Research On Physical Layer Security Technology Based On Quantum Noise

The rapid development of information technology has brought unprecedented convenience to people's life.While enjoying convenience,people should always be alert to possible security threats.As the infrastructure of carrying information,the security of optical fiber communication is paid more and more attention.In order to solve the security problem of optical fiber communication,cryptography is a widely used to prevent information from being eavesdropped.However,with the improvement of computing power,especially the development of quantum computer,the communication network under the protection of classical cryptography becomes more and more fragile.Moreover,classical cryptography cannot meet the need of preventing information interception in fiber channel.In recent years,optical fiber physical layer security protection technology,as an important supplement to the classical cryptography based on computational security,has been widely concerned and paid attention to by researchers in related fields.Optical fiber physical layer security protection technology can effectively improve the anti-interception ability of information in optical fiber channel.This paper takes quantum noise physical layer security technology as the core,and takes physical layer encryption technology and physical layer key distribution technology as the technical route.To improve the performance of quantum noise stream encryption system,a method based on quantization noise preprocessing at the transmitter and DFTs-OFDM technology is proposed to improve the security and transmission performance of the system.A key distribution scheme based on fiber channel feature extraction is proposed to solve the problem of limited key distribution distance and key generation rate.Aiming at the integration of encryption transmission and key distribution,an integrated method of secure transmission and key distribution based on differential element mapping scheme is proposed,which integrates the previously independent secure transmission system and key distribution system.The main work and innovative achievements of this paper are summarized as follows:1)A quantization noise pre-processing method at the transmitter in quantum noise stream encryption system is proposed.Quantization noise is used to mask the transmitted signal,which improves the security performance of quantum noise stream encryption system.The principle of quantum noise stream encryption(QNSC)scheme is discussed,and the influence of quantization noise on quantum noise stream encryption system in digital to analog converter(DAC)is analyzed theoretically.A quantum noise stream encryption system based on single carrier coherent transmission is simulated.A 10 Gbit/s single carrier quantum noise stream encryption transmission system using PSK and QAM signal formats with coherent optical detection is studied.The performance of quantum noise stream encryption system is analyzed in four scenarios.The system performance under different transmission distance scenarios is analyzed.The performance of the system in the back to back scenario is analyzed.The effects of DAC resolution and constellation size on system safety performance is analyzed under high optical signal-to-noise ratio(OSNR).The quantum noise stream encryption system is affected by DAC quantization noise and amplifier spontaneous emission noise under low OSNR optical back to back conditions.Simulation results show that the security performance of quantum noise stream encryption system can be significantly improved by using quantization noise preprocessing at the transmitter.In addition,as long as the total noise of the system remains unchanged,its transmission performance will not be affected.2)A scheme of quantum noise stream encryption system based on DFTs-OFDM technology is proposed.By adjusting the amplitude limiting rate of DFTs-OFDM signal,the transmission performance of quantum noise stream encryption system is effectively improved.Simulation and experiment verify the 10 Gbit/s quantum noise stream encryption coherent transmission system based on DFTs-OFDM.Comparing the transmission performance of PSK/QNSC and QAM/QNSC at different transmission distances,the results show that PSK/QNSC can obtain better transmission performance.By increasing the size of PSK/QNSC and QAM/QNSC signal constellation space,the safety performance of the system can be significantly improved.The effect of signal clipping rate on transmission performance was studied with DAC of different resolution.Simulation and experimental results show that,in the case of low resolution DAC,Q-factor first increases and then decreases with the increase of signal clipping rate.In the case of high DAC resolution,reducing the signal clipping rate does not significantly improve the Q-factor.Adjusting the signal limiting rate can effectively improve the transmission performance of the system.3)A physical layer key distribution scheme based on feature extraction of optical fiber channel is proposed,which provides an innovative way to solve the key distribution problem of optical fiber physical layer.Both sides of legal communication extract channel features by measuring the dynamic change of bit error rate(BER)in the return channel of fiber ring.Because the channel is affected by various random interferences and physical parameters,the measured BER will change randomly.When both communication parties measure BER of optical fiber loop at the same time,a relatively consistent BER curve can be measured due to the short-term reciprocity of optical fiber channel.After quantizing the BER,the consistency key is generated.Because optical amplifiers can be used in this scheme,the distance of key distribution is much longer than that of quantum key distribution scheme.The experiment verifies the 200 km physical layer key distribution system based on fiber channel feature extraction.After quantifying the measured dynamic variation curve of BER,the experiment obtained the initial key with the key generation rate of 400 kbit/s and the key consistency of 98%.In the experiment,the system is simulated by eavesdropping attack.Experimental results show that the system has good anti-eavesdropping performance.On this basis,an integrated method of encryption transmission and key distribution based on differential element mapping scheme is proposed.The combination of independent secure transmission system and key distribution system can save the reconstruction cost of optical fiber communication system.Finally,its performance is verified by simulation and experiment.