Blockchain Papers

Kwok Ping Tsang, Zichao Yang

No abstract is available for this record.

Dean Fantazzini, Nikita Kolodin

This paper investigates the relationship between the bitcoin price and the hashrate by disentangling the effects of the energy efficiency of the bitcoin mining equipment, bitcoin halving, and of structural breaks on the price dynamics. For this purpose, we propose a methodology based on exponential smoothing to model the dynamics of the Bitcoin network energy efficiency. We consider either directly the hashrate or the bitcoin cost-of-production model (CPM) as a proxy for the hashrate, to take any nonlinearity into account. In the first examined subsample (01/08/2016–04/12/2017), the hashrate and the CPMs were never significant, while a significant cointegration relationship was found in the second subsample (11/12/2017–24/02/2020). The empirical evidence shows that it is better to consider the hashrate directly rather than its proxy represented by the CPM when modeling its relationship with the bitcoin price. Moreover, the causality is always unidirectional going from the bitcoin price to the hashrate (or its proxies), with lags ranging from one week up to six weeks later. These findings are consistent with a large literature in energy economics, which showed that oil and gas returns affect the purchase of the drilling rigs with a delay of up to three months, whereas the impact of changes in the rig count on oil and gas returns is limited or not significant.

Daniele De Wrachien

Technological infrastructures based on distributed ledger technologies (DLTs) like blockchain technology (BCT) are new digital technologies combining peer-to peer networking and cryptography to create immutable public ledgers characterized by decentralization, collective maintenance, consensus trust and reliable data. DLT, today considered as an interdisciplinary topic, is expected to transform current economic organization and governance, and can be considered one of the evolutionary next steps for agriculture, particularly for current state-of-the-art of precision agriculture.

Jonathan H. Clark

Distributed ledger technology (DLT) stands to benefit industries such as financial services with transparency and censorship resistance. DLT systems need to be scalable to handle mass user adoption. Mass user adoption is required to demonstrate the true value of DLT. This dissertation first analyses scalability in ethereum and EOS. Currently, ethereum 1.0 uses proof of work (PoW) and handles only 14 transactions per second (tps) compared to Visa's peak 47 000 tps. Ethereum 2.0, known as Serenity, introduces sharding, proof of stake (Casper), plasma and state channels in and effort to scale the system. EOS uses a delegated proof of stake (DPoS) protocol, where 21 super-nodes, termed ‘block producers' (BPs), facilitate consensus, bringing about significant scalability improvements (4000 tps). The trade-off is decentralisation. EOS is not sufficiently decentralised because the BPs yield significant power, but are not diverse. This dissertation conducts an empirical analysis using unsupervised machine learning to show that there is a high probability collusion is occurring between certain BPs. It then suggests possible protocol alterations such as inverse vote weighting that could curb adverse voting behaviour in DPoS. It further analyses whether universities are suitable BP's before mapping out required steps for universities to become block producers (leading to improved decentralisation in EOS)

Konstantin Mironov, Sergey Trishin, Vadim Kartak, Amir Makhmutov · 5 authors

In this article we look through the task of ensuring availability and integrity of information processed within the Internet of things (IoT) networks. Such networks include sensors, actuators and other devices that are data sources, gateways and data stream hubs that transmit information from sensors to the Internet, and servers that store the received data, process them and provide access to users. We propose to apply distributed ledger technology (DLT) to ensure integrity and accessibility of data in IoT, which is why it is proposed. As an example, we consider DLT application for data protection in the energy industry. We consider a system for processing and storing data on the production and consumption of electricity in a decentralized electricity network. A review of existing projects related to the use of distributed ledger technologies in the energy sector is carried out. However, an important obstacle for using DLT in IoT is that IoT devices often do not have the required computing power. This paper indicates further ways of research that are associated with overcoming this obstacle in the application of distributed ledger technologies in the energy field.

