Abstract: Aiming at the security hole of RFID system and tag’s cost,we proposed a crossover based ultra-lightweight RFID authentication protocol(CURAP),and proved the correctness and security of this protocol with BAN logic formal analysis method．CURAP defines crossover operation involving bitwise XOR and left rotation．And data updating operation only is occurred in the reader,then the tag makes simple bitwise XOR extraction from transmission message．Security analysis and performance evaluation show that CURAP not only provides strong mutual authentication,resists various attacks,but also can lessen the computation requirement and storage space on tags,fit for low-cost RFID system.

Key words: RFID,Authentication protocol,BAN logic,Ultra-lightweight,Crossover