Joint Encryption Scheme Based on the Chaotic DCT Matrix and SLM Algorithm in an OFDM-PON System

In order to effectively solve the problem of data transmission security and peak-to-average ratio (PAPR) in an orthogonal frequency division multiplexing passive optical network (OFDM-PON) transmission system, in this paper, a joint encryption scheme of discrete cosine transform (DCT) and selective mapping (SLM) based on chaotic mapping is proposed. In this scheme, the chaotic sequence of a 3D Lorenz chaotic system is used as the row and column index of the DCTmatrix and the phase factor of SLM to resist selective plaintext attack, and the system encryption is realized while reducing PAPR. (e theoretical analysis and numerical simulation show that the common OFDM-PON, the proposed algorithm, can obtain a PAPR suppression gain of ∼4.8 dB and improve the receiver sensitivity by ∼4 dB (BER@10 3). In addition, it shows that, with the increase of row/column index mismatch of the DCTmatrix, the bit error rate of the system increases gradually. An encrypted data transmission of 8GB/s 16-QAM optical OFDM signals is successfully simulated over a 20 km standard single-mode fiber, which proves the excellent confidentiality of the proposed secure transmission.