Research On Key Technologies Of Physical Layer Security In Optical Access Network

With the emergence of novel business such as ultra-high-definition video,large-set database and cloud computing,more and more data is preferred to be transmitted through the network.Passive optical network(PON)has become the mainly used access network in the world for its large bandwidth,high speed and low cost.However,the incidents of information leakages occur frequently in the PON.In recent years,the security enhancement technology for the physical layer based on chaotic encryption has attained great attentions.It shows strong randomness and large key space,providing an effective way to enhance information security in the physical layer of optical networks.This paper focuses on the demand of physical layer security for optical access networks.Addressing the information security risks in the PON,the chaotic encryption method is adopted for the physical layer to increase the security performance of orthogonal frequency division multiplexing(OFDM)PON and prevent information from being tampered with,stolen or destroyed during the transmission process.Based on the orthogonal multiple access encryption,the non-orthogonal multiple access encryption in the power domain and the non-orthogonal multiple access encryption in the code domain,this paper pays more attentions on the studies of synchronous encryption in both bit-and symbol-levels,enhanced security of multiple superimposed signals in the power domain and synchronous encryption with public and private keys.Moreover,the security and effectiveness of these proposals are all verified in the physical layers of the optical access networks.The main contents and innovation points of this paper are as follows:(1)To resolve the cracking vulnerabilities when the bit or the symbollevel encryption is used separately,the enhanced deoxyribonucleic acid(DNA)encoding in bit-level combined with the Arnold non-isometric matrix scrambling in symbol-level is proposed.This scheme adopts Logistic chaos and four-dimensional Chen hyperchaos to generate the chaotic sequence required for the encryption.The synchronous encryption for OFDM-PON in both bit-and symbol-level is realized by adopting the base cross exchange in the traditional DNA encoding algorithms and combining with the Arnold non-isometric matrix scrambling.Meanwhile,to save the emission power,a coordinated optimization scheme based on the combination of the DNA encryption with the Huffman-coded probability shaping is proposed.This scheme can improve both the security performance and bit error rates of PON with carrier-free amplitude phase.(2)To increase the number of users in the access network and improve the spectral efficiency,a non-orthogonal multiple access in the chaotic power domain based on the amino acid and extended ZigZag transform encryption is proposed.The amino acid encryption can be achieved by transcribing DNA into messenger ribonucleic acid.Afterwards,the degree of scrambling is further increased by adopting the extended ZigZag transformation encryption.Under the premise of the enhancement in security,the power allocation ratio can also be adjusted in real-time according to users’ needs,balancing the fairness of the transmission of user signals.(3)To enhance the security of the access network and further improve the transmission performance of OFDM signals,a public-private key encryption scheme based on chaotic selective mapping and partial transmission sequence is proposed in sparse code division multiple access OFDM systems.The proposed scheme not only effectively enhances the security performance of the physical layer of the optical access network,but reduces the peak to average power ratio of the OFDM signals and improves the sensitivity of the signal receivers,which are verified by the experiments.