A physical layer security key distribution apparatus and method in multi-core fiber communication

Abstract

The application relates to the field of optical communication technology and discloses a physical layer security key distribution device and method in multi-core optical fiber communication, which comprises a common source generation module, a multi-core optical fiber link transmission module, a local signal receiving module, a remote signal receiving module and a post-processing module; the common source generation module is used for generating a multi-wavelength driving signal, and after the multi-wavelength driving signal is divided into two parts, the two parts are respectively transmitted to the local signal receiving module and the multi-core optical fiber link transmission module; the local signal receiving module is used for driving to generate a first sequence and a first keying code according to the multi-wavelength driving signal; the multi-core optical fiber link transmission module is used for transmitting the multi-wavelength driving signal to the remote signal receiving module; the remote signal receiving module is used for driving to generate a second sequence and a second keying code according to the multi-wavelength driving signal; the keying code and the second keying code are respectively transmitted to the remote signal receiving module and the local signal receiving module through a wireless channel; and the post-processing module obtains a consistent random number used for encryption according to the first sequence and the second sequence. The application can realize high-speed key distribution, and improves the system security without increasing the system complexity and cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical communication technology, in particular to a physical layer security key distribution device and method in multi-core fiber communication. BACKGROUND

[0002] Optical fiber communication has become a key technology for modern data transmission due to its high bandwidth, low signal attenuation and long distance transmission. Under the guidance of the Broadband China strategy, broadband communication has entered the era of gigabit access network and 100G backbone network. However, the transmission capacity of single-mode optical fiber has reached the theoretical limit, while multi-core optical fiber has gradually been applied in broadband communication due to its large capacity transmission and low crosstalk advantage obtained by space division multiplexing. Nowadays, multi-core optical fiber has been laid in practical links up to hundreds of kilometers, and gradually developed to thousands of kilometers. The application of multi-core optical fiber is an inevitable trend. With the increasing dependence of information transmission on optical fiber networks, optical fiber communication systems are facing increasingly severe security challenges. Ensuring the confidentiality, integrity and availability of data transmitted through optical fibers has become one of the core problems in the design of current optical fiber communication systems. Among them, the security problem of single-mode optical fiber communication mainly reflects the risk of signal eavesdropping. Although single-mode optical fiber has certain security in physics, its signal transmission is not easy to be directly monitored, but it can be extracted by complex technical means without interrupting the transmission. This eavesdropping behavior may lead to unauthorized access, threatening the security of sensitive information. While multi-core optical fiber with intermediate cores is difficult to directly extract sensitive information from the intermediate core due to the interference of outer core information from known bending eavesdropping, which makes existing eavesdropping methods ineffective. However, in order to prevent unknown eavesdropping methods, encryption is also needed to prevent potential risks of leakage. Therefore, ensuring encryption and security key distribution has become a key link in building a secure communication system.

[0003] In the face of the current large number of multi-core optical fiber networks and these potential eavesdropping risks, a mechanism is needed that can encrypt sensitive information in time during high-speed information communication. This is a process that reflects the compatibility of security key distribution and optical fiber communication. First, the key distribution system needs to be compatible with the optical transmission link, and second, the key distribution process can be parallel to communication.

[0004] The key distribution based on algorithm has the risk of being cracked due to the great increase of computer performance at present, so people have carried out extensive research on the way of key generation through the physical layer. Among them, quantum key distribution is difficult for eavesdroppers to obtain information due to the single quantum non-replicable characteristics, but the single quantum transmission requires special quantum channels, which is incompatible with the existing fiber communication system, and there is also the problem of rate bottleneck. In the classical physical layer key distribution, the physical unclonable device has the problem of limited key length, and the channel reciprocity based method has the problem of limited transmission distance, both of which are difficult to meet the current high-speed information communication. Among them, the key generation based on chaotic laser is outstanding due to its high speed, high complexity, long transmission distance and other advantages. In addition, the optical signal generated by the chaotic laser can also be applied to optical fiber transmission, which is a potential solution.

[0005] Chaotic laser is used as a physical entropy source to generate high-speed random numbers due to its wide spectrum and large amplitude random fluctuation characteristics. In addition, two chaotic lasers can achieve chaotic synchronization under the condition of structure and parameter matching, and produce highly correlated chaotic waveforms which can be used for key distribution. The key distribution based on chaotic laser correlation is that the legitimate users use synchronized chaotic lasers or wideband noise sources as correlated signal sources and modulate them with independent random signals, and finally select the chaotic time sequence in the same modulation state to extract consistent keys.

