Physical layer encryption scheme based on biological genetic variation mechanisms in CO-OFDM system

With the rise of quantum computing and sophisticated cyber-attacks, traditional cryptographic methods face challenges in securing optical physical layer data transmission. This study proposes what we believe to be a novel approach by integrating biological genetic variation mechanisms (BGVM) with signal encryption in coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. A mapping model between genetic structures and optical orthogonal frequency division multiplexing (OFDM) signals is constructed, and a dual encryption mechanism including mutation-guiding encryption mechanism (MGEN) and reorganization-guiding encryption mechanism (RGEN) is established to disrupt the data positions on subcarriers. In the system, the key sequences are generated by a four-dimensional hyperchaotic system, which exhibits good randomness and unpredictability. Experiment is successfully conducted to realize physical layer secure transmission of the CO-OFDM signal over 80 km standard single mode fiber (SSMF). The proposed scheme has low time complexity and the key space is extended to 10¹¹⁹⁴ approximately, when the number of subcarriers N = 256.