Bourdain writes with news out of the University of Arkansas, where researchers are looking for ways to combat counterfeit RFID tags
. Passive tags typically wait for a reader to transmit a signal of the appropriate strength and frequency before sending their own transmission. The scientists found that the amount of power required to trigger this varies quite a bit from one tag to the next, especially when many different frequencies are sampled. This and other physical characteristics give the tag its own "fingerprint" that is independent of the signal information stored in its memory, which the researchers say will facilitate the detection of cloned tags.