Radio Frequency Identification (RFID) is considered to be a promising identification approach in ubiquitous sensing technology. The operation of RFID systems in complicated applications often involves a situation in which numerous tags are present in the interrogation zone of a single reader interfering with each other simultaneously. In this paper, using complementary two-model estimation method, we propose a novel collision avoidance identification method based on the framed Aloha scheme. The underlying mathematical theories and two parameters estimation models have also been well discussed. Furthermore, the implementations of RFID systems in advanced applications may pose security and privacy risks to both organizations and individuals. Using randomly Key-Changed Identification, we propose an eavesdropping-proof security protocol based on cryptographic one way hash functions for passive RFID tags in this paper. Compared with several existing methods, our proposed protocol shows some security improvements as well as gives a reasonable and compatible approach that could be easily employed in practical situations. Finally, simulation results and illustration are given to verify the proposed anti-collision identification method as well as show clearly the whole operating procedure of the security protocol.
