Chaotic Nonlinear Encryption Scheme for CPAs Resistance and PAPR Reduction in OFDM-PON

In this letter, a chaos-based nonlinear encryption scheme is presented to enhance the physical layer security and reduce the peak-to-average power ratio (PAPR) in an orthogonal frequency division multiplexing passive optical network (OFDM-PON). A four-dimensional (4D) hyper chaotic system is utilized to generate the chaotic binary sequences and construct the nonlinear substitution boxes (S-boxes). With the help of these S-boxes, nonlinear transformation bit data are generated through a cyclic XOR operation with chaotic binary data to improve the resistance against chosen-plaintext attacks (CPAs). A specially designed chaotic constant amplitude zero autocorrelation matrix is used to reduce the PAPR and allow for encryption. We verify the resistance against CPAs with completely dynamic cipher texts in an
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10-Gb/s encrypted OFDM-PON transmission over a distance of 25 km. Compared with the standard OFDM-PON, our proposed scheme achieves
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2.8-dB PAPR reduction, which compensates for any sensitivity deterioration.