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.
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.
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.
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.
Boris Radovanov, Aleksandra Marcikić, Nebojša Gvozdenović
Because of increasing interest in cryptocurrency investments, there is a need to quantify their variation over time. Therefore, in this paper we try to answer a few important questions related to a time series of cryptocurrencies. According to our goals and due to market capitalization, here we discuss the daily market price data of four major cryptocurrencies: Bitcoin (BTC), Ethereum (ETH), Ripple (XRP) and Litecoin (LTC). In the first phase, we characterize the daily returns of exchange rates versus the U.S. Dollar by assessing the main statistical properties of them. In many ways, the interpretation of these results could be a crucial point in the investment decision making process. In the following phase, we apply an autocorrelation function in order to find repeating patterns or a random walk of daily returns. Also, the lack of literature on the comparison of cryptocurrency price movements refers to the correlation analysis between the aforementioned data series. These findings are an appropriate base for portfolio management. Finally, the paper conducts an analysis of volatility using dynamic volatility models such as GARCH, GJR and EGARCH. The results confirm that volatility is persistent over time and the asymmetry of volatility is small for daily returns.
Summary Decentralization, in the form of mesh networking and blockchain, two promising technologies, is coming to the telecommunications industry. Mesh networking allows wider low‐cost Internet access with infrastructures built from routers contributed by diverse owners, whereas blockchain enables transparency and accountability for investments, revenue, or other forms of economic compensations from sharing of network traffic, content, and services. Crowdsourcing network coverage, combined with crowdfunding costs, can create economically sustainable yet decentralized Internet access. This means that every participant can invest in resources and pay or be paid for usage to recover the costs of network devices and maintenance. While mesh networks and mesh routing protocols enable self‐organized networks that expand organically, cryptocurrencies and smart contracts enable the economic coordination among network providers and consumers. We explore and evaluate two existing blockchain software stacks, Hyperledger Fabric (HLF) and Ethereum geth with Proof of Authority (PoA) intended as a local lightweight distributed ledger, deployed in a real city‐wide production mesh network and in laboratory network. We quantify the performance and bottlenecks and identify the current limitations and opportunities for improvement to serve locally the needs of wireless mesh networks, without the privacy and economic cost of relying on public blockchains.
Jianbo Gao, Han Liu, Chao Liu, Qingshan Li · 6 authors
While Ethereum smart contracts enabled a wide range of blockchain applications, they are extremely vulnerable to different forms of security attacks. Due to the fact that transactions to smart contracts commonly involve cryptocurrency transfer, any successful attacks can lead to money loss or even financial disorder. In this paper, we focus on the overflow attacks in Ethereum, mainly because they widely rooted in many smart contracts and comparatively easy to exploit. We have developed EASYFLOW, an overflow detector at Ethereum Virtual Machine level. The key insight behind EASYFLOW is a taint analysis based tracking technique to analyze the propagation of involved taints. Specifically, EASYFLOW can not only divide smart contracts into safe contracts, manifested overflows, well-protected overflows and potential overflows, but also automatically generate transactions to trigger potential overflows. In our preliminary evaluation, EASYFLOW managed to find potentially vulnerable Ethereum contracts with little runtime overhead. A demo video of EASYFLOW is at https://youtu.be/QbUJkQI0L6o.
One major shortcoming of permissionless blockchains such as Bitcoin and Ethereum is that they are unsuitable for running Computationally Intensive smart Contracts (CICs). This prevents such blockchains from running Machine Learning algorithms, Zero-Knowledge proofs, etc. which may need non-trivial computation. In this paper, we present YODA, which is to the best of our knowledge the first solution for efficient computation of CICs in permissionless blockchains with guarantees for a threat model with both Byzantine and selfish nodes. YODA selects one or more execution sets (ES) via Sortition to execute a particular CIC off-chain. One key innovation is the MultI-Round Adaptive Consensus using Likelihood Estimation (MIRACLE) algorithm based on sequential hypothesis testing. M I RACLE allows the execution sets to be small thus making YODA efficient while ensuring correct CIC execution with high probability. It adapts the number of ES sets automatically depending on the concentration of Byzantine nodes in the system and is optimal in terms of the expected number of ES sets used in certain scenarios. Through a suite of economic incentives and technical mechanisms such as the novel Randomness Inserted Contract Execution (RICE) algorithm, we force selfish nodes to behave honestly. We also prove that the honest behavior of selfish nodes is an approximate Nash Equilibrium. We present the system design and details of YODA and prove the security properties of MIRACLE and RICE. Our prototype implementation built on top of Ethereum demonstrates the ability of YODA to run CICs with orders of magnitude higher gas per unit time as well as total gas requirements than Ethereum currently supports. It also demonstrates the low overheads of RICE.
