Radio Frequency identification (RFID) raises privacy concerns such as malicious traceability and clandestine information collection. In this paper, we consider the need for scalable privacy protecting scheme as RFID technology will grow more prevalent. Our contribution is twofold: First we propose a lightweight privacy protecting scheme that aims at reducing the calculation burden on the back-end database. Our protocol achieves more scalable tag identification by taking advantage of the characteristics of some current RFID applications; Second, we evaluate the performance of our protocol in terms of computational load for the database and we examine how this performance varies according to applications. Moreover we analyze our protocol against various attacks and demonstrate the security of our proposed scheme.