[0006] Currently, the way of using synchronized chaotic lasers as a correlation signal source is to use a common source to generate chaotic light through phase modulation or dispersion feedback, and then inject two response lasers to control the state of chaotic signals through keying. In the case of consistency, the key is extracted. Prior art (CN109672533A) provides a high-speed key distribution device based on semiconductor laser chaos synchronization. By controlling the feedback intensity and polarization state, chaotic signals can be output in both linear polarization modes. A random bit generator is used to key the polarization state. When the polarization state of the feedback light corresponding to the two response lasers is consistent, the two lasers can obtain chaotic signals with good synchronization performance. Literature (Optics Express, Vol. 30, pp. 23953-23966, 2022) reports that chaotic light injection into a feedback-free distributed feedback laser modulates the phase of the output chaotic self-carrier and performs delay shift keying. Although the transmission distance is only 40 km, the key distribution rate can reach 2.1 Gbit / s. Literature (Optics Express, Vol. 28, pp. 37919-37935, 2020) reports that chaotic light generated by mirror feedback is injected into a response laser with dispersion shift keying. In the simulation, a high-speed physical key distribution of 1.2 Gb / s is realized. This technical route uses a single-wavelength analog signal as a driving source and transmits in a single-mode fiber. However, domestic land and submarine cables have developed to thousands of kilometers. Chaotic signals as analog signals are inevitably disturbed by channel damage during transmission, which further affects compatibility. At the same time, since transmission is carried out in a single-mode fiber, it is not as secure as multi-core fiber transmission in terms of transmission capacity.

[0007] The principle is to inject wideband noise light into the chaotic laser, and the state of the chaotic signal is controlled by keying. Prior art (CN112653545A) provides a key distribution system based on distributed feedback laser injection optical power keying, uses a wideband noise light source to output a wideband noise light signal, and then uses a power adjustable laser module to key the optical power. Only lasers with the same power modulation can be synchronized. At present, the literature (Physical Review L, Vol. 108, 070602, 2012) reports that two responding lasers are realized by phase noise modulation of continuous light injection, which realizes a key distribution rate of 120 km and 128 kbit / s. The literature (Optics Express, Vol. 31, pp. 42838-42849, 2023) reports that the wideband noise light generated by a superluminescent diode is injected into a responding distributed feedback laser after being filtered to synchronize the chaos, and a special random sequence modulation method is used to realize a key generation rate of 2.55 Gbit / s. However, since the wideband noise signal is still an analog signal, the transmission medium is still limited to a single-mode optical fiber, and there are still problems of limited transmission distance of hundreds of kilometers and difficulty in compatibility with communication processes.

[0008] The above-mentioned schemes based on chaotic lasers all use analog signals for transmission. In long-distance transmission processes such as kilometer optical fiber cables, the channel damage is more serious, and multiple hardware devices are needed to compensate for channel dispersion and nonlinear damage, which will greatly increase the cost and is difficult to be compatible with communication systems. At the same time, using analog signal transmission will also sacrifice channel capacity. In addition, in single-mode optical fiber transmission, the capacity is limited, and the security still has potential threats. SUMMARY

[0009] The primary object of the present application is to overcome the problems existing in the prior art, and to provide a physical layer security key distribution device in multi-core optical fiber communication. The present application can realize high-speed key distribution, and improve the system security without increasing the system complexity and cost.

[0010] As another object of the present application, a method suitable for the device described above is provided.

[0011] As another object of the present application, a non-volatile storage medium suitable for storing a computer program implemented according to the method is provided.

[0012] In order to realize the primary purpose of the present application, the present application provides a physical layer security key distribution device in multi-core optical fiber communication, comprising: a common source generating module, a multi-core optical fiber link transmission module, a local signal receiving module, a remote signal receiving module and a post-processing module, the first signal output end of the common source generating module is connected with the signal input end of the local signal receiving module, the second signal output of the common source generating module is connected with the signal input end of the multi-core optical fiber link transmission module, the signal output end of the multi-core optical fiber link transmission module is connected with the signal input end of the remote signal receiving module, the signal output end of the local signal receiving module and the signal output end of the remote signal receiving module are connected with the post-processing module,

[0013] The common source generating module is used for generating a multi-wavelength driving signal, and after the multi-wavelength driving signal is divided into two parts, the two parts are transmitted to the local signal receiving module and the multi-core optical fiber link transmission module through the first signal output end and the second signal output end respectively; the local signal receiving module is used for driving to generate a first sequence and a first keying code according to the multi-wavelength driving signal; the multi-core optical fiber link transmission module is used for transmitting the multi-wavelength driving signal to the remote signal receiving module; the remote signal receiving module is used for driving to generate a second sequence and a second keying code according to the multi-wavelength driving signal; the first keying code and the second keying code are transmitted to the remote signal receiving module and the local signal receiving module through a wireless channel respectively, the post-processing module samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and then according to the exchanged keying codes, the inconsistent parts of the two groups of random numbers are discarded, the consistent key is retained, and a consistent random number used for encryption is obtained.

