With the rapid advancement of network communication and big data technologies, the Internet of Things (IoT) has permeated every facet of our lives. Meanwhile, the interconnected IoT devices have generated a substantial volume of data, which possess both economic and strategic value. However, owing to the inherently open nature of IoT environments and the limited capabilities and the distributed deployment of IoT devices, traditional access control methods fall short in addressing the challenges of secure IoT data management. On the one hand, the single point of failure issue is inevitable for the centralized access control schemes. On the other hand, most decentralized access control schemes still face problems such as token underutilization, the insecure distribution of user permissions, and inefficiency.This paper introduces a blockchain-based access control framework to address these challenges. Specifically, the proposed framework enables data owners to host their data and achieves user-defined lightweight data management. Additionally, through the strategic amalgamation of smart contracts and hash-chains, our access control scheme can limit the number of times (i.e., n-times access) a user can access the IoT data before the deadline. This also means that users can utilize their tokens multiple times (predefined by the data owner) within the deadline, thereby improving token utilization while ensuring strict access control. Furthermore, by leveraging the intrinsic characteristics of blockchain, our framework allows data owners to gain capabilities for auditing the access records of their data and verifying them. To empirically validate the effectiveness of our proposed framework and approach, we conducted extensive simulations, and the experimental results demonstrated the feasibility and efficiency of our solution.

Intelligent Transport Systems (ITS) have received growing attention recently driven by technical advances in Industrial Internet of Vehicles (IIoV). In IIoV, vehicles report traffic data to management infrastructures to achieve better ITS services. To ensure security and privacy, many anonymous authentication-enabled data reporting protocols are proposed. However, these protocols usually require a large number of preloaded pseudonyms or involve a costly and irrevocable group signature. Thus, they are not ready for realistic deployment due to large storage overhead, expensive computation costs, or absence of malicious users' revocation. To address these issues, we present a novel data reporting protocol for edge-assisted ITS in this paper, where the traffic data is sent to distributed edge nodes for local processing. Specifically, we propose a new anonymous authentication scheme fine-tuned to fulfill the needs of vehicular data reporting, which allows authenticated vehicles to report unlimited unlinkable messages to edge nodes without huge pseudonyms download and storage costs. Moreover, we designed an efficient certificate update scheme based on a bivariate polynomial function. In this way, malicious vehicles can be revoked with time complexity $\mathcal {O}$ (1). The security analysis demonstrates that our protocol satisfies source authentication, anonymity, unlinkability, traceability, revocability, nonframeability, and nonrepudiation. Further, extensive simulation results show that the performance of our protocol is greatly improved since the signature size is reduced by at least 8%, the computation costs in message signing and verification are reduced by at least 56% and 67%, respectively, and the packet loss rate is reduced by at least 14%.

The advent of the Internet of Medical Things (IoMT) has greatly fastened the digitization of current medical institutions. Mobile crowdsourcing is an effective strategy for health data collection in IoMT environments to overcome the data-scarce problem. However, due to the openness of IoMT networks, users’ identities and sensitive data may be leaked during IoMT crowdsourcing. Meanwhile, IoMT crowdsourcing may introduce low-quality data from unreliable participants. Multireceiver signcryption is a promising mechanism to ensure confidentiality and authenticity in an efficient manner. However, existing multireceiver signcryptions cannot fully meet the needs of IoMT crowdsourcing in terms of privacy protection, on-demand participation, and malicious behavior resistance. In this article, we integrate attribute-based credentials with multireceiver encryption and propose a novel multireceiver conditional anonymous signcryption (MCAS) scheme for crowdsourced IoMT environments to address the above challenge. Specifically, conditional anonymous authentication with selective attribute disclosure is achieved, thereby allowing a worker to self-disclose some attributes and anonymously certify his/her crowdsourcing qualifications, and also achieving the traceability of malicious behaviors. Meanwhile, one-to-many secure data sharing with outsourced data signcryption and unsigncryption is realized to prevent the leakage of sensitive IoMT data and mitigate the computational burden of power-limited mobile devices. Moreover, rigorous security analysis demonstrates that our MCAS scheme achieves the expected properties, i.e., confidentiality, anonymity, fine-grained authentication, traceability, and nonrepudiation. Extensive experimental results show that our MCAS outperforms state-of-the-art schemes, demonstrating our scheme’s appropriateness for IoMT crowdsourcing.

In Cooperative Intelligent Transport Systems (C-ITS), vehicles can disseminate announcements to the traffic Application Server (AS) and nearby vehicles to enhance traffic safety and efficiency. To build reliable dissemination environments, various threshold announcement approaches are proposed, wherein receivers accept a traffic event only when t (threshold) vehicles have endorsed it. Among these approaches, group signaturebased approaches have emerged as promising choices for C-ITS due to their optimal tradeoff among certificate management, privacy protection, and traceability. However, existing group signature-based approaches have three limitations: 1) Announcement verification is time-consuming, making them unable to meet the fast authentication requirement of C-ITS. 2) Receivers face significant storage burdens in maintaining numerous traffic events and endorsements. 3) Unsuitable for vehicle-to-AS announcement dissemination as their one-by-one dissemination mode would impose unaffordable costs to the central AS, which limits their applicability in certain scenarios. To overcome these issues, we design an efficient group signature scheme tailored to reliable anonymous announcement dissemination. Building upon this scheme, we further present a novel threshold anonymous announcement protocol, which optimizes the announcement's dissemination mode and enables efficient batch verification. Specifically, instead of the traditional one-by-one dissemination, a compressed anonymous announcement with t endorsements is disseminated to receivers. This dissemination mode facilitates immediate announcement processing, eliminates the need for extensive traffic information maintenance, and is suitable for both Vehicle-to-Vehicle (V2V) and vehicle-to-AS announcement dissemination scenarios. Meanwhile, regardless of the threshold t, the announcement can be verified with only a small constant number of pairing and scalar multiplication operations. The theoretical analysis demonstrates that our protocol achieves the expected properties, and extensive simulation results show that our protocol outperforms the state-of-the-art protocols, indicating the performance and practicability of our protocol

With the increasingly prominent value of big data, data sharing within enterprises and organizations has become increasingly popular, and many institutions have established data centers to achieve effective data storage and sharing. Meanwhile, cyberspace data security and privacy have become the most critical issue that people are concerned about since shared data often involves commercial secrets and sensitive information. At present, data encryption techniques have been applied to protect the security of the sensitive data stored in and shared by the data centers. However, the challenges of efficient data sharing, secure management of decryption keys, deduplication of the plaintext, and transparency and auditability of the data access arise. These challenges may obstruct the development of data sharing in data-driven systems. To meet these challenges, we propose a secure and trustworthy data sharing scheme and introduce blockchain, proxy re-encryption (PRE), and trusted execution environments (TEEs) into the data-driven systems. Our scheme mainly enables (1) automatic distribution and management of the decryption keys, (2) reduction of the reduplicative data, and (3) trustworthy data sharing and recording. Finally, we implement the proposed scheme and compare it with other existing schemes. It is demonstrated that our scheme reduces the computation and communication overhead.