Bitcoin is a novel protocol with the potential of enabling a decentralized and trustless cryptographic currency, and its underlying technology named blockchain operates on a worldwide basis via a complex set of rules originally proposed by Nakomoto in 2008. In Bitcoin blockchain, miners provide computational services (i.e. mining) to get profits from the fixed rewards of newly found block and also transaction fees from recording the users’ transactions to the blocks. With the decreasing of the fixed new block reward, transaction fees will play the role as the main profit source of miners, thus provide important supports for the sustainability and vitality of the Bitcoin system. Therefore, it is of great necessity to research transaction fees. In this paper, we investigate transaction fees in a queuing game with non-preemptive priority, in which both the miners’ mining rewards and the users’ time cost are highlighted. Then, we conduct theoretical analysis of the game, getting five types of Nash equilibria of the game. We also find that the over-long waiting time will bring negative marginal profits on transaction fees to some users with low time cost, therefore, they will not be willing to offer transaction fees.
Blockchain technology has the characteristics of decentralization, security and non-modifiable. The consensus algorithm is the core of blockchain framework, which solves the problem of mutual trust among nodes in the distributed network. Selecting the appropriate consensus algorithm or not directly affects the performance of blockchain. However, existing private blockchain platform lacks theory and data support for the performance analysis of the consensus algorithm. This paper proposes a method to evaluate the performance of consensus algorithm in private blockchain platforms of Ethereum and Hyperledger Fabric. Through quantitative analysis of latency and throughput, we obtain the performance evaluation results of consensus algorithms with different numbers of transactions. The results show that the consensus mechanism induces performance bottleneck. Besides, Practical Byzantine Fault Tolerance (PBFT) consistently outperforms Proof-of-Work (PoW) in terms of latency and throughput under varying workloads. This paper contributes to providing not only the quantitative data support for the further research of consensus algorithm, but also the guidance to the blockchain practitioners in the selection of consensus mechanism.
Péter Garamvölgyi, Imre Kocsis, Benjamin Gehl, Attila Klenik
Applications of Distributed Ledger Technologies (DLTs) in IoT and Cyber-Physical Systems (CPS) are rapidly emerging. However, developing correct and resilient smart contracts for these use cases is even less understood than it is for cryptocurrency-based contracts. This paper presents an initial approach for generating smart contracts for coordinating the usage of cyber-physical system elements from UML statecharts. While the current target platform is Ethereum, our approach can easily be extended to other blockchain platforms.
With the rapid development of cryptocurrency and its underlying blockchain technologies, platforms such as Ethereum and Hyperledger began to support various types of smart contracts. Smart contracts are computer protocols intended to digitally facilitate, verify, or enforce the negotiation or performance of a contract. Smart contracts have broad range of applications, such as financial services, prediction markets and Internet of Things (IoT), etc. However, there are still many challenges such as security issues and privacy disclosure that await future research. In this paper, we present a comprehensive overview on blockchain powered smart contracts. First, we give a systematic introduction for smart contracts, including the basic framework, operating mechanisms, platforms and programming languages. Second, application scenarios and existing challenges are discussed. Finally, we describe the recent advances of smart contract and present its future development trends, e.g., parallel blockchain. This paper is aimed at providing helpful guidance and reference for future research efforts.
