Ehab Zaghloul, Tongtong Li, Matt W. Mutka, Jian Ren
Current systems used by medical institutions for the management and transfer of Electronic Medical Records (EMRs) can be vulnerable to security and privacy threats. In addition, these systems are centralized, often lack interoperability, and give patients limited or no access to their own EMRs. In this article, we propose a novel distributed data sharing scheme that applies the security benefits of blockchain to address these concerns. We deploy smart contracts on Ethereum blockchain and utilize a distributed storage system to alleviate the dependence on the record-generating institutions to manage and share patient records. To preserve privacy of patient records, we implement our smart contracts as a method to allow patients to verify attributes prior to granting access rights. Our proposed scheme also facilitates selective sharing of medical records among staff members that belong to different levels of a hierarchical institution. We provide extensive security, privacy, and evaluation analyses to show that our proposed scheme is both efficient and practical.
Purpose Considering the different motivation for the creation of each of these cryptocurrencies, the purpose of this paper is to examine whether there is a dominant external factor in the cryptocurrency world. Using a novel two-step time and frequency independent methodology, the authors examine a large scope of cryptocurrencies and external factors within the same period, and analytical framework. Design/methodology/approach The examined cryptocurrencies are Bitcoin, Ethereum, Ripple, Litecoin, Monero and Dash. In total, 18 external factors from 5 factor families are selected based on the mining motivation of these cryptocurrencies. The study first examines discrete wavelet transform-based (WTB) correlations, reduce the dimension and focuson relevant pairs. Selected pairs are further examined by wavelet coherence to capture the intermittent nature of the relationships allowing the most needed “Flexibility of frequency and time domains”. Findings Each coin appears to operate as a unique character with the exception of Bitcoin and Litecoin. There is no prominent external driver. The cryptocurrency market is not a clear substitute for a specific factor or market. Two-step WTB filtered wavelet coherence analysis help us to analyze a large number of factor without the loss of focus. The co-movements within the cryptocurrencies spillover from Ethereum to altcoins and later to Bitcoin. Originality/value The study presents one of the first examples of two-step WTB filtered wavelet coherence analysis. The methodology suggests an approach for simultaneous examination of large number of variables. The scope of the study provides a rather holistic view of the co-movements of external factors and major cryptocurrencies.
Actualmente, la tecnologia blockchain se encuentra en constante evolucion, pero a pesar de su innovadora tecnologia, no solo se tienen modelos teoricos y conceptuales acerca de sus posibles usos y finalidades, sino que tambien estan empezando a existir aplicaciones basadas en blockchain que cambiaran el modo de realizar multiples gestiones, asi como la obtencion de nuevos conceptos como el de identidad soberana que se esta implementando en Alastria Blockchain Ecosystem. Alrededor de la tecnologia blockchain existen una serie de problemas que requieren un estudio intensivo, con el objetivo de la obtencion de soluciones, o posibles alternativas que mitiguen dichos problemas, como la actualizacion de los Smart Contracts, es decir, poder modificar los contratos sin perder informacion hasta la posibilidad de utilizar aplicaciones blockchain en multiples dispositivos. Para abordar los problemas que se han encontrado, en primer lugar, se ha realizado un estudio de las tres principales blockchains, Ethereum, Hyperledger Fabric y Corda, asi como cuales son las principales componentes de estas y los diferentes conceptos que hay que entender para saber como funciona. Estos conceptos incluyen, el objetivo y funcion de los nodos, el concepto de wallet, con el cual los usuarios pueden interactuar con la blockchain, el concepto de criptografia que aporta seguridad a una blockchain y por ultimo los diferentes algoritmos de consenso que existen. Por otro lado, se ha realizado un estudio de los diferentes lenguajes de programacion y herramientas que se utilizan para la implementacion y construccion de las tres principales blockchains que se han comentado anteriormente. Tambien se ha explicado cual es el papel y el objetivo que tiene OpenZeppelin dentro de la implementacion de los Smart Contracts, asi como las ventajas que aporta su uso. Una vez que ya se tienen claros los conceptos que engloba una blockchain, se ha realizado un estudio exhaustivo del modelo de identidad soberana que se esta implementando