Abstract:

In order to improve the confidentiality of physical layer of wireless communications,a dynamic double-layer generalized multi-parameter weighted fractional Fourier transform (DDL-GMPWFRFT) secure communication method based on two-dimensional Hénon-cosine-exponent (2D-HCE) chaotic encryption is proposed.A 2D-HCE hyper-chaotic map is constructed by introducing the cosine and power-exponent nonlinear terms to Hénon map,which is verified by using Lyapunov exponential and system bifurcation diagram.64 kinds of double-layer GMPWFRFTs (DL-GMPWFRFTs) are designed and constructed based on GMPWFRFT and double-layer WFRFT structure.2D-HCE chaotic sequence is used to implement the amplitude-phase encryption of constellation,and DL-GMPWFRFT transformation type is randomly selected for the dynamic transformation encryption of constellation to further conceal the modulated signal style and improve the system’s defense ability against parameter detection.Simulated results show that the constellation map encrypted by the proposed method presents a Gaussian distribution,and the keyspace is up to 2²¹⁸.The key sensitivity is much higher,and the bit error rate of eavesdropper is still in the range from 0.4 to 0.5 even if there is an error of 10^-15 between the key from an eavesdropper and the correct key.

Key words: physical layer security, chaotic encryption, dynamic function encryption, double-layer generalized multi-parameter weighted fractional Fourier transform