Analysis of RFID Mutual Authentication Protocols

In order to secure RFID transactions, an authentication scheme has originally been included as part of the "EPC Gen2" industrial standard. This scheme, however, has been found to have some weaknesses. To overcome such weaknesses, some authors have proposed new schemes to improve its security. Two of the latest proposals are the Lim-Li protocol and the Konidala-Kim-Kim protocol presented in 2007. We propose an attack that can be applied to both these protocols. In both cases, the search space for the password(s) used have been drastically reduced, which effectively breaks the security of these protocols.