Date Added: Jan 2010
RFID tag is a small and inexpensive microchip, which is capable of transmitting unique identifier through wireless network in a short distance. If a group of RFID tags can be scanned simultaneously by one reader, RFID Group proof could be generated. Group proof can be used in various applications, such as good management, which is usually achieved using barcode system. A lot of RFID group proof schemes have been proposed by many researchers. In this paper, the authors introduce some existing group proof schemes and then analyze their vulnerabilities to the privacy. Moreover, they propose a new attack model which threatens the privacy of user by tracking tags in a group.