Abstract The emerging blockchain technology is expected to contribute to the transformation of ownership, government services and global supply chains. By analysing a crisis that occurred with one of its frontrunners, Ethereum, in this article I explore the discrepancies between the purported governance of blockchains and the de facto control of them through expertise and reputation. Ethereum is also thought to exemplify libertarian techno‐utopianism. When ‘The DAO’, a highly publicized but faulty crowd‐funded venture fund was deployed on the Ethereum blockchain, the techno‐utopianism was suspended, and developers fell back on strong network ties. Now that the blockchain technology is seeing an increasing uptake, I shall also seek to unearth broader implications of the blockchain for the proliferation or blockage of global finance and beyond. Contrasting claims about the disruptive nature of the technology, in this article I show that, by redeeming the positive utopia of ontic, individualized debt, blockchains reinforce our belief in a crisis‐ridden, financialized capitalism.
We increasingly live in a world where there is a balance between the rights to privacy and the requirements for consent, and the rights of society to protect itself. Within this world, there is an ever-increasing requirement to protect the identities involved within financial transactions, but this makes things increasingly difficult for law enforcement agencies, especially in terms of financial fraud and money laundering. This paper reviews the state-of-the-art in terms of the methods of privacy that are being used within cryptocurrency transactions, and in the challenges that law enforcement face.
Blockchain technology has been recommended for the sustainability in the manufacturing industry, owing to its benefits in terms of real-time transparency and cost savings. To verify this, we first examine how firms can employ distributed ledger technology by adopting blockchain technology to achieve real-time transparency and cost savings. We also review the current blockchain technology applications in the financial industry and supply chains to explain this technology’s mechanisms for enabling real-time transparency and cost savings in the manufacturing industry. Finally, we theoretically compare the profits of manufacturing firms in two managerial delegation games under a duopoly situation. This theoretical model suggests that the real-time transparency and cost savings secured by blockchain technology improve the profitability and competitiveness of manufacturing firms, which, in turn, assure the sustainability in the manufacturing industry.
This paper examines the day of the week effect in the cryptocurrency market using a variety of statistical techniques (average analysis, Student's t-test, ANOVA, the Kruskal–Wallis test, and regression analysis with dummy variables) as well as a trading simulation approach. Most crypto currencies (LiteCoin, Ripple, Dash) are found not to exhibit this anomaly. The only exception is BitCoin, for which returns on Mondays are significantly higher than those on the other days of the week. In this case the trading simulation analysis shows that there exist exploitable profit opportunities; however, most of these results are not significantly different from the random ones and therefore cannot be seen as conclusive evidence against market efficiency.
Smart contracts (SC) are one of the most appealing features of blockchain technologies facilitating, executing, and enforcing predefined terms of coded contracts without intermediaries. The steady adoption of smart contracts on the Ethereum blockchain has led to tens of thousands of contracts holding millions of dollars in digital currencies and small mistakes during the development of SC on immutable blockchains have already caused substantial losses and involve the danger for future incidents. Hence, today the secure development of smart contracts is an important topic and several attacks and incidents related to vulnerable smart contracts could have been avoided. To foster a secure development process of SC this paper summarizes known vulnerabilities in smart contracts found by literature research and analysis. It compares currently available code analysis tools for their capabilities to identify and detect vulnerabilities in smart contracts based on a taxonomy for vulnerabilities. Finally, based on the TheDOA attack the paper shows an example for the adoption of best practices to avoid severe vulnerabilities in smart contracts.
Cryptocurrencies are being widely adopted to perform various online-based transactions; therefore, they are required to maintain a consensus to ensure a secured transaction. Blockchain comprises a distributed ledger, which holds digital records of individual crypto-transactions. Besides recording a particular activity, blockchain also ensures that the contents of the ledger are decided based on agreements of distinct participants. Various consensus mechanisms are followed by blockchain to ensure blocks are being summed up representing legitimate data on the network. However, the major consensus protocols comprise various limitations; and these are prone to different types of cyber attacks, such as Distributed denial-of-service, 51% attack, Double-spending, Long-range attack. In this paper, we analyze several attack vectors that can cause serious security threats due to the loopholes in the consensus mechanism. Our study involves examining 3 significant consensus mechanisms, which are followed by major cryptocurrencies. We also discuss the limitations of individual consensus mechanisms and demonstrate their robustness towards various attack vectors. We conclude that, although blockchain comprises proper consensus mechanisms to enhance secured crypto-transaction, unfortunately, it is not strong enough to defend against some cryptocurrency attacks which could discourage some users to adopt this technology.
