Pavel V. Sukharev, Dmitry S. Silnov, Maxim O. Shishkin
In terms of cryptocurrency, mining is a process of creating a new transaction block to add it to the blockchain. The cryptocurrency protocol should ensure the reliability of new transaction blocks. One of the popular mining protocols is the Proof-of-Work protocol, which requires the miner to perform a certain work to verify its right to add a new block into the blockchain. To perform this work, high-performance hardware is used, such as GPU. On the program level, hardware needs special computing framework, for example, CUDA or OpenCL. In this article, we discuss Ethereum cryptocurrency mining using the OpenCL standard. The Ethereum cryptocurrency is the most popular cryptocurrency with GPU-based mining. There are several open-source implementations of the Ethereum cryptocurrency miners. The host-part of the OpenCL-miner is considered, which makes the research results independent of the mining algorithm and allows using the results of the research in the mining of other cryptocurrencies. During the research, we have found the problems, which lead to mining productivity loss, and we are looking for the ways to resolve these problems and thus increase mining performance. As part of solving these problems, we have developed the algorithm for the functioning of the miner and proposed the methodology of determining the optimal size of OpenCL work, which allows to reduce the impact of problems found and achieve maximum mining productivity using OpenCL framework.
Apart from the good utilization of the blockchain, there are different challenges that are there at the blockchain system. The problem is that despite several advantages of a blockchain, the current blockchain networks cannot support at large scale application system. Some of the major problems that blockchain technology suffering from are scalability, privacy, and interoperability. The major issue of blockchain technology is scalability. The problem of scalability means that the capacity to process a transaction on a blockchain is very limited and slow. If we think about financial transactions and we compare the ethereum blockchain or the Bitcoin blockchain to the financial transactions provided by Visa MasterCard or any other centralized company, then we would see a difference between them. The difference is that ten to fifteen transactions per second are performed by blockchain-based decentralized cryptocurrency systems in comparison to several thousand transactions per second by a centralized credit-card system.
Since 2013, Initial Coin Offerings (ICO) have allowed companies to attract financing with the help of cryptocurrencies. Statistics of ICO shows that the ICO market is increasing and demand for funds continues to grow with claims of over $ 15 billion raised in the first half of 2018. The increasing volumes of investment in ICO projects as an alternative method to venture capital or IPO are caused by, for example, the possibility of reselling the received tokens at a higher price after the launch of the project or obtaining the company’s services at lower prices. While the importance of the topic is growing, there is the absence of fundamental works emphasizing the determinants of an ICO’s success. The scientific novelty of the forthcoming research consists in the formation of the model evaluation of ICO success. Using econometric analysis based on data for 1392 projects, we show that the volatility of the main cryptocurrencies has a significant impact on the success of ICO. The constraints of the platform for Smart Contacts (ERC-20) and dependence on the Ethereum volatility overcome all other factors. Our data contributes to existing literature and shows the insignificance e of the sector of the project, almost all location region and fl of infl e of quality of the team. This result may be explained by the uncertainty of the investor about the project (weak signals), absence of the regulation and legal framework. This result is beneficial for owners of companies since it is an argument for decreasing costs for marketing.
This paper describes a decentralized electronic voting system using blockchain technology with peer-to-peer network rather than the centralized voting system of server-client structure. In the proposed system, an Ethereum-based private blockchain network is configured and decentralized applications are implemented to store and distribute voting data to all nodes participating in the network to create secure and reliable electronic voting system. Smart contracts for electronic voting are implemented using the Solidity language and distributed to a configured network so that all users can view and vote on elections, and voting data are shared and contrasted by all users in the network, which makes it possible to build a safer and more reliable electronic voting system without third party involvement.
Abstract This chapter first describes the current use of the term “decentralized” as applied to permissionless blockchains like Bitcoin and Ethereum. Then, it analyzes the complex, contested nature of the term, delving into issues such as the different domains where power is exercised in blockchain systems and the fluid nature of power concentration and diffusion in these systems. Next, it provides examples of events that reveal sites of concentrated power in permissionless blockchain systems, focusing on the activities of software developers and miners. Finally, it explores the significant implications for law of using a fuzzy term like “decentralized” to make legal decisions, as misunderstandings about power hidden in the term can lead to flawed decisions across a wide swath of legal fields.