Anil Savio Kavuri, Alistair Milne

This paper is an examination of adoption of distributed ledgers in financial services. We review more than one hundred initiatives and a large practitioner literature, considering fourteen areas of application and seven case studies, in order to provide both a conceptual analysis of these technologies and to review their current and prospective adoption in financial services. There are several component technologies applied in distributed ledger, many offering substantial commercial and operational benefits even applied outside of a distributed ledger and best viewed as part of the broader picture of ongoing digitalization of financial services using various data technologies. Our findings suggest that decision makers can take a pragmatic approach to distributed ledgers, not be concerned about this technology upending their business but be open to cross industry co-operation where this is strategically justified and to then adopt what works to improve outcomes for customers and other stakeholders. Overall, distributed ledgers and crypto assets, are really a distraction from the wider and more important issues of ongoing digitisation and automation of financial services. Data sharing and cross industry co-operation – as well as well as enlightened public policy to promote adoption of new technologies, competition and prudential and systemic safety – are crucial to this digital revolution. This does not depend on widespread adoption of distributed ledgers.

Mustafa Mustafa, Shahnawaz Khan, Eleftherios

Purpose: The paper aims to review the academic research work done in the area of Islamic financial technology. The Islamic FinTech area has been classified into three broad categories of the Islamic FinTech, Islamic Financial technology opportunities and challenges, Cryptocurrency/Blockchain sharia compliance and law/regulation. Finally, the study identifies and highlights the opportunities and challenges that Islamic Financial institutions can learn from the conventional FinTech organization across the world. Approach/Methodology/Design: The study collected 133 research studies (50 from Social Science Research Network (SSRN), 30 from Research gate, 33 from Google Scholar and 20 from other sources) in the area of Islamic Financial Technology. The study presents the systematic review of the above studies. Findings: The study classifies the Islamic FinTech into three broad categories namely, Islamic FinTech opportunities and challenges, Cryptocurrency/Blockchain sharia compliance and law/regulation. The study identifies that the sharia compliance related to the cryptocurrency/Blockchain is the biggest challenge which Islamic FinTech organizations are facing. During our review we also find that Islamic FinTech organizations are to be considered as partners by the Islamic Financial Institutions (IFI’s) than the competitors. If Islamic Financial institutions want to increase efficiency, transparency and customer satisfaction they have to adopt FinTech and become partners with the FinTech companies. Practical Implications: The study will contribute positively to the understanding of Islamic Fintech for the academia, industry, regulators, investors and other FinTech users. Originality/Value: The study believes to contribute positively to understanding of Fintech based technology like cryptocurrency/Blockchain from sharia perspective.

Mohammad Madine, Ammar Battah, Ibrar Yaqoob, Khaled Salah · 8 authors

Personal health records (PHRs) are valuable assets to individuals because they enable them to integrate and manage their medical data. A PHR is an electronic application through which patients can manage their health information. Giving patients control over their medical data offers an advantageous realignment of the doctor-patient dynamic. However, today's PHR management systems fall short of giving reliable, traceable, trustful, and secure patients control over their medical data, which poses serious threats to their authenticity and accuracy. Moreover, most of the current approaches and systems leveraged for managing PHR are centralized that not only make medical data sharing difficult but also poses a risk of single point of failure problem. In this paper, we propose Ethereum blockchain-based smart contracts to give patients control over their data in a manner that is decentralized, immutable, transparent, traceable, trustful, and secure. The proposed system employs decentralized storage of interplanetary file systems (IPFS), proxy re-encryption, and trusted reputation-based oracles to securely fetch, store, and share patients' medical data. We present algorithms along with their full implementation details. We evaluate the proposed smart contracts using two important performance metrics, such as cost and correctness. Furthermore, we provide security analysis and discuss the generalization aspects of our solution. We outline the limitations of the proposed approach. We make the smart contract source code publicly available on Github.

Ch. V. N. U. Bharathi Murthy, M. Lawanya Shri, Seifedine Kadry, Sangsoon Lim

Blockchain technology is a distributed ledger with records of data containing all details of the transactions carried out and distributed among the nodes present in the network. All the transactions carried out in the system are confirmed by consensus mechanisms, and the data once stored cannot be altered. Blockchain technology is the necessary technology behind Bitcoin, which is a popular digital Cryptocurrency. “Cloud computing is a practice of using a network of remote servers hosted on the internet to store, manage, and process data, rather than a local server or a personal computer.” It is still facing many challenges like data security, data management, compliance, reliability. In this article, we have mentioned some of the significant challenges faced by the cloud and proposed solutions by integrating it with blockchain technology. We tend to investigate a brief survey on earlier studies focused on blockchain integrating with the cloud to depict their supremacy. In this survey, we have also developed architecture integrating blockchain with cloud revealing the communication between blockchain and cloud.

