Smart contracts on Ethereum handle millions of U.S. Dollars and other financial assets. In the past, attackers have exploited smart contracts to steal these assets. The Ethereum community has developed plenty of tools to detect vulnerable smart contracts. However, there is no standardized data set to evaluate these existing tools, or any new tools developed. There is a need for an unbiased standard benchmark of real-world Ethereum smart contracts. We have created ScrawlD: an annotated data set of real-world smart contracts taken from the Ethereum network. The data set is labelled using 5 tools that detect various vulnerabilities in smart contracts, using majority voting.
Internet-of-Things enables interconnection of billions of devices, which perform autonomous operations and collect various types of data. These things, along with their generated huge amount of data, need to be handled efficiently and securely. Centralized solutions are not desired due to security concerns and scalability issue. In this article, we propose HIBEChain, a hierarchical blockchain system that realizes scalable and accountable management of IoT devices and data. HIBEChain consists of multiple permissioned blockchains that form a hierarchical tree structure. To support the hierarchical structure of HIBEChain, we design a decentralized hierarchical identity-based signature (DHIBS) scheme, which enables IoT devices to use their identities as public keys. Consequently, HIBEChain achieves high scalability through parallel processing as blockchain sharding schemes, and it also implements accountability by use of identity-based keys. Identity-based keys not only make HIBEChain more user-friendly, they also allow private key recovery by validators when necessary. We provide detailed analysis of its security and performance, and implement HIBEChain based on Ethereum source code. Experiment results show that a 6-ary, (7,10)-threshold, 4-level HIBEChain can achieve 32,000 TPS, and it needs only 9 seconds to confirm a transaction.
As the first crisis faced by Crypto-assets, Covid-19 updated the debate about their safehaven properties. Our paper tries to analyze the safe-haven properties of Crypto-assets and Gold for European assets. We find that Gold has not been more efficient than Cryptoassets (Tether, Cardano and Dogecoin) as safe-haven during the market crash due to Covid-19 in March 2020. We also found that during the study period Bitcoin, Ethereum, Litecoin and Ripple were just diversifiers for the European indices. Finally, Tether, Cardano and Dogecoin showed hedging properties like Gold before and after the market crash.
Bu çalışmanın amacı COVID-19 pandemi döneminde kripto para fiyatlarında balon oluşup oluşmadığının araştırılmasıdır. Bu amaçla piyasa değeri en yüksek 3 kripto para olan Bitcoin (BTC), Ethereum (ETH) ve Binance Coin (BNB) fiyatlarına ilişkin, 10/03/2020-06/07/2021 tarihlerini kapsayan veri seti GSADF testiyle analiz edilmiştir. Yapılan analizler sonucunda incelenen her üç kripto paranın da fiyatlarında balon olduğu tespit edilmiştir. Buna ek olarak verileri analiz edilen kripto paralarda tespit edilen fiyat balonlarının dönemlerinin benzer olması, balon tespit edilen dönemlerde piyasanın tamamını etkileyen fiyat hareketleri olduğu yönünde güçlü kanıtlar sunmuştur. Çalışmanın düzenleyici otoriteler ve yatırımcılar açısından önemli sonuçlar ortaya koyduğu düşünülmektedir. COVID-19 pandemisi ya da piyasalar üzerinde benzer etkiler yapabilecek finansal kriz ortamlarında yatırımcılar oluşabilecek fiyat balonlarına dikkat etmeli ve yatırım kararlarında bu durumu göz önünde bulundurmalıdır. Son olarak finansal piyasaları düzenleyici taraflar söz konusu dönemlerde yatırımcıları oluşabilecek olumsuz durumlardan korumak adına gerekli adımları atmalıdırlar.
