Aiming at the privacy protection of lightweight nodes based on Bloom filters in blockchain, this paper proposes a new privacy protection method. Considering the superimposition effect of query information, node and Bloom filter are regarded as the two parties of the game. A privacy protection mechanism based on the mixed strategy Nash equilibrium is proposed to judge the information query. On this basis, a Bloom filter privacy protection algorithm is proposed when the probability of information query and privacy, not being leaked, is less than the node privacy protection. It is based on variable factor disturbance, adjusting the number of bits’ set to 1 in the Bloom filter to improve the privacy protection performance in different scenarios. The experiment uses Bitcoin transaction data from 2009 to 2019 as the test data to verify the effectiveness, reliability, and superiority of the method.
Qi Zhang, Hai Lv, Junwei Ma, Jingye Li · 5 authors
Blockchain has the advantages of decentralization and distributed sharing of global ledger, but at the same time, it also has the risk of data privacy leakage. In order to prevent the privacy of blockchain users from being stolen by malicious attackers, there is still a large space for development of various protection mechanisms. At first, this paper analyzes the architecture of chain block, the Blockchain data privacy threat mainly summarized data for the application layer, network layer, data privacy threats to privacy, consensus layer data and transaction layer data privacy threats to privacy, and respectively summarized this paper introduces the principle of all kinds of privacy protection mechanism, characteristics, and different ways of implementation, Finally, it points out the future research direction of blockchain data privacy protection.
Nirmalee I. Raddatz, Joshua G. Coyne, Philip Menard, Robert E. Crossler
Data breaches and cyber incidents are on the rise, and companies continually research new technologies to defend against attacks and protect customer data. The blockchain is a data store designed to promote data privacy, as well as transaction integrity. Enterprises in several industries, especially banking, have investigated the implementation of blockchain-based databases to replace centralised databases as one mechanism for protecting customers’ data by separating transactional data from personally identifiable information. Despite the blockchain’s privacy protections, consumers remain largely unaware of these benefits. Building on the Health Belief Model (HBM), we include privacy concerns and inertia as critical factors that influence consumers’ perceptions of blockchain-based databases’ benefits. Using a sample of 304 respondents, we test a theoretical model incorporating these factors. Our study results indicate threat severity, threat susceptibility, awareness, and inertia significantly influence the perceived benefits of blockchain, which has a significant positive influence on consumers’ intention to switch to blockchain-based applications. Although consumers’ comfort with the status quo of traditional banking mechanisms is a significant barrier to the realisation of blockchain banking applications benefits, additional awareness of consumer privacy protections can persuade customers to use the blockchain-based applications, especially if they exhibit heightened privacy concerns.
Abel Binu Jacob, Pratiyush Prakash, Prashant Karhana, Pravati Swain
The information process of each and every individual is dependent on the Digital Identity Management (DIM) system. To decrease the requirement of remembering multiple passwords and authenticate digital Identity with improved security, we propose an optimized solution by using distributed ledger technology and smart contracts for the DIM system, i.e., Blockchain. The smart contract ensures that the user's registration process occurs only once and the required details are securely shared to the websites with the user's consent. Compared to traditional and existing digital identity management systems, the proposed Blockchain-based Web-Access through Biometrics verification ensures the user's identity in one-time registration. It provides secure and easy access to respective websites.
With smart vehicles interconnected with multiple systems and other entities, whether they are people or IoT devices, the importance of a digital identity for them has emerged. We present in this paper how a Self-Sovereign Identities combined with blockchain can provide a solution to this end, in order to decentralize the identity management and provide them with capabilities to identify the other entities they interact with. Such entities can be the owners of the vehicles, other drivers and workshops that act as service providers. Two use cases are examined along with the interactions between the participants, to demonstrate how a decentralized identity management solution can take care of the necessary authentication and authorization processes. Finally, we test the system and provide the measurements to prove its feasibility in real-life deployments.
The rise of Internet of Things (IoT) technology promotes the rapid development of location services industry. The idea of smart connectivity also provides a new direction for Location-Based Social Networks (LBSNs). However, due to limited calculate ability and internal storage space of IoT devices, historical location data of users is generally stored in the central server, which is likely to cause the disclosure of users’ private data. In this paper, we propose a Blockchain-enabled Privacy-Preserving Location Sharing (B-PPLS) scheme, which is a new framework that not only protects user location privacy but also provides effective location sharing services for users. For B-PPLS, location data owners can share the location area instead of location coordinates to Requesters, in order to realize the location privacy preserving. Also, the Merkle hash tree is utilized to divide the location area, so as to realize the multilevel privacy preserving. Furthermore, four algorithms are proposed to achieve the four stages of initialization, location record, location sharing, and location verification, respectively. Finally, we analyze the security of the proposed B-PPLS scheme and compare the performance with other related location privacy-preserving schemes by experimental evaluation.
