Digital Chaos-based Matrix Precoding Encryption In Optical Orthogonal Frequency Division Multiple Transmission

Nowadays,orthogonal frequency-division multiplexing?OFDM?is widely introduced in modern optical communication networks,while the optical network security is becoming increasingly challenging.Digital chaos has advantages of initial sensitivity and random-like property,so it can be easily blended with cryptography and OFDM.Matrix precoding encryption based on digital chaos in Optical OFDM transmission is proposed in this paper,at the same time,experimental verification and theoretical research are done to demonstrate the superiority of the performance and the feasibility of the practice.The whole research can be divided into three parts as follows:?1?Chaotic discrete Fourier transform?DFT?matrix precoding encryption:In OFDM transmission system,the DFT matrix preprocess is added before IFFT.Chaotic sequence is implanted in the traditional DFT matrix so that the dynamic DFT matrix is able to encrypt the signal while maintains the original properties.This encryption scheme has the advantages of large key space,reducing PAPR to improve the transmission performance,no need of side band information and lower computational complexity.?2?Chaotic discrete cosine transform?DCT?matrix precoding encryption:In the traditional OFDM system,Two DCT matrix based on digital chaos are introduced before IFFT to respectively preprocess the real and imaginary parts of the signals,at the same time the new DCT matrixes can still reduce the PAPR.The encryption algorithm has the advantages of strong security,good transmission performance and flexible implementation.?3?Plaintext chaos feedback encryption against chosen-plaintext attack:XOR operation between the previous ciphertext from plaintext and the dynamic parameters of chaotic system is implemented to get new dynamic chaos to insure the security.This encryption scheme can effectively resist the chosen/known plaintext attacks,for plaintext can influence of multiple ciphertext.Experimental results show that the encryption system has enhanced security and good transmission performance,in addition,the key space is increased to 10¹⁶ times.In a word,this encryption scheme is able to resist chosen-plaintext attacks and exhaustive attack more effectively.