MobiShare: Flexible privacy-preserving location sharing in mobile online social networks

Location sharing is a fundamental component of mobile online social networks (mOSNs), which also raises significant privacy concerns. The mOSNs collect a large amount of location information over time, and the users´ location privacy is compromised if their location information is abused by adversaries controlling the mOSNs. In this paper, we present MobiShare, a system that provides flexible privacy-preserving location sharing in mOSNs. MobiShare is flexible to support a variety of location-based applications, in that it enables location sharing between both trusted social relations and untrusted strangers, and it supports range query and user-defined access control. In MobiShare, neither the social network server nor the location server has a complete knowledge of the users´ identities and locations. The users´ location privacy is protected even if either of the entities colludes with malicious users.