Opt Express. 2021 Jun 7;29(12):18976-18987. doi: 10.1364/OE.427133.
This study proposes an encryption scheme combining cellular automata (CA) and DNA encoding to improve security of a coherent optical orthogonal frequency division multiplexing (CO-OFDM) system, wherein key sequences are generated with good randomness and unpredictability by a 4-dimensional hyper-chaotic system. A base scrambling pseudo random binary sequence (PRBS) generated by the CA is introduced, which results in better scrambling effect and randomness in the conventional complex DNA encoding. The randomness, complexity and security of the system is enhanced due to 6 variable keys (key space of ∼10). An experiment conducted in a 40 GHz 16QAM CO-OFDM system over an 80 km standard single mode fiber (SSMF) shows that the authorized user can successfully decrypt the received signal, while the eavesdroppers cannot derive useful information with bit error rate (BER) at approximately 0.5. An allowable optical signal to noise ratio (OSNR) penalty of 0.5 dB will be introduced to achieve same BER before and after encryption due to the error propagation of cellular automata.
本研究提出了一种将元胞自动机（CA）和 DNA 编码相结合的加密方案，以提高相干光正交频分复用（CO-OFDM）系统的安全性，其中通过 4 维超混沌系统生成具有良好随机性和不可预测性的密钥序列。引入了由 CA 生成的基置乱伪随机二进制序列（PRBS），这使得传统的复杂 DNA 编码具有更好的置乱效果和随机性。由于 6 个变量密钥（密钥空间约为 10），系统的随机性、复杂性和安全性得到了提高。在 80km 标准单模光纤（SSMF）上的 40GHz 16QAM CO-OFDM 系统中的实验表明，授权用户可以成功解密接收到的信号，而窃听者在误码率（BER）约为 0.5 时无法获得有用信息。由于元胞自动机的误差传播，在加密前后将引入 0.5dB 的允许光信噪比（OSNR）代价，以实现相同的 BER。