[0014] Further, the common source generating module comprises: a first long-cavity Fabry-Perot laser, an intensity modulator, a first arbitrary waveform generator, a first gain adjustable electric amplifier, a first erbium-doped fiber amplifier, a fiber grating and an optical coupler,

[0015] The output end of the first long-cavity Fabry-Perot laser is connected with the light input end of the intensity modulator, the output end of the first arbitrary waveform generator is connected with the input end of the first gain adjustable electric amplifier, the output end of the first gain adjustable electric amplifier is connected with the electric input end of the intensity modulator, the light output end of the intensity modulator is connected with the input end of the first erbium-doped fiber amplifier, the output end of the first erbium-doped fiber amplifier is connected with the input end of the fiber grating, the output end of the fiber grating is connected with the input end of the optical coupler, the first signal output end of the optical coupler is connected with the signal input end of the local signal receiving module, and the second signal output end of the optical coupler is connected with the signal input end of the multi-core optical fiber link transmission module.

[0016] Further, the multi-core fiber link transmission module comprises a first fan-in fan-out, a seven-core fiber, a second fan-in fan-out, a communication signal transmitter and a communication signal receiver,

[0017] The second signal output end of the optical coupler in the common source generation module is connected with the fourth input end of the first fan-in fan-out in the multi-core fiber link transmission module, the fourth output end of the first fan-in fan-out is connected with the input end of the seven-core fiber, the output end of the seven-core fiber is connected with the fourth input end of the second fan-in fan-out, the fourth output end of the second fan-in fan-out is connected with the signal input end of the remote signal receiving module, the output end of the communication signal transmitter is connected with the first input end of the first fan-in fan-out, and the first output end of the second fan-in fan-out is connected with the communication signal receiver.

[0018] Further, the local signal receiving module comprises a first programmable optical filter, a first polarization controller, a first Mach-Zehnder interferometer, a second arbitrary waveform generator, a second gain adjustable electrical amplifier, a second long-cavity Fabry-Perot laser, a first photoelectric detector,

[0019] The first signal output end of the optical coupler in the common source generation module is connected with the input end of the first programmable optical filter in the local signal receiving module, the output end of the first programmable optical filter is connected with the input end of the first polarization controller, the output end of the first polarization controller is connected with the optical input end of the first Mach-Zehnder interferometer, the output end of the second arbitrary waveform generator is connected with the input end of the second gain adjustable electrical amplifier, and the output of the second arbitrary waveform generator also needs to be sent to the remote signal receiving module through a wireless channel, the output end of the second gain adjustable electrical amplifier is connected with the electrical input end of the first Mach-Zehnder interferometer, the optical output end of the first Mach-Zehnder interferometer is connected with the input end of the second long-cavity Fabry-Perot laser, the output end of the second long-cavity Fabry-Perot laser is connected with the input end of the first photoelectric detector, and the output end of the first photoelectric detector is connected with the input end of the post-processing module.

[0020] Further, the output of the second arbitrary waveform generator is random, the phase output of the first Mach-Zehnder interferometer changes with the change of the voltage of the input signal of the second arbitrary waveform generator, and the state of the second long-cavity Fabry-Perot laser changes with the change of the phase output of the first Mach-Zehnder interferometer.

[0021] Further, the off-site signal receiving module comprises a dispersion compensation fiber, a second programmable optical filter, a second polarization controller, a second Mach-Zehnder interferometer, a third arbitrary waveform generator, a third gain adjustable electrical amplifier, a third long-cavity Fabry-Perot laser, and a second photodetector.

[0022] The fourth output end of the second fan-in / fan-out in the multi-core fiber link transmission module is connected with the input end of the dispersion compensation fiber in the off-site signal receiving module, the output end of the dispersion compensation fiber is connected with the input end of the second programmable optical filter, the output end of the second programmable optical filter is connected with the input end of the second polarization controller, the output end of the second polarization controller is connected with the optical input end of the second Mach-Zehnder interferometer, the output end of the third arbitrary waveform generator is connected with the input end of the third gain adjustable electrical amplifier, and the output of the third arbitrary waveform generator is also sent to the local signal receiving module through a wireless channel, the output end of the third gain adjustable electrical amplifier is connected with the electrical input end of the second Mach-Zehnder interferometer, the optical output end of the second Mach-Zehnder interferometer is connected with the input end of the third long-cavity Fabry-Perot laser, the output end of the third long-cavity Fabry-Perot laser is connected with the input end of the second photodetector, and the output end of the second photodetector is connected with the input end of the post-processing module.

[0023] Further, the output of the third arbitrary waveform generator is random, the phase output of the second Mach-Zehnder interferometer changes with the change of the voltage of the input signal of the third arbitrary waveform generator, and the state of the third long-cavity Fabry-Perot laser changes with the change of the phase output of the second Mach-Zehnder interferometer.

