Fine-Grained Secure Friend Discovery Scheme in Mobile Social Networks

In mobile social networks, users can look for friends by matching their attributes. In order to solve the problem that the user's attribute is easy to be stolen by the attackers in the single authority center and performance bottleneck occurs in the peak of service, this work proposes a scheme where a multi-attribute management center hierarchically manages user attributes' sub-keys. The scheme involves several attribute centers which perform fine-grained management on different user attributes. After the friend requester's attributes meet the friend access control policy of the friend-making initiator, the friend requester can correctly combine the sub-keys into a complete decryption key and decrypt the user's data file to store in the friend-making server. By introducing hierarchical management in terms of attribute sub-keys, the proposed scheme not only effectively prevents key disclosure when the single-authority management center suffers from attacks, but also improves the computation efficiency of friend profile matching through cooperative work of multiple attribute center. Experiments are conducted to check whether the proposed scheme can challenge the chosen plaintext attack, and certify that the scheme can achieve CPA secure level while effectively protecting the user's privacy security. Extensive comparisons with existing schemes demonstrate the ability of the proposed scheme to entail the lowest computational overheads and provide excellent user experience. © Copyright 2018, Institute of Software, the Chinese Academy of Sciences. All rights reserved.