Research On Physical Layer Encryption Method For Dynamic Optical Access Network

Recently,with the rapid development of the Internet technology,a variety of new technologies continue to appear,such as artificial intelligence,large data,cloud technology,Internet of Things and so on.At the same time,the security incidents against the Internet have intensified recently,and the losses and bad influences caused by the incidents are also increasing.As a result,people are paying more and more attention to the security of the Internet.As an important part of the Internet,optical access network is the "last kilometer" that the entire network connect to users.However,due to the way of broadcasting in the downlink and there are security risks in some optical devices,optical access network is facing security problems such as eavesdropping and jamming.Therefore,enhancing the security of the optical access network can effectively improve the security of the entire network.Recently,there are a variety of methods to enhance the security of optical access networks,including optical encryption,optical coding,optical steganography,quantum key distribution,upper layer encryption,chaotic laser secure communication and physical layer encryption.Among the above methods,physical layer encryption has been received more and more attention due to its advantages such as flexible encryption,the operation of various data,the protection of all data and the low complexity of implementation.In addition,owing to its fully support of software-defined networking(SDN)solution,good compatibility with the existing PON,good transparency,low cost and simple bandwidth allocation,digital filter multiple access passive optical network(DFMA-PON)is considered as one of the preferred options for next generation optical access network technology.Therefore,the research of this thesis mainly focused on the physical layer security of DFMA-PON.The main innovative work of this thesis is summarized as follows:1.This thesis study the phase mismatch value(sensibility)of digital filters in DFMA-PON by using MATLAB and optical simulation software VPI.The simulation results show that in both B2 B and 25 km cases,the corresponding digital filter has almost the same phase sensibility,while the phase sensibility is different to filters with different central frequencies or filter type but all phase sensibility is around 0.2 rad.And for a certain digital filter,different optical fiber transmission length(no more than 25 km)or filter length have little effect on the phase sensibility of the digital filter.2.Based on the phase sensibility of digital filter,this thesis proposes two physical layer security enhancement technologies,including chaotic phase masking(PM)encryption and chaotic PM based exclusive OR-PM(XOR-PM)encryption.The most important feature of chaotic PM encryption is that all digital filters introduce a random phase obtained by chaotic system,and the phase of digital filter is updated continuously during filtering.As to XOR-PM encryption,the original bit data is performed XOR encryption,so that the two-dimensional encryption can be achieved.The simulation of chaotic PM encryption and XOR-PM encryption have been carried out by using MATLAB and VPI.The simulation results show that both technologies can effectively enhance the physical layer security of DFMA-PON.Compared with chaotic PM encryption,XOR-PM encryption has better security performance.3.This thesis proposes two physical layer security technologies based on frame interleaving,including time and frequency scrambling-PM(TFS-PM)and Joseph ring based Josephus frame interleaving-PM(JFI-PM).Compared with chaotic PM encryption,TFS-PM encryption has a better security performance,which is mainly because the data frame is scrambled in time domain and frequency domain.However,for the reason that the time and frequency scrambling is performed by scrambling matrix while the generation of scrambling matrix has a relatively high complexity,so the encryption complexity of TFS-PM encryption is higher.Compared with TFS-PM encryption,the JFIPM encryption does not need to produce the scrambling matrix,so it has relatively lower encryption complexity.The experiment of TFS-PM encryption has been carried out and the experimental result shows that TFS-PM encryption can effectively enhance the physical layer security of DFMA-PON.The simulation of JFI-PM encryption has been carried out by using MATLAB and VPI.The simulation results show that JFI-PM encryption can effectively enhance the physical layer security of DFMA-PON.