffectiveness of static analysis techniques due to the incapabilities of CFT identification.
Yorghos Voutos, Γεώργιος Δρακόπουλος, Phivos Mylonas
Smart agriculture is increasingly becoming a paramount financial sector with important implications on a global scale. The real time weather and soil status monitoring as well as the desired higher food quality are major drivers behind this technological, ecological, and financial trend. This work explores the enticing prospect of combining IoT and smart contract technologies with smart agriculture in order to deliver not only higher quality agricultural products, but also improving the associated supply chain and agricultural logistics, thus resulting in multiple benefits for all the parties involved. Emphasis is placed on deriving similarity metrics for tuples describing soil and climate conditions based on numerical and possibly categorical data. Moreover, a sample implementation of one such metric is given in Solidity, a high level language for formulating smart contracts designed for the Ethereum Virtual Machine is also provided as a concrete example. Finally, aspects of agricultural asset digitization, a crucial step for smart contracts relying on physical objects are also discussed.
The smart contract on the blockchain allows credible transactions without a third party. These transactions are traceable and irreversible. The deployment and implementation of smart contracts in Ethernet will consume some gas, which will directly affect the cost of smart contracts. In order to reduce the consumption of gas during the execution of smart contracts, this article proposes an optimization algorithm for generating business process smart contracts. First, business process modeling notation (BPMN) models are extended to Petri nets. Second, Petri nets are simplified to find nodes in BPMN models that can be considered fusion tasks. Using new mapping rules from the BPMN model to solidity language, BPMN model is generated into Ethereum Smart contract model. In the BPMN models with multilayer fusion task, experimental results show that the proposed algorithm can save 15% gas on average for business processes with multiple fusion tasks.
Zhenzhen Li, Jiangpan Hou, Hai Wang, Chencheng Wang · 6 authors
Ethereum is a blockchain platform that can run smart contracts and implement decentralized applications over a peer-to-peer(P2P) network. As the second-largest cryptocurrency in the world, Ethereum has attracted a lot of attention from industry and academia. Researches on Ethereum and other blockchain platforms focus on application, smart contracts, and P2P networks. Most of works use the data collected by active crawling, and rarely obtained data from the passive monitoring perspective, especially in the blockchain P2P network analysis. In this work, we propose a passive method using traffic association and machine learning to conduct online Ethereum node detection in NetFlow data, and monitor the Ethereum nodes in NetFlow traffic to gather nodes connection dataset. Based on the dataset, multi-dimensional measurement and analysis is made in order to reveal the true performance of Ethereum network.
Meryam Essaid, Daeyong Kim, Soo Hoon Maeng, Sejin Park · 5 authors
Recently Distributed Denial-of-Service (DDoS) are becoming more and more sophisticated, which makes the existing defence systems not capable of tolerating by themselves against wide-ranging attacks. Thus, collaborative protection mitigation has become a needed alternative to extend defence mechanisms. However, the existing coordinated DDoS mitigation approaches either they require a complex configuration or are highly-priced. Blockchain technology offers a solution that reduces the complexity of signalling DDoS system, as well as a platform where many autonomous systems (Ass) can share hardware resources and defence capabilities for an effective DDoS defence. In this work, we also used a Deep learning DDoS detection system; we identify individual DDoS attack class and also define whether the incoming traffic is legitimate or attack. By classifying the attack traffic flow separately, our proposed mitigation technique could deny only the specific traffic causing the attack, instead of blocking all the traffic coming towards the victim(s).
The 21stcentury is all about modernization and accepting new technologies. The Blockchain Technology is a prominent and reliable technology that is getting into almost every industry today. After it was first initiated in 2008, it has tremendously gained traction. Within a short span of 10 years, it is commendable that it has grown massively and has been easily accepted worldwide. Though the first application of this technology is cryptocurrency, blockchain technology has transcended to support more applications as well. Developers have been smart enough to study the underlying protocol and customize it according to their own requirements. Today, blockchain offers multiple functionalities like decentralization, security, transparency and democracy.Two such giants which are most popular in the blockchain world are - Bitcoin and Ethereum. The elemental difference between these two platforms of the blockchain technology is the purpose for which they have been created. In this paper, the underlying differences between these two blockchain platforms will be overviewed. Both these applications are cryptocurrencies, but the focus in this paper would be on the comparison of the the underlying concepts and their protocols. The objective of both platforms, the differences in their architectures and the consensus or agreement mechanism used between the participants would be summarized along with the scalability factors and limitations. This paper will provide a brief overview of both these platforms and a clear idea about their use in the industry today.