Ahsan Manzoor, Madhusanka Liyanage, An Braeken, Salil S. Kanhere · 5 authors
Data is central to the Internet of Things (IoT) ecosystem. Most of the current IoT systems are using centralized cloud-based data sharing systems, which will be difficult to scale up to meet the demands of future IoT systems. Involvement of such third-party service provider requires also trust from both sensor owner and sensor data user. Moreover, the fees need to be paid for their services. To tackle both the scalability and trust issues and to automatize the payments, this paper presents a blockchain based proxy re-encryption scheme. The system stores the IoT data in a distributed cloud after encryption. To share the collected IoT data, the system establishes runtime dynamic smart contracts between the sensor and data user without the involvement of a trusted third party. It also uses a very efficient proxy re-encryption scheme which allows that the data is only visible by the owner and the person present in the smart contract. This novel combination of smart contracts with proxy re-encryption provides an efficient, fast and secure platform for storing, trading and managing of sensor data. The proposed system is implemented in an Ethereum based testbed to analyze the performance and the security properties.
Energy storage units (ESUs) enable several attractive features of modern smart grids such as enhanced grid resilience, effective demand response, and reduced bills. However, uncoordinated charging of ESUs stresses the power system and can lead to a blackout. On the other hand, existing charging coordination mechanisms suffer from several limitations. First, the need for a central charging coordinator (CC) presents a single point of failure that jeopardizes the effectiveness of the charging coordination. Second, a transparent charging coordination mechanism does not exist where users are not aware whether the CC is honest or not in coordination charging requests among them in a fair way. Third, existing mechanisms overlook the privacy concerns of the involved customers. To address these limitations, in this paper, we leverage the blockchain and smart contracts to build a decentralized charging coordination mechanism without the need for a centralized charging coordinator. First ESUs should use tokens for anonymously authenticate themselves to the blockchain. Then each ESU sends a charging request that contains its State-of-Charge (SoC), Time-to-complete-charge (TCC) and amount of required charging to the smart contract address on the blockchain. The smart contract will then run the charging coordination mechanism in a self-executed manner such that ESUs with the highest priorities are charged in the present time slot while charging requests of lower priority ESUs are deferred to future time slots. In this way, each ESU can make sure that charging schedules are computed correctly. Finally, we have implemented the proposed mechanism on the Ethereum test-bed blockchain, and our analysis shows that execution cost can be acceptable in terms of gas consumption while enabling decentralized charging coordination with increased transparency, reliability, and privacy preserving.
Energy storage units (ESUs) enable several attractive features of modern smart grids such as enhanced grid resilience, effective demand response, and reduced bills. However, uncoordinated charging of ESUs stresses the power system and can lead to mass blackout. On the other hand, existing charging coordination mechanisms suffer from several limitations. First, the need for a central charging controller (CC) presents a single point of failure that jeopardizes the effectiveness of the charging coordination. Second, existing mechanisms overlook privacy concerns of the involved customers. To address these limitations, in this paper, we leverage the blockchain and smart contracts to build a decentralized charging coordination mechanism without the need for centralized charging coordinator. After each ESU sends a charging request to the smart contract address on the blockchain, the smart contract will run the charging coordination mechanism in a self-executed manner such that ESUs with the highest priority are charged in the present time slot while charging requests of lower priority ESUs are deferred to future time slots. We have implemented the proposed mechanism on the Ethereum blockchain and our analysis shows that the blockchain enables a decentralized charging coordination with increased transparency, reliability, and privacy preservation.
