Research On Hardware Characteristics-based Secure Key Distribution And Application In Physical Layer Of Optical Networks

Optical fiber communication networks,which enable most network traffic and connections worldwide,are an important infrastructure in cyberspace.However,they also pose a risk of cyber attacks that threaten the physical social stability and safety.Therefore,secure communication solutions for physical layer of optical communication networks have become an urgent practical demand.Secure key distribution,one of the essential technologies,can provide fundamental security for secure communication systems and enables data encryption.This dissertation focuses on the hardware characteristics-based key distribution in the physical layer of optical networks.The goal is to achieve a high key generation rate,system stability,low resource occupation,and cross-layer application.The main contributions and innovations of this dissertation are summarized below.(1)A joint source-channel key generation model is proposed to overcome the key generation rate limitation imposed by the slow varying fiber channel.The model uses a broadband entropy source to increase the rate and a reciprocal fiber channel to ensure information theory-level security.The dissertation analyzes the principle of key generation rate improvement under the model and verifies its feasibility by a numerical simulation.An experimental setup is built based on an analog chaos entropy source and the reciprocal channel.A symmetric key distribution with a rate of 4.3 Gbit/s in a 10-km standard singlemode fiber is achieved.The generated security key has good randomness.The proposal outperforms the key distribution system based on the fiber itself in terms of generation rate and provides insights for the design of high-speed key distribution in the optical network physical layer.(2)To address the instability caused by non-reciprocal components in key distribution over fiber channel,a stable key distribution scheme based on orthogonal polarization and reciprocal fiber channel is proposed.The linear polarization is covered by amplitude modulation in orthogonal polarization modes.The polarization measurement isolated from the shared fiber and the optimized post-processing quantization are adopted to enhance the system stability.A stable key distribution system is built based on a discrete digital chaos entropy source and a 10-km standard single-mode fiber.The system stabilizes the correlation coefficient of analog measurement signals at 0.928 and the key generation rate at 2.07 Gbit/s for 30 minutes.The scheme improves the stability of the key distribution system and provides guidance on identifying and avoiding the non-reciprocal components in system design.(3)A stealthy transmission technology based on modulator bias control and neural network is proposed to reduce the occupation of transmission overhead and channel resources in the key reconciliation.The stealth embedding of reconciliation data is realized by adjusting the bias point.The neural network is used to extract the stealth data.A stealth transmission system is experimentally implemented based on the dither signal-based bias control and convolutional neural network.A 20-km transmission of 250-kbit/s stealthy reconciliation data with the 10-Gbit/s on-off keying format service data is realized.The scheme can effectively decrease the transmission overhead and channel resources occupation in the key reconciliation.The proposed technology can make the key reconciliation stealthier and assist in enhancing the security of key distribution system.(4)To improve the efficiency of physical layer encryption in optical networks,a crosslayer data encryption scheme based on compressive sensing and security key is proposed.The physical layer security key can provide an information theory-level security foundation.The compressive sensing method can reduce the transmitted data amount and eliminate the redundancy and correlation of plaintext.The simulation results in the image encryption verify the effectiveness of data volume compressing and data redundancy removal.The encrypted image achieves an information entropy of 7.98,close to the ideal maximum of 8.The restored image has a peak signal-to-noise ratio of 31.1 d B,indicating a good restoration performance.The scheme integrates the physical layer key with the compressive sensing encryption.It is a cross-layer application that couples the physical layer key distribution system and the upper-layer encryption algorithm in optical networks.