Bob-Tree: An efficient B +-tree based index structure for geographic-aware obfuscation

Abstract

The privacy protection of personal location information increasingly gains special attention in the field of location-based services, and obfuscation is the most popular technique aiming at protecting this sensitive information. However, all of the conventional obfuscation techniques are geometry-based and separated from the database level. Thus, the query processing has two time-consuming phases due to the number of disk accesses required to retrieve the user's exact location, and the location obfuscation. Also, since these techniques are geometry-based, they cannot assure location privacy when the adversary has knowledge about the geography of the obfuscated region. We address these problems by proposing Bob-tree, an index structure that is based on Bdual-tree and contains geographic-aware information on its nodes. Experiments show that Bob-tree provides a significant improvement over the algorithm separated from the database level for query processing time and location privacy protection. © 2011 Springer Berlin Heidelberg.