Chaotic Multilevel Separated Encryption for Security Enhancement of OFDM-PON

Hanhan Wei,Kun Qiu,Tingwei Wu,Huan Huang,Chongfu Zhang

doi:10.1109/access.2019.2938910

Abstract

A chaotic multilevel separated encryption (CMSE) scheme is proposed for physical layer security enhancement of orthogonal frequency division multiplexing passive optical network (OFDM-PON). In the proposed scheme, symbols in an OFDM signal are divided into several sub-matrices by matrix mapping and then encrypted by different algorithms selected from a set of alternative encryption algorithms based on 1D logistic chaotic systems separately. The signal processed by this scheme is encrypted at four levels. The four encryption levels depend on a matrix mapping rule, the specific algorithms, the order of used encryption algorithms and the key of each chaotic system. Any one of these conditions is essential for proper decryption. Compared with traditional methods, this scheme adds two new encryption levels and replaces the unique employed algorithm with multiple algorithms, which improves the security of system at the expense of a slightly increased complexity. An encrypted signal transmission of 22.06 Gb/s bit rate is successfully demonstrated over a back-to-back (BTB) system and a 25-km standard single mode fiber (SSMF). The experimental results prove that the CMSE scheme does not deteriorate the system performance and has good security against illegal attacks for future access networks.

Highlights

Orthogonal frequency division multiplexing passive optical network (OFDM-PON) is considered as a hopeful solution to provide large broadband and low-cost services for generation multi-user access networks, which is mainly due to its advantages like flexible resource allocation, high spectrum efficiency, strong robustness against fiber dispersion and so on [1], [2]
We propose a chaotic multilevel separated encryption (CMSE) scheme aiming at the physical layer security enhancement of OFDM-PON
In order to improve the physical layer security of OFDM-PON, we have proposed and experimentally verified a chaotic multilevel separated encryption scheme

Summary

INTRODUCTION

Orthogonal frequency division multiplexing passive optical network (OFDM-PON) is considered as a hopeful solution to provide large broadband and low-cost services for generation multi-user access networks, which is mainly due to its advantages like flexible resource allocation, high spectrum efficiency, strong robustness against fiber dispersion and so on [1], [2]. The encrypted sub-matrices are rearranged to a new matrix and sent as a transmitted signal after subsequent processing To decrypt this signal accurately, the matrix mapping rule, the specific encryption algorithms, the applied order of encryption algorithms and the secure keys of chaotic systems should be obtained, which means that the signal is encrypted at four encryption levels. Static key distribution technique is adopted to pre-share the secure keys between the OLT and ONUs. After the matrix mapping and separated encryption, all sub-matrices are rearranged to a new matrix M based on the inverse mapping rule R− and converted from frequency domain to time domain by the inverse fast Fourier transform (IFFT). To recover the encrypted signal correctly, the mapping rule R, m kinds of encryption algorithms selected from ψ, their applied order and the secure keys are needed, which indicates that the data are encrypted at four levels. We add two encryption levels in the proposed CMSE scheme, which improves the randomness of data and provides better security for OFDM-PON

ENCRYPTION EXAMPLE

RESULTS AND DISCUSSIONS

CONCLUSION