[0024] In order to achieve another object of the present application, a physical layer security key distribution method in multi-core fiber communication is also provided, which is based on the physical layer security key distribution device in multi-core fiber communication, and comprises the following steps:

[0025] The common source generation module generates a multi-wavelength driving signal, divides the multi-wavelength driving signal into two parts to obtain a first signal and a second signal, and transmits the first signal and the second signal to a local signal receiving module and a multi-core fiber link transmission module through a first signal output end and a second signal output end respectively, and the multi-core fiber link transmission module transmits the second signal to an off-site signal receiving module.

[0026] The local signal receiving module and the remote signal receiving module select signals of the same wavelength from the first signal and the second signal respectively, and generate a first sequence and a first key code, a second sequence and a second key code according to the selected signals, wherein the first key code and the second key code are transmitted to the remote signal receiving module and the local signal receiving module through a wireless channel respectively.

[0027] The post-processing module samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and then, according to the exchanged key codes, discards the inconsistent parts of the two groups of random numbers and retains the consistent keys to obtain consistent random numbers for encryption.

[0028] Further, the same wavelength is within .

[0029] In order to achieve another object of the present application, a computer readable storage medium having a computer program stored thereon is also provided, and the computer program is executed by a processor to implement the physical layer security key distribution method in multi-core fiber communication.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The present application drives the lasers of two places by using digital signals as a common source, wherein the common source uses a long cavity Fabry-Perot laser to simulate the generation of multi-wavelength digital signals, and then improves the randomness and bandwidth of the signals through the scrambling effect of the fiber grating; after the selection of the wavelength is negotiated, both parties of the secret communication can use a programmable optical filter to filter the multi-wavelength digital signals in order to select the corresponding wavelength, and due to the characteristics that the combination of wavelengths satisfies permutation and combination and the different wavelengths are basically irrelevant, when there are enough wavelengths as selection conditions, a large key space can be provided, and after the same wavelength is selected, the state of the random keying laser also needs to be selected, only when the two lasers output the same state, the consistent signal can be output for key extraction, and since the phase change also has a key space, the system security is significantly improved through the cascaded modulation of the two ways; the space division multiplexing technology is also used, the middle core is used for key generation, and the outer core is used for communication, and due to the physical mechanism of the multi-core fiber, it is difficult for an eavesdropper to eavesdrop the information of the middle core, and since the common source uses digital signals, the communication signal can be used for transmission, which reduces the light source and reduces the system complexity, and also realizes the combination with communication. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a structure diagram of a physical layer security key distribution device in multi-core fiber communication according to Embodiment 1 of the present application;

[0033] Figure 2A public source signal spectrum diagram for the embodiment 1 of the present application;

[0034] Figure 3 A digital signal timing diagram contained for each wavelength of the embodiment 1 of the present application;

[0035] Figure 4 A timing diagram of the scrambled digital signal of the embodiment 1 of the present application;

[0036] Figure 5 A partial synchronous output signal timing diagram intercepted by a response laser for the embodiment 1 of the present application, wherein Alice and Bob are the two parties of communication;

[0037] Figure 6 A 15-item Nist random number test overview diagram for the embodiment 1 of the present application;

[0038] Figure 7 A physical layer security key distribution method flow chart in a multi-core optical fiber communication for the embodiment 2 of the present application.

[0039] BRIEF DESCRIPTION OF DRAWINGS

[0040] 1, a public source generation module; 101, a first long-cavity Fabry-Perot laser; 102, an intensity modulator; 104, a first arbitrary waveform generator; 103, a first gain adjustable electric amplifier; 105, a first erbium-doped fiber amplifier; 106, a fiber grating; 107, an optical coupler; 2, a multi-core optical fiber link transmission module; 201, a first fan-in fan-out; 202, a seven-core optical fiber; 203, a second fan-in fan-out; 204, a communication signal transmitter; 205, a communication signal receiver; 3, a local signal receiving module; 301, a first programmable optical filter; 302, a first polarization controller; 303, a first Mach-Zehnder interferometer; 305, a second arbitrary waveform generator; 304, a second gain adjustable electric amplifier; 307, a second long-cavity Fabry-Perot laser; 306, a first photodetector; 4, a remote signal receiving module; 401, a dispersion compensation optical fiber; 402, a second programmable optical filter; 403, a second polarization controller; 404, a second Mach-Zehnder interferometer; 406, a third arbitrary waveform generator; 405, a third gain adjustable electric amplifier; 408, a third long-cavity Fabry-Perot laser; 407, a second photodetector; 501, a post-processing module (501) DETAILED DESCRIPTION

[0041] The specific embodiments of the present application are described in further detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0042] In the description of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0043] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] In addition, in the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0045] Embodiment 1

