Research On Dynamic Key Management Method Of Secure Access Network

With the rapid development of technologies such as 5G,blockchain,cloud computing,and big data,network security threats have gradually intensified.Optical access networks are an important component of communication networks,and their downstream channels are prone to eavesdropping due to broadcast communication.Therefore,the research on enhancing information security in optical access networks has become one of the current important topics.The mainstream optical access network security technologies include upper layer encryption,physical layer security enhancement,and laser chaotic secure communication.Physical layer security enhancement technology has the advantages of flexible implementation,full data processing,and large key space,and is considered to be one of the preferred solutions for secure access.Orthogonal frequency division multiplexing passive optical network（OFDM-PON）has the advantages of high dispersion tolerance,high frequency spectral efficiency,anti-multipath interference,and is considered as the mainstream technology of optical access network.In view of this,this thesis will study chaotic encryption and dynamic key management methods for OFDM-PON optical access network.The main work and contributions include the following aspects.（1）A chaotic secure key distribution and synchronization method for OFDM-PON is proposed.The chaotic encryption,signal synchronization and key distribution are combined to make use of the redundancy of the contents in the synchronization header.The key information is embedded in the synchronization header sequence and transmitted after encryption.The receiver first decrypts the information,and then calculates the correlation to get the peak value.The position of the synchronization head is at the peak value.The extracted key can be used as the parameter required for the next communication.The research results have verified that this method can ensure its secure and effective dynamic key distribution and signal synchronization,providing nearly a key space of 2⁵¹².Compared with other schemes,it reduces the probability of peak synchronization during the synchronization process and maintains synchronization stability,thereby improving the transmission performance of the system.（2）A chaotic Hilbert motion security encryption and key management method for OFDM-PON is proposed.The efficient and convenient key generation,fast identity authentication and information integrity verification are comprehensively considered.First,the chaotic sequence is generated through the chaotic system,the basic form,distance and position of Hilbert motion are selected according to the chaotic parameters,and then the data is scrambled,and the scrambled result is calculated as a hash value as a digital signature.In key management,Hilbert motion is used to iteratively generate keys in the key space,and the relevant key information and digital signature are embedded in the synchronization header for transmission.The research results have verified that this method can effectively improve the security of OFDM-PON system data,successfully achieving dynamic key generation,distribution,and identity authentication.It can increase the traditional physical layer key generation rate from～kbit/s to 3.84Mbit/s,providing a key space of 6.4×10⁹¹.Compared with other schemes,it consumes less storage space and ensures the integrity of system data.