Privacy, facilitated by a confluence of cryptography and decentralization, is one of the primary motivations for the adoption of cryptocurrencies like Bitcoin. Alas, Bitcoins privacy promise has proven illusory, and despite growing interest in privacy-centric blockchains, most blockchain users remain susceptible to privacy attacks that exploit network-layer information and access patterns that leak as users interact with blockchains. Understanding if and how blockchain-based applications can provide strong privacy guarantees is a matter of increasing urgency. Many researchers advocate using anonymous communications networks, such as Tor, to ensure access privacy. We challenge this approach, showing the need for mechanisms through which non-anonymous users can (i) publish transactions that cannot be linked to their network addresses or to their other transactions, and (ii) fetch details of specific transactions without revealing which transactions they seek. We hope this article inspires blockchain researchers to think beyond Tor and tackle these important access privacy problems head-on.
A health-care system gathers comprehensive physiological information and medical records, making its data more important than ever. For example, for years now, the National Health Insurance Administration (https://www.nhi.gov.tw/English/) of Taiwan has requested every doctor, whether in a medical center or private clinic, to upload the diagnosis result, treatment, and prescription. These anamneses have also been stored in the National Health Insurance Research Database (http://nhird.nhri.org.tw/en/index.html) since 1 March 1995, and 99.9% of the Taiwanese population have been enrolled since 2014. With this comprehensive database, analytics tools can be run to uncover useful information to further understand the etiological factors for rare disorders. This database is successful primarily because Taiwan is a small but densely populated island, making it relatively easy for the government to collect most, if not all, the anamneses.
Although the blockchain is widely acknowledged as one of the most disruptive technologies emerged in the last decades, many implementation hurdles at the technical, regulatory and governance level still prevent a widespread adoption of services based on open networks. This research discusses the role Trust Service Providers may play in permissioned blockchains, providing a reliable ecosystem in which services can be safely developed and preserved in the long run. As case study, the paper outlines the main features of TrustedChain®, the first blockchain network of European Trust Service Providers specifically designed for highly sensitive sectors, with cutting-edge applications for public administration, e-government, banking, e-health and industry. Emphasis is thus placed on systemic trust, law compliance, adequate technical performance, confidentiality of transactions and long term preservation of data as essential conditions for blockchain networks to thrive and accomplish complex tasks in an effective and reliable way.
Intelligence is one of the most important aspects in the development of our future communities. Ranging from smart home to smart building to smart city, all these smart infrastructures must be supported by intelligent power supply. Smart grid is proposed to solve all challenges of future electricity supply. In smart grid, in order to realize optimal scheduling, an SM is installed at each home to collect the near-real-time electricity consumption data, which can be used by the utilities to offer better smart home services. However, the near-real-time data may disclose a user's private information. An adversary may track the application usage patterns by analyzing the user's electricity consumption profile. In this article, we propose a privacy-preserving and efficient data aggregation scheme. We divide users into different groups, and each group has a private blockchain to record its members' data. To preserve the inner privacy within a group, we use pseudonyms to hide users' identities, and each user may create multiple pseudonyms and associate his/ her data with different pseudonyms. In addition, the bloom filter is adopted for fast authentication. The analysis shows that the proposed scheme can meet the security requirements and achieve better performance than other popular methods.
Blockchain technologies, such as smart contracts, present a unique interface for machine-to-machine communication that provides a secure, append-only record that can be shared without trust and without a central administrator. We study the possibilities and limitations of using smart contracts for machine-to-machine communication by designing, implementing, and evaluating AGasP, an application for automated gasoline purchases. We find that using smart contracts allows us to directly address the challenges of transparency, longevity, and trust in IoT applications. However, real-world applications using smart contracts must address their important trade-offs, such as performance, privacy, and the challenge of ensuring they are written correctly.
Since most of the organizations are going online these days, such organizations have become dependent to their data over the internet. Hence, it has become more critical to secure data by taking adequate security measures. One of the measures that can be taken to secure data from attackers and intruders is access control. Along with the changing trend, even the data used is evolving. `Bitcoin' is the new data that has gained importance in the market. Every third person in the world has Bitcoin to their share. So it becomes important to secure Bitcoin and the information it possesses. Blockchain helps in preventing Bitcoin - the digital currency and therefore stores the information securely. In this paper, we survey and study how the rising of Blockchain technology has affected traditional transactional banking and also outline possible directions for future research.
Jun 1, 2018·2018 IEEE 20th International Conference on High Performance Computing and Communications; IEEE 16th International Conference on Smart City; IEEE 4th International Conference on Data Science and Systems (HPCC/SmartCity/DSS)
The construction of smart city involves multiple corporate organizations and government agencies, while smart city operations often require data across organizations. This paper describes a blockchain-based approach to exchange information in smart cities that assists sharing data across multiple, non-trusted organizations. The proposed method enables an organization safely use data from another organization to participate in business operations without accessing the data. The data that participates in operations is in an encrypted form stored only in the executor sandbox. Consensus calculations are performed on multiple nodes by smart contract. After the confirmation through multiple nodes, the result of the calculation will be returned to the applicant. Thus, the risk of data leakage could be avoided. Our proposed method can effectively prevent the access to the information from being illegally obtained, used, and tampered. Also it ensures the reliable use of the data which enables the effective information sharing and protection of information among multiple organizations in the smart city applications.
The use of distributed ledger technologies introduces new security and privacy challenges. These challenges are dependent on properties of the ledgers, such as transaction latency and throughput. Some use cases may be outright impossible to implement securely, or in a privacy-retaining manner. Consequently, it is important that these concerns are taken into account when distributed ledger technologies are evaluated and selected as building blocks for higher-level systems. In this paper, we illustrate these concerns through use case examples. We discuss the implications these concerns on the use of distributed ledgers within higher-level systems, such as in SOFIE, a DLT-based approach to securely and openly federate IoT systems.