Over the last few years, there is a growing need for researchers to study various accessible methods to develop Electronic Health Records in order to help physicians access patient data while maintaining privacy of the health data. However, there lie several challenges due to the accessibility of various Internet of Things sensors and wearables that collect user’s physiological and mental health data. Therefore, it is crucial to secure such data in the healthcare ecosystem so that it is not retrievable by third parties. In this vein, we have used the concepts of blockchain to provide patient control of their own data and the liberty to choose the specific medical caregivers they want to share their data with. We have implemented a large-scale information architecture to access EHRs based on hyperledger fabric model. Setting distributed ledger of the blockchain node can be used for setting up central network of the edge computing that could be visualized as the vectorized decentralized edge computing. We have framed data privacy and accessibility issues in healthcare and proposed an integrated blockchain-based architecture. This chapter describes an approach to address limitations such as permissioned blockchain that uses off-chain storage of the data assets, and this is accessed through a standard browser and mobile app. There are three main components to the proposed system: a blockchain-based access control module, off-chain data storage and a role-centered web user interface. The implementation in the hyperledger framework is described as an example use of patient-centered health data management.
Michael Froehlich, Charlotte Kobiella, Albrecht Schmidt, Florian Alt
Engaging first-time users of mobile apps is challenging. Onboarding task flows are designed to minimize the drop out of users. To this point, there is little scientific insight into how to design these task flows. We explore this question with a specific focus on financial applications, which pose a particularly high hurdle and require significant trust. We address this question by combining two approaches. We first conducted semi-structured interviews (n=16) exploring users’ meaning-making when engaging with new mobile applications in general. We then prototyped and evaluated onboarding task flows (n=16) for two mobile cryptocurrency apps using the minimalist instruction framework. Our results suggest that well-designed onboarding processes can improve the perceived usability of first-time users for feature-rich mobile apps. We discuss how the expectations users voiced during the interview study can be met by applying instructional design principles and reason that the minimalist instruction framework for mobile onboarding insights presents itself as a useful design method for practitioners to develop onboarding processes and also to identify when not to.
Michael Froehlich, Maurizio Raphael Wagenhaus, Albrecht Schmidt, Florian Alt
Cryptocurrencies have increasingly gained interest in practice and research alike. Current research in the HCI community predominantly focuses on understanding the behavior of existing cryptocurrency users. Little attention has been given to early users and the challenges they encounter. However, understanding how interfaces of cryptocurrency systems support, impede, or even prevent adoption through new users is essential to develop better, more inclusive solutions. To close this gap, we conducted a user study (n=34) exploring challenges first-time cryptocurrency users face. Our analysis reveals that even popular wallets are not designed for novice users’ needs, stopping them when they would be ready to engage with the technology. We identify multiple challenges ranging from general user interface issues to finance and cryptocurrency-specific ones. We argue that these challenges can and should be addressed by the HCI community and present implications for building better cryptocurrency systems for novice users.
Online Social Networks (OSNs) have become one of the most popular applications of the daily life of users in the worldwide. Today, the number of Social Media users is more than 4 billion, and this trend increases year after year with a high impact on the privacy issue. During the last years, decentralization of social services has been considered as a big opportunity to overcome the main privacy issues in OSNs, and not only (fake news, censorship, etc.). Blockchain technology represents today the most well-known decentralized technique, which has been taken into account to develop the new generation of decentralized social platforms. Blockchain-based Online Social Media (BOSMs) are decentralized Social Media platforms that use the blockchain technology as the underlying technology or as a tool in order to provide rewarding strategies. In this tutorial, we will highlight the BOSMs scenario by presenting their main characteristics and how data could be collected and analysed.
Vulnerable individuals have a limited ability to make reasonable financial decisions and choices and, thus, the level of care that is appropriate to be provided to them by financial institutions may be different from that required for other consumers. Therefore, identifying vulnerability is of central importance for the design and effective provision of financial services and products. However, validating the information that customers share and respecting their privacy are both particularly important in finance and this poses a challenge for identifying and caring for vulnerable populations. This position paper examines the potential of the combination of two emerging technologies, Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs), for the identification of vulnerable consumers in finance in an efficient and privacy-preserving manner.