Regio A. Michelin, Ali Dorri, Marco Steger, Roben Castagna Lunardi · 7 authors
There is increased interest in smart vehicles acting as both data consumers and producers in smart cities. Vehicles can use smart city data for decision-making, such as dynamic routing based on traffic conditions. Moreover, the multitude of embedded sensors in vehicles can collectively produce a rich data set of the urban landscape that can be used to provide a range of services. Key to the success of this vision is a scalable and private architecture for trusted data sharing. This paper proposes a framework called SpeedyChain, that leverages blockchain technology to allow smart vehicles to share their data while maintaining privacy, integrity, resilience, and non-repudiation in a decentralized and tamper-resistant manner. Differently from traditional blockchain usage (e.g., Bitcoin and Ethereum), the proposed framework uses a blockchain design that decouples the data stored in the transactions from the block header, thus allowing fast addition of data to the blocks. Furthermore, an expiration time for each block is proposed to avoid large sized blocks. This paper also presents an evaluation of the proposed framework in a network emulator to demonstrate its benefits.
Since the security and fault tolerance is the two important metrics of the data storage, it brings both opportunities and challenges for distributed data storage and transaction. The traditional transaction system of storage resources, which generally runs in a centralized mode, results in high cost, vendor lock-in, single point failure risk, DDoS attack and information security. Therefore, this paper proposes a distributed transaction method for cloud storage based on smart contract. First, to guarantee the fault tolerance and decrease the storing cost for erasure coding, a VCG-based auction mechanism is proposed for storage transaction, and we deploy and implement the proposed mechanism by designing a corresponding smart contract. Especially, we address the problem - how to implement a VCG-like mechanism in a blockchain environment. Based on private chain of Ethereum, we make the simulations for proposed storage transaction method. The results showed that proposed transaction model can realize competitive trading of storage resources, and ensure the safe and economic operation of resource trading.
Data security, data reliability and data availability are the challenges the world has always been solving. Election and Voter data are very crucial for a democratic nation. India, in this respect, brings its own challenges. A lot of financial resources are spent to conduct elections. At times, people are unable to cast their vote because they are unable to travel back to their constituency. Either way, the regular public lifestyle is affected for days in a row. Notwithstanding the best efforts, the whole process is susceptible to unauthorized access and unauthorized deeds. In this paper use of Blockchain Technology, powered by Ethereum to overcome the challenges in existing voting system.
The recent major scientific conferences on the Innovatube Frontier (IFS) have focused on four areas of pioneering technologies, including Artificial Intelligence, Internet of Things, Blockchain and Augmented Reality / Virtual Reality. Blockchain has gained a lot of attention, because not only it is the technology that has created the fever of the Bitcoin and Ethereum digital coins, but also because of its great potentials that can change the nature of the real world and in everyone's lives. There have been various studies on blockchain, however, in reality the percentage of people who understand blockchain remain minute. This paper will highlight the important role of blockchain technology in the development of our future world, especially for developing countries.
Alexander Yakubov, Wazen M. Shbair, Nida Khan, Radu State · 6 authors
Pretty Good Privacy (PGP) is one of the most prominent cryptographic standards offering end-to-end encryption for email messages and other sensitive information. PGP allows to verify the identity of the correspondent in information exchange as well as the information integrity. PGP implements asymmetric encryption with certificates shared through a network of PGP key servers. Many recent breaches show that certificate infrastructure can be compromised as well as exposed to operational errors. In this paper we propose a new PGP management framework with the key server infrastructure implemented using blockchain technology. Our framework resolves some problems of PGP key servers focusing in particular on fast propagation of certificate revocation among key servers and elimination of man-in-the-middle risk. We also provided user access right control where only the certificate holder can change information related to the certificate. We designed and developed a prototype for key server deployment on permissioned Ethereum blockchain. Permissioned blockchain should allow to control the costs of PGP key server infrastructure maintenance at the present level.
A decentralized ride-or carsharing application is among the early proposals of what smart contracts on blockchains may enable in the future. To facilitate use cases in the field of location-based services (LBS), smart contracts need to receive trustworthy positioning information, and be able to process them. We propose an approach on how geofences can be defined in smart contracts, and how supplied positions can be evaluated on whether they are contained in the geofence or not. The approach relies on existing location encoding systems like Geohashes and S2 cells that can transform polygons into a grid of cells. These can be stored in a smart contract to represent a geofence. An oracle run by a mobile network provider can submit network-based positioning information to the contract, that compares it with the geofence. We evaluate the location encoding systems on their ability to model city geofences and mobile network cell position estimates and analyze the costs associated with storing and evaluating received oracle-positions in an Ethereum-based smart contract implementation. Our results show that S2 encodings perform better than Geohashes, that the one-time cost of geofence definition corresponds linearly with the number of grid cells used, and that the evaluation of oracle-submitted locations does not incur high costs.
