Replacing cryptography with ultra wideband (UWB) modulation in secure RFID

Existing secure RFID tags rely on digital cryptographic primitives in the form of hashes and block ciphers, which lead to large system latencies, high tag powerconsumption and large tag silicon area. In addition, existing passive RFID systems rely on simple coding and modulation schemes using narrowband radio frequencies, which can easily be eavesdropped or jammed. To address the above problems, we propose a new approach for secure passive RFDs based on ultra wideband (UWB) communications. We adopt time-hopped pulse-position modulation (TH-PPM), in which the hopping sequence is known only to the reader and the tag. By adopting the hopping sequence as a secret parameter for the UWB communication link, eavesdropping of the communication is extremely difficult. Thus, we can avoid digital cryptography and support privacy directly at the physical-communication layer.