Self-sovereign identity (SS) has become a trend within the digital identity circles. This new paradigm places a user in the centre and allows them to have more control over their identity information. Such a concept has swiftly found its enthusiasts, who also actively experiment on SSI implementation in the public sector. Although SSI does not imply having any technology at the backbone, it is usually discussed in the blockchain context. This article explores what opportunities this new identity concept can bring to the public sector and the associated challenges in this process. Also, we seek to examine the dependency of SSI on blockchain technology. For this, we study the existing knowledge on SSI from the literature and interview industry experts to elucidate this phenomenon. Using the thematic analysis technique, we propose a framework for assessing the opportunities and challenges, using the case of Belgium as an example, showcasing the potential of SSI and what barriers it still needs to overcome. We conclude that although blockchain does contribute to achieving SSI, it is not the silver bullet for it.
Marta Bellés-Muñoz, Jordi Baylina, Vanesa Daza, José L. Muñoz
The benefits of blockchain technologies for industrial applications are unquestionable. However, it is a considerable challenge to use a transparent system like blockchain and at the same time provide privacy to sensitive data. Privacy technologies permit conducting private transactions about sensitive data over transparent networks, but their inherent complexity has been overwhelming for many developers. Closing the gap between developers and privacy-preserving technologies would help to the full adoption of the privacy by design framework for blockchain software. To this end, in this paper we present the software tools we have implemented to bring complex privacy technologies closer to developers and facilitate the job of implementing privacy-enabled blockchain applications.
Abstract Voting refers to the submission of an election or an opinion on a specific matter by expressing an intention on the ballot to a certain place. The existing voting method has the burden of counting time and cost. For this reason, research has been conducted to introduce an e-voting system. However, despite the advantages of e-voting, it is not widely used due to the risk of manipulation of voting results and various requirements. Recently, in order to reduce the risk of data manipulation, research is being conducted to apply the blockchain, a technology that guarantees data integrity, to e-voting. Blockchain guarantees the integrity of data, but has a weakness in secrecy. This paper applies the critical encryption technique to the blockchain and satisfies the requirements for voting such as verifiability, anonymity, fairness, non-reusability, competence, safety, transparency, and non-ticketing. We propose a system design and implementation method. The proposed blockchain-based e-voting system provides voter anonymity by issuing a voter certificate based on a blockchain address. The e-voting election monitoring committee generates a threshold group encryption key, and the proposed blockchain-based e-voting system guarantees confidentiality by a threshold group encryption algorithm during the voting process. The voting result is encrypted through a homomorphic encryption algorithm and stored in the blockchain. Thus, the released voting results ensure safety, confidentiality, transparency, and non-vote ticketing. In addition, the proposed blockchain-based e-voting system guarantees the unity and competence of voting through the blockchain’s smart contract.
Developments in blockchain technology coupled with rapid developments in network technologies have disrupted traditional business and service models. One such application is in the domain of healthcare. However, the domain's sensitive nature and complexity require blockchain-enabled e-healthcare to ensure utilitarianism while suitably addressing the associated ethical challenges. In this milieu, the paper attempts to identify and evaluate the parameters of ethical challenges associated with blockchain adoption in e-healthcare. This paper contributes to the extant body of knowledge by presenting a critical review of the ethical considerations at the meso level of blockchains in e-healthcare. Based on findings from the literature, the study identified nine parameters of blockchain ethics. Of these, Accuracy and Right to be Forgotten were found to be most critical in terms of ethical dilemmas in healthcare applications. No evidence of ethical dilemma could be found with respect to Accountability and Data Ownership. As these services are deployed over networks, all these challenges are further evaluated in the context of 6G network-based models. This will not only provide the stakeholders with a holistic view of the ethical challenges in various blockchain-enabled healthcare applications but also enable a meticulous transition to the 6G network.
