At this stage, the application of Private Set Intersection (PSI) protocols is essential for smart homes. Oblivious Key-Value Stores (OKVS) can be used to design efficient PSI protocols. Constructing OKVS with a cuckoo hashing graph is a common approach. It increases the number of hash functions while reducing the possibility of collisions into rings. However, the existing OKVS construction scheme requires a high time overhead, and such an OKVS applied to PSI protocols would also have a high communication overhead. In this paper, we propose a method called 3-Hash Garbled Cuckoo Graph (3H-GCG) for constructing cuckoo hash graphs. Specifically, this method handles hash collisions between different keys more efficiently than existing methods, and it can also be used to construct an OKVS structure with less storage space. Based on the 3H-GCG, we design a PSI protocol using the Vector Oblivious Linear Evaluation (VOLE) and OKVS paradigm, which achieves semi-honest security and malicious security. Extensive experiments demonstrate the effectiveness of our method. When the set size is $2^{18}$–$2^{20}$, our PSI protocol is less computationally intensive than other existing protocols. The experiments also show an increase in the ratio of raw to constructed data of about 7.5%. With the semi-honest security setting, our protocol achieves the fastest runtime with the set size of $2^{18}$. With malicious security settings, our protocol has about 10% improvement in communication compared with other existing protocols.

Although the copyright protection schemes supported by blockchain have significantly changed traditional copyright data management, there are still some data security challenges that cannot be ignored, especially the secure access and controllable management of copyright data. Quantum computing attacks also pose a threat to its security. Targeting these issues, we design and propose a blockchain copyright protection scheme based on attribute-based encryption (ABE). In this scheme, the security advantages of blockchain technology are utilized to ensure the authenticity and integrity of copyright data. Based on lattice cryptography and the decision ring learning with errors (R-LWE) problem, a new ABE algorithm that supports searchable ciphertext and policy updates is designed. Then, we introduce it into the blockchain copyright protection scheme, which enables secure access to copyright data and fine-grained control. In addition, the lattice cryptography can strengthen this scheme against quantum attacks. Through security analysis, our scheme can prove to be secure against adaptive chosen keyword attacks, selective chosen plaintext attacks, and adaptive chosen policy attacks in the random oracle model. More importantly, the comparison analysis and experimental results show that our proposed approach has lower computation costs and storage costs. Therefore, our scheme has better security and performance in copyright protection.

The blockchain-enabled industrial Internet of Things (IIoT) faces security threats such as quantum computing attacks and privacy disclosure. Targeting these issues, in this study, we design a new lattice-based linkable ring signature (LRS) scheme, which is used to achieve privacy protection for the blockchain-enabled IIoT. Firstly, by using the trapdoor generation algorithm on the lattice and the rejection sampling lemma, we propose a new lattice-based LRS scheme with anti-quantum security and anonymity. Then, we introduce it into blockchain. Through the stealth address and key image technologies, we construct a privacy protection scheme for blockchain in the IIoT, and this LRS scheme protects identity privacy for users through anonymous blockchain. In addition, it also can resist the double spending attack with the linking user’s signature. Lastly, we provide a security analysis, and it is proven that our ring signature scheme satisfies correctness, anonymity, unforgeability and linkability. Compared with other similar schemes, the performance simulation indicates that our scheme’s public key and signature are shorter in size, and its computation overhead and time cost are lower. Consequently, our novel LRS scheme is more secure and practical, which provides privacy protection and anti-quantum security for the blockchain-enabled IIoT.

User profile matching can establish social relationships between different users in the social network. If the user profile is matched in plaintext, the user's privacy might face a security challenge. Although there exist some schemes realizing privacy-preserving user profile matching, the resource-limited users or social service providers in these schemes need to take higher computational complexity to ensure the privacy or matching of the data. To overcome the problems, a novel privacy-preserving user profile matching protocol in social networks is proposed by using t-out-of n servers and the bloom filter technique, in which the computational complexity of a user is reduced by applying the Chinese Remainder Theorem, the matching users can be found with the help of any t matching servers, and the privacy of the user profile is not compromised. Furthermore, if at most t 1 servers are allowed to collude, our scheme can still fulfill user profile privacy and user query privacy. Finally, the performance of the proposed scheme is compared with the other two schemes, and the results show that our scheme is superior to them.