STEP: Source traceability elimination for privacy against global attackers in sensor networks

Preserving privacy is one of the most challenging yet essential issues in many mission critical WSN applications. As most of the existing privacy solutions additionally inject fake traffic assuming limited local adversary models, they can be easily defeated by highly motivated global attackers that monitor the entire network communications. We propose a scheme against a global adversary model, named Source Traceability Elimination for Privacy (STEP) using heterogeneous links. The STEP uses wormhole pairs (WHPs) to hide the communication of an original source location and scatter it to a remote location. Unlike the existing privacy mechanisms, the STEP provides privacy without incurring any additional communication overhead. We quantify a source location privacy level, evaluate the STEP with various parameters, and discuss its effect when used with other privacy techniques simultaneously.