Privacy-Preserving RFID-Based Search System

The employment of mobile readers (or mobile phone collaborated with a Radio frequency identification (RFID) reader) opens a novel application for RFID technology. In particular, an RFID tag search system has been designed to find a particular tag in a group of tags using a mobile reader. Unfortunately, privacy infringement and availability issues in the search system have not been adequately addressed to date. In this paper, we propose a novel RFID tag search protocol that will enhance mobile reader user privacy while being able to operate under conditions of unstable connection to a central server. First, the proposed protocol preserves the privacy of mobile reader users. The privacy of the mobile reader user is at risk because the signal strength emitted from a mobile reader is much stronger than that from the tag, exposing the location of the mobile reader user and thus compromising the user's privacy. Thus far, such privacy issues have been overlooked. The second issue is presented because of wireless connections that are either unreliable or too remote, causing a mobile reader to disconnect from the central server. The proposed protocol enables serverless RFID tag searches with passive tags, which obtain operating power from the mobile reader. In unstable environments, the protocol can successfully locate specific tags without any server.