Grégory Claeys, Maria Demertzis, Konstantinos Efstathiou
This Policy Contribution tries to answer two main questions: can cryptocurrencies acquire the role of money? And what are the implications for central banks and monetary policy? Money is a social institution that serves as a unit of account, a medium of exchange and a store of value. With the emergence of decentralised ledger technology (DLT), cryptocurrencies represent a new form of money: privately issued, digital and enabling peer-to-peer transactions. Historically, currencies fulfil their main functions successfully when their value is stable and their user network sufficiently large. So far, cryptocurrencies are arguably falling short against these criteria. They resemble speculative assets rather than money. Primarily this is because of their inherent volatility, which is the by-product of their inelastic supply, and which limits their widespread use as a medium of exchange. Cryptocurrency protocols could theoretically evolve to limit their volatility and correct their current deficiencies. If successful, this could lead to an increase in their popularity as an alternative to official currencies. A successful alternative to official currencies could put pressure on those who manage official currencies to provide better policies. But the widespread substitution of central bank currency for cryptocurrencies would effectively create parallel currencies. This by itself could create risks to the effectiveness of monetary policy, to financial stability and ultimately to growth. Nevertheless, the risks of cryptocurrencies becoming serious contenders remain small as long as fiat currencies issued by the world's major central banks continue to deliver effectively the three traditional functions of money. It would take a deep crisis of trust in official currencies for their widespread substitution by cryptocurrencies to materialise. For cryptocurrencies to replace official currencies they would have to overcome a triple challenge. First, the supply of cryptocurrency would need to act as an instrument (or identify a different instrument) that affects the economy. Second, in the presence of fractional reserve banking, the supply would need to respond to liquidity crises and act as a lender of last resort in order to safeguard financial stability. Third, there would need to be a system of checks and balances to keep the agent, ie the cryptocurrency issuer, accountable to the principal, ie society, which is not possible because cryptocurrencies are automatically and privately-issued. For these reasons, official currencies controlled by inflation-targeting independent central banks still appear to be a far superior technology than cryptocurrencies to provide the money functions.
Abstract Initial coin offerings (ICOs) have emerged as a new mechanism for entrepreneurial finance, with parallels to initial public offerings, venture capital, and presale crowdfunding. In a sample of more than 1,500 ICOs that collectively raise ${\$}$12.9 billion, we examine which issuer and ICO characteristics predict successful real outcomes (increasing issuer employment and avoiding enterprise failure). Success is associated with disclosure, credible commitment to the project, and quality signals. An instrumental variables analysis finds that ICO token exchange listing causes higher future employment, indicating that access to token liquidity has important real consequences for the enterprise. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.
Van Hoa Nguyen, Yvon Bésanger, Quoc Tuan Tran, Minh Tri Le
As more and more distributed renewable energy resources are integrated to the grid, the traditional consumers have become the prosumers who can sell back their surplus energy to the others who are in energy shortage. This peer-to-peer (P2P) energy transaction framework benefits the end users, financially and in term of energy security; and the network operators, in term of flexibility in DRES management, peak load shifting and regulation of voltage/frequency. Environmentally, P2P energy transaction also helps to reduce carbon footprint, reduces DRES payback period and incentivizes the installation of DRES. The current centralized market model is no longer suitable and it is therefore necessary to develop an adapted decentralized architecture for the advanced P2P energy transaction framework intra/inter-micro grid. In this paper, we discuss several distributed ledger approaches for such framework: Blockchain, Block Lattice and Directed Acyclic Graph (the Tangle). The technical advantages of these architectures as well as the persistent challenges are then considered.
Distributed Ledger (DL) has gained huge attention in the last years and will shift the conduction of business in the future. Until today, because of the great dynamics in the field a systematic approach to structure and define the field of DL does not exist. This led to a heterogeneous landscape of DL definitions and thus, misleading discussions. This paper gives a systematic overview of principles relevant to understand and structure the DL field. Furthermore, based on this it describes DL concepts and shows examples of protocols. The result can then be used for further research but also as a basis for successful collaborations in the field of DL.
Abstract Blockchain educational technology has created assessment and management tools for learner credentials that are permanent, transparent and sustainable while giving users direct access. Personal encrypted credentials enable users to shape lifelong learning pathways and personalizes education according to individual values and needs. They allow for the permanent documentation of both formal and informal learning based on transversal competencies, adjustable across the economic sector and responsive to situational needs. Badging was the initial response to online credentialing. Mozilla’s open digital badges have become the unofficial global standard and the specifications remain free. They may be viewed in e-portfolios and social networks. Yet, if issuers cease hosting badges, they become invalid even when authentic. Some experiments with blockchain technology remedy this situation by creating a permanent, secure and sustainable infrastructure for learning records. The MIT Media Lab has produced the bitcoin based Blockcerts; whereas the Knowledge Institute, Open University, UK has developed Ethereum’s Smart Contracts to document Microcredentials (Badges). Both are Open Source products. Most EU nations are experimenting with educational blockchain. The technology creates an infrastructure to document, store and manage credentials and provides learners with a sustainable record of achievements they can control. It also benefits universities by reducing administrative costs and bureaucracy.
