Internet-of-Things (IoT) are increasingly operating in the zero-trust environments where any devices and systems may be compromised and hence untrusted. In addition, data collected by and sent from IoT devices may be shared with and processed by edge computing systems, in order to reduce the reliance on centralized (cloud) servers, leading to further security and privacy issues. To cope with these challenges, this paper proposes an innovative blockchain-enabled information sharing solution in zero-trust context to guarantee anonymity yet entity authentication, data privacy yet data trustworthiness, and participant stimulation yet fairness. This new solution is able to support filtering of fabricated information through smart contracts, effective voting, and consensus mechanisms, which can prevent unauthenticated participants from sharing garbage information. We also prove that the proposed solution is secure in the universal composability framework, and further evaluate its performance over an Ethereum-based blockchain platform to demonstrate its utility.

Building Information Modeling (BIM) is envisioned as an indispensable opportunity in the architecture, engineering, and construction (AEC) industries as a revolutionary technology and process. Smart construction relies on BIM for manipulating information flow, data flow, and management flow. Currently, BIM model has been explored mainly for information construction and utilization, but rare works pay efforts to information security, e.g., critical model audit and sensitive model exposure. Moreover, few BIM systems are proposed to chase after upcoming computing paradigms, such as mobile cloud computing, big data, blockchain, and Internet of Things. In this paper, we make the first attempt to propose a novel BIM system model called bcBIM to tackle information security in mobile cloud architectures. More specifically, bcBIM is proposed to facilitate BIM data audit for historical modifications by blockchain in mobile cloud with big data sharing. The proposed bcBIM model can guide the architecture design for further BIM information management system, especially for integrating BIM cloud as a service for further big data sharing. We propose a method of BIM data organization based on blockchains and discuss it based on private and public blockchain. It guarantees to trace, authenticate, and prevent tampering with BIM historical data. At the same time, it can generate a unified format to support future open sharing, data audit, and data provenance.

The volume, variety and value of data generated by Internet of Things (IoT) devices are expected to increase significantly in foreseeable future, hence, reinforcing the importance of secure and efficient access control solutions for these devices and their networks. However, existing access control solutions are not generally lightweight or scalable, particularly for geographically disperse, inexpensive resource constrained IoT devices. To tackle above challenges, we propose a lightweight consortium blockchain based architecture to enable intelligent autonomous access control for IoT devices. In our architecture, intelligent blockchain facilitates the storing of access policies, provision of authentication services for data access control, and trust evaluation for access request nodes through token accumulation mechanism. Specifically, the user's access request is approved only after it is confirmed by the blockchain network. To ensure the reliability of authenticity, a compromised resistant consensus algorithm is adapted and implemented to defend against at most 1/3 compromised authenticators. In addition, a cross-domain and flexible access control model is not only used to support data sharing among various users but can also be used for access control for exceptional blockchain situations. We explain how our system meets our design goals of reliability, availability, confidentiality, integrity, lightweight, security and scalability. In addition, we also analyze the proposed system's performance from computational, storage and network overheads (e.g. running cryptographic algorithms on a Raspberry Pi 4B), and the findings suggest that the time to run typical cryptographic algorithms is in the microsecond range.

In large-scale Internet of Things, centralized authentication imposes several critical challenges in terms of vast identity management, authentication overhead, and single point of failure. Distributed identity management has been envisioned as a promising approach for mitigating above all, but the security and performance of the overall solution have not been extensively evaluated. In this paper, we proposed a decentralized identity management scheme based on blockchain for tackling large-scale Internet of Things such as VANET. We implement smart contracts to support large-scale user access control, together with design trust management methods for reputation evaluation and credit penalty mechanisms, which can prevent various types of attacks in distributed identification contexts. The experiment results and analysis justified that our scheme is scalable with good performance. Specifically, the system response is on a millisecond scale and all the functions consume within 250ms. Also, the time consumption of the query maintains a manageable delay within 0.5ms no matter the remarkable growth of users. Finally, we observe that the throughput of the current blockchain platform could meet the requirement of our scheme with the increasing number of users’ upload request in real-world simulation.

Federated Learning (FL) enables multiple clients to collaboratively train a model without sharing their private data. However, the deployment of FL in real-world applications is vulnerable to various attacks from both malicious servers and clients. While cryptographic methods are effective in resisting server-side attacks, they undermine the capability of client-side defenses that rely on plaintext updates. Several valuable defenses targeting hybrid attacks have been devised to address this challenge, concentrating on specific client-side threats. To improve scalability, we continue this research line to introduce a generic architecture covering more client-side attacks. In this paper, we propose a general architecture to enhance client-side defenses from plaintext to ciphertext domains. This architecture not only supports the server-side defenses, but also accommodates a broader range of client-side defenses, including Norm-based, Krum-based, and Cosine-based strategies. The core of our architecture is generic detection under ciphertext, which tackles the following conflict of integrating server-side and client-side defenses. That is, the former aims to protect parameters from exposure while the latter demands plaintext updates. We prove the security of our architecture through the Universal Composability framework. Additionally, we provide a comprehensive instantiation and extensive evaluations to demonstrate the effectiveness and robustness of our approach. Our experiments show that our architecture can maintain the effectiveness of current client-side defenses when parameters are encrypted, thus effectively resisting hybrid attacks.

The increasing volume of user and household data and number of smart meters compound the challenge of ensuring efficiency and privacy protection of electricity trading in existing smart grids. Therefore, to minimize the cost and latency in electricity trading, in this article, we design a new architecture for smart meters that can support transactions (using a blockchain-based wallet) and initiate transmission switch instructions (using smart contacts). Specifically, our approach comprises a decentralized peer-to-peer electricity trading scheme to enable automated electricity transmission (using smart contract instead of some centralized entity), and our blockchain-based anonymous authentication scheme to facilitate fast and privacy-aware roaming, in order to achieve privacy protection. We demonstrate that our proposed scheme is secure under the universally composable framework.