RFID (radio frequency identification) is a small electronic device that consists of small chip and an antenna. The biggest challenge for RFID technology is to provide benefits without degrading the secutiry level. This paper proposes a new RFID authentication protocol based on the lightweight stream cipher Enhanced-Bivium. In terms of security we show that the protocol is robust under the attack of spoofing and replay, tracking and desynchronization. As the protocol uses Enhanced-Bivium as both one-way function and random number generator and Enhanced-Bivium only need to be computed once by tags in each session, therefore the strategy is very eligible for low-cost RFID system compared with previous works.