Enhancing RFID Privacy via Antenna Energy Analysis

For RFID tags to gain general acceptance, they will have to offer powerful and flexible privacy mechanisms. We propose that a key aspect of RFID communication with passive tags, namely its required energy transference from an external antenna, may offer previously unexamined promise when developing privacy mechanisms. We present two proposals for such mechanisms. In the first mechanism, analysis of the received signal by the tags can be used to estimate reader distance (and hence trust). In the second, antenna energy is used to power a tiered authentication scheme, in which tags reveal more information about themselves to more trusted and/or “energetic” readers.