Crowdsensing of Internet of Vehicles (IoV) can make full of use of the mobility of vehicles to provide data collection services to individuals in deed. In this paper, we elaborate on the framework, operation procedures of both centralized and distributed crowdsensing frameworks in IoV, and analyze the system complexity, secure communication, data storage and other problems facing the current architecture. In order to solve these problems, this paper proposed a crowdsensing framework of IoV based on blockchain and smart contract on the basis of introducing vehicular edge computing; Secondly, a multi-level smart contracts interaction system were built which designed a detailed multi-module smart contract; Finally, a specific scheme for performing sensing tasks is presented on this framework, showing the communication between different entities. The simulation test and performance evaluation certify the availability, security and convenience of the framework.
The blockchain, with its key characteristics of decentralization, persistence, anonymity, and auditability, has become a solution to overcome the overdependence and lack of trust for a traditional public key infrastructure on third-party institutions. Because of these characteristics, the blockchain is suitable for solving certain open problems in the service-oriented social network, where the unreliability of submitted reviews of service vendors can cause serious security problems. To solve the unreliability problems of submitted reviews, this paper first proposes a blockchain-based identity authentication scheme and a new trusted service evaluation model by introducing the scheme into a service evaluation model. The new trusted service evaluation model consists of the blockchain-based identity authentication scheme, evaluation submission module, and evaluation publicity module. In the proposed evaluation model, only users who have successfully been authenticated can submit reviews to service vendors. The registration and authentication records of users' identity and the reviews for service vendors are all stored in the blockchain network. The security analysis shows that this model can ensure the credibility of users' reviews for service vendors, and other users can obtain credible reviews of service vendors via the review publicity module. The experimental results also show that the proposed model has a lower review submission delay than other models.
A movement for a more transparent and decentralized Internet is globally attracting more attention. People are becoming more privacy-aware of their online identities and data. The Internet is constantly evolving. Web2 focused on companies that provide services in exchange for personal user data. Web3 commits to user-centricity using decentralization and zero-server architectures. The current digital society demands a global change to empower citizens and take back control. Citizens are locked into big-tech for personal data storage and their for-profit digital identity. Protection of data has proven to be essential, especially due to increased home Internet traffic during the COVID pandemic. Citizens do not possess their own travel documents. The European Commission aims to transition this governmental property towards self-sovereign identity, introducing many new opportunities. Citizens are locked into banks with non-portable IBAN accounts and unsustainable legacy banking infrastructures. Migration to all-digital low-fraud infrastructures and healthier competitive ecosystems is essential. The overall challenge is to return the power to citizens and users again. The transition to a more decentralized Internet is the first crucial step in the realization of user-centricity. This thesis presents the first exploratory study that integrates governmental-issued travel documents into a (decentralized) societal infrastructure. These self-sovereign identities form the authentic base to a private and secure transfer of money and data, and can effectively provide trust in authenticity that is currently missing in online conversations. A fully operational zero-server infrastructure that incorporates all our requirements has been developed for Android using the P2P network overlay IPv8, and a personalized blockchain called TrustChain...
Secure cross-domain authorization and authentication (AA) enable application service providers (ASPs) to allow users for resource access from different trusted domains. In this article, we propose a unified blockchain-assisted secure cross-domain AA framework for smart city, which can guarantee transparent cross-domain resource access while preserving user privacy. In the framework, ASPs can flexibly delegate their authentication capabilities to the blockchain, and users authorized by different ASPs can be authenticated by the blockchain where the authentication events are publicly audited and traced. Since the blockchain is publicly accessible, users’ sensitive identity attributes may be exposed during the authentication process. To address privacy leakage caused by the authentication events, several privacy-preserving techniques, including threshold-based homomorphic encryption, zero-knowledge proof, and random permutation, are exploited to hide users’ sensitive information on the blockchain. Moreover, to improve user revocation efficiency, we integrate a cryptographic accumulator and secure hash functions into the framework where ASPs are allowed to revoke their users through a global revocation contract. Our security analysis shows that the proposed framework can achieve all desirable security and privacy properties, and a proof-of-concept prototype has been developed to demonstrate the correctness and efficiency of the proposed framework.
