Mobile common friends discovery with friendship ownership and replay-attack resistance

Online social networking applications are nearly ubiquitous, but are currently limited to trusted infrastructure. For example, two unfamiliar users can exploit their social proximity to discover common friends, but otherwise face considerable difficulty in discovering of things they may have in common. However, social proximity depends on access personal data, raising concerns regarding potential data leakage from databases, the degree of trust in the particular social proximity, and user unwillingness to disclose the nature of personal friendships. Previous works have used mobile middleware to provide alternatives to hosting personal data in a fixed database, but these approaches still require users to divulge private information. Other approaches have used private-preserved decentralized online social networks to solve centralization and privacy issues, but these methods are still subject to other security problems such as mutual authentication, data-spoofing and replay attacks. This paper proposes the development of secure mobile common friends discovery methods to preserve the privacy of friendship data, establish mutual authentication between contact users, provide mutual proof of friendship, and provide protection against friendship spoofing and replay attacks. The proposed methods are shown to be secure and efficient, and are implemented in mobile phones that allow users to find common friends securely in seconds.