Md. Abdur Rahman, M. Shamim Hossain, Mohammad Saiful Islam, Nabil Alrajeh · 5 authors

Recent advancements in the Internet of Health Things (IoHT) have ushered in the wide adoption of IoT devices in our daily health management. For IoHT data to be acceptable by stakeholders, applications that incorporate the IoHT must have a provision for data provenance, in addition to the accuracy, security, integrity, and quality of data. To protect the privacy and security of IoHT data, federated learning (FL) and differential privacy (DP) have been proposed, where private IoHT data can be trained at the owner's premises. Recent advancements in hardware GPUs even allow the FL process within smartphone or edge devices having the IoHT attached to their edge nodes. Although some of the privacy concerns of IoHT data are addressed by FL, fully decentralized FL is still a challenge due to the lack of training capability at all federated nodes, the scarcity of high-quality training datasets, the provenance of training data, and the authentication required for each FL node. In this paper, we present a lightweight hybrid FL framework in which blockchain smart contracts manage the edge training plan, trust management, and authentication of participating federated nodes, the distribution of global or locally trained models, the reputation of edge nodes and their uploaded datasets or models. The framework also supports the full encryption of a dataset, the model training, and the inferencing process. Each federated edge node performs additive encryption, while the blockchain uses multiplicative encryption to aggregate the updated model parameters. To support the full privacy and anonymization of the IoHT data, the framework supports lightweight DP. This framework was tested with several deep learning applications designed for clinical trials with COVID-19 patients. We present here the detailed design, implementation, and test results, which demonstrate strong potential for wider adoption of IoHT-based health management in a secure way.

Jie Xu, Shuang Guo, David Xie, Yaxuan Yan

Blockchain implementation in agriculture has begun. Blockchain is recognized as an emerging technology in the agri-foods industry which may provide an efficient and robust mechanism for enhancing food traceability and a transparent and reliable way to validate quality, safety, and sustainability, of agri-foods. However, the technology is in its nascency, therefore, this review was written to foster discussion and encourage the application of blockchain technology, especially in the agri-food industry. In this review, the working principle of blockchain for data recording and tracking is briefly described. The collaboration models for the current blockchain applications on agri-foods are summarized. Furthermore, the specific utilization of blockchain to enhance safety and quality of agri-foods is discussed in four aspects: enhance the data transparency, realize data traceability, improve the food safety and quality monitoring, and reduce the cost of financial transactions. A case study on a Walmart pork traceability system has been provided to demonstrate how blockchain may be used to enhance the food traceability. Finally, challenges and future trends of blockchain technology in agri-foods concerning data/cost management, data security, and data integration are discussed. Blockchain technology reveals a promising approach to foster a future of agri-foods system in a way that is safer, healthier, more sustainable, and reliable.

Ahmad Akmaluddin Mazlan, Salwani Mohd Daud, Suriani Mohd Sam, Hafiza Abas · 6 authors

Blockchain technology is a private, secure, trustworthy, and transparent information exchange performed in a decentralised manner. In this case, the coordination and validation efforts are simplified as the records are designed to update regularly and there is no difference in the two databases. This review focuses on how the blockchain addresses scalability challenges and provides solutions in the healthcare field through the implementation of blockchain technology. Accordingly, 16 solutions fell under two main areas, namely storage optimization and redesign of blockchain. However, limitations persist, including block size, high volume of data, transactions, number of nodes, and protocol challenges. This review consists of six stages, namely identification of research question, procedures of research, screening of relevant articles, keywording based on the abstract, data extraction, and mapping process. Through Atlas.ti software, the selected keywords were used to analyse through the relevant articles. As a result, 48 codes and 403 quotations were compiled. Manual coding was performed to categorise the quotations. The codes were then mapped onto the network as a mapping process. Notably, 16 solutions fell under two main areas, namely storage optimization and redesign of blockchain. Basically, there are 3 solutions compiled for storage optimization and 13 solutions for the redesign of the blockchain, namely blockchain modelling, read mechanism, write mechanism, and bi-directional network.