As the confidentiality and scalability of smart contracts have become a crucial demand of blockchains, off-chain contract execution frameworks have been promising. Some have recently expanded off-chain contracts to Multi-Party Computation (MPC), which seek to transition the on-chain states by off-chain MPC. The most general problem among these solutions is MPT, since its off-chain MPC takes on- and off-chain inputs, delivers on- and off-chain outputs, and can be publicly verified by the blockchain, thus capable of covering more scenarios. However, existing Multi-Party Transaction (MPT) solutions lack at least one of data availability, financial fairness, delivery fairness, and delivery atomicity. These properties are crucially valued by communities, e.g., the Ethereum community, or users. Even worse, these solutions require high-cost interactions between the blockchain and off-chain systems. This paper proposes a novel MPT-enabled off-chain contract execution framework, DECLOAK. DECLOAK is the first to achieve data availability of MPT, and our method can apply to other fields that seek to persist user data on-chain. Moreover, DECLOAK solves all mentioned shortcomings with even lower gas costs and weaker assumptions. Specifically, DECLOAK tolerates all but one Byzantine party and TEE executors. Evaluating on 10 MPTs, DECLOAK reduces the gas cost of the SOTA, Cloak, by 65.6%. Consequently, we are the first to not only achieve such level secure MPT in practical assumption, but also demonstrate that evaluating MPT in the comparable gas cost to normal Ethereum transaction is possible. And the cost superiority of DECLOAK increases as the number of MPT parties grows.
Abstract This study is an attempt to evaluate the compliance problem regarding the current status of the establishment of agreed‐upon interfaces for tokens, which are the most important type of applications of the Ethereum blockchain. The authors analysed the existing application programming interface standard interface called Ethereum Request for Comment 20 (ERC‐20), proposed functional ERC‐20 specifications, and evaluated the real‐world token smart contracts that have been deployed and used for transactions on a blockchain. For the evaluation, the authors developed an automatic tool with a test suite based on the proposed functional specifications. The authors' experiment revealed that no top‐100 market capitalization token smart contracts turned out to agree perfectly based on the functional specifications. In addition, the authors found the de facto standard behaviour deduced through testing with the functional specifications and suggested a possible countermeasure for the compliance problem in dealing with multiple tokens together.
There is an urgent need to control global warming caused by humans to achieve a sustainable future. CO2 levels are rising steadily, and while countries worldwide are actively moving toward the sustainability goals proposed during the Paris Agreement in 2015, we are still a long way to go from achieving a sustainable mode of global operation. The increased popularity of cryptocurrencies since the introduction of Bitcoin in 2009 has been accompanied by an increasing trend in greenhouse gas emissions and high electrical energy consumption. Popular energy tracking studies (e.g., Digiconomist and the Cambridge Bitcoin Energy Consumption Index (CBECI)) have estimated energy consumption ranges from 29.96 TWh to 135.12 TWh and 26.41 TWh to 176.98 TWh, respectively for Bitcoin as of July 2021, which are equivalent to the energy consumption of countries such as Sweden and Thailand. The latest estimate by Digiconomist on carbon footprints shows a 64.18 MtCO2 emission by Bitcoin as of July 2021, close to the emissions by Greece and Oman. This review compiles estimates made by various studies from 2018 to 2021. We compare the energy consumption and carbon footprints of these cryptocurrencies with countries around the world and centralized transaction methods such as Visa. We identify the problems associated with cryptocurrencies and propose solutions that can help reduce their energy consumption and carbon footprints. Finally, we present case studies on cryptocurrency networks, namely, Ethereum 2.0 and Pi Network, with a discussion on how they can solve some of the challenges we have identified.
As computer vision is prevalently used for mail-in ballot processing and counting, it becomes a point of centralized trust in postal voting. We propose DVote, a prototype system of postal voting that provides decentralized trust in computer vision. With blockchain and layer-2 technologies, DVote decentralizes the computation and model training of computer vision to a group of scrutineers that hold the AnyTrust assumption, i.e., at least one member is honest. Consequently, the computational integrity is anchored to the trustworthiness of a large public blockchain such as Ethereum.
The purpose of our study is to figure out the transitions of the cryptocurrency market due to the outbreak of COVID-19 through network analysis, and we studied the complexity of the market from different perspectives. To construct a cryptocurrency network, we first apply a mutual information method to the daily log return values of 102 digital currencies from January 1, 2019, to December 31, 2020, and also apply a correlation coefficient method for comparison. Based on these two methods, we construct networks by applying the minimum spanning tree and the planar maximally filtered graph. Furthermore, we study the statistical and topological properties of these networks. Numerical results demonstrate that the degree distribution follows the power-law and the graphs after the COVID-19 outbreak have noticeable differences in network measurements compared to before. Moreover, the results of graphs constructed by each method are different in topological and statistical properties and the network's behavior. In particular, during the post-COVID-19 period, it can be seen that Ethereum and Qtum are the most influential cryptocurrencies in both methods. Our results provide insight and expectations for investors in terms of sharing information about cryptocurrencies amid the uncertainty posed by the COVID-19 pandemic.