Ali Dorri, Clemence Roulin, Shantanu Pal, Sarah Baalbaki · 6 authors
In recent years, blockchain technology has received tremendous attention. Blockchain users are known by a changeable public key (PK) that introduces a level of anonymity; however, studies have shown that anonymized transactions can be linked to deanonymize the users. Most of the existing studies on user deanonymization focus on monetary applications; however, the blockchain has received extensive attention in nonmonetary applications such as the Internet of Things (IoT). In this article, we study the impact of deanonymization on the IoT-based blockchain. We populate a blockchain with data of smart home devices and then apply machine learning algorithms in an attempt to classify the transactions to a particular device that, in turn, risks the privacy of the users. Two types of attack models are defined: 1) informed attacks: where attackers know the type of devices installed in a smart home and 2) blind attacks: where attackers do not have this information. We show that machine learning algorithms can successful classify the transactions with 90% accuracy. To enhance the anonymity of the users, we introduce multiple obfuscation methods which include combining multiple packets into a transaction, merging ledgers of multiple devices, and delaying transactions. The implementation results show that these obfuscation methods significantly reduce the attack success rates to 20%–30% and, thus, enhance the user privacy.
Blockchain technology, recognized for its decentralized and privacy-preserving capabilities, holds potential for enhancing privacy in contact tracing applications. Existing blockchain-based contact tracing frameworks often overlook one or more critical design details, such as the blockchain data structure, a decentralized and lightweight consensus mechanism with integrated tracing data verification, and an incentive mechanism to encourage voluntary participation in bearing blockchain costs. Moreover, the absence of framework simulations raises questions about the efficacy of these existing models. To solve above issues, this article introduces a fully third-party independent blockchain-driven contact tracing (BDCT) framework, detailed in its design. The BDCT framework features an Rivest-Shamir-Adleman (RSA) encryption-based transaction verification method (RSA-TVM), achieving over 96% accuracy in contact case recording, even with a 60% probability of individuals failing to verify contact information. Furthermore, we propose a lightweight reputation corrected delegated proof of stake (RC-DPoS) consensus mechanism, coupled with an incentive model, to ensure timely reporting of contact cases while maintaining blockchain decentralization. Additionally, a novel simulation environment for contact tracing is developed, accounting for three distinct contact scenarios with varied population density. Our results and discussions validate the effectiveness, robustness of the RSA-TVM and RC-DPoS, and the low storage demand of the BDCT framework.
May Alhajri, Ahmad Salehi Shahraki, Carsten Rudolph
The rapid advances in fitness wearable devices are redefining privacy around interactions. Fitness wearables devices record a considerable amount of sensitive and private details about exercise, blood oxygen level, and heart rate. Privacy concerns have emerged about the interactions between an individual's raw fitness data and data analysis by the providers of fitness apps and wearable devices. This paper describes the importance of adopting and applying legal frameworks within the fitness tracker ecosystem. In this review, we describe the studies on the current privacy policies of fitness app providers, heuristically evaluate the methods for consent management by fitness providers, summarize the gaps identified in our review of these studies, and discuss potential solutions for filling the gaps identified. We have identified four main problems related to preserving the privacy of users of fitness apps: lack of system transparency, lack of privacy policy legibility, concerns regarding one-time consent, and issues of noncompliance regarding consent management. After discussing feasible solutions, we conclude by describing how blockchain is suitable for solving these privacy issues.
