Research On Key Techniques Of Post-processing For Optical Communication Physical Layer Key Distribution

With the booming development of the Internet industry,national cyber security and privacy of individual data are becoming increasingly significant.The optical communication physical layer security is vulnerable to attack.Although optical fiber cables are naturally immune to electromagnetic and radio frequency interferences,they are difficult to resist eavesdropping attacks from lines and nodes.The security of communication is based on ciphering the confidential information with secure keys,shared only by legitimate users.One promising and cost-effective approach is to leverage the unpredictable and random properties of transmission channels and convert the environmental randomness to secure keys.It employs an asymmetry in the measurement complexity between the legal and illegal users as a security mechanism,and thus provides high-level security regardless of the attacker's computational power.But the distributed keys are stochastic but inconsistent and cannot be applied to cryptographic communication systems directly.Based on the problem,the main research and innovation of this paper are as follows:Firstly,aiming at the inconsistence of keys which are obtained from the existing optical communication physical layer key distribution schemes,this paper proposes a secure key correction model.The BBBSS,Cascade,Winnow algorithms are introduced into optical communication physical layer key distribution to correct the distributed raw keys.Secondly,the existing post-processing protocol cannot cope with the fluctuation of key consistency rate and performs worse.The ratelss spinal code is introduced into information reconciliation to cope with the fluctuation of key consistency rate,and the security of proposed algorithm is proved theoreticallyThirdly,there is still no whole post-processing protocol for optical communication physical layer key distribution.A post-processing protocol based on spinal code for optical communication physical layer key distribution is proposed.The protocol first quantifies the measured channel feature into bit streams.And the inconsistent keys are corrected in information reconciliation step.Finally,the consistent keys are compressed during privacy amplification,the key reaches secure with the least amount of information consumed.Then,the protocol is evaluated in the physical layer key distribution experiment based on bit error rate of loop.The final secure key rate can reach 353.8 kbps and the key consistency rate achieves 100%in 300 km single-span fiber experiment.