actualmente en Alastria. En cuanto a dicho modelo, se destaca los tres roles que existen, el del subject, el del issuer y el del service provider. Por otro lado, existen una serie de objetos que hacen posible la interaccion entre los roles listados anteriormente. Con el objetivo de resolver el problema de que los Smart Contracts de Alastria no son actualizables, se ha realizado un estudio y se ha propuesto un primer aproximamiento de arquitectura para los Smart Contracts que se basa en el patron eternal storage. De esta manera, lo que se propone es tener separados en contratos diferentes los datos de la logica, con el objetivo de ir modificando solo los contratos que albergan la logica, consiguiendo de esta manera que los contratos de Alastria sean actualizables. Con el mismo objetivo de resolver ciertos problemas que se han encontrado, se ha realizado una auditoria a los Smart Contracts de Alastria. En dicha auditoria se han encontrado una serie de vulnerabilidades en los contratos. Este punto ha sido muy importante ya que los Smart Contracts de Alastria se van a encontrar en produccion para el nuevo concepto de identidad soberana. El principal objetivo de este modelo de identidad soberana es que los usuarios sean en todo momento los unicos duenos de sus datos y sepan en todo momento quien esta haciendo uso de ellos y con que finalidad, asi como mejorar los procesos de alta en las diferentes entidades que prestan servicios que los usuarios consumen. Por otro lado, se ha realizado una investigacion sobre como obtener o activar una serie de metricas para la consecucion de una serie de informacion que vislumbre luz acerca del correcto funcionamiento de aplicaciones basadas en blockchain. Para abordar la necesidad de que un subject pueda utilizar su identidad en mas de un dispositivo se ha realizado un estudio utilizando los HSM, servidores hardware que permiten almacenar claves y tienen la capacidad de firma. En dicho estudio se ha obtenido como resultado, la posibilidad de almacenar los keystores en dichos HSM, para que los usuarios hagan uso de sus keystores desde multiples dispositivos, asi como mejorar la seguridad a la hora de hacer uso del keystore. A pesar de que la tecnologia no es una limitacion en este aspecto, cabe destacar que estos servidores tienen un precio bastante elevado, con lo cual cada usuario no puede tener un HSM propio, con lo cual se tendria que llegar a un acuerdo entre las empresas para poner a disposicion de los usuarios estos servidores siempre y cuando se quieran securizar altamente el uso de estos keystores. Por ultimo, el creciente uso de esta tecnologia, en la que las empresas estan anadiendo a sus modelos de negocio se debe a sus numerosas ventajas. Se trata de una tecnologia que permite el tratamiento de datos de manera segura, confidencial e inmutable y de esta manera el tratamiento de estos datos se vuelve transparente.---ABSTRACT---Currently, the blockchain technology is in constant evolution but, despite its innovative technology, not only we do have theoretical and conceptual models about its possible uses and purposes, but also, applications based on this technology are coming to light. Those will change the way in which we carry out different managements, as well as obtaining new concepts, such as the sovereign identity that is being implemented in Alastria Blockchain Ecosystem. Around the blockchain technology there are a series of problems that require intensive study, with the aim of obtaining solutions, or possible alternatives that mitigate these problems, such as updating contracts, i.e. making the contracts upgradeable to the possibility of using blockchain applications on multiple devices. To address the problems encountered, firstly, a study has been carried out of the three main blockchains, Ethereum, Hyperledger Fabric and Corda, as well as what the main components of these are and the different concepts that need to be understood in order to know how they work. These concepts include, the objective and function of the nodes, the concept of wallet, with which users can interact with the blockchain, the concept of cryptography that provides security to a blockchain and finally the different consensus algorithms that exist. On the other hand, a study of the different programming languages and tools used for the implementation and construction of the three main blockchains mentioned above has been carried out. It has also been explained, which is the role and objective that OpenZeppelin has within the implementation of the Smart Contracts, as well as the advantages that the use of it brings. Once the concepts of a blockchian are clear, a comprehensive study of the model of sovereign identity currently being implemented in Alastria has been carried out. Regarding this model, the three existing roles are highlighted: the subject, the issuer, and