Thomas Durieux, João F. Ferreira, Rui Abreu, Pedro E. D. Cruz
Over the last few years, there has been substantial research on automated analysis, testing, and debugging of Ethereum smart contracts. However, it is not trivial to compare and reproduce that research. To address this, we present an empirical evaluation of 9 state-of-the-art automated analysis tools using two new datasets: i) a dataset of 69 annotated vulnerable smart contracts that can be used to evaluate the precision of analysis tools; and ii) a dataset with all the smart contracts in the Ethereum Blockchain that have Solidity source code available on Etherscan (a total of 47,518 contracts). The datasets are part of SmartBugs, a new extendable execution framework that we created to facilitate the integration and comparison between multiple analysis tools and the analysis of Ethereum smart contracts. We used SmartBugs to execute the 9 automated analysis tools on the two datasets. In total, we ran 428,337 analyses that took approximately 564 days and 3 hours, being the largest experimental setup to date both in the number of tools and in execution time. We found that only 42% of the vulnerabilities from our annotated dataset are detected by all the tools, with the tool Mythril having the higher accuracy (27%). When considering the largest dataset, we observed that 97% of contracts are tagged as vulnerable, thus suggesting a considerable number of false positives. Indeed, only a small number of vulnerabilities (and of only two categories) were detected simultaneously by four or more tools.
Stefan Schorradt, Edita Bajramović, Felix Freiling
With industrial control systems (ICSs) being increasingly networked, the need for sound forensic capabilities for such systems increases. One vital source of information in forensic investigation are log files. Techniques for secure logging aim to protect log files from manipulation. We investigate how a blockchain can enable secure logging for ICSs. We argue that a blockchain fits well both into general models of secure logging and into the Purdue model for ICSs. We report on experiences from connecting the syslog functionality of a Siemens SIMATIC S7-1500 programmable logic controller to the public Ethereum blockchain network. While the level of manipulation protection is comparably high, the transaction time for the public Ethereum blockchain severely limits the usefulness of this type of secure logging for ICSs.
Ethereum is a distributed blockchain that can execute smart contracts, which inter-communicate and perform transactions automatically. The execution of smart contracts is paid in the form of gas, which is a monetary unit used in the Ethereum blockchain. The Ethereum Virtual Machine (EVM) provides the metering capability for smart contract execution. Instruction costs vary depending on the instruction type and the approximate computational resources required to execute the instruction on the network. The cost of gas is adjusted using transaction fees to ensure adequate payment of the network. In this work, we highlight the "real" economics of smart contracts. We show that the actual costs of executing smart contracts are disproportionate to the computational costs and that this gap is continuously widening. We show that the gas cost-model of the underlying EVM instruction-set is wrongly modeled. Specifically, the computational cost for the SLOAD instruction increases with the length of the blockchain. Our proposed performance model estimates gas usage and execution time of a smart contract at a given block-height. The new gas-cost model incorporates the block-height to eliminate irregularities in the Ethereum gas calculations. Our findings are based on extensive experiments over the entire history of the EVM blockchain.
The number of IoT devices is growing at an exponential rate.It is expected that by 2020, there will be approximately 30 billion internet-connected devices and 500 billion by 2030.Not only, does it increase security concerns but will give rise to interoperability issues.In this paper, the recently introduced Ethereum network will be utilised with respect to Internet of Things to create an infrastructure compatible with IoT devices.With an addition of an automated, immutable smart contract that will aid the interoperability of various devices through the heterogenousfriendly Ethereum network.The true potential of Ethereum, when combined with IoT, will be explored and demonstrated.Demonstrated through an implementation in which power will be provided to a room embedded with various IoT devices upon payment (in the form of rent) into a landlord's smart contract [1].
<sec> <title>BACKGROUND</title> Personal health record (PHR) security, correctness, and protection are essential for health and medical services. Blockchain architecture can provide efficient data retrieval and security requirements. Exchangeable PHRs and the self-management of patient health can offer many benefits to traditional medical services by allowing people to manage their own health records for disease prevention, prediction, and control while reducing resource burdens on the health care infrastructure and improving population health and quality of life. </sec> <sec> <title>OBJECTIVE</title> This study aimed to build a blockchain-based architecture for an international health record exchange platform to ensure health record confidentiality, integrity, and availability for health management and used Health Level 7 Fast Healthcare Interoperability Resource international standards as the data format that could allow international, cross-institutional, and patient/doctor exchanges of PHRs. </sec> <sec> <title>METHODS</title> The PHR architecture in this study comprised 2 main components. The first component was the PHR management platform, on which users could upload PHRs, view their record content, authorize PHR exchanges with doctors or other medical health care providers, and check their block information. When a PHR was uploaded, the hash value of the PHR would be calculated by the SHA-256 algorithm and the PHR would be encrypted by the Rivest-Shamir-Adleman encryption mechanism before being transferred to a secure database. The second component was the blockchain exchange architecture, which was based on Ethereum to create a private chain. Proof of authority, which delivers transactions through a consensus mechanism