The Security Network Coding System With Physical Layer Key Generation in Two-Way Relay Networks

Network coding is one of the key technologies to improve the throughput, efficiency, and reliability of two-way relay networks (TWRNs). However, it also brings some new security problems when the physical layer security is considered. In this paper, we present security network coding schemes with key generation from multipath channels to enhance the security performance for TWRN. First, a joint key generation (JKG) approach is proposed, which generates secret keys based on channel impulse responses of multipath channels. Different from the traditional approaches, key exchange is not necessary for the JKG approach such that the eavesdroppers cannot obtain any information about secret keys. Then, an adaptive quantization algorithm is proposed to adaptively choose different parameters for quantization in key generation, which can improve the secret key rate with an acceptable secret key disagreement probability and can still work even if the SNR is low. Finally, security network coding systems are constructed to combine the key generation approaches with the proposed algorithm. Simulation results show that the proposed schemes are valid and secure against wiretap attacks.