Blockchain Papers

Hao Wang, Shenglan Ma, Hong‐Ning Dai, Muhammad Imran · 5 authors

No abstract is available for this record.

Erasmus Mundus Joint International Doctoral Fellow in Law, Science and Technology, European Union, O.I. Konashevych

The use of blockchain technology, in particular, data insertion (anchoring, hashing) in the blockchain as a way of signing documents or imparting legal properties to facts is researched. A comparative analysis of the known methods of using electronic digital signature with the method of inserting data into the blockchain is carried out. The following issues were addressed. What is the data insertion in the blockchain and what properties do the data acquire? What is the difference between insertion, anchoring, and hashing on the blockchain? What is the difference between blockchain hashing and a digital signature on a document? Will the document be legally binding if it is anchored in the blockchain? What conditions must be met to give legal force for the document? How can anchoring be used to sign contracts, certify evidence that has legal value, denote time stamps, confirm authorship and copyrights, as well as transfer them, issue, and transfer power of attorney and delegate other rights, issue and transfer bearer instruments?

Chinnapong Angsuchotmetee, Pisal Setthawong, Sapjarern Udomviriyalanon

Voting is an essential activity in the modern democracy. To facilitate the voting process, there are several attempts on proposing an electronic voting system such that, the voting and tallying processes can be done efficiently and the results would be accountable to the public. To date, however, an online electronic voting system has been rarely adopted in practice due to the possibility of having the voting result tampered through vote-rigging or cyber-attacking. In 2009, the blockchain algorithm was proposed by Satoshi Nakamoto. Blockchain is a technique for recording transactions between self-auditing ledgers in an open, distributed, permanent, and verifiable manner. Even though blockchain was originally designed for a financial applications, it is possible to apply blockchain to other domains, including in the implementation of an online decentralized-based electronic voting system. In this study, the architecture of a blockchain-based electronic voting system, named \textit{BlockVOTE}, is proposed. The architecture design and all related formal definitions are given. To validate the proposal, two BlockVOTE prototypes were implemented using two different blockchain application frameworks. The performance analysis of both versions of the prototypes are given. The analysis of both technical and management aspects on the possibility of adopting the proposed decentralized voting system in an actual voting scenario is also given at the end of this study.

Ajay Kumar Shrestha, Ralph Deters, Julita Vassileva

The tremendous technological advancement in the last few decades has brought many enterprises to collaborate in a better way while making intelligent decisions. The use of Information Technology tools in obtaining data of people's everyday life from various autonomous data sources allowing unrestricted access to user data has emerged as an important practical issue and has given rise to legal implications. Various innovative models for data sharing and management have privacy and centrality issues. To alleviate these limitations, we have incorporated blockchain in user modeling. In this paper, we constructed a decentralized data sharing architecture with MultiChain blockchain in the travel domain, which is also applicable to other similar domains including education, health, and sports. Businesses that operate in the tourism industries including travel and tour agencies, hotels and resorts, shopping malls are connected to the MultiChain and they share their user profile data via stream in the MultiChain. The paper presents the hotel booking service for an imaginary hotel as one of the enterprise nodes, which collects user profile data with proper validation and will allow users to decide which of their data to be shared thus ensuring user control over their data and the preservation of privacy. The data from the repository is converted into an open data format while sharing via stream in the blockchain so that other enterprise nodes, after receiving the data, can easily convert them and store into their own repositories. The paper presents an evaluation of the performance of the model by measuring the latency and memory consumption with three test scenarios that mostly affect the user experience. The node responded quickly in all of these cases.

Yue Zhang, Jian Weng, Jiasi Weng, Ming Li · 5 authors

With the popularity of Blockchain comes grave security-related concerns. Achieving privacy and traceability simultaneously remains an open question. Efforts have been made to address the issues, while they may subject to specific scenarios. This paper studies how to provide a more general solution for this open question. Concretely, we propose Onionchain, featuring a suite of protocols, offering both traceability and privacy. As the term implies, our Onionchain is inspired by Onion routing. We investigate the principles of Onion routing carefully and integrate its mechanism together with Blockchain technology. We advocate the Blockchain community to adopt Onionchain with the regards of privacy and traceability. To this end, a case-study of Onionchain, which runs in the context of Vehicular Ad Hoc Networks (VANETs), is proposed, providing the community a guideline to follow. Systematic security analysis and extensive experiments are also conducted to validate our secure and cost-effective Onionchain.

