Date Added: May 2010
In this paper, the authors classify the RFID distance bounding protocols having bitwise fast phases and no final signature. They also give the theoretical security bounds for two specific classes, leaving the security bounds for the general case as an open problem. As for the classification, they introduce the notion of k-Previous Challenge Dependent (k-PCD) protocols where each response bit depends on the current and k-previous challenges and there is no final signature. They treat the case k = 0, which means each response bit depends only on the current challenge, as a special case and define such protocols as Current Challenge Dependent (CCD) protocols.