based on identity, was used for consensus. The hash value was calculated based on the previous hash value, block content, and timestamp by a hash function. </sec> <sec> <title>RESULTS</title> The PHR blockchain architecture constructed in this study is an effective method for the management and utilization of PHRs. The platform has been deployed in Southeast Asian countries via the Asia eHealth Information Network (AeHIN) and has become the first PHR management platform for cross-region medical data exchange. </sec> <sec> <title>CONCLUSIONS</title> Some systems have shown that blockchain technology has great potential for electronic health record applications. This study combined different types of data storage modes to effectively solve the problems of PHR data security, storage, and transmission and proposed a hybrid blockchain and data security approach to enable effective international PHR exchange. By partnering with the AeHIN and making use of the network’s regional reach and expert pool, the platform could be deployed and promoted successfully. In the future, the PHR platform could be utilized for the purpose of precision and individual medicine in a cross-country manner because of the platform’s provision of a secure and efficient PHR sharing and management architecture, making it a reasonable base for future data collection sources and the data analytics needed for precision medicine. </sec>
Investing into a new product or service is a high-risk, high-return activity. This is best symbolized by the observation that the return over investment distribution of startups is a power law. Introduction of new products or services to the market might fail to generate profit even though there is a demand. Early adopters are also penalized, as they often pay a high price for something which will end up being cheaper, and might lose their warranty if the firm goes bankrupt. Innovation is slowed down. We propose to equally redistribute part of the generated profit at the end of a predefined time period to previous customers using Ethereum smart contract. Because customers are aware of the amount they would get back, their behaviors will change. The return over investment distribution and therefore the risk and return balance of the firms will also be affected. We formally define both a classic market and a market that is using our proposed system, and present an architecture to deploy such system. A preliminary numerical simulation is provided.
Patrick McCorry, Surya Bakshi, Iddo Bentov, Sarah Meiklejohn · 5 authors
State channels are a leading approach for improving the scalability of blockchains and cryptocurrencies. They allow a group of distrustful parties to optimistically execute an application-defined program amongst themselves, while the blockchain serves as a backstop in case of a dispute or abort. This effectively bypasses the congestion, fees and performance constraints of the underlying blockchain in the typical case. However, state channels introduce a new and undesirable assumption that a party must remain online and synchronised with the blockchain at all times to defend against execution fork attacks. An execution fork can revert a state channel's history, potentially causing financial damage to a party that is innocent except for having crashed. To provide security even to parties that may go offline for an extended period of time, we present Pisa, the first protocol to propose an accountable third party who can be hired by parties to cancel execution forks on their behalf. To evaluate Pisa, we provide a proof-of-concept implementation for a simplified Sprites and we demonstrate that it is cost-efficient to deploy on the Ethereum network.
Blockchains such as Bitcoin and Ethereum execute payment transactions securely, but their performance is limited by the need for global consensus. Payment networks overcome this limitation through off-chain transactions. Instead of writing to the blockchain for each transaction, they only settle the final payment balances with the underlying blockchain. When executing off-chain transactions in current payment networks, parties must access the blockchain within bounded time to detect misbehaving parties that deviate from the protocol. This opens a window for attacks in which a malicious party can steal funds by deliberately delaying other parties' blockchain access and prevents parties from using payment networks when disconnected from the blockchain.
Blockchain, a potentially disruptive technology, advances many different applications, e.g., crypto-currencies, supply chains, and the Internet of Things. Under the hood of blockchain, it is required to handle different kinds of digital assets and data. The next-generation blockchain ecosystem is expected to consist of numerous applications, and each application may have a distinct representation of digital assets. However, digital assets cannot be directly recorded on the blockchain, and a tokenization process is required to format these assets. Tokenization on blockchain will inevitably require a certain level of proper standards to enrich advanced functionalities and enhance interoperable capabilities for future applications. However, due to specific features of digital assets, it is hard to obtain a standard token form to represent all kinds of assets. For example, when considering fungibility, some assets are divisible and identical, commonly referred to as fungible assets. In contrast, others that are not fungible are widely referred to as non-fungible assets. When tokenizing these assets, we are required to follow different tokenization processes. The way to effectively tokenize assets is thus essential and expecting to confront various unprecedented challenges. This paper provides a systematic and comprehensive study of the current progress of tokenization on blockchain. First, we explore general principles and practical schemes to tokenize digital assets for blockchain and classify digitized tokens into three categories: fungible, non-fungible, and semi-fungible. We then focus on discussing the well-known Ethereum standards on non-fungible tokens. Finally, we discuss several critical challenges and some potential research directions to advance the research on exploring the tokenization process on the blockchain. To the best of our knowledge, this is the first systematic study for tokenization on blockchain.