Nowadays, a great number of healthcare data are generated every day from both medical institutions and individuals. Healthcare information exchange (HIE) has been proved to benefit the medical industry remarkably. To store and share such large amount of healthcare data is important while challenging. In this paper, we propose BlocHIE, a Blockchain-based platform for healthcare information exchange. First, we analyze the different requirements for sharing healthcare data from different sources. Based on the analysis, we employ two loosely-coupled Blockchains to handle different kinds of healthcare data. Second, we combine off-chain storage and on-chain verification to satisfy the requirements of both privacy and authenticability. Third, we propose two fairness-based packing algorithms to improve the system throughput and the fairness among users jointly. To demonstrate the practicability and effectiveness of BlocHIE, we implement BlocHIE in a minimal-viable-product way and evaluate the proposed packing algorithms extensively.
Joaõ Pedro Dias, Hugo Sereno Ferreira, Ângelo Martins
Access control is a crucial part of a system's security, restricting what actions users can perform on resources. Therefore, access control is a core component when dealing with e-Health data and resources, discriminating which is available for a certain party. We consider that current systems that attempt to assure the share of policies between facilities are prone to system's and network's faults and do not assure the integrity of policies lifecycle. By approaching this problem with the use of a distributed ledger, namely a consortium blockchain, where the operations are stored as transactions, we ensure that the different facilities have knowledge about all the parties that can act over the e-Health resources while maintaining integrity, auditability, authenticity, and scalability.
International Journal of Computer Sciences and Engineering (A UGC Approved and indexed with DOI, ICI and Approved, DPI Digital Library) is one of the leading and growing open access, peer-reviewed, monthly, and scientific research journal for scientists, engineers, research scholars, and academicians, which gains a foothold in Asia and opens to the world, aims to publish original, theoretical and practical advances in Computer Science,Information Technology, Engineering (Software, Mechanical, Civil, Electronics & Electrical), and all interdisciplinary streams of Computing Sciences. It intends to disseminate original, scientific, theoretical or applied research in the field of Computer Sciences and allied fields. It provides a platform for publishing results and research with a strong empirical component. It aims to bridge the significant gap between research and practice by promoting the publication of original, novel, industry-relevant research.
The paper proposes a legal definition of the notions of blockchain and smart contract from the point of view of the intellectual property right.Therefore, this research brings to light the effects of new technology on the positive law and, above all, on the notion of contract.By applying the blockchain technique, the parties optimize costs and significantly reduce the time needed to produce legal effects, particularly by eliminating third parties.However, this technique creates a real series of legal issues that already give jurists the opportunity to develop new theories of law by finding solutions to them.
Aaron Zimba, Zhaoshun Wang, Mwenge Mulenga, Nickson Herbert Odongo
The popularity of cryptocurrencies has continued to grow drastically over the past decade and this has drawn significant attention to various threat actors. Cybercriminals are now employing unconventional means to acquire cryptocurrencies at the expense of benign Internet users. This paper investigates the state-of-the-art crypto mining attacks by examining the malware code and the behavioral analysis upon execution. It examines the two most common attack approaches; web browser-based crypto mining which leverages JavaScript and installable binary crypto mining where the malware runs in memory. Furthermore, the paper investigates how cybercriminals endeavor to establish a persistence mechanism and avoid detection. The results from static and dynamic analysis uncover the techniques employed by the malware to exploit potential victims. Indicators of compromise are drawn from the uncovered artifacts which can be used as inputs to intrusion detection systems to help mitigate such cyber-attacks.