Sofiane Benahmed, Ivan Pidikseev, Rasheed Hussain, Jooyoung Lee · 7 authors
Development of Distributed Ledger Technology (DLT)-based applications requires an appropriate platform that meets the application requirements. However, due to the abundance of such platforms such as Ethereum, NEM, IOTA, and OpenChain, and the differences among them in terms of scalability, throughput, and features, it is not easy to select a platform for a given use-case. Selection of the right DLT platform is pivotal for the performance of applications and thus-forth directly affects consumer satisfaction. Therefore, the aforementioned factors must be taken into account to decide on a particular platform. To fill this gap, in this paper, we conduct a comparative analysis of different DLT platforms. The choice of platform is based on their popularity and current market share as well as the evolving trends and approaches. In essence, we choose Ethereum, EOS, Hyperledger Sawtooth and NEO. We compare these platforms from both development and performance perspectives. The comparison revealed that Sawtooth provides a huge customization capability that affects the performance and EOS maintains a stable throughput under varying network scales and loads.
Since it takes time and effort to put a new product or service on the market,\none would like to predict whether it will be a success. In general this is not\npossible, but it is possible to follow best practices in order to maximise the\nchance of success. A smart contract is intended to encode business logic and is\ntherefore at the heart of every new business on the Ethereum blockchain. We\nhave investigated how to measure the success of smart contracts, and whether\nsuccessful smart contracts have characteristics that less successful smart\ncontracts lack. The appearance of a smart contract on a listing website such as\nEtherscan or StateoftheDapps is such a characteristic. In this paper, we\npresent a three-pronged analysis of the relative success of listed smart\ncontracts. First, we have used statistical analysis on the publicly visible\ntransaction history of the Ethereum blockchain to determine that listed\ncontracts are significantly more successful than their unlisted counterparts.\nNext, we have conducted a survey among more than 200 developers via an\nanonymous online survey about their experience with the listing process. A\nsignificant majority of respondents do not believe that listing a contract\nitself contributes to its success, but they believe that the extra attention\nthat is typically paid in tandem with the listing process does contribute.\nFinally, based on the respondents' answers, we have drafted 10 recommendations\nfor developers and validated them by submitting them to an international panel\nof experts.\n
Sunbeom So, Myungho Lee, Jisu Park, Heejo Lee · 5 authors
We present VERISMART, a highly precise verifier for ensuring arithmetic safety of Ethereum smart contracts. Writing safe smart contracts without unintended behavior is critically important because smart contracts are immutable and even a single flaw can cause huge financial damage. In particular, ensuring that arithmetic operations are safe is one of the most important and common security concerns of Ethereum smart contracts nowadays. In response, several safety analyzers have been proposed over the past few years, but state-of-the-art is still unsatisfactory; no existing tools achieve high precision and recall at the same time, inherently limited to producing annoying false alarms or missing critical bugs. By contrast, VERISMART aims for an uncompromising analyzer that performs exhaustive verification without compromising precision or scalability, thereby greatly reducing the burden of manually checking undiscovered or incorrectly-reported issues. To achieve this goal, we present a new domain-specific algorithm for verifying smart contracts, which is able to automatically discover and leverage transaction invariants that are essential for precisely analyzing smart contracts. Evaluation with real-world smart contracts shows that VERISMART can detect all arithmetic bugs with a negligible number of false alarms, far outperforming existing analyzers.
