Secure Tag Search in RFID Systems Using Mobile Readers

One of the important features of an RFID system is its ability to search for a particular tag among a group of tags. In order to ensure privacy and security of the tags, the search has to be conducted in a secure fashion. To our knowledge not much work has been done in this secure search area of RFID. The minimal work that has been done do not comply with the EPC C1G2 (Class-1 Gen-2) standard since most of them use expensive hash operations or sophisticated encryption schemes that cannot be implemented in the low-cost passive tags that are highly resource constrained. Our work aims to fill this gap by proposing a protocol that is based on simple XOR encryption and 128 bit pseudo random number generators (PRNG), operations that can be easily implemented on low-cost passive tags. Thus, our protocol enables large scale implementations and achieves EPC C1G2 compliance while meeting the security requirements. The protocol provides additional protection by hiding the pseudo-random number during all transmissions using a blind-factor.