the service provider. On the other hand, there are a series of objects that make possible the interaction between the roles listed above. In order to solve the problem that Alastria's Smart Contracts are not upgradeable, a study has been carried out and a new architecture has been proposed for Smart Contracts based on eternal storage. In this way, what is proposed is to have the logic data separated into different contracts, with the objective of modifying only the contracts that contain the logic, thus making Alastria contracts upgradeable. With the same objective of solving certain problems that have been found, an audit has been carried out on Alastria's Smart Contracts. In this audit, a series of vulnerabilities were found in the contracts. This point has been very important since Alastria Smart Contracts will be in production for the new concept of sovereign identity. The main objective of this model of sovereign identity is that users are at all times the sole owners of their data and know at all times who is making use of them and for what purpose, as well as improving the onboarding processes in the different entities that provide services that users consume. On the other hand, research has been carried out on how to obtain or activate a series of metrics for the achievement of a series of information that will shed light on the correct functioning of blockchain-based applications. To address the problem of a subject being able to use its identity on more than one device, a study has been carried out with the HSM (Hardware Secure Module), hardware servers that allow the storage of keys and have the capacity of signature. The result of this study is that, if keystores can be stored in these HSMs, users can use their keystores from multiple devices. Although the technology is not a limitation in this aspect, it should be noted that these servers have a fairly high price, so that each user cannot have their own HSM, so that an agreement would have to be reached between the companies to make these servers available to users as long as they want to make the use of these keystores highly secure. Finally, the use of this technology is growing by leaps and bounds, being added to the business models of companies due to its many advantages. It is a technology that, not only, allows the treatment of data in a secure, confidential, and immutable way, but in this way, the treatment of this data becomes transparent.
Marten Sigwart, Michael Borkowski, Marco Peise, Stefan Schulte · 5 authors
Abstract As data collected and provided by Internet of Things (IoT) devices power an ever-growing number of applications and services, it is crucial that this data can be trusted. Data provenance solutions combined with blockchain technology are one way to make data more trustworthy by providing tamper-proof information about the origin and history of data records. However, current blockchain-based solutions for data provenance fail to take the heterogeneous nature of IoT applications and their data into account. In this work, we identify functional and non-functional requirements for a secure and extensible IoT data provenance framework, and conceptualise the framework as a layered architecture. Evaluating the framework using a proof-of-concept implementation based on Ethereum smart contracts, we conclude that our framework can be used to realise data provenance concepts for a wide range of IoT use cases. While blockchain technology generally poses constraints on scalability and privacy, we discuss multiple solutions aiming to overcome these issues.
Direct bartering allows for the trading of assets with or without the use of money. In this paper, we introduce a smart contract written in the Solidity language for the Ethereum blockchain that implements a distributed and autonomous direct barter exchange operated by crowds. Since ERC20 smart contract tokens are widely used for initial coin offerings (ICOs), our implementation provides autonomous bartering services for ERC20 tokens. The non-fungible ERC721 token, as well as Ethereum Name Service (ENS) name bartering, are also supported. Because finding a feasible bartering solution for bids involving multiple tokens is NP-hard in general, our exchange only provides escrow and swapping services. It assumes feasible solutions are submitted by bartering problem solvers from the crowd who run a solver locally on their machines. Bartering problem solvers are incentivized to submit solutions to the autonomous exchange by awarding them with excess tokens that are left over after granting the bidders the tokens they requested in their bids. Our system, called BarterMachine, can perhaps be used to facilitate a global barter economy. The BarterMachine prototype is available for testing on the Ethereum Ropsten network at https://bartermachine.github.io/bartermachine/ropsten/.
