With the advent of various mobile IoT devices, a large amount of e-health record (EHR) data has been generated. This data has great potential to improve medical research. However, there are many challenges regarding the sharing of medical data. Firstly, users are more inclined to interact anonymously. Secondly, verifying the validity of certificates in the case of anonymous interactions is challenging. In addition, it is necessary to uncover the identities of the actual interacting parties in the event of malicious behavior. Therefore, we address the above challenges and propose group signatures with time constraints to support anonymous and traceable EHR data sharing. First, we propose a group signature scheme that supports traceability. Second, to address the issue of validating anonymous certificates, we propose group signatures with time constraints that enable dynamic updates to validity. Through this, we can dynamically revoke group members. Lastly, security proofs and efficiency analyses demonstrate that our scheme is both secure and efficient.

The rapid evolution of the smart grid has made the security and reliability of communication within the power system an urgent and critically important issue. To address this challenge, authentication and key agreement (AKA) protocols have gained significant attention and are regarded as indispensable tools for ensuring the secure operation of the smart grid. However, traditional AKA protocols are plagued by a series of issues, including cumbersome certificate management, delayed certificate revocation, and vulnerability to man-in-the-middle attacks. With the emergence of certificate-less public key cryptography (CL-PKC), the integration of conventional AKA protocols with CL-PKC has emerged as a prominent trend. This paper presents an enhanced certificate-less AKA protocol for smart grids, named ECL-AKA. Firstly, the paper outlines the architecture and security model of this protocol. Subsequently, it presents the complete workflow of the ECL-AKA protocol. Notably, the ECL-AKA protocol introduces a private key verification step before key agreement, allowing for rapid screening of malicious requests at a lower computational cost, thereby enhancing the protocol’s resistance to various types of attacks. In addition, the ECL-AKA’s security is formally established through rigorous theoretical proofs based on the random oracle model in the paper. Finally, comparative experimental analysis demonstrates that the ECL-AKA exhibits lower computational and communication overhead while satisfying essential security attributes.

Currently, power data trading typically relies on Web pages as the conventional mode of mediation. Nevertheless, dishonest trading Web may secretly resell the data sets of grid companies or have no way of knowing what the buyer has done with the power data, thereby compromising the privacy of power user. This article proposes a privacy-preserving supply-demand consistency matching service scheme (PPMSE) to address the problem of whether the power data provided by the seller aligns with the requirements of the buyer in power data trading. The scheme utilizes enhanced public-key searchable encryption (PKSE) to establish a matching environment that fulfills privacy protection needs, thereby facilitating consistency matching between supply and demand, all while preserving user privacy. Then, the PPMSE ensures that matching service can only occur within the designated platform by equipping the power data trading cloud platform with public and private keys. Additionally, by applying ciphertext policy attribute-based encryption (CP-ABE) to the data processing tasks of the buyer, the scheme enables the seller to decrypt and obtain what the buyer has done with the data after successful matching and meeting specific attributes. Ultimately, a comprehensive analysis and performance evaluation are provided, validating the feasibility and superiority of the proposed scheme.

With the rapid development of the smart grid (SG), the security and reliability of communication for SG has become an urgent and critical issue. The authentication and key agreement (AKA) protocol has emerged as important means to address the security challenges in smart grid. This paper proposes a novel certificateless authentication and key agreement protocol (NCL-AKA) for the smart grid, which overcomes the limitations of existing AKA protocol such as complex certificate management, untimely certificate revocation, and man-in-the-middle attacks. Firstly, the system architecture and threat model of the proposed protocol is presented. Then, the correctness and security of the proposed protocol are analyzed. Finally, comparative experiments and analysis reveal that the NCL-AKA has lower computational cost and communication overhead.

Internet of Medical Things (IoMT) technologies significantly improve the quality of health care, especially at the time when COVID-19 is becoming a worldwide pandemic. Due to the complexity of devices and user nodes in the IoMT system, there should be some ways to ensure the security and quality of the service or information. Decentralized trust management techniques are efficient means of promoting application security and reliability in these cases. However, the majority of currently utilized access control schemes cannot be applied in decentralized trust management systems or perform poorly owing to the numerous restrictions of decentralized systems. In this article, we present a policy-hiding and multiauthority key generation CP-ABE scheme (PM-CPABE) for decentralized trust management systems, which could provide fine-grained access control capabilities. Meanwhile, the proposed scheme does not require any fully trusted entity, thus it can be well adapted to decentralized trust management systems. The scheme also implements policy hiding to protect user privacy. In addition, it supports large universe and outsourced decryption. The security analyses and performance comparisons give evidence of our scheme is secure and efficient.