RFIDs and secret handshakes

Abstract

We tackle the problem of defending against ghost-and-leech (a.k.a. proxying, relay, or man-in-the-middle) attacks against RFID tags and other contactless cards. The approach we take -- which we dub secret handshakes -- is to incorporate gesture recognition techniques directly on the RFID tags or contactless cards. These cards will only engage in wireless communications when they internally detect these secret handshakes. We demonstrate the effectiveness of this approach by implementing our secret handshake recognition system on a passive WISP RFID tag with a built-in accelerometer. Our secret handshakes approach is backward compatible with existing deployments of RFID tag and contactless card readers.