Follow blockchain research across journals, conferences, and preprint repositories.
2,085 results · page 75 of 87
Xiaohan Zhang, Honggang Hu
No abstract is available for this record.
Eva Raquel Porras Gonzalez, José María Martín Martín, José Manuel Guaita Martínez
The blockchain distributed ledger technology offers a secure, transparent, verifiable, democratic, decentralised, efficient, and tamper-resistant way to record and transfer data. Now much of the discussion revolves around the attributes that determine its many potential applications as this technology is expected to help transform sectors that are hampered by inefficiencies as well as facilitate the appearance of new business models based on distributed markets and technology. Given this technological revolution has already started, the core objectives of this article are to acquaint the reader with the technology and with the current and latent applications of this innovation while recognising its potential worldwide economic impact. To accomplish these goals we review the literature encompassing both academic and professional works that refer to the characteristics and properties of the blockchain, its many existent and plausible applications, and the reasons for its anticipated global economic repercussions.
Zhitao Wan, Minqiang Cai, Xianghua Lin, Jinqing Yang
No abstract is available for this record.
Santiago Bragagnolo, Matteo Marra, Guillermo Polito, Elisa Gonzalez Boix
Analysing the blockchain is becoming more and more relevant for detecting attacks and frauds on cryptocurrency exchanges and smart contract activations. However, this is a challenging task due to the continuous growth of the blockchain. For example, in early 2017 Ethereum was estimated to contain approximately 300GB of data [1], a number that keeps growing day after day. In order to analyse such ever-growing amount of data, this paper argues that blockchain analysis should be treated as a novel type of application for Big Data platforms. In this paper we explore the application of parallelization techniques from the Big Data domain, in particular Map/Reduce, to extract and analyse information from the blockchain. We show that our approach significantly improves the index generation by 7.77 times, with a setup of 20 worker nodes, 1 Ethereum node and 1 Database node. We also share our findings of our massively parallel setup for querying Ethereum in terms of architecture and the bottlenecks. This should help researchers setup similar infrastructures for analysing the blockchain in the future.
Aida Kamišalić, Muhamed Turkanović, Saša Mrdović, Marjan Heričko
No abstract is available for this record.
Wei-Meng Lee
In the previous chapter, you learned how to create your own private Ethereum test network so that you can try out the various Ethereum transactions, such as transferring Ethers to different accounts and performing mining. You also learned how to create accounts so that you can hold your own Ethers. In this chapter, you will learn how to use a Chrome extension known as the MetaMask. The MetaMask Chrome extension is an Ethereum wallet that allows you to hold your Ethereum account, and it will be an essential tool to help you develop and test Smart Contracts in the next few chapters.
Hwan Park, Misun Kim, Seojaehyun
No abstract is available for this record.
Yuan Zhang, Chunxiang Xu, Nan Cheng, Hongwei Li · 6 authors
We propose Chronos+, an accurate blockchain-based time-stamping scheme for outsourced data, where both the storage and time-stamping services are provided by cloud service providers. Specifically, Chronos+integrates a file into a transaction on a blockchain once the file is created, which guarantees the file's latest creation time to be the time when the block containing the transaction is appended to the blockchain. A sufficient number of consecutive blocks that are latest confirmed on the blockchain is embedded into the file at the creation time. These blocks serve as a time-dependent random seed to prove the earliest creation time, due to blockchains' chain quality property. Chronos+makes the file's timestamp corresponding to a time interval formed by the earliest and latest creation times which are derived from the heights of the corresponding blocks. Due to blockchains' chain growth property, such a height-derived timestamp can ensure that the time intervals' range is within a few minutes so as to guarantee the accuracy. We also point out potential threats towards outsourced time-sensitive files and present security analyses to prove that Chronos+is secure against these threats. Comprehensive performance evaluations demonstrate the efficiency and practicality of Chronos+.
