Research On Physical Hidden Authentication Technology Based On Overlapping Transmission

With the rapid development of communication technology,wireless communication plays an increasingly important role in people's lives.Due to the shared medium of wireless communication,the attacker can easily intercept the signals of legitimate users and attack the communication process for profit.Therefore,the security of wireless communication system is facing great challenges.In order to avoid the access and attack of illegal users,wireless communication systems usually need to verify the identity of access devices,which is called authentication process.Conventional authentication methods are implemented by exchanging encrypted user's identity information.The encrypted authentication signals are still under the threat of being intercepted and attacked.This paper studies a covert authentication technology based on overlapping transmission in physical layer.The core idea is that the transmitter superimposes a low-power tag signal on the conventional transmission signal,and then the receiver utilizes the tag signal characteristics to authenticate the identity.In this way,the normal access and communication process of legitimate users are guaranteed,which makes it difficult for the attackers to carry out malicious attacks through disguised their identities.Firstly,this paper introduces the typical physical layer overlapping transmission authentication scheme based on hash mapping in detail,which is put forward by Verma.Based on sending data blocks and user keys,this scheme generates tag signals through hash map,which makes the tag signals time-varying and difficult to crack.This scheme has poor authentication performance under low SNR conditions,mainly because the small difference of input data of hash map will lead to huge difference of output data.Aiming at the disadvantage of hash-based authentication scheme,this paper proposes to use compression matrix to reduce the length of the input data of hash map.By improving the fault-tolerant ability of input data of hash map to sending data,the authentication performance of the system under low SNR conditions can be improved.Subsequently,this paper proposes an overlapping transmission authentication scheme based on chaotic sequences.The chaos sequence has lots of advantages,such as long period,good correlation performance,etc.Therefore,using chaotic sequence to improve the generation process of tag signal can further improve the effectiveness of authentication system.Finally,from the perspective of concealment,a physical layer overlapping transmission authentication scheme with variable transmission rate of tag signal is proposed.Because the tag signal transmitted at fixed symbol rate has cyclostationary property,the attacker can always detect and intercept the tag signal through square spectrum and cyclic spectrum after a long period of observation and analysis,which threatens the security of the system.The variable rate transmission method proposed in this paper can greatly suppress the cyclic stationarity of tag signal by randomizing the symbol rate,thus improving the anti-interception ability of tag signal.The simulation results show that the proposed physical layer overlapping transmission authentication scheme with variable transmission rate of tag signal not only has good authentication performance,but also has good concealment performance.