One-Time Pad Strategy Combined With Dynamic Key Embedding and Multi-Level Chaotic Encryption for RoF

Chaotic encryption is a potential scheme for the communication security of radio-over-fiber (RoF) system. In this paper, a one-time pad strategy combined with dynamic key embedding and multi-level chaotic encryption is experimentally demonstrated for RoF system. The keys are divided into dynamic and static key. The static key is randomly selected and encrypt dynamic key which is extracted according to the transmission information. The dynamic key is employed in polar coding encryption (bit- level) and static key is employed in dynamic key embedding, constellation masking (symbol-level) and chaotic synchronization. The receiver selects the required static key according to the synchronization information and recovers the dynamic key from the received data, which realizes the one-time pad strategy and greatly enhances the security of the system. Transmission experiments are successfully conducted over 50 km standard single-mode fiber (SSMF) and 5 m wireless channel. Compared with the traditional OFDM, the experimental results show the proposed scheme adopting successive cancellation list 8 (SCL8) decoder can acquire ∼2.1 dB gain at the BER of 10−3. In addition, experiments verify the influence of code length, code rate and different modulation formats, which further explains the feasibility of the scheme. Experiments show that the proposed scheme has great practical potential for future optical wireless secure communication.