Rantai pasok finansial (Supply Chain Finance/SCF) merupakan topik baru dalam penelitian manajemen rantai pasok (Supply Chain Management). SCF bertujuan melakukan diversifikasi sumber pendanaan dari perusahaan dengan modal terbatas dan meningkatkan efisiensi keuangan seluruh jaringan rantai pasok perusahaan. SCF telah menjadi sumber pendanaan jangka pendek bagi ribuan usaha mikro, kecil dan menengah (UMKM). Penelitian tentang SCF yang ada sekarang ini masih menggunakan framework keuangan konvensional dan belum ada penelitian SCF yang menggunakan framework keuangan Islam. Penelitian ini bertujuan untuk mengembangkan framework dan system SCF berdasarkan prinsip- prinsip syariah Islam berupa platform crowdfunding syariah dengan menggunakan teknologi blockchain dan smart contract . Rancangan system yang dihasilkan pada penelitian ini menggunakan smart contract yang dijalankan menggunakan protocol Ethereum untuk mencegah adanya penipuan/penggelapan dan meningkatkan system keamanan dari platform yang dirancang, sesuai dengan karaktrist i k blockchain yang sangat sulit di - hack.
With the popularity of artificial intelligence(AI), intelligent agents are potential to positively change people's lives in every aspect. Meanwhile, blockchain technology opens a new era of value exchange with trustless security among strangers. Its decentralized architecture and cryptography based data storage pattern bring light to vast application areas with high security and scalability requirements. In this work, we provide a general solution for intelligence application development on blockchain. Specifically, we propose a novel design of a smart agent inspired by the smart contract concept in the blockchain. Based on the proposed smart agents, a system architecture composed by smart agents is built supported by blockchain, where the agent network and blockchain network is overlapped. Then, a demonstration of the proposed architecture is designed in a case where private data required to be "properly protected" in a distributed manner. The implementation of the designed system is further conducted in the Ethereum development environment, showing the effectiveness and applicability of the proposed architecture in developing a secure distributed application.
Blockchain is maintained as a global log between a network of nodes and uses cryptographic distributed protocols to synchronize the updates. As adopted by Bitcoin and Ethereum these update operations to the ledger are serialized, and executed in batches. To safeguard the system against the generation of conflicting sets of updates and maintain the consistency of the ledger, the frequency of the updates is controlled, which severely affects the performance of the system. This paper presents Converging Directed Acyclic Graph (CDAG), as a substitute for the chain and DAG structures used in other blockchain protocols. CDAG allows multiple parallel updates to the ledger and converges them at the next step providing finality to the blocks. It partitions the updates into non-intersecting buckets of transactions to prevent the generation of conflicting blocks and divide the time into slots to provide enough time for them to propagate in the network. Multiple simultaneous updates improve the throughput of CDAG, and the converging step helps to finalize them faster, even in the presence of conflicts. Moreover, CDAG provides a total order among the blocks of the ledger to support smart contracts, unlike some of the other blockDAG protocols. We evaluate the performance of CDAG on Google Cloud Platform using Google Kubernetes Engine, simulating a real-time network. Experimental results show that CDAG achieves a throughput of more than 2000 transactions per second and confirms them well in under 2 minutes. Also, the protocol scales well in comparison to other permissioned protocols, and the capacity of the network only limits the performance.
With the rise of cryptocurrency tokens as a new asset class, the question of the fair evaluation of a cryptocurrency token has become a question of increasing importance. We estimate the pricing kernel with which users price factors affecting their token holdings. We investigate how traditional risk factors such as market risk are evaluated, as well as how blockchain specific risk factors are priced in. In order to do so, we introduce an asset pricing model and modify its properties to make it applicable to cryptocurrency markets. We group the risk factors into market related and Bitcoin- and Ethereum blockchain specific risk factors. We find that blockchain specific risk factors are priced in. There is evidence that risk factors have moved from Bitcoin to Ethereum specific risk factors with an increasing importance of market factors, providing evidence for a decoupling of on-chain and off-chain trading activity.
Oliver James Scholten, Nathan Hughes, Sebastian Deterding, Anders Drachen · 6 authors
Ethereum crypto-games are a booming and relatively unexplored area of the games industry. While there is no consensus definition yet, 'crypto-games' commonly denotes games that store tokens, e.g. in-game items, on a distributed ledger atop a cryptocurrency network. This enables the trading of game items for cryptocurrency, which can then be exchanged for regular currency. Together with their chance-based mechanics, this makes crypto-games part of the recent convergence of digital gaming and gambling. In a first effort to scope the field, this paper surveys popular crypto-games, which use the Ethereum cryptocurrency, to tease out characteristic technical properties and gameplay. It then compares the games' features with criteria found in current legal and psychological definitions of gambling. We find that the popular crypto-games selected meet a combined legal and psychological definition of gambling, and conclude with ramifications for future research.