For passive type RFID tags, EPCglobal Class 1 Generation-2 Revision is used widely as a de facto standard. As it was designed for low cost, it is quite vulnerable to security issues, such as privacy concerns. This paper1 presents a new RFID mutual authentication protocol, which is designed to be configured on EPC Gen2 platform and to meet various security requirements while providing efficiency using PRNG (Pseudo Random Number Generator). Group-ID is used to minimize the authentication time. Security analysis of the proposed protocol is discussed.