Olga Labazova, Tobias Dehling, Ali Sunyaev
Blockchain is a decentralized digital ledger that challenges existing business models and theories by shifting the trust from institutions towards algorithms. However, the number of successfully developed blockchain-based systems remains low. This points towards a research gap between blockchain applications and technical blockchain characteristics. We answer the research question: What application areas fit blockchains with what technical characteristics? We develop a taxonomy, which comprises six blockchain application areas that are classified across eight technical dimensions. We demonstrate the utility of the taxonomy on ninety-nine blockchain-based systems. We contribute to the scientific literature by delimiting blockchain application areas, identifying new technical dimensions, and linking application and technical knowledge on blockchain to guide development of blockchain-based systems. For practitioners, we present an overview of current blockchain-based systems.
Suman Kumar Das, Diptesh Pandey, Barnali Dey, Suparna DasGupta · 5 authors
An inclusive project is classified and alienated into several tasks where as task management is one of the foremost components of project management, since the roles and tasks assigned by the manager of this component to each employee working on a project. In scrupulous there are several ways to track the status of work and this monitoring is also required to find the efficiency of an individual and at the time of the annual and mid- term appraisal and all these monitoring records can be used to give qualifications to associates and employees. In this work, the authors have proposed a system along with the solution based on the ERC20 token which is identified as blockchain platform based on Ethereum in which they can implement Project Task Management which is tamper proof and as well as can track the assigned task of an employee on real time basis.
Emanuel Palm
In the wake of the financial crisis of 2008, Bitcoin emerged as a radical new alternative to the fiat currencies of the traditional banking sector. Through the use of a novel kind of probabilistic consensus algorithm, Bitcoin proved it possible to guarantee the integrity of a digital currency by relying on network majority votes instead of trusted institutions. By showing that it was technically feasible to, at least to some extent, replace the entire banking sector with computers, many significant actors started asking what else this new technology could help automate. A subsequent, seemingly inevitable, wave of efforts produced a multitude of new distributed ledger systems, architectures and applications, all somehow attempting to leverage distributed consensus algorithms to replace trusted intermediaries, facilitating value ownership, transfer and regulation. In this thesis, we scrutinize distributed ledger technologies in terms of how they could help facilitate the digitization of contractual cooperation, especially in the context of the supply chain and manufacturing industries. Concretely, we consider them from three distinct technical perspectives, (1) performance, (2) interoperability and (3) integration. Voting systems, with or without probabilistic mechanisms, require significant time and resources to operate, for which reason it becomes relevant to investigate how the costs of running those systems can be mitigated. In particular, we consider how a blockchain, a form of distributed ledger, can be pruned to in order to reduce disk space requirements. Furthermore, no technical system part of a larger business is an island, but will have to be able to interoperate with other systems to maximize the opportunity for automation. For this reason, we also consider how transparent message translation between systems could be facilitated, as well as presenting a formalism for expressing the syntactic structure of message payloads. Finally, we propose a concrete architecture, the Exchange Network, that models contractual interactions as negotiations about token exchanges rather than as function invocations and state machine transitions, which we argue lowers the barrier to compatibility with conventional legal and business practices. Even if no more trusted institutions could be replaced by any forthcoming distributed ledger technologies, we believe contractual interactions becoming more digital would lead to an increased opportunity for using computers to monitor, assist or even directly participate in the negotiation, management and tracking of business agreements, which we see as more than enough to warrant the cost of further developing of the technology. Such computer involvement may not just save time and reduce costs, but could also enable new kinds of computer-driven economies. In the long run, this may enable new levels of resource optimization, and not just within large organizations, but also smaller companies, or even the homes of families and individuals.
Paulius Danielius, Tomas Savenas, Saulius Masteika
No abstract is available for this record.
Shihab Shahriar Hazari, Qusay H. Mahmoud
A blockchain is a distributed ledger forming a distributed consensus on a history of transactions, and is the underlying technology for the Bitcoin cryptocurrency. However, its applications are far beyond the financial sector. The transaction verification process for cryptocurrencies is much slower than traditional digital transaction systems. One approach to increase transaction speed and scalability is to identify a solution that offers faster Proof of Work. In this paper, we propose a method for accelerating the process of Proof of Work based on parallel mining rather than solo mining. The goal is to ensure that no more than two or more miners put the same effort into solving a specific block. The proposed method includes a process for selection of a manager, distribution of work and a reward system. This method has been implemented in a test environment that contains all the characteristics needed to perform Proof of Work for Bitcoin and has been tested, using a variety of case scenarios, by varying the difficulty level and number of validators. Preliminary results show improvement in the scalability of Proof of Work up to 34% compared to the current system.