In the current global situation-burdened by, among others, a vast number of\npeople without formal identification, digital leap, the need for health\npassports and contact tracking applications-providing private and secure\ndigital identity for individuals, organizations and other entities is crucial.\nThe emerging self-sovereign identity (SSI) solutions rely on distributed ledger\ntechnologies and verifiable credentials and have the potential to enable\ntrustful digital interactions. In this human-centric paradigm, trust among\nactors can be established in a decentralized manner while the identity holders\nare able to own and control their confidential data. In this paper, we build on\nobservations gathered in a field study to identify the building blocks,\nantecedents and possible outcomes of SSI ecosystems. We also showcase\nopportunities for researchers and practitioners to investigate this phenomenon\nfrom a wide range of domains and theories, such as the digital innovation\necosystems, value co-creation, surveillance theory, or entrepreneurship\ntheories.\n
Identity management has been ripe for disruption over the past few years due to recurring incidents of data breaches that have led to personal information leaks and identity theft. The rise of blockchain technology has paved the way for the development of self-sovereign identity (SSI)—a new class of user-controlled resilient identity management systems that are enabled by distributed ledger technology. This paper examines how SSI management can be used in a public transportation sector that spans different operators in multiple countries. Specifically, the paper explores how a blockchain-based decentralized identity management system can draw on the SSI framework to provide high-level security and transparency for all involved parties in public transportation ecosystems. Accordingly, building on analyses of the existing public transportation ticketing solutions, we elicited requirements of a comparable system based on the SSI principles. Next, we developed a low-fidelity prototype to showcase how passengers can utilize standardized travel credentials that are valid across different transportation networks in Europe. The proposed system eliminates the need for multiple travel cards (i.e., one for each transportation provider) and empowers individuals to have better control over the use of their identities while they utilize interoperable ticketing systems across Europe. Overall, building on the public transportation case, we offer a proof-of-concept that shows how individuals can better manage their identity credentials via the SSI framework.
In this study, we overview the problems associated with the usability of cryptocurrency wallets, such as those used by ZCash, for end-users. The concept of "holistic privacy," where information leaks in one part of a system can violate the privacy expectations of different parts of the system, is introduced as a requirement. To test this requirement with real-world software, we did a 60 person task-based evaluation of the usability of a ZCash cryptocurrency wallet by having users install and try to both send and receive anonymized ZCash transactions, as well as install a VPN and Tor. While the initial wallet installation was difficult, we found even a larger amount of difficulty integrating the ZCash wallet into network-level protection like VPNs or Tor, so only a quarter of users could complete a real-world purchase using the wallet.
In a corpus of 45,821 app reviews of the top five mobile cryptocurrency wallets, we identified and qualitatively analyzed 6,859 reviews pertaining to the user experience (UX) with those wallets. Our analysis suggests that both new and experienced users struggle with general and domain-specific UX issues that, aside from frustration and disengagement, might lead to dangerous errors and irreversible monetary losses. We reveal shortcomings of current wallet UX as well as users’ misconceptions, some of which can be traced back to a reliance on their understanding of conventional payment systems. For example, some users believed that transactions were free, reversible, and could be canceled anytime, which is not the case in reality. Correspondingly, these beliefs often resulted in unmet expectations. Based on our findings, we provide recommendations on how to design cryptocurrency wallets that both alleviate the identified issues and counteract some of the misconceptions in order to better support newcomers.
Ya Chen, Yazhe Wang, Yu Wang, Mingxuan Li · 6 authors
Telephony networks serve as a reliable communication channel, and phone numbers are usually used to authenticate users' identities in telephony networks. However, modern telephony networks does not provide end-to-end authentication for phone numbers, making it difficult for a receiver to confirm a caller's real identity. Moreover, due to the lack of effective authentication solutions for users, phone numbers are usually exploited to commit identity theft, credit card fraud, or telecom harassment by phone number spoofing attacks. In this paper, we propose a blockchain-based identity authentication system for telephony networks, CallChain. CallChain issues verifiable digital identities to users which bound a user to his/her phone number. Based on the digital identity, CallChain provides end-to-end identity authentication between the caller and receiver in the data channel without modifying the core technologies in telephony networks. In the proposed system, users first register decentralized identities (DIDs) and store them in the blockchain distributed ledger. Then Call Center issues verifiable PhoneNumber Credentials to users. And finally users conduct end-to-end identity authentication based on these PhoneNumber Credentials before the call is established. We implement a prototype as an App for Android-based phones based on an open source blockchain platform Hyperledger Indy. Moreover, we detect that CallChain only adds a worst-case 2.1 seconds call establishment overhead and can resist DDoS attacks effectively.
Privacy protection to medical & healthcare data is one of the bottleneck problems in Internet information fusion. In order to balance data processing capability with privacy concerns, a distributed dynamic authorisation method based on blockchain is proposed to realise trustworthy data access. URLs (Universal Resource Locator) are included in the authorisation information to indicate the data access interface as well as separating patients’ privacy data from blockchain to improve data process efficiency. The contents of smart contracts are demonstrated in a case study to validate the usability of the proposed authorisation method in medical data access between different hospitals.