Java toward privacy preserving and collusion resistance in a location proof updating system

APPLAUS is a system proposed to address the issue of malicious users cheating on their locations for location-sensitive services. It uses Bluetooth-enabled mobile devices that are near each other to mutually generate location proofs and send updates to a location proof server. The devices use periodically changed pseudonyms to protect the privacy of their real locations from each other and the untrusted server. The system also develops a user-centric model where individuals evaluate their own location privacy levels before accepting location proof requests. It presents approaches for outlier detection to defend against colluding attacks, including betweenness ranking and correlation clustering. Experimental results show APPLAUS can effectively provide location proofs while significantly preserving source location privacy and detecting colluding attacks.