Giovanni Mirabelli, Vittorio Solina

Blockchain is today one of the most interesting and debated research topics. Blockchain technology was implemented for the first time in the financial sector a few years ago. However, it is currently used in many other areas, such as: healthcare, smart cities, smart contracts, energy markets, government sector. The success of this technology mainly lies in the following properties: reliability, transparency, immutability. In this study, we collect and analyze the main contributions in the literature about the application of blockchain in the agricultural sector, focusing on food traceability issues. Considering the quick growth of this technology and the high number of published documents in recent months, there is a need to catalog the different methodologies, proposed by the various scholars. Our aim is to detect the current research trends and possible future challenges. In the agricultural context, the need for an adequate traceability system is motivated by several bad habits and problems, such as the wide use of pesticides and fertilizers in fruits and vegetables, which are extremely harmful for human health. Moreover, in the last few years, the consumers’ attention about the quality of agricultural products has considerably increased. The present study shows that the blockchain technology is still in its early stage. Although there are several proposals in the literature, still a limited number of applications have been put into use in the real context. From the point of view of scientific research, only some countries are investing in this technology: China and United States are among the most active, but Italy is also very involved in this phenomenon. Overall, the blockchain technology appears very promising, but still many efforts are needed to reach the maturation stage.

Emanuele Bellini, Youssef Iraqi, Ernesto Damiani

Distributed Ledger Technologies (DLTs), like Blockchain, are characterized by features such as transparency, traceability, and security by design. These features make the adoption of Blockchain attractive to enhance information security, privacy, and trustworthiness in very different contexts. This paper provides a comprehensive survey and aims at analyzing and assessing the use of Blockchain in the context of Distributed Trust and Reputation Management Systems (DTRMS). The analysis includes academic research as well as initiatives undertaken in the business domain. The paper defines two taxonomies for both Blockchain and DTRMS and applies a Formal Concept Analysis. Such an approach allowed us to identify the most recurrent and stable features in the current scientific landscape and several important implications among the two taxonomies. The results of the analysis have revealed significant trends and emerging practices in the current implementations that have been distilled into recommendations to guide Blockchain's adoption in DTRMS systems.

Alexander Mikroyannidis, Allan Third, John Domingue, Michelle Bachler · 5 authors

The emergence of the blockchain promises to revolutionise not only the financial world but also lifelong learning in various ways. Blockchain technology offers opportunities to thoroughly rethink how we find educational content and tutoring services online, how we register and pay for them, as well as how we get accredited for what we have learned and how this accreditation affects our career trajectory. This chapter explores the different aspects of lifelong learning that are affected by this new paradigm and describes an ecosystem that places the learner at the centre of the learning process and its associated data. This chapter also discusses the possibilities that will be afforded by the combination of trustworthy educational data enhanced with meaningful web-accessible linked data, and what these developments will mean for learners, educators, and the employment market.

Javier Arcenegui, Rosario Arjona, Iluminada Baturone

No abstract is available for this record.

Wulf A. Kaal

Most of the applications and uses of digital assets are improved and expanded with well-functioning and well-governed DAOs. The article evaluates the technical and internal governance solutions promulgated by DAO projects. Particular emphasis is placed on the duality of feedback effects between internal DAO governance and external DAO legal designs.