J. Harvey, Ines Branco‐Illodo

New currencies designed for user anonymity and privacy – widely referred to as “privacy coins” – have forced governments to listen and legislate, but the political motivations of these currencies are not well understood. Following the growing interest of political brands in different contexts, we provide the first systematic review of political motivations expressed in cryptocurrency whitepapers whose explicit goal is “privacy.” Many privacy coins deliberately position themselves as alternative political brands. Although cryptocurrencies are often closely associated with political philosophies that aim to diminish or subvert the power of governments and banks, advocates of privacy occupy much broader ideological ground. We present thematic trends within the privacy coin literature and identify epistemic and ethical tensions present within the communities of people calling for the adoption of entirely private currencies.

Domenico Rotondi, Marco Saltarella, Gaetano Giordano, Francesco Pellecchia

Abstract Compliance of distributed ledger technology (DLT) based solutions with the European Union General Data Protection Regulation (EU GDPR) is currently a hot topic both from a technical point of view, as well as from a legal and normative one. Flexible working is a new working model where employees can perform their work activity without specific time and space constraints. In this context privacy and information trustworthiness are relevant and, therefore, on the one hand it can gain benefit from using DLT based solutions, on the other hand it must comply with the GDPR. This paper describes a solution that combines DLTs and the new Ciphertext‐Policy Attribute Based Encryption cryptographic techniques to support compliance with the EU GDPR in the context of flexible working. The devised solution is being concretely experimented, in the context of the EU H2020 CITADEL project, by the Municipality of Bari (Italy).

Matthew Johnson, Michael N. Jones, Mark Shervey, Joel T. Dudley · 5 authors

Decentralized apps (DApps) are computer programs that run on a distributed computing system, such as a blockchain network. Unlike the client-server architecture that powers most internet apps, DApps that are integrated with a blockchain network can execute app logic that is guaranteed to be transparent, verifiable, and immutable. This new paradigm has a number of unique properties that are attractive to the biomedical and health care communities. However, instructional resources are scarcely available for biomedical software developers to begin building DApps on a blockchain. Such apps require new ways of thinking about how to build, maintain, and deploy software. This tutorial serves as a complete working prototype of a DApp, motivated by a real use case in biomedical research requiring data privacy. We describe the architecture of a DApp, the implementation details of a smart contract, a sample iPhone operating system (iOS) DApp that interacts with the smart contract, and the development tools and libraries necessary to get started. The code necessary to recreate the app is publicly available.

Loïc Lesavre, Priam Varin, Peter Mell, Michael L. Davidson · 5 authors

Identity management systems (IDMSs) are widely used to provision user identities while managing authentication, authorization, and data sharing within organizations and on the web. Traditional identity systems typically suffer from single points of failure, lack of interoperability, and privacy issues, such as enabling mass data collection and user tracking. Blockchain technology has the potential to alleviate these concerns: it can support the ability for users to control the custody of their own identifiers and credentials, enabling novel data ownership and governance models with built-in control and consent mechanisms. Hence, blockchain-based IDMSs, which could benefit both users and businesses, are beginning to proliferate. This work categorizes these systems into a taxonomy based on differences in blockchain architectures, governance models, and other salient features. Context is provided for the taxonomy through the description of related terms, emerging standards, and use cases while highlighting relevant security and privacy considerations.

Jamila Alsayed Kassem, Sarwar Sayeed, Héctor Marco-Gisbert, Zeeshan Pervez · 5 authors

Identity management (IdM) is a method used to determine user identities. The centralized aspect of IdM introduces a serious concern with the growing value of personal information, as well as with the General Data Protection Regulation (GDPR). The problem with currently-deployed systems and their dominating approach, with identity providers (IdP) and single-point services, is that a third party is in charge of maintaining and controlling the personal data. The main challenge to manage data securely lies in trusting humans and institutes who are responsible for controlling the entire activity. Identities are not owned by the rightful owners or the user him/herself, but by the mentioned providers. With the rise of blockchain technology, self-sovereign identities are in place utilizing decentralization; unfortunately, the flaws still exist. In this research, we propose DNS-IdM, a smart contract-based identity management system that enables users to maintain their identities associated with certain attributes, accomplishing the self-sovereign concept. DNS-IdM has promising outcomes in terms of security and privacy. Due to the decentralized nature, DNS-IdM is able to avoid not only the conventional security threats, but also the limitations of the current decentralized identity management systems.

