Enhancing location privacy in Mobile IPv6 by using redundant home agents

Mobile IP allows mobile nodes (MN) to keep reachability from correspondent nodes (CN) while moving around in the Internet. Every MN has a fixed home address (HoA) maintained by the node called home agent (HA.) The HA acts as a proxy of the MN, and forwards all packets sent to the HoA. In order to continue communication, the MN tells its location to the HA by sending binding updates (BU) every time it moves. Since the source and destination addresses of BUs are clear to nodes between the MN and the HA, the movements of the MN may be traced by the third person who links BUs with their destination addresses. In this paper, we propose an extension to Mobile IPv6 to protect location privacy. By employing multiple HAs, MNs can permutate destination addresses of BUs and make it hard to link BUs. We have implemented a prototype system by extending the UMIP (USAGI-patched Mobile IPv6 for Linux), and conducted some experiments. The results show that only communication delays for traversing the additional path are observed.