Ji Woong Kim, Su Jin Kim, Won Chul Cha, Taerim Kim
This study aims to introduce a novel blockchain-applied personal health records (PHR) application and validate its user experience. The system transmits the part corresponding to the patient’s personal information off-chain and prevents data forgery and falsification by storing encrypted data on-chain. Patients may easily trace the opt-in and opt-out history of their consent data and dynamically store the consent system for data exchange on the blockchain. A mixed-method study using a questionnaire, in-depth interviews, and usability evaluation were conducted for 30 participants. The system usability score was 74.0, indicating the high usability of the application. Those who were familiar with blockchain showed confidence in the application, but those unfamiliar wanted their data to be safe using another way. Most of the participants were interested in exchanging and using their medical data and considered security important but those unfamiliar wanted their data to be safe using another way. We found that participants were concerned about data security and considered a blockchain-based PHR as a novel way to store and exchange their medical information securely. Blockchain is not a visible technology. However, a blockchain-applied PHR must be able to win user trust through visualizations, certificates, and system descriptions.
Jaehyeon Kim, Sejong ÂLee, Yushin Kim, Sunghyun Cho
This paper discusses an attack scenario that infers identity in a blockchain-based smart healthcare system. There is a privacy vulnerability because blockchain data is open to all participants. Invasion of privacy is a significant problem in a blockchain-based smart healthcare system that utilizes personal information. We analyze the blockchain graph to infer a user's identity. Then, we construct account-transaction graphs using transactions on the blockchain. A graph embedding algorithm generates features of account-transaction graphs. The generated features are used to identify blockchain participants using machine learning algorithms. We evaluate our attack scenario by applying embedding algorithms in Ethereum. The results showed an inference performance of up to 0.94 in the f1-score.
Secure and real-time communication is an essential condition in mobile vehicular networks, and this requires secure authentication and seamless access enabled by roaming services. As a security inspector, roaming authentication ensures that legitimate users can access the network securely. However, today’s roaming authentication protocols authenticate users with the help of centralized authentication servers, leading to the risk of the single point of failure and roaming fraud. The massive device access in 5G networks further exacerbates the losses when problems occur. In light of it, we propose a decentralized fraud-proof roaming authentication framework based on blockchain. We leverage smart contracts to implement a roaming authentication protocol, including user/AP registration, authentication, and revocation. For higher efficiency, we utilize the Bloom filter for the revocation process. In addition, we design an unforgeable and undeniable billing scheme based on hash chain technology. Security and performance analysis show that the proposed roaming authentication scheme can provide the required security features while incurring an acceptable authentication delay.
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Cryptocurrency systems can be subject to deanonimization attacks by exploiting the network-level communication on their peer-to-peer network. Adversaries who control a set of colluding node(s) within the peer-to-peer network can observe transactions being exchanged and infer the parties involved. Thus, various network anonymity schemes have been proposed to mitigate this problem, with some solutions providing theoretical anonymity guarantees. In this work, we model such peer-to-peer network anonymity solutions and evaluate their anonymity guarantees. To do so, we propose a novel framework that uses Bayesian inference to obtain the probability distributions linking transactions to their possible originators. We characterize transaction anonymity with those distributions, using entropy as metric of adversarial uncertainty on the originator's identity. In particular, we model Dandelion, Dandelion++ and Lightning Network. We study different configurations and demonstrate that none of them offers acceptable anonymity to their users. For instance, our analysis reveals that in the widely deployed Lightning Network, with 1% strategically chosen colluding nodes the adversary can uniquely determine the originator for about 50% of the total transactions in the network. In Dandelion, an adversary that controls 15% of the nodes has on average uncertainty among only 8 possible originators. Moreover, we observe that due to the way Dandelion and Dandelion++ are designed, increasing the network size does not correspond to an increase in the anonymity set of potential originators. Alarmingly, our longitudinal analysis of Lightning Network reveals rather an inverse trend -- with the growth of the network the overall anonymity decreases.
