REAL: A Reciprocal Protocol for Location Privacy in Wireless Sensor Networks
K-anonymity has been used to protect location privacy for location monitoring services in wireless sensor networks (WSNs), where sensor nodes work together to report k-anonymized aggregate locations to a server. Each k-anonymized aggregate location is a cloaked area that contains at least k persons. However, an attack model is identified to show that overlapping aggregate locations still pose privacy risks because an adversary can infer some overlapping areas with less than k persons that violates the k-anonymity privacy requirement. A reciprocal protocol for location privacy (REAL) is proposed in WSNs. In REAL, sensor nodes are required to autonomously organize their sensing areas into a set of non-overlapping and highly accurate k-anonymized aggregate locations. To confront the three key challenges in REAL, namely, self-organization, reciprocity property and high accuracy, a state transition process is designed, a locking mechanism and a time delay mechanism, respectively. The results show that REAL protects location privacy, provides more accurate query answers, and reduces communication and computational costs.