Globalization and the changes that have affected the world economy conditioned the development of new models of thinking, investing, trading and payment methods in the world economy. The end of XX and beginning of the XXI century was marked by rapid technological progress, which has not bypassed any economic sector, and all households have experienced the change. Cryptocurrencies represent a new model of trade and payments, but also a way of making some form of earnings. It is a form of property that is used as a digital asset exchange using cryptographic algorithms for mining new values, but also as a way of ensuring the security of transactions in a given system. It is still early for assessments. However, the future might show what kind of impact would this kind of payment have, as well as its impact on tourism development.
International Journal of Computer Sciences and Engineering (A UGC Approved and indexed with DOI, ICI and Approved, DPI Digital Library) is one of the leading and growing open access, peer-reviewed, monthly, and scientific research journal for scientists, engineers, research scholars, and academicians, which gains a foothold in Asia and opens to the world, aims to publish original, theoretical and practical advances in Computer Science,Information Technology, Engineering (Software, Mechanical, Civil, Electronics & Electrical), and all interdisciplinary streams of Computing Sciences. It intends to disseminate original, scientific, theoretical or applied research in the field of Computer Sciences and allied fields. It provides a platform for publishing results and research with a strong empirical component. It aims to bridge the significant gap between research and practice by promoting the publication of original, novel, industry-relevant research.
Distributed applications based on the Ethereum blockchain have a great advantage in the analysis of the history of group work and the contribution factor to a group project of each group member. In these applications, multiple users share resources and their histories together in a robust way thanks to the characteristics of the blockchain that is practically impossible to be forged or modified. However, there has not yet been developed a scheme for providing a systematic management scheme of a group of users or authentication of the members of the group to allow the members to use shared resources through various access rights.
Proposed cryptographic protocol with zero-knowledge proof on elliptic curves using one-way hash function, allowing to establish the truth of allegation and does not convey any additional information about the approval. Cryptographic protocols based on zero-knowledge proof allow identification, key exchange and other cryptographic operations to be performed without leakage of sensitive information during the information exchange. The implementation of the cryptographic protocol of the zero-knowledge proof on the basis of the mathematical apparatus of elliptic curves allows to significantly reduce the size of the protocol parameters and increase the cryptographic stability (computational complexity of the hacking problem). The security of cryptosystems on elliptic curves is based on the difficulty of solving the elliptic curve discrete logarithm problem. The completeness and correctness of the protocol is determined in the work, an example of calculation is given, the cryptographic protocol is modeled on the High-Level Protocol Specification Language, the model validation and verification of the protocol are performed. Software verification of the cryptographic protocol was performed using the software modules On the Fly Model Checker and Constraint Logic based Attack Searcher. To validation the cryptographic protocol for resistance to intruder attacks was used the Security Protocol Animator package for Automated Validation of Internet Security Protocols and Applications. The security of the proposed cryptographic protocol is based on the difficulty of solving the elliptic curve discrete logarithm problem and the cryptographic stability of the hash function. To implement the cryptographic protocol, you can use the recommended elliptical curves according to DSTU 4145-2000 and the hash function GOST 34.311-95.
Manasa Sastry J. K, Astha Pandey, M. S. Dahiya, L Magwa M
Background: From the time immemorial there have been several types of crimes. With the advancement in science and technology, digital crimes have become very prominent. One among which is Bit-Coin crypto-currency frauds which are gaining momentum in the types of frauds encountered by law enforcement agencies. Bit-Coin is a growing form of digital crypto-currency that is created and held electronically that has no centralized control systems, that governs the transactions. It is the most secretive form of money transfer between two anonymous people all over the world. It is on a superficial layer used to purchase or sell goods electronically, similar to the conventional dollars that are traded digitally where individual ledgers are maintained by all the bit coin users to have access to the building block-chain. However, a masked layer consists of a dark-net where enormous amounts of money are concealed in cold storage where illegal websites and illicit commerce like ATM/ Debit/ Credit Card scams subjecting to illegal transactions rule over the deep net by utilizing the innocent public money. Case Presentation: The present study involves a case study where it was noted that innumerable ATM Debit/Credit Cards were skimmed and the illicit money was exchanged with this crypto-currency using an illicit website for bit coin mining and storing huge amounts of anonymous public money that was dictated by a few Nigerian Fraudsters running this racket all over the nation.