With the rapid development of embedded smart devices, a new data collection paradigm, mobile crowd-sensing (MCS), has been proposed. MCS allows individuals from the crowd to act as sensors and contribute their observation data. However, existing MCS systems are mostly based on third-party platforms, and there is no guarantee that a center is completely credible. In addition, security and privacy issues should not be ignored. During MCS’ execution, the participants’ various information and truth value are usually exposed, and the computation related to data privacy cannot be verified. In this paper, we integrate the blockchain into the MCS scenario to design a blockchain based privacy-preserving quality control mechanism, which prevents data from being tampered with, and denied, ensuring that the reward is distributed fairly. In the new system, we propose a privacy preserving participant selection scheme and the result can be verified (i.e., security against malicious node) without any third-party arbiter. Finally, considering the issues with sensing data privacy and efficiency in the truth discovery process, we propose a new privacy-aware crowdsensing design with iterative truth discovery based on rational secure multi-party computation. The experimental results show that compared to the prior result, the proposed solutions are highly practical and facilitate quality control without violating the participant’s privacy.
Purpose Blockchain is widely applied in e-voting, shared economy areas and other government functioning. Fragmented findings and distributed literature need consolidation for a holistic view of the research domain. The purpose of this study is to comprehensively reviews the blockchain applications for government organizations and presents the past, present and future trends of blockchain applications for government organizations. Design/methodology/approach Systematic review protocol instrumentalized the systematic review of research articles published from 2013 to 2021. Science mapping discerns scientific actors’ trends and performance analysis like most influential authors, documents and sources. Content analysis of selected data set unfolds the past, present and future of blockchain applications for government organizations. Findings Blockchain technology offers enormous potential for the transformation of government organizations and public services. The primary areas are cryptocurrency, e-voting, shared economy, smart contracts, financial and health services, tourism, logistics and water sustainability. Research limitations/implications This study reviewed only published research in journals and conference proceedings and excluded book reviews, book chapters and editorials from the review set. This study persuades governments and policymakers to invest in blockchain technology for transforming government organizations and public services. Practical implications This study highlights the importance of blockchain in government-controlled public departments, enhancing transparency and efficiency in public life. Social implications Blockchain technology enhances transparency, traceability and accountability of public records. Originality/value This study pioneers in chronologically highlighting the importance of blockchain in government-controlled public departments.
Blockchain systems come with a promise of decentralization that often stumbles on a roadblock when key decisions about modifying the software codebase need to be made. This is attested by the fact that both of the two major cryptocurrencies, Bitcoin and Ethereum, have undergone hard forks that resulted in the creation of alternative systems, creating confusion and opportunities for fraudulent activities. These events, and numerous others, underscore the importance of Blockchain governance, namely the set of processes that blockchain platforms utilize in order to perform decision-making and converge to a widely accepted direction for the system to evolve. While a rich topic of study in other areas, governance of blockchain platforms is lacking a well established set of methods and practices that are adopted industry wide. This makes the topic of blockchain governance a fertile domain for a thorough systematization that we undertake in this work. We start by distilling a comprehensive array of properties for sound governance systems drawn from academic sources as well as grey literature of election systems and blockchain white papers. These are divided into seven categories, confidentiality, verifiability, accountability, sustainability, Pareto efficiency, suffrage and liveness that capture the whole spectrum of desiderata of governance systems. We proceed to classify ten well-documented blockchain systems. While all properties are satisfied, even partially, by at least one system, no system that satisfies most of them. Our work lays out a foundation for assessing blockchain governance processes. While it highlights shortcomings and deficiencies in currently deployed systems, it can also be a catalyst for improving these processes to the highest possible standard with appropriate trade-offs, something direly needed for blockchain platforms to operate effectively in the long term.
Mike Wu, Will McTighe, Kaili Wang, István András Seres · 12 authors
A common misconception among blockchain users is that pseudonymity guarantees privacy. The reality is almost the opposite. Every transaction one makes is recorded on a public ledger and reveals information about one's identity. Mixers, such as Tornado Cash, were developed to preserve privacy through "mixing" transactions with those of others in an anonymity pool, making it harder to link deposits and withdrawals from the pool. Unfortunately, it is still possible to reveal information about those in the anonymity pool if users are not careful. We introduce Tutela, an application built on expert heuristics to report the true anonymity of an Ethereum address. In particular, Tutela has three functionalities: first, it clusters together Ethereum addresses based on interaction history such that for an Ethereum address, we can identify other addresses likely owned by the same entity; second, it shows Ethereum users their potentially compromised transactions; third, Tutela computes the true size of the anonymity pool of each Tornado Cash mixer by excluding potentially compromised transactions. A public implementation of Tutela can be found at https://github.com/TutelaLabs/tutela-app. To use Tutela, visit https://www.tutela.xyz.