Blockchain technology is ready to disrupt nearly every industry and business model, and the energy sector is no exception. Energy businesses across the world have already started exploring the use of blockchain technology in large-scale energy trading systems, peer-to-peer energy trading, project financing, supply chain tracking, and asset management among other applications. Information and Communication Technologies (ICTs) recently started revolutionizing the energy landscape, and now blockchain technology is providing an additional opportunity to make the energy system more intelligent, efficient, transparent, and secure in the longer term. The idea of this paper is to examine more closely the use of blockchain technology for its possible application in the energy efficiency industry and to determine how it could make energy efficiency markets more secure and transparent in the longer term. This paper examines in detail the key benefits and implications of using blockchain in the energy efficiency sector through the presentation and discussion of two case studies as possible blockchain applications—(i) the UK Energy Company Obligation scheme and (ii) the Italian White Certificate Scheme. We have presented how the key issues around trading energy efficiency savings—correctly estimating the savings, data transparency among stakeholders, and inefficient administrative processes—can be solved through the application of a blockchain-based smart contract system. Finally, this paper presents an implementation of a smart contract for trading of energy-saving certificates achieved via execution of smart contract transactions on the Ethereum blockchain.
Ning Lu, Bin Wang, Yongxin Zhang, Wenbo Shi · 5 authors
Summary Ethereum is one of the currently popular trading platform, where any one can exchange, buy, or sell cryptocurrencies. Smart contract, a computer program, can help Ethereum to encode rules or scripts for processing transactions. Because the smart contract usually handles large number of cryptocurrencies worth billions of dollars apiece, its security has gained considerable attention. In this paper, we first investigate the security of smart contracts running on the Ethereum and introduce several new security vulnerabilities that allow adversaries to exploit and gain financial benefits. Then, we propose a more practical smart contract analysis tool termed NeuCheck, in which we introduce the syntax tree in the syntactical analyzer to complete the transformation from source code to intermediate representation, and then adopt the open source library working with XML to analyze such tree. We have built a prototype of NeuCheck for Ethereum and evaluate it with over 52 000 existing Ethereum smart contracts. The results show that (1) our new documented vulnerabilities are prevalent; (2) NeuCheck improves the analysis speed by at least 17.2 times compared to other popular analysis tools (eg, Securify and Mythril; and (3) allows for cross‐platform deployment.
Naman Goel, Cyril van Schreven, Aris Filos-Ratsikas, Boi Faltings
Blockchain based systems allow various kinds of financial transactions to be executed in a decentralized manner. However, these systems often rely on a trusted third party (oracle) to get correct information about the real-world events, which trigger the financial transactions. In this paper, we identify two biggest challenges in building decentralized, trustless and transparent oracles. The first challenge is acquiring correct information about the real-world events without relying on a trusted information provider. We show how a peer-consistency incentive mechanism can be used to acquire truthful information from an untrusted and self-interested crowd, even when the crowd has outside incentives to provide wrong informations. The second is a system design and implementation challenge. For the first time, we show how to implement a trustless and transparent oracle in Ethereum. We discuss various non-trivial issues that arise in implementing peer-consistency mechanisms in Ethereum, suggest several optimizations to reduce gas cost and provide empirical analysis.
Social network advertising is currently one of the most effective advertising types available to promote a product or a brand. The problem discussed in this paper concerns the possibility to ensure that advertising reaches really interested users, and also to prove this. At this aim, we propose the use of Blockchain to store users' interest and to obtain an assertion that a user is interested in a product before the advertising is shown. The proposal has been implemented by a Solidity smart contract in Ethereum and has been shown to be effective and cheap.