[0046] As Figure 1 shown, the physical layer security key distribution device in a multi-core optical fiber communication of the preferred embodiment of the present application comprises a common source generation module 1, a multi-core optical fiber link transmission module 2, a local signal receiving module 3, a remote signal receiving module 4 and a post-processing module 501, the first signal output end of the common source generation module 1 is connected with the signal input end of the local signal receiving module 3, the second signal output of the common source generation module 1 is connected with the signal input end of the multi-core optical fiber link transmission module 2, the signal output end of the multi-core optical fiber link transmission module 2 is connected with the signal input end of the remote signal receiving module 4, the signal output end of the local signal receiving module 3 and the signal output end of the remote signal receiving module 4 are connected with the post-processing module 501,

[0047] The common source generation module 1 is used to generate a multi-wavelength drive signal, and after the multi-wavelength drive signal is divided into two parts, the two parts are transmitted to the local signal receiving module 3 and the multi-core optical fiber link transmission module 2 through the first signal output end and the second signal output end respectively; the local signal receiving module 3 is used to drive generate a first sequence and a first keying code according to the multi-wavelength drive signal; the multi-core optical fiber link transmission module 2 is used to transmit the multi-wavelength drive signal to the remote signal receiving module 4; the remote signal receiving module 4 is used to drive generate a second sequence and a second keying code according to the multi-wavelength drive signal; the first keying code and the second keying code are transmitted to the remote signal receiving module 4 and the local signal receiving module 3 through a wireless channel respectively, and the post-processing module 501 samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and then according to the exchanged keying codes, the inconsistent parts of the two groups of random numbers are discarded, and the consistent key is retained to obtain a consistent random number for encryption.

[0048] Further, in the common source generation module 1, the first long cavity Fabry-Perot laser 101 is used as a multi-wavelength optical carrier to punch the optical signal into the intensity modulator 102, the output signal of the first arbitrary waveform generator 104 can be an NRZ signal or a high-order QPSK or PAM4 signal, etc., and after the intensity of the electrical signal is amplified by the first gain adjustable electrical amplifier 103, the signal is injected into the intensity modulator 102 to simulate a multi-wavelength communication signal, Figure 2 the spectrum of the common source signal, Figure 3 the digital signal timing contained for each wavelength.

[0049] As Figure 1 shown, the modulated digital signal is injected into the first erbium-doped fiber amplifier 105 to adjust the signal strength, and then injected into the fiber grating 106 to scramble the signal to improve its randomness and bandwidth, Figure 4 the timing of the scrambled digital signal, the scrambled signal is injected into the optical coupler 107, then one output end of the optical coupler 107 is injected into the local signal receiving module, the first programmable optical filter 301 retains the signal in the local, and the other output end of the optical coupler 107 is injected into the fourth input end of the first fan-in fan-out 201 in the multi-core optical fiber link transmission module, which is ready to be sent to the remote place.

[0050] As Figure 1As shown, in the multi-core fiber optic link transmission module 2, the two outputs of the optical coupler 107 are injected into the fourth input of the first fan-in fan-out unit 201 in the multi-core link transmission module. The signal enters the middle core of the seven-core fiber 202 to start transmission. After being transmitted to the remote end, the signal will enter the fourth input of the second fan-in fan-out unit 203 through the middle core of the seven-core fiber 202, ready for reception by the remote end. At the same time, the communication signal generated by the communication signal transmitter 204 enters the outer core of the seven-core fiber 202 through one input of the fan-in fan-out unit. After the outer core is output, the receiving end uses the communication signal receiver 205 to receive the communication signal, thereby simulating normal communication between users during the key distribution process. The two communicating parties communicate normally in the outer core, while the inner core is used to transmit a common digital signal source to control the synchronization of the response laser in the key distribution system, enabling parallel communication with the key distribution system during the communication process.

[0051] like Figure 1 As shown, in the local signal receiving module 3, the signal is first injected from one output terminal of the optical coupler 107 into the first programmable optical filter 301 in the local signal receiving module to select the wavelength of the signal. Then, the wavelength-selected signal is injected into the first polarization controller 302 to control the signal as linearly polarized light injected into the laser. Subsequently, the signal is injected into the first Mach-Zehnder interferometer 303. Since the phase change of the first Mach-Zehnder interferometer 303 is adjusted by the second arbitrary waveform generator 305, the second arbitrary waveform generator 305 outputs a random NRZ signal. The first Mach-Zehnder interferometer 303 will output signals with different phases according to the signal voltage change of the second arbitrary waveform generator 305. The keying code generated by the second arbitrary waveform generator 305 will be transmitted to the remote end through the wireless channel. Then, the phase-controlled signal is injected into the second long cavity Fabry-Perot laser 307.

[0052] Specifically, since the laser is phase sensitive, different phases of the injected signal will result in different laser outputs. Finally, the output of the second long cavity Fabry-Perot laser 307 is injected into the first photodetector 306 to convert the signal into an electrical signal, which is then sampled and quantized by the post-processing module 501.

