| The foundation of information security is secure communication.Modern secure communication means that the information is encrypted by the key and then transmitted through the secret channel.Shannon's secret communication scheme“one-time-pad”requires that the key be discarded after use,the key length is larger than the information length,and the key generation cannot be predicted.The mathematical algorithm-based key distribution is mainly based on a deterministic mathematical algorithm,and the result is used as a key.The security of algorithm key depends on the computing power of the computer.The mathematical algorithm-based key distribution has a computational security based on the premise that the attacker has limited computation ability.The number of keys generated by the algorithm cannot meet the requirement of“one-time-pad”,and the key will still be reused.To meet the requirement of“one-time-pad”,researchers explore quantum key distribution and classical physical layer key distribution.Quantum key distribution(QKD)can resist against the powerful computation ability,but the QKD rate is limited by the low efficiency of single photon detection,and the typical key distribution rate is kbit/s.The key distribution of classical physical layer is limited by key space,long recovery time and limited noise bandwidth.The key distribution rate is only kbit/s,which cannot meet the demand of high-speed communication.The semiconductor laser with external disturbance can produce broadband chaotic laser.Chaotic laser has the characteristics of large amplitude,random fluctuation,and broadband spectrum,which can be applied to generate high-speed random number.The typical random number generation rate is Gbit/s?Tbit/s.In addition,the chaotic laser can achieve high-quality chaotic synchronization in the case of parameter matching.Combining chaotic synchronization technology with high-speed physical random number technology,it is expected to realize high-speed physical random key distribution based on chaotic synchronization.In the key distribution system based on chaos synchronization,the mutual coupling structure can expose the entropy source information of the response laser,which makes the key distribution system have security risks;although the commonly drive chaos synchronization structure can hide part of the entropy source information of the response laser,the traditional closed-loop chaos synchronization method still has some defects,such as high residual correlation of the driving laser and response laser,long synchronization recovery time and so on.Therefore,it is necessary to explore a key distribution scheme to improve the response rate of the laser.To increase the security of the driving laser and speed up the key distribution rate,a common signal driven chaotic synchronization system and a key distribution system are proposed and numerically simulated.The detailed work of this paper is as follows:Firstly,an open-loop chaotic synchronization system driven by common signal based on M-Z interferometer is proposed.The driving chaotic signal is injected into the response laser after passing through the unbalanced M-Z interferometer set in the legitimate communication client.When the parameters of M-Z interferometer are the same,the driving chaotic signal can also be synchronized.After the response laser is injected with the same driving chaotic signal,the common signal drive open-loop chaotic synchronization is realized.Furthermore,the influence of the nonlinear transformation of the delayed self-interference on the synchronization between the driving chaotic signal and the output signal of the response laser is analyzed by numerical simulation,and the influence of the chaotic synchronization system on the injection intensity,the angular frequency detuning and the internal parameter detuning of the laser on the chaotic synchronization is studied.The results show that the correlation between the driving signal and the response signal can be kept at a low level(?0.25),and the high chaotic synchronization state(?0.99)of the two response lasers can be achieved simultaneously;the chaotic synchronization system can realize the common signal driven open-loop chaotic synchronization within a certain parameter mismatch range.Secondly,a key distribution scheme based on M-Z interferometer is proposed to drive the open-loop chaotic synchronization by common signal.The open-loop chaotic synchronization system driven by common signal based on M-Z interferometer realizes the co drive open-loop chaotic synchronization of the response laser.A phase modulator is set on one arm of M-Z interferometer,and the phase of the phase modulator is modulated by the random code generated by the random code generator.In this paper,phase shift keying(PSK)is used to synchronize chaotic systems.Both sides of the communication implement double threshold quantization on the keyed chaotic synchronization time series to generate random key.After exchanging and comparing the keying parameters,the legitimate users retain the random bits generated from the synchronized chaos as the shared keys to realize the key distribution.Furthermore,the key distribution system is constructed by numerical simulation,and the phase shift keying chaotic synchronization is realized on both sides of the user;the recovery time of 5000 synchronization times is analyzed statistically;the influence of keying phase mismatch and laser internal parameter mismatch on chaotic synchronization and bit error rate is studied;the chaotic driving signal with or without M-Z interferometer is analyzed and compared in the presence of eavesdropper,And get the key with different bit error rate.The results show that the key distribution system can complete the key distribution while ensuring the high security of the drive response.The open-loop chaotic synchronization structure can shorten the synchronization recovery time to 1.8 ns and has high stability.Finally,a secure key distribution system with 1.28 Gbit/s and BER lower than 3.8×10-3 is implemented. |
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