In this growing world, Internet has changed so much to an extent that it turned into a powerful tool in every aspects of our lives.E-auction is one of those things which helps the bidders to take part in an auction online over the air. In a sealed bid third parties need to pay an extra cost to help the buyers and sellers carry out their exchange without any hassle. But there can be a breach of trust by the third parties. Owners of the auction or the company that is auctioning can have direct entry to it when the auction is run on a decentralized platform. When the users auction off something on the chain, the smart contract takes control of the auctioned asset and thereafter it manages the bids associated. In this paper, we execute a smart contract for a verifiable sealed-bid auction on the Ethereum blockchain. The type of auction used is sealed-bid in which the bidders submit their bids privately and each bidder can participate only once. As per the biddings received, the highest bidder wins and pays the highest corresponding highest submitted bid. Additionally, before the auction ends the bidder can withdraw the bid after submitting it. In such a case the bidder will have another chance to place the bid. This smart contract implementation abides by the true essence of a sealed-bid, to be precise, no information about the biddings is leaked to the bidders except for the highest bid
Purpose The purpose of this paper is to investigate the short- and long-run dynamic linkages between selected cryptocurrencies, several major world currencies and major equity indices. The results show that despite sharing some common characteristics, the cryptocurrencies do not reveal any short- and long-term stochastic trends with exchange rates and/or equity returns. The dynamics of each cryptocurrency with the Chinese Yuan appears to be more turbulent than that with the other exchange rates. Each cryptocurrency appears to follow its own trend in the global financial market and is independent of the exchange rates or the global stock markets, thus making them suitable for inclusion in global investment portfolios. Design/methodology/approach The cryptocurrencies examined are Bitcoin, Dash, Ethereum, Monero, Stellar and XRP. In addition, data were collected on major exchange rates with respect to the US dollar, namely, the euro, British pound, Japanese yen and Chinese Yuan. Finally, the following major stock market indices were selected: SP500, DAX, DJIA, CAC, FTSE, NIKKEI, Hang Seng and Shanghai. The study applied vector autoregressive (VAR) model and Engle’s (2002) dynamic conditional correlation generalized autoregressive conditional heteroskedasticity (DCC-GARCH) specification. Findings First, it was found that cryptocurrencies do not interact with each other because their correlations are weak and do not share a common long-run path; thus they are not cointegrated. Second, impulse response analysis from the VAR models indicate different reactions of each cryptocurrency to both exchange rate and equity shocks and that cryptocurrencies appear to be isolated from market-driven shocks. Third, the ups and downs in the cryptocurrencies’ dynamic conditional correlations (from the DCC-GARCH models) indicate that all cryptocurrencies were susceptible to speculative attacks and market events. Research limitations/implications This paper examines the dynamic linkages among the most important cryptocurrencies with major exchange rates and equity markets and, to the best of the authors’ knowledge, is the first paper to do so. Thus, interested market agents would gain valuable insights as to whether this new form of asset might be used for conducting monetary policies and portfolio construction on a global setting. Originality/value The paper contributes to the scant literature on the dynamic linkages among major cryptocurrencies and global financial assets. In general, given the differential relationships of each crypto with the equity markets, one could infer that they represent a decent short-run investment vehicle within a well-diversified, global asset portfolio (as they may increase the returns and reduce the overall risk of the portfolio).
Ten years after the introduction of the Bitcoin protocol, an increasing number of art-tech startups and more or less independent initiatives have begun to explore second-generation blockchains such as Ethereum and the emergent practice of tokenization (i.e., the issuance of new cryptoassets primarily to self-fund decentralized projects) as a means to intervene in the structures and processes underlying the rampant financialization of art. Yet amidst the volatility of the cryptocurrency market, tokenization has been critiqued as a way to reinscribe and proliferate current financial logics in this new space. Acknowledging such critiques, in this essay I foreground the novelty of cryptotokens and blockchains by exploring different examples of how tokenization has been deployed in the art market-milieu. In spite of recent attempts to extend the scarcity-based paradigm to blockchains, I argue that cryptotokens do introduce differences in kind in the ways in which value generation and distribution are expressed and accounted for in digital environments. In this context, artistic approaches to tokenization can illuminate new aspects of the affordances of these technologies, toward the disintermediation of art production and its networked value from the current institutional-financial milieu. This can open up new ways to reimagine and reprogram financial and social relations, and gesture toward new opportunities and challenges for a practice of digital design focused on the ideation and realization of cryptoeconomic systems.