Léo Robert, Daiki Miyahara, Pascal Lafourcade, Takaaki Mizuki

International audience

Emerson B. Tomaz, José Cláudio do Nascimento, Abdelhakim Hafid, José Neuman de Souza

The advent of miniaturized mobile devices with wireless communication capability and integrated with biosensors has revolutionized healthcare systems. The devices can be used by individuals as wearable accessories to collect health data regularly. This type of medical assistance supported by mobile devices to monitor patients and offer health services remotely is known as mobile health (mHealth). Although mHealth provides many benefits and has become popular, it can pose severe privacy risks. Many features in mHealth are managed through a smartphone. Thus, one of the most worrying issues involves communication between the monitoring devices and the smartphone. When communication uses Bluetooth, it is standard for a device to be paired with the smartphone; but generally, it is not exclusively associated with a specific mHealth app. This characteristic can allow a data theft attack by a malicious app or fake data injection by an illegitimate device. To address this issue, we present an authentication scheme based on Non-Interactive Zero-Knowledge Proof that is lightweight enough to run on mHealth devices with minimal resources. Our scheme ensures that legitimate devices interact exclusively with the official mHealth application. To ensure the patient's privacy-preserving throughout the system, we address the issues of storing, managing, and sharing data using blockchain. Since there is no privacy in the standard blockchain, we present a scheme in which the health data transmitted, stored, or shared are protected by Attribute-Based Encryption. The outcome is a system with fine-grained access control, entirely managed by the patient, and an end-to-end privacy guarantee.

Wanxin Li, Hao Guo, Mark Nejad, Chien‐Chung Shen

Incorporation of connected vehicle (CV) data into real-time traffic management systems presents a host of new challenges resulting from the current lack of data integrity and data privacy in traffic networks. Over the past few years, blockchain technologies have been inspiring extensive innovations in the transportation field. However, due to the transparency property, sensitive data stored on the blockchain would be accessible to anyone, resulting in a lack of privacy. In this paper, we propose a decentralized and location-aware architecture to address the data integrity along with the privacy-preserving issues in blockchain-based traffic management systems. Our proposed architecture integrates with permissioned and modular blockchain network and non-interactive zero-knowledge range proof (ZKRP) protocol. We develop the prototype system on the Hyperledger Fabric platform and Hyperledger Ursa cryptographic library. The performance results show that our approach is effective and feasible for real-time traffic management while preserving the data privacy requirements.

Christian Catalini, Ravi Jagadeesan, Scott Duke Kominers

No abstract is available for this record.

Ping He, Dunzhe Tang, Jingwen Wang

Proof-of-Stake consensus algorithm solves major drawbacks of PoW blockchain network including high energy consumption and low transaction capacity. However, PoS still faces centralization problems like PoW. In this paper, we propose an economic framework for PoS blockchain network based on staking pool optimization problem and evaluate stake concentration in the network. We prove that stake concentration is encouraged in a finite staking pool PoS blockchain network, but continued consolidation among staking pools is limited and a stable equilibrium always exists where no staking pool has incentive to deviate. Further, we prove that lower pool fixed cost and higher transaction fee raise stable equilibrium pool number and lead to higher network decentralization level. As an extension, we show that wealth discrepancy exacerbates stake centralization while tilted stakeholder selection function mitigates stake centralization.

Dimitris Karakostas, Aggelos Kiayias, Mario Larangeira

Blockchain protocols based on Proof-of-Stake (PoS) depend—by nature—on the active participation of stakeholders. If users are offline and abstain from the PoS consensus mechanism, the system’s security is at risk, so it is imperative to explore ways to both maximize the level of participation and minimize the effects of non-participation. One such option is stake representation, such that users can delegate their participation rights and, in the process, form “stake pools”. The core idea is that stake pool operators always participate on behalf of regular users, while the users retain the ownership of their assets. Our work provides a formal PoS wallet construction that enables delegation and stake pool formation. While investigating the construction of addresses in this setting, we distil and explore address malleability, a security property that captures the ability of an attacker to manipulate the delegation information associated with an address. Our analysis consists of identifying multiple levels of malleability, which are taken into account in our paper’s core result. We then introduce the first ideal functionality of a PoS wallet’s core which captures the PoS wallet’s capabilities and is realized as a secure protocol based on standard cryptographic primitives. Finally, consider the wallet core in conjunction with a PoS ledger and investigate how delegation and stake pools affect a PoS system’s security.

Zhiping Lin, Di Xu, Ruixia Shi, Gangshu Cai

No abstract is available for this record.