Flexible Privacy Protection for RFID Tags via Selective Identifier Masking

In this paper, we propose a selective identifier masking scheme to prevent eavesdropping or unauthorized reading of the unique identifier of RFID tags. In our system, we differentiate between tags that require privacy protection (private tags) and tags that do not require protection (public tags). Under an environment whereby private and public tags co-exist, the proposed scheme uses an active RFID device to selectively transmit a secret mask when a tag identifier is reported to a reader. This induces bit collisions between the tag identifier and the mask. An eavesdropper or an unauthorized interrogator would not be able to resolve the collided bits without knowledge of the secret mask. Hence, the tag identifier is protected against disclosure. Simulations were conducted to investigate the overhead incurred under the scheme. In addition, theoretical analyses were carried out to examine the ´same-bit´ problem and its effects on the scheme. In general, we find that our proposed scheme is simple, practical and secure under a realistic threat model as compared to other similar approaches.