Philipp Brüne
Cryptocurrencies, blockchain technology and smart contracts could fundamentally change the way how financial products and financial services are implemented and operated. While many frameworks for implementing such blockchain applications already exist, these are usually implemented using languages either considered “fancy” today, like e.g. Go, or are traditionally used for system software, such as C++. On the other hand, the core business applications e.g. in financial services are typically implemented using enterprise platforms such as Java Enterprise Edition (EE) and/or COBOL. Therefore, to improve the integration of blockchain technology in such applications, in this paper we argue in favor of a legacy-friendly distributed ledger solution by introducing QWICSchain, an implementation build on web services using established open-source enterprise technologies such as Java EE and PostgreSQL. It supports the parallel execution of transactions on the blockchain and in existing legacy applications, thus enabling the blockchain-based modernization of existing IT infrastructures.
Benjamin Agbo, Yongrui Qin, Richard Hill
The significant growth and adoption of Internet of Things (IoT) solutions has led to tremendous increase in the generation of data. The need for high speed data processing has become very important to meet with the ever increasing volume and velocity of IoT data, due to the large scale and distributed nature of IoT infrastructure and networks. Present cloud based technologies are struggling to meet up with these needs for real time data processing in the midst of enormous amounts of data. The success of bitcoin has inspired more research in the application of Distributed ledger technologies in various domains. The decentralized nature of these platforms have enabled security and privacy of data in previous research and their architecture has a potential for enabling large scale decentralized data processing. In this paper, we identify some open areas of research in the use of distributed ledger technology and propose a framework for storing, analyzing and ensuring the security of large volumes of IoT data.
Hye-Young Paik, Xiwei Xu, H. M. N. Dilum Bandara, Sung Une Lee · 5 authors
In a blockchain-based system, data and the consensus-based process of recording and updating them over distributed nodes are central to enabling the trustless multi-party transactions. Thus, properly understanding what and how the data are stored and manipulated ultimately determines the degree of utility, performance, and cost of a blockchain-based application. While blockchains enhance the quality of the data by providing a transparent, immutable, and consistent data store, the technology also brings new challenges from a data management perspective. In this paper, we analyse blockchains from the viewpoint of a developer to highlight important concepts and considerations when incorporating a blockchain into a larger software system as a data store. The work aims to increase the level of understanding of blockchain technology as a data store and to promote a methodical approach in applying it to large software systems. First, we identify the common architectural layers of a typical software system with data stores and conceptualise each layer in blockchain terms. Second, we examine the placement and flow of data in blockchain-based applications. Third, we explore data administration aspects for blockchains, especially as a distributed data store. Fourth, we discuss the analytics of blockchain data and trustable data analytics enabled by blockchain. Lastly, we examine the data governance issues in blockchains in terms of privacy and quality assurance.
Madhusudan Singh, Shiho Kim
No abstract is available for this record.
Taneli Hukkinen, Juri Mattila, Kari Smolander, Timo Seppälä · 5 authors
In recent years, information systems have not been largely evaluated by their operating costs, but mainly by their strategic benefit and competitive advantage. As blockchain-based decentralized applications become more commonplace, representing a shift towards fully consumption-based distributed computing, a new mode of thinking is required of developers, with meticulous attention to computational resource efficiency. This study improves on a blockchain application designed for conducting microtransactions of electricity in a nanogrid environment. By applying the design science research methodology, we improve the efficiency of the application’s smart contract by 11 %, with further improvement opportunities identified. Despite the results, we find the efficiency remains inadequate for public Ethereum deployment. From the optimization process, we extrapolate a set of general guidelines for optimizing the efficiency of Ethereum smart contracts in any application.