To name or explain an IS phenomenon one often selectively integrates features from one or more concepts from domains familiar to end users. Consider “smart contract”, which integrates features from two domains: IT and law. However, such selective feature integration often remains implicit to its users, resulting in ambiguous features of novel IS concepts. This ambiguity can be opportunistically exploited. A prominent case, reported in this paper, is a hacker’s interpretation of a “smart contract”, who equated exploiting vulnerabilities in code to using terms and conditions in a legal contract. In so doing s/he legitimized, towards the Ethereum community, gaining a significant amount of cryptocurrencies. The contribution of this research in progress paper is to propose conceptual blending, an approach from cognitive linguistics, for systematically analyzing possible interpretations of IS concepts. For illustration purposes, we employ the aforementioned “smart contract” case and present two blends: a prima facie interpretation, and an authorial intent blend. In our focus on analyzing interpretations of IS concepts, this paper constitutes a first step in a larger project aiming at using instruments from cognitive linguistics for discourse analysis in the field of IS.
In recent years, the blockchain technology has matured and established new opportunities in the digital world. With the release of the Blockchain 2.0, the Ethereum Network and smart contracts, it is now possible to operate applications decentralized and independently. These applications promise lower transaction costs, better efficiency and higher security. However, there is still a lack of in-depth understanding and standardization within the variety of recently developed smart contracts. In addition, there is still no proper taxonomy that structures the technical elements of a smart contract and makes them comparable. Hence, we develop a smart contract taxonomy using an inductive research approach. Following Nickerson et al. (2013) we analyze the smart contracts of 47 gambling DApps to identify the 18 dimensions and 41 characteristics of your technical and code-based taxonomy. In future research, we will continue to expand the developed taxonomy and include other application areas. Finally, a general taxonomy for research and product development will be available to science and practice, ensuring a consistent and standardized implementation of smart contracts.
Adrian Hofmann, Fabian Josef Schatz, Axel Winkelmann
The blockchain technology has gained significant popularity among different users around the world by promising them a fully decentralized network independent from trusted third parties, governments or other central authorities. Instead of trusting a single instance, the trust is distributed among a large group of people, that validate transactions and add those to the blockchain. This process, referred to as "mining", has experienced trends of centralization, possibly presenting a major threat to the security and usability of blockchains. So far there is only a limited understanding of the mechanisms behind centralization of mining power. To better understand the underlying mechanisms, we investigated the major Proof-of-Work blockchains (Bitcoin, Ethereum and Litecoin) as well as their successful forks (Bitcoin Cash, Bitcoin SV, Ethereum Classic). We found that the mining ecosystem seems to be self regulating and adapts timely to foreseeable changes. Only unforeseeable adjustments, such as a split of the blockchain, result in strong temporary fluctuations and centralization. Our results provide a thorough understanding of the mining ecosystem and gives reliable indicators for governance control in major public blockchains.
Huashan Chen, Marcus Pendleton, Laurent Njilla, Shouhuai Xu
Blockchain technology is believed by many to be a game changer in many application domains. While the first generation of blockchain technology (i.e., Blockchain 1.0) is almost exclusively used for cryptocurrency, the second generation (i.e., Blockchain 2.0), as represented by Ethereum, is an open and decentralized platform enabling a new paradigm of computing—Decentralized Applications (DApps) running on top of blockchains. The rich applications and semantics of DApps inevitably introduce many security vulnerabilities, which have no counterparts in pure cryptocurrency systems like Bitcoin. Since Ethereum is a new, yet complex, system, it is imperative to have a systematic and comprehensive understanding on its security from a holistic perspective, which was previously unavailable in the literature. To the best of our knowledge, the present survey, which can also be used as a tutorial, fills this void. We systematize three aspects of Ethereum systems security: vulnerabilities, attacks, and defenses. We draw insights into vulnerability root causes, attack consequences, and defense capabilities, which shed light on future research directions.
