Radio Frequency Identification (RFID) is an advanced object identification technology that has already been applied in various industries. However, the insecure nature of the communication channel between readers and tags makes RFID systems vulnerable to various kinds of attacks. In recent years, many new methods have been proposed to improve the security of RFID systems, such as disabling tags, agent management and establishing cryptographic protocols. Among them, we focus on the last approach, which is more economic and convenient in certain cases. The first part of our work is to categorize typical existing RFID protocols according to their security levels. The result is vitally important to RFID system administrators who need to find different protocols to be implemented in their systems. The trade-off to be made in decision is that higher security level typically implies worse performance. We examine the performance in two aspects: the look-up cost in RFID reader’s back-end database and the tag-related cost. The tag-related cost includes the cryptographic operation cost (cryptographic computation cost along with access operatio
