Multilayer Dynamic Encryption for Security OFDM-PON Using DNA-Reconstructed Chaotic Sequences Under Cryptanalysis

In this paper, a multilayer dynamic encryption scheme using deoxyribonucleic acid reconstructed chaotic sequences (DNA-RCS) under cryptanalysis is firstly proposed, which aims at enhancing the security of orthogonal frequency division multiplexing passive optical network (OFDM-PON). We adopt DNA coding to reconstruct chaotic sequences, the selected coding rules and the number of chaotic sequence blocks divided are then random, the randomness and security of encryption sequences are improved. The transmitted signal is encrypted in two layers. The first layer is hybrid chaotic permutation and diffusion. Each symbol can be encrypted by the combination of a single non-repetitive permutation and plaintext-related diffusion. It makes encryption not only depend on the chaotic sequences but also relate to the order of permutation. The second layer is a dynamic Josephus permutation. By taking the unit as the permutation object, the scrambling efficiency is increased. Also, the counting period is randomly selected, which can enhance the security of the system. The number of tests needed to break a secure transmission for an attacker can reach up to $3.096\times 10^{106}$ . An encryption signal with 22.06Gb/s is successfully demonstrated over a 25-km standard single-mode fiber (SSMF) and a back-to-back (BTB) system. It is proved that the proposed scheme does not degrade the system performance and can effectively resist various attacks by the performance analysis model based on cryptanalysis.