Cryptocurrency has seen an explosive growth in recent years, thanks to the evolvement of blockchain technology and its economic ecosystem. Besides Bitcoin, thousands of cryptocurrencies have been distributed on blockchains, while hundreds of cryptocurrency exchanges are emerging to facilitate the trading of digital assets. At the same time, it also attracts the attentions of attackers. Fake deposit, as one of the most representative attacks (vulnerabilities) related to exchanges and tokens, has been frequently observed in the blockchain ecosystem, causing large financial losses. However, besides a few security reports, our community lacks of the understanding of this vulnerability, for example its scale and the impacts. In this paper, we take the first step to demystify the fake deposit vulnerability. Based on the essential patterns we have summarized, we implement DEPOSafe, an automated tool to detect and verify (exploit) the fake deposit vulnerability in ERC-20 smart contracts. DEPOSafe incorporates several key techniques including symbolic execution based static analysis and behavior modeling based dynamic verification. By applying DEPOSafe to 176,000 ERC-20 smart contracts, we have identified over 7,000 vulnerable contracts that may suffer from two types of attacks. Our findings demonstrate the urgency to identify and prevent the fake deposit vulnerability.
Blockchain technology provides an auditable and tamper-proof distributed storage infrastructure for information records. This can be leveraged to support distributed workflow management. Compared to proof-of-work consensus, popularized by Bitcoin and Ethereum, blockchains based on BFT (byzantine fault tolerance) ordering consensus trade scalability for immediacy and finality of consensus. This makes them easier to use as distribution infrastructure, as applications need not be adapted to deal with eventual consistency and delayed consensus of proof-of-work blockchains. Hence, applications such as workflow engines can be easily ported to such a blockchain infrastructure to take advantage of their decentralized integrity assurance and information distribution model. In this paper we describe how the YAWL workflow engine can be used on a BFT based blockchain infrastructure to enable collaborative workflows across different organizations.
As criptomoedas surgem como uma maneira diferenciada de se efetuar pagamentos, principalmente no âmbito online. As criptomoedas se tratam de um modelo de moeda virtual cujas principais características são a descentralização e o anonimato de seus usuários. O presente trabalho buscou relacionar as criptomoedas com o setor do turismo, tomando por base um levantamento bibliográfico para compreender o que são as criptomoedas e o seu funcionamento, seguido de uma análise de 255 notícias em portais de notícias especializados em negócios que tratavam de criptomoedas e suas aplicações no mercado. Com isso constatou-se que as cinco criptomoedas mais utilizadas para venda de serviços turísticos são o Bitcoin, Litecoin, Bitcoin Cash, Ethereum e DASH. Algumas características dessas criptomoedas como o seu preço e taxa para realização de transação foram abordadas na pesquisa para melhor entender como elas poderiam ser implementadas no setor turístico. Conclui-se que as criptomoedas são uma forma diferente de se efetuar transações que pode trazer comodidade e ao mesmo tempo riscos para os turistas. Agradecimentos ao CNPq pela concessão de bolsa para realização da pesquisa.
Carlos Barreto, Taha Eghtesad, Scott Eisele, Áron Lászka · 6 authors
Power grids are undergoing major changes due to the rapid adoption of intermittent renewable energy resources and the increased availability of energy storage devices. These trends drive smart-grid operators to envision a future where peer-to-peer energy trading occurs within microgrids, leading to the development of Transactive Energy Systems. Blockchains have garnered significant interest from both academia and industry for their potential application in decentralized TES, in large part due to their high level of resilience. In this paper, we introduce a novel class of attacks against blockchain based TES, which target the gateways that connect market participants to the system. We introduce a general model of blockchain based TES and study multiple threat models and attack strategies. We also demonstrate the impact of these attacks using a testbed based on GridLAB-D and a private Ethereum network. Finally, we study how to mitigate these attack.
The equity and currency tokens are typically two kinds of initial coin offerings (ICOs) like Bitcoin or Ethereum based on the platform of Blockchains to provide a particular product or service, it is very important to study the mechanism of Blockchain Ecosystems. The goal of this paper is to explain the stable in the sense for the existence of consensus equilibria for mining gap games by using one new concept called ‘consensus games (CG)’ under the framework of Blockchain Ecosystems which mainly mean the economic activities by taking into the account of three types of different factors which are expenses, reward mechanism and mining power for the work on blockschain by applying consensuses including the ‘Proof of Work’ due to Nakamoto in 2008 as a special case.