Christian Rondanini, Barbara Carminati, Elena Ferrari

Selection criteria regulating IoT device discovery involve confidentiality issue on the information the constraints convey. A promising approach to cope with this issue is leveraging on blockchain technology and smart contracts to implement the overall discovery process deployment. However, due to the blockchain design, data within the blockchain is public and smart contracts cannot access data outside the blockchain, unless through the exploitation of Oracles. On the one hand, this brings benefits of trust decentralization, transparency, and accountability of the discovery process. On the other hand, it carries serious consequences on confidentiality and privacy as well as on Oracles trustworthiness. For these reasons, in this paper, we investigate how to ensure data confidentiality during the discovery process of IoT devices on blockchain even in the presence of an untrusted Oracle.

Georgy Ishmaev

This paper looks at the development of blockchain technologies that promise to bring new tools for the management of private data, providing enhanced security and privacy to individuals. Particular interest presents solutions aimed at reorganizing data flows in the Internet of Things (IoT) architectures, enabling the secure and decentralized exchange of data between network participants. However, as this paper argues, the promised benefits are counterbalanced by a significant shift towards the propertization of private data, underlying these proposals. Considering the unique capacity of blockchain technology applications to imitate and even replace traditional institutions, this aspect may present certain challenges, both of technical and ethical character. In order to highlight these challenges and associated concerns, this paper identifies the underlying techno-economic factors and normative assumptions defining the development of these solutions amounting to technologically enabled propertization. It is argued that without careful consideration of a wider impact, such blockchain applications could have effects opposite to the intended ones, thus contributing to the erosion of privacy for IoT users.

Yang Zhao, Jun Zhao, Linshan Jiang, Rui Tan · 5 authors

Internet-of-Things (IoT) companies strive to get feedback from users to improve their products and services. However, traditional surveys cannot reflect the actual conditions of customers' due to the limited questions. Besides, survey results are affected by various subjective factors. In contrast, the recorded usages of IoT devices reflect customers' behaviours more comprehensively and accurately. We design an intelligent system to help IoT device manufacturers to take advantage of customers' data and build a machine learning model to predict customers' requirements and possible consumption behaviours with federated learning (FL) technology. The FL consists of two stages: in the first stage, customers train the initial model using the phone and the edge computing server collaboratively. The mobile edge computing server's high computation power can assist customers' training locally. Customers first collect data from various IoT devices using phones, and then download and train the initial model with their data. During the training, customers first extract features using their mobiles, and then add the Laplacian noise to the extracted features based on differential privacy, a formal and popular notion to quantify privacy. After achieving the local model, customers sign on their models respectively and send them to the blockchain. We use the blockchain to replace the centralized aggregator which belongs to the third party in FL. In the second stage, miners calculate the averaged model using the collected models sent from customers. By the end of the crowdsourcing job, one of the miners, who is selected as the temporary leader, uploads the model to the blockchain. Besides, to attract more customers to participate in the crowdsourcing FL, we design an incentive mechanism, which awards participants with coins that can be used to purchase other services provided by the company.