Blockchain and Artificial Intelligence (AI) have propelledadvances and growth that have resulted in development across pretty much every industry. AI alludes to machines that are worked to perform shrewd errands that have generally been refined by people. Blockchain is a decentralized organization of PCs, which records and stores information to show an ordered arrangement of occasions on a straightforward and permanent record framework. AI and blockchain are ending up being an incredible amazing pair, improving pretty much. It is evident that AI and blockchain ideas are spreading at a wonderful rate. The two innovations have a particular level of mechanical intricacy and multidimensional business suggestions. In any case, a typical misconstruing idea about blockchain, specifically, is that “a blockchain is decentralized and accordingly nobody controls it.” In any case, the fundamental improvement of a blockchain framework is as yet credited to a group of center designers. Accept keen agreement, for instance, it’s anything but an assortment of codes (or capacities) and information (or states) that are modified and sent on a blockchain (say, Ethereum) by various human software engineers. It is, hence, shockingly, less inclined to be liberated from escape clauses and imperfections. Regardless of the sector in which they are used, anything from grocery store network coordinations and medical records exchange to media sovereignty and monetary security is being revamped with blockchain and AI. Blockchain–AI assembly is inescapable on the grounds that both are arrangements with information and worth. Blockchain empowers secure capacity and sharing of information or anything of significant worth. AI can examine and create bits of knowledge from information to produce esteem.
The globally acknowledged accelerating crypto hype has put a lot of work on researchers and analysts. This new marvel of digital currencies requires a lot of attention, for it to become conventional worldwide. Virtual coins or cryptographic forms of money utilize encryption framework, so called the Block Chain technology, that manage the formation and supply of coins and exchanges must be recognized from a financial examination point of view. Subsequently, it is essential to inspect which social, money related & macroeconomic components decide its cost with a specific end goal to know the degree and outcomes of the economy. This paper aims to study different internal and external factors that affect cryptocurrencies’ prices. A sample of four digital coins with largest market capitalization has been selected. Daily price data from the years 2015 to 2020 of Bitcoin with other altcoins such as Ethereum, Ripple and Litecoin has been taken. Internal factors consist of demand and supply variables and also the attractiveness associated with its increasing hype. Other factors include KSE-100 Index (Karachi Stock Exchange), USD-PKR (Dollar to Pakistani Rupee) exchange rate and oil prices from PSO (Pakistan State Oil). ARDL analysis has been done to study the effect of these factors on the prices of crypto coins. Our analysis shows that circulating supply has a significant effect on Ethereum and Ripple prices in the long run. Attractiveness has been significant on the prices of Ethereum only.
Blockchain technologies loom large among the controversial topics of public debate. Like any technology, blockchain offers various ways to imagine alternative models of politics and society. Arguably, the most common interpretation treats it as the technology for techno-anarchism and a tool for total decentralization. This paper focuses on an overlooked genealogy of the politics of the blockchain – the classic republican theory. We consider whether republican practices could shed light on certain aspects of blockchain communities and understand their governance better. Our paper offers a historical analysis of governance visions inscribed in Bitcoin and Ethereum, arguably the most influential applications.
Abstract Blockchain is a pioneering technology that allows the creation of innovative information exchange ecosystems thanks to unique properties, such as immutability, distribution and transparency. By combining this technology with the emergent internet of things (IoT), many innovative business models can be created. The main objective of this work is to present the design and an initial implementation of a decentralized rental system that takes advantage of smart contracts developed on a public blockchain, combined with the potential of the IoT and its intimate relationship with cyber-physical systems. The logic to be implemented in the blockchain is applied in this paper by using the Ethereum programming language, so that the developed application covers the entire car rental process offered in traditional web applications, but adding more autonomy, functionalities and ease of use for both lessees and lessors. Following Ethereum application development guidelines, all business logic is located in the smart contracts implemented in the network, where they can be used to control the car rental system. While this is a work in progress, the results obtained in the first proof of concept have been very promising.
