【Abstract】In this article, we address the problem of secure sensitive data sharing for the specified recipients in Blockchain Internet of Things (BIoT). To do it, we present a cryptographic solution to meet the requirements of decentralization and convenience through key management and programmable ciphertext. First, we design a new ciphertext-policy decentralized-key attribute-based encryption (CP-DK-ABE) scheme. After the master secret key is shared into all full nodes in the form of threshold secret sharing, a decentralized multiparty computation protocol is used to generate the user's private key in an interactive way. Meanwhile, the attribute subkeys associated with the private key can be reconstructed by obtaining a fragment from each of full nodes, so as to achieve the cooperative management of attribute key through all of full nodes. Furthermore, following the blockchain's script system, we introduce five new opcodes to represent ciphertext in the programmable format. Such a mechanism provides flexible capability to represent the logical relationship of the access control policy among attribute subciphers in the CP-DK-ABE ciphertext by the scripting language. As a result, the processes of encryption and decryption are implemented entirely by the script interpreter on the blockchain node, thereby greatly improving the convenience of programming in BIoT devices. In addition, we prove that the proposed CP-DK-ABE scheme is key private and semantically secure for a limited number of corrupted full nodes under the decisional linear and bilinear Diffie-Hellman assumption, respectively.
【Keywords】Encryption; Blockchains; Cryptography; Internet of Things; Authorization; Hospitals; Cardiology; Attribute-based encryption (ABE); Blockchain Internet of Things (BIoT); decentralized key; programmable ciphertext; script system
【Abstract】Owing to the introduction of blockchain (BC) technology, a decentralized identity (DID) model has been proposed to replace conventional identity models based on centralized authorities. The BC platform operated by various participants provides a new root-of-trust functionality for entity identification and access control. Each entity generates and registers its own identifier and credential (public key) to the BC such that any entity can obtain the other entity's public key. When the corresponding private key is compromised, the key rotation to generate and register a new key pair should be performed. However, the current approach for cryptographically binding a decentralized identifier with a public key induces a serious security problem that results in both identity-stealing attacks and multiple identifiers for a single entity. A new DID to address the security problem above is proposed herein, which is based on a newly proposed cryptographic primitive (infinite one-way hash chain), as well as its security analysis and performance evaluation on Hyperledger Fabric and Contiki Cooja simulator. To demonstrate the applicability of the proposed DID to various security protocols, an authenticated key exchange protocol is also designed.
【Abstract】The concept of time release provides a new mode of sending information to the future, where the message will be available after a certainly specified period. Time-release encryption (TRE), as a promising approach, has a widespread releasing application and ensures data confidentiality. TRE relies on two main frameworks, one based on the time-lock puzzle and the other based on a trusted third party, while this primitive is impeded by frameworks' unreliability limitations and time disclosure. We present ReleaseSC, a decentralized and privacy-aware system that combines smart contract with TRE. ReleaseSC leverages a novel three-part architecture that harmonizes time release and contracts, enabling efficient time-hidden smart contract. Our prototype is with reasonable performance through EVM evaluations on both private chain and official test network. ReleaseSC is built on the top of a new cryptographic notion named ID-based TRE that supports a flexible time policy and preserves the to-be-released time. We propose an ID-based TRE instantiation and show rigorous security analysis in formal security models. The insight from ReleaseSC will open more possibilities to address security issues in hybridized cryptography-blockchain systems.
【Abstract】Access control is a fundamental component of the design of distributed ledgers, influencing many aspects of their functionality, such as fairness, efficiency, traditional notions of network security, and adversarial attacks such as Denial-of-Service (DoS) attacks.(1) In this work, we consider the security of a recently proposed access control protocol for directed acyclic graph-based distributed ledgers. We present a number of attack scenarios and potential vulnerabilities of the protocol and introduce a number of additional features which enhance its resilience. Specifically, a blacklisting algorithm, which is based on a reputation-weighted threshold, is introduced to handle both spamming and multirate malicious attackers. A solidification request component is also introduced to ensure the fairness and consistency of the network in the presence of attacks. Finally, a timestamp component is also introduced to maintain the consistency of the network in the presence of multirate attackers. Simulations to illustrate the efficacy and robustness of the revised protocol are also presented.
【Abstract】Recently, the Industrial Internet of Things plays a vital role in the new round of technology innovation and industry competition, where the identity resolution system is its key component. However, there are some problems in the existing Handle-based identity resolution architecture. Therefore, a trusted identifier co-governance architecture is proposed, and a prototype system is designed and implemented in this article. Specifically, we design a blockchain-based decentralized framework for identifier service, identifier life cycle management based on smart contract, and a data storage mechanism for a trusted identifier. The whole architecture could solve the problems of single point of failure, data tampering, and governance deviation, and reduce the trust cost in the process of data circulation. The simulation results reveal that the system has achieved good results in terms of delay and throughput.
【Abstract】The shared mobility concept is seen as disruptive and transformative for the automotive industry. Shared mobility is changing the way we choose our travel mode, from just owning a car to e-hailing, car-sharing, and other relevant mobility solutions. There is a growing interest of car manufacturers (original equipment manufacturers or OEMs) in car-sharing as an expansion strategy. Similarly, blockchain technology is seen as another disruptive technology, which can potentially change how the data is stored and accessible via its immutable, transparent, and trustworthy features. Motivated by these two current trends, this paper aims to explore how blockchain and IoT technologies together can drive shared mobility forward. We have presented a high-level architecture for a blockchain-IoT-based platform for promoting shared mobility combining car-sharing and car-leasing. We also demonstrated a prototype implemented from the OEM's point of view by developing a blockchain-IoT-based platform streamlining car-sharing and leasing processes by taking into consideration of primary stakeholders (such as OEMs, a peer-to-peer car-sharing provider, leasing company and insurance provider as well as public authorities). This work also demonstrates that the design of such an integrated platform depends on the right balance between the key design principles (such as security and privacy, authenticity, traceability and reliability, scalability, and interoperability) in the context of car-sharing platforms.