Yulia M. Beketnova, Grigory O. Krylov, Leonid I. Polyakov, Andrey S. Denisenko · 5 authors
The object of the research is the leading national fiat currencies and transnational anonymous analogues of the currency. They have received the slang name of cryptocurrencies. The subject of the study is volatility. It is the most important financial indicator in the management of financial flows, as a measure of risk of using a financial instrument at a specified time interval. The subject of the research requires consideration of digital goods of limited emission, which are the product of energy conversion into information in the form of a program code on a tangible medium. The limited amount of the emission for these goods without the syndrome of “printing press” has served as a basis for the name “cryptocurrency” and “digital gold”. The issue of cryptocurrency is a reward in the competitive procedure of checking transactions in peer-to-peer networks that implement the technology of distributed registries, and it is essentially a by-product of their functioning. The significant feature of such a product is anonymity and cross-border. They give rise to fundamental legal issues. Cryptocurrency obtaining technology is available to general public and has become an innovative phenomenon. The latest financial phenomena need to be investigated, so it is necessary to conduct a multilateral scientific analysis, identification and comparison of cryptocurrency with the fiat currency. The article compares the volatility of different currencies such as fiat (US dollar, euro, Chinese yuan and Japanese yen) and the most popular cryptocurrencies (Bicoin, Litecoin, Ethereum and Monero) at the present time. The aim of the study is to obtain new estimates of cryptocurrency based on the use of tools such as GARCH model, simple historical volatility (SHV) and developed by the authoring tool, which is based on the Chaikin method.
EOSIO has become one of the most popular blockchain platforms since its mainnet launch in June 2018. In contrast to the traditional PoW-based systems (e.g., Bitcoin and Ethereum), which are limited by low throughput, EOSIO is the first high throughput Delegated Proof of Stake system that has been widely adopted by many decentralized applications. Although EOSIO has millions of accounts and billions of transactions, little is known about its ecosystem, especially related to security and fraud. In this paper, we perform a large-scale measurement study of the EOSIO blockchain and its associated DApps. We gather a large-scale dataset of EOSIO and characterize activities including money transfers, account creation and contract invocation. Using our insights, we then develop techniques to automatically detect bots and fraudulent activity. We discover thousands of bot accounts (over 30% of the accounts in the platform) and a number of real-world attacks (301 attack accounts). By the time of our study, 80 attack accounts we identified have been confirmed by DApp teams, causing 828,824 EOS tokens losses (roughly \$2.6 million) in total.
Cryptocurrencies, such as Bitcoin, Ethereum or Ripple, are discussed as a new form of money. Typically, money fulfills three core functions: 1) medium of exchange, 2) store of value, and 3) unit of account. To examine whether individuals consider cryptocurrencies as money, we conduct three studies. Study 1 (N=57) provides valid and reliable measurement items for the three core functions of money. Study 2 (N=95) shows that the general perception about the fulfillment of the core functions is rather positive for cryptocurrencies. The results from Study 3 (N=99) furthermore reveal that Bitcoin is perceived significantly better in fulfilling all three functions than Ethereum or Ripple. The findings suggest that cryptocurrency research needs to include or at least control for the basic perceptions of core functions when examining individuals' adoption or use of cryptocurrency as money. Furthermore, the findings suggest that existing knowledge from Bitcoin use or adoption research cannot be easily transferred to the context of another cryptocurrency.
With the recent considerable developments in the Internet of Things (IoT), billions of resource-constrained devices are interconnected through the internet. Monitoring this huge number of IoT devices that are heterogeneous in terms of underlying communication protocols and data format is challenging. The majority of existing IoT device monitoring solutions heavily rely on centralized architectures. Since using centralized architectures comes at the expense of trusting an authority, it has several inherent drawbacks, including vulnerability to security attacks, lack of data privacy, and unauthorized data manipulation. Hence, a new decentralized approach is crucial to remedy these drawbacks. One of the most promising technologies which is widely used to provide decentralization is blockchain. Additionally, to ease the burden of communication overhead and computational power on resource-constrained IoT devices, fog computing can be exploited to decrease communication latency and provide better network scalability. In this paper, we propose a scalable blockchain-based architecture for monitoring IoT devices using fog computing. To demonstrate the feasibility and usability of the proposed solution, we have implemented a proof-of-concept prototype, leveraging Ethereum smart contracts. Finally, a comprehensive evaluation is conducted. The evaluation results indicate that the proposed solution is significantly scalable and compatible with resource-constrained IoT devices.