[0053] like Figure 1 As shown, in the remote signal receiving module 4, the signal is first connected from the fourth output end of the second fan-in fan-out unit 203 in the multi-core fiber optic link transmission module to the dispersion compensation fiber 401 in the remote signal receiving module to compensate for the dispersion of the seven-core fiber. Then, the signal is connected to the second programmable optical filter 402 to select the wavelength of the signal. Here, the wavelength that is consistent with that of the local end needs to be selected. If they are inconsistent, the signals of the two sides will be uncorrelated.

[0054] like Figure 1As shown, the wavelength-selected signal is injected into the second polarization controller 403 for controlling the signal as linearly polarized light into the laser, and then the signal is injected into the second Mach-Zehnder interferometer 404, since the phase change of the second Mach-Zehnder interferometer 404 is adjusted by the third arbitrary waveform generator 406, the third arbitrary waveform generator 406 outputs a random NRZ signal, and the second Mach-Zehnder interferometer 404 outputs signals with different phases according to the signal voltage change of the third arbitrary waveform generator 406, and here the output signal of the third arbitrary waveform generator 406 can be inconsistent with the output signal of the second arbitrary waveform generator 305, because the remote end sends the keying code to the local end through the wireless channel to realize the exchange of the keying code in the wireless channel.

[0055] Specifically, the phase-controlled signal is injected into the third long-cavity Fabry-Perot laser 408, and the two lasers will output synchronized signals under the same phase injection, and will be unsynchronized under different phase injection, and finally the output of the third long-cavity Fabry-Perot laser 408 is injected into the second photodetector 407 to convert the optical signal into an electrical signal, Figure 5 In response to the partial synchronization output signal timing diagram intercepted by the laser, Alice and Bob are the communication parties, and then enter the post-processing module 501 for sampling and quantization, the local and remote ends select the random numbers generated by the same keying code and discard the random numbers of different times, and finally the communication parties obtain consistent keys for encryption, and 10 Mbit of signals collected at the same time are quantized and the same keying part is retained, and finally 2.25 Mbit of keys are generated under the error code rate of 1.4e-3 which is lower than the hard decision threshold of 3.8e-3, and under the condition that the key rate is not limited by the device, Gbit / s of high-speed key generation can be achieved, Figure 6 In order to pass the 15-item Nist random number test overview, which requires that the P-value value needs to be greater than 0.01.

[0056] As can be seen from the specific embodiment, the high-speed physical layer key distribution method and system compatible with the optical fiber communication system proposed by the application are as follows: the communication parties select wavelengths from a common multi-wavelength digital signal source, and then key the state of the laser through the Mach-Zehnder interferometer, since the multi-wavelength characteristic of the long-cavity Fabry-Perot laser and the large key space of the phase change, it is difficult for the eavesdropper to crack the security parameters, and in addition, the transmission is carried out in the middle core of the seven-core optical fiber, which can also exert an additional physical layer protection, and finally the communication parties extract consistent keys through the synchronized laser output of consistent signals, and the signals are encrypted and transmitted in the outer core of the seven-core optical fiber, realizing the secure and secret communication process of a system, and this scheme provides important value for future secure encryption communication based on semiconductor lasers.

[0057] Embodiment 2

[0058] As Figure 7 shown, the method for distributing security key in physical layer of multi-core optical fiber communication comprises the following steps:

[0059] S1: a common source generates a multi-wavelength driving signal, divides the multi-wavelength driving signal into two parts to obtain a first signal and a second signal, and transmits the first signal and the second signal to a local signal receiving module and a multi-core optical fiber link transmission module through a first signal output end and a second signal output end respectively, and the multi-core optical fiber link transmission module transmits the second signal to a remote signal receiving module;

[0060] S2: the local signal receiving module and the remote signal receiving module select signals of the same wavelength from the first signal and the second signal respectively, the same wavelength is within a certain range, and generate a first sequence and a first key code, a second sequence and a second key code according to the selected signals, and the first key code and the second key code are transmitted to the remote signal receiving module and the local signal receiving module through a wireless channel respectively;

[0061] S3: a post-processing module samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and according to the exchanged key codes, discards the inconsistent parts of the two groups of random numbers, retains the consistent key, and obtains consistent random numbers for encryption.

[0062] The method of the embodiment is based on the device of embodiment 1, therefore, the optional items proposed in embodiment 1 are applicable to the embodiment, which will not be repeated here.

[0063] Embodiment 3

[0064] The embodiment of the application further provides a computer readable storage medium, which stores a computer program, and the computer storage program is executed by a processor to realize the method for distributing security key in physical layer of multi-core optical fiber communication.