【Abstract】Blockchain technology allows public parties to agree on a common state without relying on a central authority. Despite it brings many innovative use cases, the technology is still in its early stage that needs improving on many aspects. One of the issues is to deliver blockchain data more efficiently. Named Data Networking (NDN), a new network paradigm, is designed to make content distribution with ease by enabling in-network caching and built-in multicasting, which blockchain technologies can take advantage. Moreover, blockchain may contribute to extending NDN application ecosystems including decentralized applications. Therefore, it is instrumental to have a working blockchain system that runs on NDN platform to supports its research and development. In this work, we design and implement an NDN-based Ethereum blockchain platform. We propose new protocols for propagating blockchain data making full use of NDN features for the delivery of transactions and blocks. Our experiments show that the distribution of blockchain data in NDN is more efficient than that of IP network. The latency of block delivery is also reduced, which in turn supports tuning blockchain parameter for better security. Our developed blockchain client is freely distributed as an open-source project. We hope that it can provide a platform to foster blockchain research on NDN in the future.
【Abstract】Researchers interested in blockchains are increasingly attuned to questions of governance, including how blockchains relate to government, the ways blockchains are governed, and ways blockchains can improve prospects for successful self-governance. Our paper joins this research by exploring the implications of the Governing Knowledge Commons (GKC) framework to analyze governance of blockchains. Our novel contributions are making the case that blockchain networks represent knowledge commons governance, in the sense that they rely on collectively-managed technologies to pool and manage distributed information, illustrating the usefulness and novelty of the GCK methodology with an empirical case study of the evolution of Bitcoin, and laying the foundation for a research
【Abstract】In this article, we analysed the problems of electronic medical records (EMRs) and found that the EMRs generated by different hospitals for the same patient are mutually independent and duplication and data sharing are difficult among hospitals. In order to solve this problem, this paper proposes an efficient and secure cross-domain sharing scheme of EMRs based on edge computing. The program allows the doctor to access the personal history EMRs through the patient's authorization so that the doctor can understand the patient's history of illness and, on this basis, generate a new medical record for the patient. Then, the doctor sends the EMRs to the edge server, and the server calculates the ciphertext and adds it to the patient's personal medical record to complete the case update. Analysis shows that this solution can effectively prevent data tampering and forgery through blockchain and avoid privacy leakage problems in plaintext sharing by using searchable encryption and by relying on edge servers to solve nearby computing tasks and divert the computing capacity of cloud servers to improve efficiency. The security proof shows that the scheme satisfies the complex problem of the BDH assumption. Performance analysis shows that the scheme is feasible and efficient.
【Abstract】Based on the reception of DLT/blockchain, this article argues that legal discourse is subject to hype cycle dynamics. Thinking in hype cycle categories provides a structured way for analysing the legal implications of a particular innovation. This critical engagement with enthusiasts, sceptics and pragmatists through the different stages may help to present a more realistic picture of DLT/blockchain's potential from a legal perspective in the short and medium term. Consequently, this article discusses the potential for disruption to the legal system envisaged by enthusiasts at the height of inflated expectations, attempts to deconstruct the arguments levelled at the technology by its detractors during the trough of disillusionment, charts the emerging legal landscape that seeks to harness the potential of DLT/blockchain up the slope of enlightenment, and concludes by risking a glimpse towards the plateau of productivity.
【Abstract】This research explores the role of Blockchain Technology (BCT) integrated with Reverse Supply Chain Networks (RSCN) and evaluates the relationship between BCT and sustainability performance. A qualitative research design was employed to develop a conceptual framework for BCT in RSCN. This research collected and analysed primary and secondary data from four cases as focal-actors. These focal-actors are from multi-industries in Jordan, namely food, pharmaceuticals, electronics, and toys. These actors are lead-firms and have experience working with RSCNs and technology applications such as BCT. Primary data were acquired from interviews with managers working in these industries, which were supported by the analysis of secondary data that identified two types of themes: internally focused and externally focused BCT-integrated drivers of RSCNs. The analysis also identified how they leverage sustainability performance improvements, including their use of RSCN approaches and features. This research is one of the few attempts to explore BCT integrated into RSCN for better sustainability performance that contributes to the theoretical and practical knowledge of supply chains within emerging economies. All types of actors-as-stakeholders involved with national programs and projects can adopt the new framework. The key findings contribute to the field of RSCN where the adoption of BCT as a broad-based strategy to attain sustainability goals and reverse chain activities along the supply chain is a goal.
【Abstract】Starting from the earlier civilisation till date, money plays a crucial part in the transfer of goods and services. With this digital world, the money also changes its faces from paper money to digital currency called cryptocurrency without any central bank, which runs on top of the technology called blockchain. The trendiest cryptocurrency is bitcoin. Forecasting the daily price is a challenging task due to its nonlinearity. Most of the researchers tried to predict using various statistical and machine learning models which were not satisfactory because of its large dataset with more noise. The intention is to design a deep learning multiplicative long short-term memory model to estimate the price of bitcoin with an attention mechanism using technical indicators which gives better accuracy and a very less error rate. The proposed model is compared with some existing models, say long short-term memory, peephole, gated recurrent unit and multiplicative long short-term memory on the presence and absence of technical indicators. The comparative result shows that the proposed model outperforms the existing models in terms of mean square error, root mean square error and mean absolute error when evaluated with two benchmark datasets.