Yang Zhao, Jun Zhao, Linshan Jiang, Rui Tan · 8 authors

Home appliance manufacturers strive to obtain feedback from users to improve their products and services to build a smart home system. To help manufacturers develop a smart home system, we design a federated learning (FL) system leveraging the reputation mechanism to assist home appliance manufacturers to train a machine learning model based on customers' data. Then, manufacturers can predict customers' requirements and consumption behaviors in the future. The working flow of the system includes two stages: in the first stage, customers train the initial model provided by the manufacturer using both the mobile phone and the mobile edge computing (MEC) server. Customers collect data from various home appliances using phones, and then they download and train the initial model with their local data. After deriving local models, customers sign on their models and send them to the blockchain. In case customers or manufacturers are malicious, we use the blockchain to replace the centralized aggregator in the traditional FL system. Since records on the blockchain are untampered, malicious customers or manufacturers' activities are traceable. In the second stage, manufacturers select customers or organizations as miners for calculating the averaged model using received models from customers. By the end of the crowdsourcing task, one of the miners, who is selected as the temporary leader, uploads the model to the blockchain. To protect customers' privacy and improve the test accuracy, we enforce differential privacy on the extracted features and propose a new normalization technique. We experimentally demonstrate that our normalization technique outperforms batch normalization when features are under differential privacy protection. In addition, to attract more customers to participate in the crowdsourcing FL task, we design an incentive mechanism to award participants.

Monica Thomas

Security of IoT devices and applications can be improved by using the emerging Blockchain Technology which uses decentralised interaction and scalable architectures with security and distributed trust. In this work a review of Lightweight scalable Blockchain is proposed for security and privacy of IoT devices. An IoT scenario of smart home is used for illustrative purposes but this proposed architecture is wellsuited for diverse IoT applications. Effectiveness of this architecture is analysed using common threat models which provides an appropriate assessment for security and privacy implementation for smart home.

Francisco Luis Benítez-Martínez, María Visitación Hurtado, Esteban Romero‐Frías

No abstract is available for this record.

David López, Bilal Farooq

Blockchain has the potential to render the transaction of information more secure and transparent. Nowadays, transportation data are shared across multiple entities using heterogeneous mediums, from paper collected data to smartphone. Most of this data are stored in central servers that are susceptible to hacks. In some cases shady actors who may have access to such sources, share the mobility data with unwanted third parties. A multi-layered Blockchain framework for Smart Mobility Data-market (BSMD) is presented for addressing the associated privacy, security, management, and scalability challenges. Each participant shares their encrypted data to the blockchain network and can transact information with other participants as long as both parties agree to the transaction rules issued by the owner of the data. Data ownership, transparency, auditability and access control are the core principles of the proposed blockchain for smart mobility data-market. In a case study of real-time mobility data sharing, we demonstrate the performance of BSMD on a 370 nodes blockchain running on heterogeneous and geographically-separated devices communicating on a physical network. We also demonstrate how BSMD ensures the cybersecurity and privacy of individual by safeguarding against spoofing and message interception attacks and providing information access management control.

Raquel Carvalho

Public procurement relies in an apparent irreconcilability between competition, which implies some confidentiality, and transparency. The latest Public Procurement Directives have made e-procurement a mandatory feature. Since blockchain technology has been developed and designed to accomplish integrity, transparency, efficiency and data accuracy, goals which are very much appreciated in public procurement, an interesting question then arises: is there room to apply this technology within public procurement procedures? Will smart contracts be an interesting tool within public procurement? Considering public duties such as data protection, which must be complied with by contracting authorities, and some blockchain features such as non-withdrawable information and the likely broad access to the information there enclosed, one can be drawn to conclude that there is no possible conciliation between these two procedures. The mandatory e-procurement implies some neighbouring problems with this technology. Yet, are there any technological solutions for some of the drawbacks?

Charlotte Ducuing

Under the phrase “code is law” and based on its “trustless trust”, blockchain has emerged as a disrupting technology considered by some as an alternative to the law. Based on a study of real-life blockchain-based decentralised applications (Dapps), this article takes blockchain developers at their word and adopts the point of view of users: can blockchain live up to its promise and enable them to transact with each other without the need for the trust granted by the law? The article particularly highlights that users need to be able to ascertain that a self-advertised Dapp indeed qualifies as one. Blockchain technology may make it possible to do away with trust in third parties, but this is not enough. Users also need to trust that an alleged Dapp genuinely is one, and blockchain alone cannot provide this. Beyond Dapps, it is argued that blockchain needs the complementary role of the law to deliver its promises and especially to authenticate blockchain “virtues”. The EU certification mark is identified as a promising form of co-regulation for that purpose.

Florian Guggenmos, Jannik Lockl, Alexander Rieger, Gilbert Fridgen

No abstract is available for this record.