Preuves à divulgation nulle de connaissance efficaces à base de réseaux euclidiens et applications Le chiffrement à base de réseaux euclidiens a connu un grand essor durant les vingt dernières années. Autant grâce à l’apparition de nouvelles primitives telles que le chiffrement complètement homomorphe, que grâce à l’amélioration des primitives existantes, comme le chiffrement á clef publique ou les signatures digitales, qui commencent désormais à rivaliser avec leurs homologues fondés sur la théorie des nombres. Cela dit les preuves à divulgation nulle de connaissance, bien qu’elles représentent un des piliers des protocols de confidentialité, n’ont pas autant progressé, que ce soit au niveau de leur expressivité que de leur efficacité. Cette thèse s’attelle dans un premier temps à améliorer l’état de l’art en matière de preuves à divulgation nulle de connaissance. Nous construisons une preuve d’appartenance à un sous ensemble dont la taille est indépendante de l’ensemble en question. Nous construisons de même une preuve de connaissance amortie qui est plus efficace et plus simple que toutes les constructions qui la précèdent. Notre second propos est d’utiliser ces preuves à divulgation nulle de connaissance pour construire de nouvelles primitives cryptographiques. Nous concevons une signature de groupe dont la taille est indépendante du groupe en question, ainsi qu’un schéma de vote électronique hautement efficace, y compris pour des élections à grand échelle.
Joaõ Pedro Dias, Hugo Sereno Ferreira, Ângelo Martins
Access control is a crucial part of a system's security, restricting what actions users can perform on resources. Therefore, access control is a core component when dealing with e-Health data and resources, discriminating which is available for a certain party. We consider that current systems that attempt to assure the share of policies between facilities are prone to system's and network's faults and do not assure the integrity of policies lifecycle. By approaching this problem with the use of a distributed ledger, namely a consortium blockchain, where the operations are stored as transactions, we ensure that the different facilities have knowledge about all the parties that can act over the e-Health resources while maintaining integrity, auditability, authenticity, and scalability.
A problem facing healthcare record systems throughout the world is how to share the medical data with more stakeholders for various purposes without sacrificing data privacy and integrity. Blockchain, operating in a state of consensus, is the underpinning technology that maintains the Bitcoin transaction ledger. Blockchain as a promising technology to manage the transactions has been gaining popularity in the domain of healthcare. Blockchain technology has the potential of securely, privately, and comprehensively manage patient health records. In this work, we discuss the latest status of blockchain technology and how it could solve the current issues in healthcare systems. We evaluate the blockchain technology from the multiple perspectives around healthcare data, including privacy, security, control, and storage. We review the current projects and researches of blockchain in the domain of healthcare records and provide the insight into the design and construction of next generations of blockchain-based healthcare systems.
Zhe Yang, Kan Yang, Lei Lei, Kan Zheng · 5 authors
Vehicular networks enable vehicles to generate and broadcast messages in order to improve traffic safety and efficiency. However, due to the nontrusted environments, it is difficult for vehicles to evaluate the credibilities of received messages. In this paper, we propose a decentralized trust management system in vehicular networks based on blockchain techniques. In this system, vehicles can validate the received messages from neighboring vehicles using Bayesian Inference Model. Based on the validation result, the vehicle will generate a rating for each message source vehicle. With the ratings uploaded from vehicles, roadside units (RSUs) calculate the trust value offsets of involved vehicles and pack these data into a “block.” Then, each RSU will try to add their “blocks” to the trust blockchain which is maintained by all the RSUs. By employing the joint proof-of-work (PoW) and proof-of-stake consensus mechanism, the more total value of offsets (stake) is in the block, the easier RSU can find the nonce for the hash function (PoW). In this way, all RSUs collaboratively maintain an updated, reliable, and consistent trust blockchain. Simulation results reveal that the proposed system is effective and feasible in collecting, calculating, and storing trust values in vehicular networks.
Md Zakirul Alam Bhuiyan, Aliuz Zaman, Tian Wang, Guojun Wang · 6 authors
The increase in reported incidents of security breaches that compromise privacy of individuals requires us to question the current model used to collect patient information. What we have learned from bitcoin and the underlying blockchain technology is that there are ways for us to protect this information by using a distributed ledger. In this paper, we review and propose a solution that can be used to manage individual health data as well as cross-institutional sharing of this information. The solution will increase clinical effectiveness and an increase in research when the data is shared with researchers. The proposed system solution based on blockchain technology that includes providers, hospitals and clinic, insurance companies, and patients. All along the ownership of the data would belong to the individual or the patient. In the solution, we suggest to adopt a private blockchain solution where all participants are known and trusted, which allows for privacy and security of the data.
In this paper, we propose an architecture for Blockchain-based Electronic Medical Records (EMRs) called GAA-FQ (Granular Access Authorisation supporting Flexible Queries) that comprises an access model and an access authorisation scheme. Unlike existing Blockchain schemes, our access model can authorise different levels of granularity of authorisation, whilst maintaining compatibility with the underlying Blockchain data structure. Furthermore, the authorisation, encryption, and decryption algorithms proposed in the GAA-FQ scheme dispense with the need to use a public key infrastructure (PKI) and hence improve the computation performance needed to support more granular and distributed, yet authorised, EMR data queries. We validated the computation performance and transmission efficiency for GAA-FQ using a simulation of GAA-FQ against an access control scheme for EMRs called ESPAC as our baseline that was not designed using a Blockchain. To the best of our knowledge, GAA- FQ is the first Blockchain-oriented access authorisation scheme with granular access control, supporting flexible data queries, that has been proposed for secure EMR information management.