A Lightweight RFID Authentication Protocol using Step by step Symmetric Key Change

The RFID system has the risk of location tracking and user privacy. Even the cryptograph access method using hash function and re-encryption is difficult to it applies because there is a limit of computing and storage capacity of Tag. In this paper, the AES is used for the lightweight authentication, and the step by step procedure could change the key value three times. This could prevent the key exposure. The symmetric keys of the tag and server are successively changed by the random number generated by tag, reader and server. As a result, the output of the tag and reader always changes. These key changes could make it possible to prevent eavesdropping, replay attack, location tracking.