A concentric CRR sensor is claimed that is used as a form of currency verification in order to combat counterfeiting currency. The system comprises applying sets of concentric CRR printed with transparent conductive ink. In one embodiment, using the CRR as a passive RFID tag, changing the ring's radii, inner or outer, and in turn, created more encryption, and thereby prevents currency counterfeiting. In one or more embodiments, the serial number of the currency bill is used as a guideline to a selection algorithm to determine the size of the radii.