Distance Bounding Protocol for Multiple RFID Tag Authentication

Relay attacks occur when an adversary simply relays signals between honest reader and tag without modifying it in any way. Since the signal content is not modified by the adversary, none of the extant cryptographic protocols are immune to such attacks. There have been several proposed protocols that purport to alleviate this problem for a single tag. We propose a protocol that considers relay attacks when multiple tags are authenticated for their simultaneous presence in the field of the reader.