LAUSR

Passive radio-frequency identification (RFID) communication raises new transmission secrecy protection challenges, since passive tags stored information lack effective information protection mechanisms. Due to constraints of passive tags, such as limited computation and storage capabilities, security solutions based on the physical-layer security (PLS) are promising candidates compared to those based on conventional lightweight cryptography. Unlike existing endeavors on PLS of RFID wireless communication, we consider an RFID system in the presence of a special proactive eavesdropper, which is able to both enhance the information wiretap and interfere with the information detection at the RFID reader simultaneously by broadcasting its own continuous-wave (CW) signal. To defend against proactive eavesdropping attacks, we propose a wiretap-channel-conscious artificial-noise (AN)-aided secure transmission scheme for the RFID reader, which first estimates both legitimate and wiretap channels and then superimposes an AN signal on the CW signal to confuse the proactive eavesdropper. The transmit power and power allocation between the AN signal and the CW signal are optimized to maximize the secrecy rate. Furthermore, we model the attack and defense process between the proactive eavesdropper and the RFID reader as a hierarchical security game and prove it can achieve the equilibrium. The simulation results show the superiority of our proposed scheme in terms of the secrecy rate and the interactions between the RFID reader and the proactive eavesdropper.