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With the proliferation of vehicular networking and data in the era of Vehicular Ad-hoc Networks (VANETs), ensuring privacy-preserving authentication and data privacy during analysis has emerged as a pivotal research focus. In this article, we propose a blockchain-assisted privacy-preserving authentication protocol Bap with user-controlled data unlinkability for VANETs. We leverage Pointcheval-Sanders (PS) signatures to design a privacy-preserving authentication protocol that supports user traceability and revocation of malicious users. Additionally, we introduce an auxiliary data processor (DP) in our model to analyze VANET data with explicit and implicit linkability. The DP is capable of linking messages on the same or different topics, enabling minimal privacy disclosure during Big Data analysis. We provide a detailed proof and demonstrate that our scheme satisfies the required properties. Finally, performance evaluations demonstrate the efficiency of our proposed scheme. While supporting the mentioned functionalities, the gas cost is limited to a small range, and the signature size is only 354 bytes.

Smart home refers to the automation and intelligent management of family life using information technology and Internet of Things technology, including various smart household appliances and low-power sensors. Low-power sensors can monitor the home environment and share data with household appliances, and users can remotely control household appliances through smartphones and other devices. With the popularity of consumer electronic devices, smart home has become an indispensable part of our life. Smart home data security and privacy leakage accidents occur frequently, how to protect data confidentiality and unforgeability for low-power smart home consumer electronics is a key problem. To solve this problem, scholars have proposed many cryptographic schemes. However, the existing schemes have low computational efficiency, high communication overhead, and poor adaptation to application scenarios. Therefore, to realize secure lightweight data sharing in smart home systems, we propose an efficient certificateless online/offline signcryption (CLOOSC) scheme without bilinear pairing. The performance analysis demonstrates that our scheme has an order of magnitude advantage in computation and communication overhead compared with bilinear pairing-based CLOOSC. Compared with the latest pairing-free CLOOSC scheme, our proposed approach significantly reduces the computational cost by one-third during the offline signcryption phase while maintaining the same communication overhead. The proposed cryptographic algorithm has made a substantial contribution to the data security sharing in smart homes.

Vehicular ad hoc networks (VANETs) connect all vehicles through wireless channels. They provide extensive real-time traffic information services that improve driving safety and traffic management efficiency. However, VANETs are vulnerable to security attacks because of the open wireless nature of their communication channels. Most security mechanisms for traditional VANETs are centralized and have certain limitations in satisfying security requirements, such as anti-single-point failure, distributed security authentication of messages, and privacy preservation in VANETs. To address these issues, herein, we propose a dual blockchain-assisted conditional privacy-preserving authentication framework and protocol for VANETs. The identity authentication and privacy preservation of vehicles in VANETs can be realized without relying on a centralized trusted third party. The proposed scheme also allows for the conditional tracking of illegal vehicles. The decentralized dynamic revocation of illegal vehicles can be realized through smart contracts, rendering the scheme efficient and scalable. We implement this scheme in an Ethereum test network to demonstrate its feasibility and conduct an in-depth security analysis and comprehensive performance evaluation of the proposed scheme. The results demonstrate that the proposed scheme is an effective solution for the development of a decentralized authentication system for VANETs.

There is a growing concern about the complete lifecycle security of data in Internet of Things (IoT). This may cause privacy and trust problems for users regarding data sources, data storage, and access control for data sharing. Blockchain is a valuable solution to the above problems through distributed ledger technology, and it has been widely applied in various fields such as public services, finance, and IoT. However, the data in IoT are characterized by a large quantity, large capacity, and timely response, and existing blockchain systems only partially resolve them for data security and performance. We propose DSChain for IoT data security to address the challenges mentioned above. Our system uses a certificateless signature to ensure a trusted data source and public auditing to ensure the integrity of stored data while using ciphertext-policy attribute-based encryption to control access to shared data. Moreover, we propose a packaging mechanism based on the Merkle Hash Tree that effectively improves system performance. We implement the DSChain and provide a detailed analysis of performance and security. The experimental results indicate that DSChain can achieve approximately 1035 transactions per second on a single peer and is scalable.

In vehicular networks, caching content on an edge server (ES) is a popular method for quickly responding to massive vehicle service requests, reducing communication delays, and enhancing driver and passenger service experiences. However, after integrating ESs with vehicular networks to provide vehicles access to the cached content in these ESs, significant challenges regarding protecting the privacy of vehicle data and communication security arise. In this study, to address security and privacy-preserving issues, we propose a secure and revocable cache-based distributed data sharing scheme for vehicular networks wherein a token authentication mechanism and multi-authority ciphertext-policy attribute-based encryption are integrated. In this scheme, both authentication and authorization capabilities are delegated to an ES while restricting access to service content to only legal vehicles, achieving proper access control between vehicles and ESs, and effectively preserving the privacy of vehicle data. Moreover, we attributed the revocations of ESs to the associated attribute authorities, eliminating the need for a system-wide update of keying materials. Through rigorous security proofs and detailed security analyses, we demonstrate that the scheme meets the security requirements of vehicular networks and can resist more security attacks. The proposed scheme achieves better balance between computational and communication costs than related schemes.

Vehicular ad-hoc networks (VANETs) have drawn a lot of attention for their potential to improve traffic efficiency and safety. To deal with anonymous authentication and message integrity during communication, many protocols have been designed. One important approach is using Ring Signature to obtain superior security and better efficiency. However, most of the previous Ring Signature-Based authentication protocols could not support the Trusted Authority (TA) to revoke the vehicle user's identity whenever it wanted. In this article, we solve this problem and realize Conditional Privacy-Preservation Authentication successfully. As part of our work, we propose the first Lattice-based Revocable Ring Signature scheme, and prove its security under the random oracle model, which could be of independent interest. It is quantum-resistant, highly efficient, and suitable for scenarios where the TA needs to be accountable. Lastly, it is worth mentioning that we adopted a similar structure with the NIST signature standard CRYSTALS-Dilithium, which will increase the richness of the algorithm and standardization.