César Soto-Valero, Martin Monperrus, Benoît Baudry
The rise of blockchain technologies has triggered tremendous research interest, coding efforts, and monetary investments in the last decade. Ethereum is the single largest programmable blockchain platform today. It features cryptocurrency trading, digital art, and decentralized finance through smart contracts. So-called Ethereum nodes operate the blockchain, relying on a vast supply chain of third-party software dependencies maintained by diverse organizations. These software suppliers have a direct impact on the reliability and the security of Ethereum. In this article, we perform an analysis of the software supply chain of Java Ethereum nodes and distill the challenges of maintaining and securing this blockchain technology.
Michael Paul Kramer, Linda Bitsch, Jon Henrich Hanf
Firms in the agri-food sector have started implementing blockchain technology to both provide transparency over the supply chain transactions and to make trust attributes visible to consumers. Besides the well-known public blockchains such as Bitcoin and Ethereum, private- and consortium-type blockchain platforms exist. The latter ones are being operated in the agri-food ecosystem contributing to the vertically cooperated supply networks that are coordinated by a focal firm. Stakeholders’ attitude and behavioral intentions toward the use of the blockchain technology impact their use behavior. The results show that permissioned blockchain governance mechanisms with consensus and incentives to motivate stakeholders are lacking in private and consortium blockchains. This study closes a research gap as understanding how the stakeholder management approach can compensate for the lack of consensus mechanisms can provide managerial guidance toward the development of an effective stakeholder management strategy, which eventually can be provided for a competitive advantage. As there is little research on the role of blockchain as a novel governance mechanism, this research will contribute to the scholarly discussion toward a common understanding.
Non-fungible tokens (NFT) have been defined as digital assets that encode items such as art, collectables, and in-game goods. They are often stored in smart contracts on a blockchain and are exchanged online, frequently using Bitcoin. As NFT became increasingly popular in the last few years, decentralized financial assets (DeFi) tokens also started receiving growing attention as financial instruments that differ from NFTs and cryptocurrencies. Based on data on NFTs, DeFi tokens, and cryptocurrency daily prices between January 15th and December 6th, 2021, we examine the correlation between NFTs, DeFi tokens and major cryptocurrencies such as Bitcoin and Ethereum. Using the volatility spillover matrix approach by Diebold and Yilmaz (2012) as applied by Dowling (2021) and including DeFis into the discussion, we find that there is very limited spillover to and from non-traditional financial markets. Also, DeFi assets appear to be relatively unconnected to cryptocurrency markets. Following the methodology by Karim, Lucey, Naeem and Uddin (2021) of the quantile connectedness approach and the cross-quantilogram model of Han, Linton, Oka and Whang (2016), we determine that positive DeFi and Crypto spillovers exceeded negative NFT spillovers. This paper concludes that both NFTs and DeFi assets show significant potential in terms of portfolio diversification since they display low correlation with cryptocurrencies, especially in the case of DeFis thanks to it being disconnected from other assets in the market, based on this year's data. This has significant implications for investors who seek to diversify their portfolios by including cryptocurrency, NFTs and DeFis as assets.
Blockchain technology has been widely used in digital currency, Internet of Things, and other important fields because of its decentralization, nontampering, and anonymity. The vigorous development of blockchain cannot be separated from the security guarantee. However, there are various security threats within the blockchain that have shown in the past to cause huge financial losses. This paper aims at studying the multi-level security threats existing in the Ethereum blockchain, and exploring the security protection schemes under multiple attack scenarios. There are ten attack scenarios studied in this paper, which are replay attack, short url attack, false top-up attack, transaction order dependence attack, integer overflow attack, re-entrancy attack, honeypot attack, airdrop hunting attack, writing of arbitrary storage address attack, and gas exhaustion denial of service attack. This paper also proposes protection schemes. Finally, these schemes are evaluated by experiments. Experimental results show that our approach is efficient and does not bring too much extra cost and that the time cost has doubled at most.