Sandi Rahmadika, Bruno Joachim Kweka, Cho Nwe Zin Latt, Kyung-Hyune Rhee
Blockchain technology combined with IoT to improve the reliability of the supply chain system is one of the topics in great demand lately. Due to the nature of blockchain, it is suitable to be applied in the supply chain to improve the level of service with security guarantees. In this paper, we present a preliminary study of blockchain in the supply chain using Ethereum smart contract to maintain ownership of digital assets and to track the origin of a product. By leveraging the proposed model, the user can be protected by minimizing the fake online trading activity because product assets that have been recorded by blockchain can be guaranteed since the data cannot be changed by anyone (tamper-proof). Further research needs to be developed, especially the connection between IoT devices and the blockchain network to improve the reliability and effectiveness of the decentralized supply chain system.
Lucie Mercenne, Kei-Léo Brousmiche, Elyes Ben Hamida
The Blockchain technology is currently considered as a major paradigm shift in software architectures and applications. Indeed, it enables the automation of business worflows, using smart contracts, and hence the collaboration between trustless entities, without having to rely on any centralized or third parties. In this context, the automated generation of smart contracts, from high level business process models, has recently received increased interests within the research community. In this paper, we introduce the Blockchain Studio framework, which is a fork of Caterpillar, and whose objective is to enable the generation and automation of role-based business workflows on Ethereum based blockchains. The architecture and implementation of Blockchain Studio are firstly discussed, followed by the analysis of the achieved benefits on a practical use case related to the management of vehicles' life-cycles and data history. Various research challenges and opportunities are then highlighted.
There has been increased interest in the use of blockchains to control Internet of Things devices either directly, or through smart contracts. Many blockchains, such as Ethereum and Fabric, have support for smart contracts. The use of public blockchains while attractive due to their decentralization and availability, do pose challenges, such as unpredictable transaction latencies and cryptocurrency price fluctuations. Transactions in the Ethereum network, such as invokations of smart contracts used to control an IoT device, have no fairness or eventuality guarantees. In this work we describe a “spam attack” method available to parties with sufficient cryptocurrency reserves to delay a statistically significant portion of transactions submitted to the Ethereum network. This paper derives estimations on the costs and effects of such an attack, and is based on an analysis of historical transactions.
Majed M. Alblooshi, Khaled Salah, Yousof Al-Hammadi
Recently, blockchain has been foreseen by industry and research community as a transformational and disruptive technology that is poised to play a major role in transforming the way we transact, trade, bank, track and register assets, and do business. Blockchain can potentially be used to provide trusted authenticity, origin, and ownership for IoT devices, in a way that is secure and decentralized without the involvement of a Trusted Third Parties (TTP) or centralized authorities and services. A TTP can be a subject to a single point of failure, and it can be disrupted, compromised or hacked. A TTP can potentially misbehave and become corrupt in the future, even if it is trustworthy now. This paper shows how Ethereum blockchain (with the powerful feature of programmability through smart contracts) can provide a trusted ownership management for medical IoT (MIoT) devices. Tracking the true ownership of MIoT devices is of a paramount importance as using counterfeited MIoT devices can be life-threatening to patients. The paper presents a general framework and solution to manage and trace back the true origin of ownership for an MIoT; whereby an MIoT device can be owned by multiple parties during its life cycle. The paper presents a detailed overview of our proposed system architecture, design, entity relationship, and interactions among all involved parties. The source code of the Ethereum smart contracts is made publicly available. Key aspects related to the algorithms, interactions, implementation and testing are discussed in the paper. Furthermore, we provide security analysis of our proposed solution in terms of satisfying the general security goals and also resiliency against popular attacks as those of DDoS, eavesdropping and replay attacks.
Reports on the development of Open and Interoperable Distributed Ledger Technology/Blockchain standards. Discusses how these standards drive global blockchain adoption and take development of the technology ecosystem to the next level. The field of blockchain or distributed ledger is growing rapidly. The lack of consensus on definitions, implementation, management, and core attributes is driving the need for standardization. Blockchain is often confused with cryptocurrencies like Bitcoin or Ethereum, but the potential applications of this technology in diverse fields, such as smart contracts, buying and selling energy, and so much more, make distributed ledger technologies one of the high-potential technologies for the future.
This paper describes the development of a road tax payment application using the Ethereum platform. The web solution was developed using the ReactJS platform. The smart contract was developed using Remix.