Yonggen Gu, Dingding Hou, Xiaohong Wu, Jie Tao · 5 authors
Distributed data storage has received more attention due to its advantages in reliability, availability and scalability, and it brings both opportunities and challenges for distributed data storage transaction. The traditional transaction system of storage resources, which generally runs in a centralized mode, results in high cost, vendor lock-in and single point failure risk. To overcome the above shortcomings, considering the storage policy with erasure coding, in this paper we propose a decentralized transaction method for cloud storage based on a smart contract, which takes into account the resource cost for distributed data storage. First, to guarantee the availability and decrease the storing cost, a reverse Vickrey-Clarke-Groves (VCG) based auction mechanism is proposed for storage resource selection and transaction. Then we deploy and implement the proposed mechanism by designing a corresponding smart contract. Especially, we address the problem of how to implement a VCG-like mechanism in a blockchain environment. Based on the private chain of Ethereum, we make the simulation for the proposed storage transaction method. The results of simulation show that the proposed transaction model can realize competitive trading of storage resources and ensure the safe and economic operation of resource trading.
Zhengwei Ni, Wenbo Wang, Dong In Kim, Ping Wang · 5 authors
With the development of decentralized consensus protocols, permissionless blockchains have been envisioned as a promising enabler for the general-purpose transaction-driven, autonomous systems. However, most of the prevalent blockchain networks are built upon the consensus protocols under the crypto-puzzle framework known as proof-of-work. Such protocols face the inherent problem of transaction-processing bottleneck, as the networks achieve the decentralized consensus for transaction confirmation at the cost of very high latency. In this paper, we study the problem of consensus formation in a system of multiple throughput-scalable blockchains with sharded consensus. Specifically, the protocol design of sharded consensus not only enables parallelizing the process of transaction validation with sub-groups of processors, but also introduces the Byzantine consensus protocols for accelerating the consensus processes. By allowing different blockchains to impose different levels of processing fees and to have different transaction-generating rate, we aim to simulate the multi-service provision eco-systems based on blockchains in real world. We focus on the dynamics of blockchain-selection in the condition of a large population of consensus processors. Hence, we model the evolution of blockchain selection by the individual processors as an evolutionary game. Both the theoretical and the numerical analysis are provided regarding the evolutionary equilibria and the stability of the processors' strategies in a general case.
Permissionless blockchain systems, such as Bitcoin, rely on users using their computational power to solve a puzzle in order to achieve a consensus. To incentivise users in maintaining the system, newly minted coins are assigned to the user who solves this puzzle. A hardware race that has hence ensued among the users, has had a detrimental impact on the environment, with enormous energy consumption and increased global carbon footprint. On the other hand, proof of stake systems incentivise coin hoarding as players maximise their utility by holding their stakes. As a result, existing cryptocurrencies do not mimic the day-to-day usability of a fiat currency, but are rather regarded as cryptoassets or investment vectors. In this work we initiate the study of minting mechanisms in cryptocurrencies as a primitive on its own right, and as a solution to prevent coin hoarding we propose a novel minting mechanism based on waiting-time first-price auctions. Our main technical tool is a protocol to run an auction over any blockchain. Moreover, our protocol is the first to securely implement an auction without requiring a semi-trusted party, i.e., where every miner in the network is a potential bidder. Our approach is generically applicable and we show that it is incentive-compatible with the underlying blockchain, i.e., the best strategy for a player is to behave honestly. Our proof-of-concept implementation shows that our system is efficient and scales to tens of thousands of bidders.
In 2008, Satoshi Nakamoto proposed an electronic cash system (bitcoin) that is completely realized by peer-to-peer technology. The core value of this scheme is that it proposes a solution based on Proof-of Work, so that the cash system can run in a peer-to-peer environment and be able to prevent double-spend attacks. Bitcoin has been developed for ten years, and since then countless digital currencies have been created. But the discussion of double-spend attacks seems to still concentrate on 51% Attacks. In fact, our research has found that there are many other way to achieve double-spend attacks. In this paper, by introducing a number of double-spend attack vulnerabilities that we have found in EOS, NEO and other large blockchain platforms, we summarized various reasons for causing double-spend attacks, and propose an efficient mitigation measure against them.
