A Blockchain-Based Privacy-Preserving Mechanism for Attribute Matching in Social Networks.

Online social network has become an indispensable part of people's life, and people are willing to make friends in social network. However, semi-honest social network platforms may reveal users' private information, which will cause great losses to users. Existing schemes either are based on Secure Multi-party Computation (SMC), which have a lot of resource consumption, or are based on vector dot product calculation, which are vulnerable to statistical attacks. In this paper, we propose an attribute matching scheme based on hierarchical blockchain and Ciphertext Policy Attribute-based Encryption (CP-ABE), which can realize attribute matching in semi-honest servers and offer fine-grained attributes selection for users to get more precise matching. Additionally, a novel blockchain architecture is proposed in our scheme, which reduces the storage consumption and improve running efficiency. Finally, we present the security analysis that the scheme can resist a variety of attacks, and the experiment results demonstrate the feasibility of the scheme.