{MobiShare}+: Security Improved System for Location Sharing in Mobile Online Social Networks

With the development of real time localization and mobile computing technology, it becomes increasingly popular for sharing individual locations in mobile online social network (mOSN), which inevitably raises significant concerns on the privacy of users’ locations. Recently, Wei et al. provided the MobiShare mechanism to enable flexible location sharing between both trusted social relations and untrusted strangers. Motivated by Wei et al.’s pioneer work, we make a further treatment on privacy-preserving location sharing in mOSN in this paper. We observe that users’ real fake identities will be potentially leaked to location service provider in Wei et al.’s work, which may lead to a variety of serious attacks. In order to fix this security issue, we propose a security improved mechanism namely MobiShare+, which employs dummy queries and private set intersection protocol to prevent the OSN service provider and location service provider from learning individual information from each other. Finally, security analysis is provided to clarify that MobiShare+ is secure in terms of location privacy and social network privacy.