Wesley Joon-Wie Tann, Xing Han, Sourav Sen Gupta, Yew-Soon Ong
Symbolic analysis of security exploits in smart contracts has demonstrated to be valuable for analyzing predefined vulnerability properties. While some symbolic tools perform complex analysis steps, they require a predetermined invocation depth to search vulnerable execution paths, and the search time increases with depth. The number of contracts on blockchains like Ethereum has increased 176 fold since December 2015. If these symbolic tools fail to analyze the increasingly large number of contracts in time, entire classes of exploits could cause irrevocable damage. In this paper, we aim to have safer smart contracts against emerging threats. We propose the approach of sequential learning of smart contract weaknesses using machine learning---long-short term memory (LSTM)---that allows us to be able to detect new attack trends relatively quickly, leading to safer smart contracts. Our experimental studies on 620,000 smart contracts prove that our model can easily scale to analyze a massive amount of contracts; that is, the LSTM maintains near constant analysis time as contracts increase in complexity. In addition, our approach achieves $99\%$ test accuracy and correctly analyzes contracts that were false positive (FP) errors made by a symbolic tool.
This essay examines in detail the properties of a well functioning monetary system - defined as money plus the mechanisms to execute payments - in both the short and long run, drawing on both theory and the lessons from history. It stresses the importance of trust and of the institutions needed to secure it. Ensuring price and financial stability is critical to nurturing and maintaining that trust. In the process, the essay addresses several related questions, such as the relationship between money and debt, the viability of cryptocurrencies as money, money neutrality, and the nexus between monetary and financial stability. While the present monetary system, with central banks and a prudential apparatus at its core, can and must be improved, it still provides the best basis to build on.
Recent technological advances are creating possibilities for novel forms of interaction, collaboration, and organization of labor in Smart Cities. In this paper, we present a reward-driven, Blockchain-backed platform acting as the technological enabler for enactment of ad-hoc, decentralized neighborhood-scale co-creation, collaboration, and citizen engagement activities.
Yury Yanovich, Igor Shiyanov, Timur Myaldzin, Ivan Prokhorov · 6 authors
Counterfeit and unaccounted postage stamps used on mailings cost postal administrations a significant amount of money each year. Corporate and individual clients become victim to stamp fraud and incur losses when security teams investigate such mailings. The blockchain technology is supposed to be a solution to make postage stamps market transparent and to guarantee invariability of stamps volume produced and used. The blockchain-based supply chain for postage stamps is introduced in the article.
Being in this digital era, technology continuously updates with new variants in providing security while performing the financial transactions. It is a mandated task for the user for conducting secure transactions in order to defend the intruders to restrict the interference. This paper deals with digital currency-Cryptocurrency, that provides a medium of secure exchange between the peers during financial management. Authors explored the internal scheme of bitcoin and the abstract view of cryptocurrency to know how the bitcoin is providing a shield during financial negotiation between peers with various application in security point of view.
We study an unsteady nonlinear fluid–structure interaction problem. We consider a Newtonian incompressible two-dimensional flow described by the Navier–Stokes equations set in an unknown domain depending on the displacement of a structure, which itself satisfies a linear wave equation or a linear beam equation. The fluid and the structure systems are coupled via interface conditions prescribing the continuity of the velocities at the fluid–structure interface and the action-reaction principle. Considering three different structure models, we prove existence of a unique local-in-time strong solution, for which there is no gap between the regularity of the initial data and the regularity of the solution enabling to obtain a blow up alternative. In the case of a damped beam this is an alternative proof (and a generalization to non zero initial displacement) of the result that can be found in [20]. In the case of the wave equation or a beam equation with inertia of rotation, this is, to our knowledge the first result of existence of strong solutions for which no viscosity is added. The key points consist in studying the coupled system without decoupling the fluid from the structure and to use the fluid dissipation to control, in appropriate function spaces, the structure velocity.
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Navier-Stokes equation solutions
Stability and Controllability of Differential Equations