Tag Group Authentication Using Bit-Collisions

Secure RFID systems should be able to authenticate individual tags to prevent genuine items from being replaced with forgeries. Conventional authentication protocols would require some form of challenge-response exchange with each individual tag. The extra transaction time needed to authenticate each individual tag sequentially might not be practically feasible, especially when readers are required to process an ever increasing volume of tagged items within a limited time. Our proposal works towards an approach that allows for multiple tags in a group to be authenticated simultaneously, as all the tags transmit their responses to a single challenge at the same time. This results in a controlled bit-collision pattern that can be used to verify that all the individual tags in a group are present and genuine.