Enhancements to a Lightweight RFID Authentication Protocol

This study extends the vulnerability analysis of a RFID authentication protocol and offers solutions to security weaknesses through enhanced measures. Vajda and Buttyan (VB) proposed a set of five lightweight RFID authentication protocols. Defend, Fu, and Juels (DFJ) did cryptanalysis on two of them - XOR and SUBSET. DFJ proposed repeated keys and nibble attacks on the XOR protocol. In this paper, we identify the source of vulnerability within VB´s original successive session key permutation algorithm. We propose three enhancements - removing bad shuffles, hopping the runs, and authenticating mutually - to prevent DFJ´s attacks, thereby significantly strengthening the XOR protocol without introducing extra resource cost.