Shazade Jameson, C. Richter, Linnet Taylor

In this paper, we investigate people’s perception of datafication and surveillance in Amsterdam Smart City. Based on a series of focus groups, we show how people understand new forms of hypervisbility, what strategies they use to navigate these experiences, and what the limitations of these strategies are. We show how people tried to discern between public and private sector actors, to differentiate who they trusted by building on the existing social contract. People also trusted the objectivity of data in relation to prior experiences of social contexts and discrimination. Lastly, we show how the experiences of some of the inhabitants in our study who were most vulnerable to hypervisibility highlight the limits to strategies based on the neutrality of data. By asking about perceived surveillance rather than emphasising actual practices of surveilling, we show differentiated contexts and strategies, providing empirical grounds to question the dominant technical framing of smart cities.

Lei Hang, Do‐Hyeun Kim

With the rapid development of communication technologies, the Internet of Things (IoT) is getting out of its infancy, into full maturity, and tends to be developed in an explosively rapid way, with more and more data transmitted and processed. As a result, the ability to manage devices deployed worldwide has been given more and advanced requirements in practical application performances. Most existing IoT platforms are highly centralized architectures, which suffer from various technical limitations, such as a cyber-attack and single point of failure. A new solution direction is essential to enhance data accessing, while regulating it with government mandates in privacy and security. In this paper, we propose an integrated IoT platform using blockchain technology to guarantee sensing data integrity. The aim of this platform is to afford the device owner a practical application that provides a comprehensive, immutable log and allows easy access to their devices deployed in different domains. It also provides characteristics of general IoT systems, allows for real-time monitoring, and control between the end user and device. The business logic of the application is defined by the smart contract, which contains rules and conditions. The proposed approach is backed by a proof of concept implementation in realistic IoT scenarios, utilizing Raspberry Pi devices and a permissioned network called Hyperledger Fabric. Lastly, a benchmark study using various performance metrics is made to highlight the significance of the proposed work. The analysis results indicate that the designed platform is suitable for the resource-constrained IoT architecture and is scalable to be extended in various IoT scenarios.

Tomasz Słapczyński

The main objective of the paper is to provide an answer to the question whether new technologies such as blockchain that enter various spheres of public life are safe for users and what impact they have on national legislations. Cryptocurrencies, which are based on blockchain technology, can be used as a means of payment, investment or capital accumulation. Therefore, blockchain becomes more and more popular. The main research method used in the paper consists of the analysis of legislation and jurisprudence as well as linguistic and purposive interpretation which affects the functioning of blockchain and cryptocurrencies. The introductory part of the paper contains a general historical outline and basic principles related to blockchain technology. Real and potential threats posed by the discussed technology are also discussed in the paper as well as the question whether governments or, more broadly, the international community, offer sufficient level of protection against risks related to the use of new technologies such as blockchain and cryptocurrencies. Using blockchain to streamline logistic activities or to speed up transactions is useful in itself, but in the hands of private entities the technology may pose a risk of losing funds if not properly secured. The financial market is and should be supervised and controlled by the state which is the guarantor of economic freedom. Another vital question is whether legislators keep up with the advances in technology. It seems that the development of blockchain technology triggers development of new legal regulations. The more blockchain technology enters everyday life, the more legal documents appear in the form of case law, legal provisions, opinions etc. The role of these documents is to regulate, define and specify new technologies as they appear.

Irni Eliana Khairuddin, Corina Sas

Bitcoin blockchain technology is a distributed ledger of nodes authorizing transactions between anonymous parties. Its key actors are miners using computational power to solve mathematical problems for validating transactions. By sharing blockchain's characteristics, mining is a decentralized, transparent and unregulated practice, less explored in HCI, so we know little about miners' motivations and experiences, and how these may impact on different dimensions of trust. This paper reports on interviews with 20 bitcoin miners about their practices and trust challenges. Findings contribute to HCI theories by extending the exploration of blockchain's characteristics relevant to trust with the competitiveness dimension underpinning the social organization of mining. We discuss the risks of collaborative mining due to centralization and dishonest administrators, and conclude with design implications highlighting the need for tools monitoring the distribution of rewards in collaborative mining, tools tracking data centers' authorization and reputation, and tools supporting the development of decentralized pools.