Jongbeen Han, Heemin Kim, Hyeonsang Eom, Jonathan Coignard · 6 authors
A blockchain is designed to make consistent and reliable agreement in an unreliable and decentralized environment. It also permits processing transactions, making smart contracts, which allows end users to perform the contracts without any intermediate entities. However, there are some challenges in retrieving the state in a smart contract on the blockchain. For example, an external database or user-defined data structures can be used to retrieve the data from a smart contract in a range, which can increase the management overhead and decrease the overall performance of the blockchain system. In this paper, we propose a scheme that enables SQL query operations in a blockchain system. In our proposed scheme, the register and query managers provide fast retrieval of range data without any user-defined data structure, and management at low cost without any external database, respectively. We have implemented our scheme on quorum which is an Ethereum-based blockchain system and evaluated it using a synthetic benchmark. The experimental results show that our system can improve the search performance up to about 22x compared with the existing system with low memory usage.
Federico Matteo Benčić, Alen Hrga, Ivana Podnar Žarko
Current consumer grade hardware running a full DLT node takes a long time to synchronize with the network and requires a lot of resources. Nodes that have never before synchronized with the network require significant resources to verify entire ledger history. The initial synchronization assumes inherent trust in the bootstrap nodes, which is a point of centralization. In the case when bootstrap nodes cannot be trusted, a new node might find itself in a malicious cluster of nodes that can either make the node waste resources before realizing that it has been exposed to malicious data, or subvert it into thinking that it has downloaded the longest chain. The Aurora algorithm is able to detect the existence of malicious cliques with a certain plausibility when a new node is attempting to synchronize with the network, and will try to exit cliques identified as malicious. If the node is unable to exit a malicious clique, the node will halt its operation. Furthermore, the same algorithm can be applied to verify if a specific transaction has been included into a referent block with a certain plausibility without the need to download the entire chain (or the header chain), or to trust centralized block explorers. Thus, the Aurora algorithm has the potential to significantly improve the scalability of DLT by reducing the time necessary for initial blockchain synchronization. Furthermore, it strengthens the trustless environment by incentivizing users not willing to run a full or even a light node to partly verify transaction inclusion without relying on third party entities.
Jinting Wang, Hao Wang
No abstract is available for this record.
Noel Portillo
A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they'll generate the longest chain and outpace attackers. The network itself requires minimal structure. Messages are broadcast on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone.
Stefan Geißler, Thomas Prantl, Stanislav Lange, Florian Wamser · 5 authors
Blockchain and distributed ledger technologies have become more and more popular and widespread during recent years. After the initial hype about the technology and many cryptocurrency related use cases, the technology slowly starts to make its way into other domains like food tracking and document management. In order to further contribute to the search of what this technology can be used for, more detailed performance evaluations are required in order to investigate key performance indicators and general limits of the technology. To this end, we develop a discrete-time queueing model that allows a detailed evaluation of the characteristics of a blockchain system, such as the transaction waiting time distribution. Furthermore, we validate the model by comparing the results to values obtained from measurements in a closed lab environment based on the Ethereum blockchain.
Weilin Zheng, Zibin Zheng, Xiangping Chen, Kemian Dai · 6 authors
Blockchain, originated from Bitcoin system, has drawn intense attention from the academic community because of its decentralization, persistency, anonymity and auditability. In the past decade, the blockchain technology has evolved and became viable for various applications beyond the domain of finance. However, due to the complexity of blockchain technology, it is usually difficult and costly for most developers or teams to build, maintain and monitor a blockchain network that supports their applications. Most common developers or teams are unable to ensure the reliability and security of the blockchain system, which to a certain extent affects the quality of their applications. In this paper, we develop a BaaS platform called NutBaaS, which provides blockchain service over cloud computing environments, such as network deployment and system monitoring, smart contracts analysis and testing. Based on these services, developers can focus on the business code to explore how to apply blockchain technology more appropriately to their business scenarios, without bothering to maintain and monitor the system.