Enhanced Privacy Preserving Group Nearest Neighbor Search

Group k-nearest neighbor (kGNN) search allows a group of n mobile users to jointly retrieve k points from a location-based service provider (LSP) that minimizes the aggregate distance to them. We identify four protection objectives in the privacy preserving kGNN search: (i) every user's location should be protected from LSP; (ii) the group's query and the query answer should be protected from LSP; (iii) LSP's private database information should...