[0065] ​In summary, the embodiment of the present application provides a physical layer security key distribution device, method and storage medium in multi-core fiber communication, which drives the lasers of two places by using digital signals as a common source, wherein the common source uses a long cavity Fabry-Perot laser to simulate the generation of a multi-wavelength digital signal, and then improves the randomness and bandwidth of the signal through the scrambling effect of the fiber grating; after the selection of the wavelength is negotiated, the two parties of the secret communication can use a programmable optical filter to filter the multi-wavelength digital signal to select the corresponding wavelength, and since the combination of the wavelengths satisfies permutation and combination and the different wavelengths are basically irrelevant, under the condition that there are enough wavelengths to be selected, a large key space can be provided, and after the same wavelength is selected, the state of the random keying laser also needs to be selected, and only when the two lasers output the same state, the same signal can be output for key extraction, and since the phase change also has a key space, the two modes are cascaded to modulate, and the security of the system is significantly improved; the space division multiplexing technology is also used, the middle core is used for key generation, and the outer core is used for communication, and since the physical mechanism of the multi-core fiber, it is difficult for the eavesdropper to eavesdrop the information of the middle core, and since the common source uses a digital signal, the communication signal can be used for transmission, which reduces the optical source and reduces the complexity of the system, and also realizes the combination with the communication.

[0066] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and replacements can be made, and these improvements and replacements should be considered as the protection scope of the present application.

Claims

1. A physical layer security key distribution apparatus in multi-core fiber communication, characterized by, The device comprises a common source generating module (1), a multi-core optical fiber link transmission module (2), a local signal receiving module (3), a remote signal receiving module (4) and a post-processing module (501), the first signal output end of the common source generating module (1) is connected with the signal input end of the local signal receiving module (3), the second signal output of the common source generating module (1) is connected with the signal input end of the multi-core optical fiber link transmission module (2), the signal output end of the multi-core optical fiber link transmission module (2) is connected with the signal input end of the remote signal receiving module (4), and the signal output end of the local signal receiving module (3) and the signal output end of the remote signal receiving module (4) are connected with the post-processing module (501), The common source generating module (1) is used for generating a multi-wavelength driving signal, and after the multi-wavelength driving signal is divided into two parts, the two parts are transmitted to the local signal receiving module (3) and the multi-core optical fiber link transmission module (2) through the first signal output end and the second signal output end respectively; the local signal receiving module (3) is used for driving to generate a first sequence and a first keying code according to the multi-wavelength driving signal; the multi-core optical fiber link transmission module (2) is used for transmitting the multi-wavelength driving signal to the remote signal receiving module (4); the remote signal receiving module (4) is used for driving to generate a second sequence and a second keying code according to the multi-wavelength driving signal; the first keying code and the second keying code are transmitted to the remote signal receiving module (4) and the local signal receiving module (3) through a wireless channel respectively, the post-processing module (501) samples and quantizes the first sequence and the second sequence, obtains two groups of random numbers, and then according to the exchanged keying codes, discards the inconsistent parts of the two groups of random numbers, retains the consistent key, and obtains the consistent random number used for encryption.

2. The physical layer security key distribution apparatus in multi-core fiber communication according to claim 1, wherein The common source generating module (1) comprises a first long-cavity Fabry-Perot laser (101), an intensity modulator (102), a first arbitrary waveform generator (104), a first gain-adjustable electric amplifier (103), a first erbium-doped fiber amplifier (105), a fiber grating (106) and an optical coupler (107), The output end of the first long-cavity Fabry-Perot laser (101) is connected with the light input end of the intensity modulator (102), the output end of the first arbitrary waveform generator (104) is connected with the input end of the first gain adjustable electric amplifier (103), the output end of the first gain adjustable electric amplifier (103) is connected with the electric input end of the intensity modulator (102), the light output end of the intensity modulator (102) is connected with the input end of the first erbium-doped fiber amplifier (105), the output end of the first erbium-doped fiber amplifier (105) is connected with the input end of the fiber grating (106), the output end of the fiber grating (106) is connected with the input end of the optical coupler (107), the first signal output end of the optical coupler (107) is connected with the signal input end of the local signal receiving module (3), and the second signal output end of the optical coupler (107) is connected with the signal input end of the multi-core fiber link transmission module (2).

3. The physical layer security key distribution apparatus in multi-core fiber communication according to claim 2, wherein, The multi-core fiber link transmission module (2) comprises a first fan-in fan-out device (201), a seven-core fiber (202), a second fan-in fan-out device (203), a communication signal transmitter (204) and a communication signal receiver (205), The second signal output end of the optical coupler (107) in the common source generation module (1) is connected with the fourth input end of the first fan-in fan-out device (201) in the multi-core fiber link transmission module (2), the fourth output end of the first fan-in fan-out device (201) is connected with the input end of the seven-core fiber (202), the output end of the seven-core fiber (202) is connected with the fourth input end of the second fan-in fan-out device (203), the fourth output end of the second fan-in fan-out device (203) is connected with the signal input end of the remote signal receiving module (4), the output end of the communication signal transmitter (204) is connected with the first input end of the first fan-in fan-out device (201), and the first output end of the second fan-in fan-out device (203) is connected with the communication signal receiver (205).