Open access
Blockchain Technology Applications and Security
Currency Recognition and Detection
Advanced Steganography and Watermarking Techniques
Lukas Mastilak, Pavol Helebrandt, Marek Galinski, Ivan Kotuliak
The whole Internet consists of thousands of autonomous systems that transfer data with one another. The BGP plays a significant role in routing, but its behaviour is essentially naive, trusting neighbours without authenticating advertised IP prefixes. This is the main reason why BGP endures various path manipulation attacks. Recently, conventional methods for securing BGP have been implemented, i.e., BGPSec with RPKI. However, these approaches are centralised with a single point of failure that may be compromised, invalidating the whole security mechanism. There have been multiple decentralised projects dealing with various mechanisms, mostly built on Ethereum and blockchain networks. Some with ambition to strengthen existing centralised mechanisms, others to replace them. In this article, we present the first comprehensive survey on blockchain solutions to enforce BGP security, with complex explanations of their contributions and a comparison with different aspects. We explain how blockchain technology can provide an alternative to prevent the false origin of IP prefixes or hijacking AS paths. Moreover, we describe new blockchain-based attacks that BGP would face after the inclusion of blockchain into the inter-domain routing. Finally, we answer the defined research questions and discuss the potential open issues for further study.
Blockchain technology could bring many advantages to our society, in many different areas. In particular, it could improve individuals’ control over their data. Through blockchain, data could be shared easily and in a secure way among different actors, thus preventing its accumulation in single points of failure. As the use of blockchain technology becomes widespread, its compatibility with Regulation (EU) 2016/679 (the General Data Protection Regulation, ‘GDPR’ or ‘Regulation’ hereafter) has emerged as a point of tension. Some have argued that blockchain pursues the same objectives as the GDPR, but it does so in ways which are different from those established by the Regulation. This is mainly due to the fact that the Regulation implies a centralized data collection system, where it is possible to single out an accountable central entity, against which users’ rights have to be safeguarded. Whereas, in public permissionless blockchain projects, the network is decentralized, no single entity is responsible for it, and the decision-making power is shared among different stakeholders. It has been argued that this incompatibility, and the resulting regulatory uncertainty, will asphyxiate the development of this technology. Being the Ethereum blockchain the one which, at the time of writing, promises to be the most suitable to be adopted in a variety of use cases, this paper assesses whether, having regard to the allocation of GDPR responsibility roles, to the legal bases and principles of data processing, and to the data subject’s rights, it is possible to consider the Ethereum blockchain GDPR-compatible.
Non-fungible tokens or NFTs are the digital assets on a blockchain. NFTs are unique and they cannot be divided like cryptocurrencies. NFTs could store digital ownership of an artwork or collections or can be fan tokens or tickets for clubs. NFTs are based on a smart contract on a blockchain network which supports them, such as Ethereum, Cardano or Polkadot. Most of the NFTs are now minted on Ethereum (ERC-20) network, but it has some main issues like high transaction fees and low speed. There are lots of domains which can be benefited from NFT technology such as art, music, gaming, sport and wildlife conservation. NFTs could be also bought or sold on lots of NFT marketplaces such as OpenSea and Chiliz. The trend is in a huge hype because the market cap and popularity of NFTs are growing significantly.
Document Verification using Blockchain Technology has a huge scope. With increasing documents generated every year, there is no systematic and simple way to verify the documents. This system could be used to the governments, organizations, employers and basically anybody who wants to verify that the given document is not forged. This could be used to verify all kinds of immutable records ranging from attendance records, birth certificates, graduation and academic credentials. The proposed system could be used by the government to construct a decentralized network to store and maintain record. This is also the best way to ensure that the documents exist in the state of their creation, that they are not tampered with by anyone. Motivated by this, we propose to develop a decentralized blockchain system using Ethereum that will serve as an application to authenticate the documents. An application will be installed to local systems in which the users will verify the documents. These local systems also known as “Nodes” or “Blocks”.Once the documents are added to blocks forming the blockchain, complex calculations are performed to find the unique hash for that particular document.This concept can be implemented through decentralized applications deployed on the blockchain. The blockchain that is intended to be used for the deployment process is the Ropsten Ethereum Network. Thus, the immutability of documents can be maintained, while providing a simple, yet secure way for authenticating/verifying documents.