Conventional electronic voting systems use a centralized scheme. A central administration of these systems manages the entire voting process and has partial or total control over the database and the system itself. This creates some problems, accidental or intentional, such as possible manipulation of the database and double voting. Many of these problems have been solved thanks to permissionless blockchain technologies in new voting systems; however, the classic consensus method of such blockchains requires specific computing power during each voting operation. This has a significant impact on power consumption, compromises the efficiency and increases the system latency. However, using a permissioned blockchain improves efficiency and reduces system energy consumption, mainly due to the elimination of the typical consensus protocols used by public blockchains. The use of smart contracts provides a secure mechanism to guarantee the accuracy of the voting result and make the counting procedure public and protected against fraudulent actions, and contributes to preserving the anonymity of the votes. Its adoption in electronic voting systems can help mitigate part of these problems. Therefore, this paper proposes a system that ensures high reliability by applying enterprise blockchain technology to electronic voting, securing the secret ballot. In addition, a flexible network configuration is presented, discussing how the solution addresses some of the security and reliability issues commonly faced by electronic voting system solutions.
With the development of the Internet of Things (IoT), the massive data sharing between IoT devices improves the Quality of Service (QoS) and user experience in various IoT applications. However, data sharing may cause serious privacy leakages to data providers. To address this problem, in this study, data sharing is realized through model sharing, based on which a secure data sharing mechanism, called BP2P-FL, is proposed using peer-to-peer federated learning with the privacy protection of data providers. In addition, by introducing the blockchain to the data sharing, every training process is recorded to ensure that data providers offer high-quality data. For further privacy protection, the differential privacy technology is used to disturb the global data sharing model. The experimental results show that BP2P-FL has high accuracy and feasibility in the data sharing of various IoT applications.
M. Francisca Hinarejos, Josep LluÃs Ferrer Gomila, Amador Jaume Barcelo
Promotional schemes, such as promotional points and coupons, are highly effective marketing tools. Through these schemes, merchants can obtain customer loyalty or attract new customers, and customers can obtain benefits when purchasing goods or services. Therefore, the use of promotional schemes is considered to be a win-win strategy. Promotional points are becoming an increasingly popular way of providing customers with discounts or gifts to incentivise the purchase of some products. However, some security issues should be addressed: forgery, double-spending, privacy, etc. Blockchain is gaining popularity in academic research and business applications, as it has the potential to change business models in numerous sectors of the economy. The characteristics of blockchain (security, immutability, efficiency, etc.) can help to provide secure solutions for blockchain-based applications in the marketing field. In this paper, we propose a multimerchant, blockchain-based promotional point scheme that allows points to be transferred between customers and preserves customers’ privacy.
Daniel Maldonado-Ruiz, Jenny Torres, Nour El Madhoun, Mohamad Badra
Since the emergence of the Bitcoin cryptocurrency, the blockchain technology has become the new Internet tool with which researchers claim to be able to solve any existing online problem. From immutable log ledger applications to authorisation systems applications, the current technological consensus implies that most of Internet problems could be effectively solved by deploying some form of blockchain environment. Regardless this ‘consensus’, there are decentralised Internet-based applications on which blockchain technology can actually solve several problems and improve the functionality of these applications. The development of these new blockchain-based solutions is grouped into a new paradigm called Blockchain 3.0 and its concepts go far beyond the well-known cryptocurrencies. In this paper, we study the current trends in the application of blockchain on the paradigm of Public Key Infrastructures (PKI). In particular, we focus on how these current trends can guide the exploration of a fully Decentralised Identity System, with blockchain as be part of the core technology.