4. The physical layer security key distribution apparatus in multi-core fiber communication according to claim 2, wherein, The local signal receiving module (3) comprises a first programmable optical filter (301), a first polarization controller (302), a first Mach-Zehnder interferometer (303), a second arbitrary waveform generator (305), a second gain adjustable electric amplifier (304), a second long-cavity Fabry-Perot laser (307), a first photodetector (306), The first signal output end of the optical coupler (107) in the common source generating module (1) is connected with the input end of the first programmable optical filter (301) in the local signal receiving module (3), the output end of the first programmable optical filter (301) is connected with the input end of the first polarization controller (302), the output end of the first polarization controller (302) is connected with the optical input end of the first Mach-Zehnder interferometer (303), the output end of the second arbitrary waveform generator (305) is connected with the input end of the second gain adjustable electric amplifier (304), and the output of the second arbitrary waveform generator (305) also needs to be sent to the remote signal receiving module (4) through a wireless channel, the output end of the second gain adjustable electric amplifier (304) is connected with the electric input end of the first Mach-Zehnder interferometer (303), the optical output end of the first Mach-Zehnder interferometer (303) is connected with the input end of the second long-cavity Fabry-Perot laser (307), the output end of the second long-cavity Fabry-Perot laser (307) is connected with the input end of the first photoelectric detector (306), and the output end of the first photoelectric detector (306) is connected with the input end of the post-processing module (501).

5. The physical layer security key distribution apparatus in multi-core fiber communication according to claim 4, wherein, The output of the second arbitrary waveform generator (305) is random, the phase output of the first Mach-Zehnder interferometer (303) changes with the change of the input signal voltage of the second arbitrary waveform generator (305), and the state of the second long-cavity Fabry-Perot laser (307) changes with the change of the phase output of the first Mach-Zehnder interferometer (303).

6. The physical layer security key distribution apparatus in multi-core fiber communication according to claim 3, wherein, The remote signal receiving module (4) comprises a dispersion compensation optical fiber (401), a second programmable optical filter (402), a second polarization controller (403), a second Mach-Zehnder interferometer (404), a third arbitrary waveform generator (406), a third gain adjustable electric amplifier (405), a third long-cavity Fabry-Perot laser (408), and a second photoelectric detector (407), The fourth output end of the second fan-in fan-out device (203) in the multi-core fiber link transmission module (2) is connected with the input end of the dispersion compensation fiber (401) in the remote signal receiving module, the output end of the dispersion compensation fiber (401) is connected with the input end of the second programmable optical filter (402), the output end of the second programmable optical filter (402) is connected with the input end of the second polarization controller (403), the output end of the second polarization controller (403) is connected with the optical input end of the second Mach-Zehnder interferometer (404), the output end of the third arbitrary waveform generator (406) is connected with the input end of the third gain adjustable electric amplifier (405), and the output of the third arbitrary waveform generator (406) is also sent to the local signal receiving module (3) through a wireless channel, the output end of the third gain adjustable electric amplifier (405) is connected with the electric input end of the second Mach-Zehnder interferometer (404), the optical output end of the second Mach-Zehnder interferometer (404) is connected with the input end of the third long-cavity Fabry-Perot laser (408), the output end of the third long-cavity Fabry-Perot laser (408) is connected with the input end of the second photoelectric detector (407), and the output end of the second photoelectric detector (407) is connected with the input end of the post-processing module (501).

7. The physical layer security key distribution apparatus in multi-core fiber communication according to claim 6, wherein, The output of the third arbitrary waveform generator (406) is random, the phase output of the second Mach-Zehnder interferometer (404) changes with the change of the input signal voltage of the third arbitrary waveform generator (406), and the state of the third long-cavity Fabry-Perot laser (408) changes with the change of the phase output of the second Mach-Zehnder interferometer (404).

8. A method for physical layer security key distribution in multi-core fiber communication, based on the physical layer security key distribution apparatus according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: A common source generation module generates a multi-wavelength driving signal, divides the multi-wavelength driving signal into two parts to obtain a first signal and a second signal, and transmits the first signal and the second signal to a local signal receiving module and a multi-core fiber link transmission module through a first signal output end and a second signal output end respectively, and the multi-core fiber link transmission module transmits the second signal to a remote signal receiving module; The local signal receiving module and the remote signal receiving module select signals of the same wavelength from the first signal and the second signal respectively, and generate a first sequence and a first keying code, a second sequence and a second keying code according to the selected signals, and the first keying code and the second keying code are transmitted to the remote signal receiving module and the local signal receiving module through a wireless channel respectively; A post-processing module samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and according to the exchanged keying codes, discards the inconsistent parts of the two groups of random numbers, retains the consistent key, and obtains consistent random numbers for encryption.

9. The method of claim 8, wherein, The same wavelength is within the same wavelength.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by a processor to implement the physical layer security key distribution method in the multi-core fiber communication according to any one of claims 8 to 9.

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