Date Added: Mar 2013
Many sensor network security schemes protect the content of messages, while the contextual information is left vulnerable by disclosing the location of the monitored objects. Preserving location privacy is important and one of the most challenging issues in many mission critical sensor network applications. Prior solutions are mostly designed to protect privacy from local attackers who eavesdrop on traffic in a small region at a time. However, they can be easily defeated by highly motivated global attackers that can trace the entire network's communication events. Although a few recent privacy solutions are proposed against global attackers, they suffer from significant communication overhead as they inject dummy traffic or send messages in a globally synchronized manner.