With the recent considerable developments in the Internet of Things (IoT),\nbillions of resource-constrained devices are interconnected through the\ninternet. Monitoring this huge number of IoT devices that are heterogeneous in\nterms of underlying communication protocols and data format is challenging. The\nmajority of existing IoT device monitoring solutions heavily rely on\ncentralized architectures. Since using centralized architectures comes at the\nexpense of trusting an authority, it has several inherent drawbacks, including\nvulnerability to security attacks, lack of data privacy, and unauthorized data\nmanipulation. Hence, a new decentralized approach is crucial to remedy these\ndrawbacks. One of the most promising technologies which is widely used to\nprovide decentralization is blockchain. Additionally, to ease the burden of\ncommunication overhead and computational power on resource-constrained IoT\ndevices, fog computing can be exploited to decrease communication latency and\nprovide better network scalability.\n In this paper, we propose a scalable blockchain-based architecture for\nmonitoring IoT devices using fog computing. To demonstrate the feasibility and\nusability of the proposed solution, we have implemented a proof-of-concept\nprototype, leveraging Ethereum smart contracts. Finally, a comprehensive\nevaluation is conducted. The evaluation results indicate that the proposed\nsolution is significantly scalable and compatible with resource-constrained IoT\ndevices.\n
Smart vehicles can cooperate in teams to perform crowdsensing tasks in smart cities. A critical challenge in this regard is to build a secure model for nondeterministic vehicle teams to achieve maximum social welfare. Although several crowdsensing models have been proposed, none of them has focused on real-time vehicle teamwork. In this article, to the best of our knowledge, we propose the first secure model, called blockchain-based nondeterministic teamwork cooperation (BNTC), for nondeterministic teamwork cooperation in a vehicular crowdsensing system. We model the system as a multiconditional NP-complete problem by explicitly considering the dynamic features of task issuers and workers. To solve the problem, we propose the winning teams selected (WTS) algorithm based on a reverse auction and utilize a knapsack-based method to solve the models. We consider the credit of teams for determining the payment. Thus, we propose a credit-based team payment (CTP) algorithm for BNTC to maximize the welfare of the system. We also propose a general blockchain-based framework to address trust issues and security challenges to make the method suitable for use in practical applications. Based on theoretical analyses and extensive simulations, we demonstrate that the proposed model performs better than the baselines and can achieve the maximum social welfare. Implementation with Ethereum suggests our model can operate within a reasonable cost.
Moses Arhinful Acquah, Na Chen, Jeng‐Shyang Pan, Hong-Mei Yang · 5 authors
Biometrics, with its uniqueness to every individual, has been adapted as a security authentication feature by many institutions. These biometric data are processed into templates that are saved on databases, and a central authority centralizes and controls these databases. This form of storing biometric data, or in our case fingerprint template, is asymmetric and prone to three main security attacks, such as fake template input, template modification or deletion, and channel interception by a malicious attacker. In this paper, we secure an encrypted fingerprint template by a symmetric peer-to-peer network and symmetric encryption. The fingerprint is encrypted by the symmetric key algorithm: Advanced Encryption Standard (AES) algorithm and then is uploaded to a symmetrically distributed storage system, the InterPlanetary File system (IPFS). The hash of the templated is stored in a decentralized blockchain. The slow transaction speed of the blockchain has limited its use in real-life applications, such as large file storage, hence, the merge with IPFS to store just the hashes of large files. The encrypted template is uploaded to the IPFS, and its returned digest is stored on the Ethereum network. The implementation of IPFS prevents storing the raw state of the fingerprint template on the Ethereum network in order to reduce cost and also prevent identity theft. This procedure is an improvement of previous systems. By adopting the method of template hashing, the proposed system is cost-effective and efficient. The experimental results depict that the proposed system secures the fingerprint template by encryption, hashing, and decentralization.
Open access
Biometric Identification and Security
Advanced Steganography and Watermarking Techniques