Hybrid Chaotic Confusion and Diffusion for Physical Layer Security in OFDM-PON

Abstract

Physical layer security is of key interest for secure passive optical networks (PONs). We propose a hybrid chaotic confusion and diffusion (HCCD)-based encryption method for physical layer security enhancement in optical orthogonal frequency division multiplexed PONs (OFDM-PONs). Here, the real (I) and imaginary (Q) parts of OFDM symbols are separately scrambled by using different permutations before performing inverse fast Fourier transform. This scheme can realize that the transmitted quadrature amplitude modulation (QAM) symbols and the symbol-to-subcarrier mapping are simultaneously changed and disrupted. The scrambling permutations are generated by an improved logistic map, whose iteration parameters are set as the security keys. 11.3-Gb/s 16 QAM and 14.1-Gb/s 32 QAM IQ scrambled OFDM signals have been successfully transmitted over 25-km standard single mode fiber in an experimental demonstration. The scrambling performance and the security of the proposed encryption scheme are further analyzed. The obtained experimental and numerical results show that the proposed HCCD-based encryption scheme has excellent resistance to illegal optical network units.