N-Mobishare: new privacy-preserving location-sharing system for mobile online social networks

Compared with traditional online social networks (OSNs), mobile OSNs (mOSNs) take a step further in that they provide the location-based services, and location-sharing is a fundamental component of mOSN. However, without privacy protection, users may be hesitant to share their locations. In this paper, we present a new privacy-preserving location-sharing system for mOSN, which is flexible to support a variety of location-based applications, in that it enables location-sharing between both trusted social relations and untrusted strangers. It allows user to dynamically change his sharing decryption key when to add or revoke a friend. We further propose a security improved system, which can be secure against neighborhood attacks. In our proposed systems, threat models are further analysed and users’ location privacy is proved secure. Implementation and evaluation show that they are efficient and practical.