Probabilistic shaping probability distribution scrambling based on a chaotic system for integrating secure transmission and adaptive key updating

A probabilistic shaping probability distribution scramble (PSPDS) scheme based on chaotic systems is proposed to fulfill both secure transmission and adaptive key updating. The chaotic Chen and logistic systems are adopted to generate a chaotic random sequence. The probabilistic shaping is achieved by constant composition distribution matching (CCDM) and probabilistic amplitude shaping architecture. The chaotic, random sequences are used to scramble the probability distribution of CCDM, improving security. The session key is embedded into a probability distribution. The legal receiver extracts the error-free session key when OSNR is higher than the requirement of the forward error correction threshold. We employ a coherent OFDM 16QAM transmission experiment on 120 km fiber, confirming our proposed scheme with a net rate of 9.95 Gbit/s. The results show that the PSPDS scheme has no encryption penalty compared with the baseline without encryption. The key updating rate has the ability to vary adaptively and reaches 224.2 Mbit/s by adjusting the block length of CCDM in our experiment. The key space reaches 10 136 . Even if an illegal party obtains a ciphertext signal, the plaintext and session key can hardly be inferred due to a probability distribution scramble.