Ethereum has become a widely used platform to enable secure, Blockchain-based financial and business transactions. However, a major concern in Ethereum is the security of its smart contracts. Many identified bugs and vulnerabilities in smart contracts not only present challenges to maintenance of blockchain, but also lead to serious financial loses. There is a significant need to better assist developers in checking smart contracts and ensuring their reliability.In this paper, we propose a web service tool, named SmartEmbed, which can help Solidity developers to find repetitive contract code and clone-related bugs in smart contracts. Our tool is based on code embeddings and similarity checking techniques. By comparing the similarities among the code embedding vectors for existing solidity code in the Ethereum blockchain and known bugs, we are able to efficiently identify code clones and clone-related bugs for any solidity code given by users, which can help to improve the users' confidence in the reliability of their code. In addition to the uses by individual developers, SmartEmbed can also be applied to studies of smart contracts in a large scale. When applied to more than 22K solidity contracts collected from the Ethereum blockchain, we found that the clone ratio of solidity code is close to 90\%, much higher than traditional software, and 194 clone-related bugs can be identified efficiently and accurately based on our small bug database with a precision of 96\%. SmartEmbed can be accessed at \url{http://www.smartembed.net}. A demo video of SmartEmbed is at \url{https://youtu.be/o9ylyOpYFq8}
Suzan Bayhan, Anatolij Zubow, Piotr Gawłowicz, Adam Wolisz
Mobile network operators (MNO) can opportunistically use the licensed bands of the primary users (PU) provided that they monitor the spectrum and stop their transmission upon detection of the PU. As deploying spectrum sensors may be prohibitively expensive, the MNO can buy spectrum sensing service from sensing helpers in its proximity. However, such a trade requires a framework with three key functions: helper selection, faulty or malicious helper identification, and payment to honest helpers. Here, we introduce Spass which provides these functions and facilitates a fair exchange between the entities without a trusted third party via smart contracts (SC) running on a blockchain network. While payments via SCs seem conceptually simple, realizing it is difficult due to the cost of using SC functions which might be prohibitive as write/computation operations on the SCs might have a cost, e.g., in Ethereum. Considering our design goals and SC-related overhead, we derive the optimal Spass parameters maximizing the MNO's profit. Moreover, we propose a K-means clustering approach to identify independent malicious helpers, and using both lossless and lossy compression on the helpers' sensing report to decrease the cost of write operations. Via simulations, we show under which conditions Spass-powered service leads to a profitable business for an MNO.
Purathani Praitheeshan, Lei Pan, Jiangshan Yu, Joseph K. Liu · 5 authors
Smart contracts are software programs featuring both traditional applications\nand distributed data storage on blockchains. Ethereum is a prominent blockchain\nplatform with the support of smart contracts. The smart contracts act as\nautonomous agents in critical decentralized applications and hold a significant\namount of cryptocurrency to perform trusted transactions and agreements.\nMillions of dollars as part of the assets held by the smart contracts were\nstolen or frozen through the notorious attacks just between 2016 and 2018, such\nas the DAO attack, Parity Multi-Sig Wallet attack, and the integer\nunderflow/overflow attacks. These attacks were caused by a combination of\ntechnical flaws in designing and implementing software codes. However, many\nmore vulnerabilities of less severity are to be discovered because of the\nscripting natures of the Solidity language and the non-updateable feature of\nblockchains. Hence, we surveyed 16 security vulnerabilities in smart contract\nprograms, and some vulnerabilities do not have a proper solution. This survey\naims to identify the key vulnerabilities in smart contracts on Ethereum in the\nperspectives of their internal mechanisms and software security\nvulnerabilities. By correlating 16 Ethereum vulnerabilities and 19 software\nsecurity issues, we predict that many attacks are yet to be exploited. And we\nhave explored many software tools to detect the security vulnerabilities of\nsmart contracts in terms of static analysis, dynamic analysis, and formal\nverification. This survey presents the security problems in smart contracts\ntogether with the available analysis tools and the detection methods. We also\ninvestigated the limitations of the tools or analysis methods with respect to\nthe identified security vulnerabilities of the smart contracts.\n