Physical layer security key distribution device and method in multi-core optical fiber communication

Abstract

The invention relates to the technical field of optical communication, and discloses a physical layer security key distribution device and method in multi-core optical fiber communication, and the device 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, 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 wireless channels, and the post-processing module obtains consistent random numbers for encryption according to the first sequence and the second sequence. According to the invention, high-speed key distribution can be realized, and the system security is improved under the condition that the system complexity and cost are not increased.

Description

Technical Field

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

[0002] Optical fiber communication has become a key technology for modern data transmission due to its superior characteristics such as high bandwidth, low signal attenuation and long-distance transmission. Broadband communication has entered the era of gigabit access networks and 100G backbone networks. However, the transmission capacity of single-mode optical fiber has reached its theoretical upper limit, and multi-core optical fiber has gradually been applied to broadband communication due to its advantages of large-capacity transmission and low crosstalk obtained by space division multiplexing. Nowadays, the laying of multi-core optical fiber in actual links has reached the level of hundreds of kilometers, and is gradually developing towards the level of thousands of kilometers. The application of multi-core optical fiber is an inevitable development 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 issues in the design of current optical fiber communication systems. Among them, the security issue of single-mode optical fiber communication is mainly reflected in the risk of eavesdropping on signals. Although single-mode optical fiber has a certain degree of physical security and its signal transmission is not easy to be directly monitored, it can extract optical signals without interrupting transmission through complex technical means. This eavesdropping behavior may lead to unauthorized access and threaten the security of sensitive information. For multi-core optical fibers with an intermediate core, it is difficult to directly extract sensitive information from the intermediate core due to known bending eavesdropping, which will be interfered by the information of the outer core, making existing eavesdropping methods ineffective. However, in order to prevent unknown eavesdropping methods, it is also necessary to encrypt it to prevent the potential risk of leakage. Therefore, ensuring encryption and distribution of security keys has become a key link in building a secure communication system.

[0003] In the face of the large number of multi-core optical fiber networks currently being laid and the potential risks of eavesdropping, there is an urgent need for a mechanism that can meet the needs of high-speed information communication and can also encrypt sensitive information in a timely manner. This is a process that reflects the compatibility of secure key distribution and optical fiber communication. First, the key distribution system needs to be compatible with the optical fiber transmission link, and second, the key distribution process can be parallel to the communication.

[0004] The key distribution method based on algorithms has the risk of being cracked due to the substantial increase in computer performance. Therefore, people have conducted extensive research on the key generation method through the physical layer. Among them, quantum key distribution is difficult for eavesdroppers to obtain information due to the non-copyability of single quantum. However, the transmission of single quantum in quantum key distribution requires special quantum channels, which are incompatible with the existing optical fiber communication system. There is also a rate bottleneck problem. In the classical physical layer key distribution, physical non-clonable devices have the problem of limited key length, and channel reciprocity has the problem of limited transmission distance. Both methods are difficult to meet the current high-speed information communication. Among them, the key generation based on chaotic lasers stands out due to its advantages such as high speed, high complexity, and long transmission distance. In addition, the optical signal generated by chaotic lasers can also be used in optical fiber transmission, which is a potential solution.

[0005] Chaotic lasers are used as physical entropy sources to generate high-speed random numbers due to their wide spectrum and large-amplitude random fluctuation characteristics. In addition, two chaotic lasers can achieve chaotic synchronization under the conditions of structural and parameter matching, and generate highly correlated chaotic waveforms that can be used for key distribution. Key distribution based on chaotic laser correlation is that legitimate users use synchronized chaotic lasers or broadband noise sources as correlation signal sources and modulate them with independent random signals, and finally select chaotic timing under the same modulation state to extract consistent keys.

[0006] At present, the method of using synchronized chaotic lasers as the source of related signals is based on the principle of using a common source to generate chaotic light through phase modulation or dispersion feedback, and then injecting two response lasers to control the state of the chaotic signal through keying, and extracting the key under the condition of consistency. For example, the prior art (CN109672533A) provides a high-speed key distribution device based on chaotic synchronization of semiconductor lasers. By controlling the feedback intensity and polarization state, both linear polarization modes can output chaotic signals, and a random bit generator is used to key the polarization state. When the polarization states of the feedback light corresponding to the two response lasers are consistent, the two lasers can obtain chaotic signals with good synchronization performance. The literature (OpticsExpress, Vol. 30, pp. 23953-23966, 2022) reports that chaotic light is injected into a distributed feedback laser without feedback, and the output chaotic self-carrier is phase modulated and delayed shift keyed. Although the transmission distance is only 40 km, the key distribution rate can reach 2.1 Gbit / s. The literature (Optics Express, Vol. 28, pp. 37919-37935, 2020) reported that chaotic light generated by mirror feedback was injected into a response laser with dispersion shift keying, and a high-speed physical key distribution of 1.2 Gb / s was achieved in simulation. This technical route uses a single-wavelength analog signal as a driving source and transmits it in a single-mode optical fiber. However, domestic land and submarine cables have developed to the thousand-kilometer level. As an analog signal, chaotic signals are inevitably interfered by channel damage during transmission, which will further affect compatibility. At the same time, due to transmission in a single-mode optical fiber, the transmission capacity and security are not as good as those of multi-core optical fibers.

[0007] Using a broadband noise source as a related signal source, the principle is to use broadband noise light to inject chaotic lasers, and also to control the state of chaotic signals through keying. For example, the prior art (CN112653545A) provides a key distribution system based on distributed feedback laser injection optical power keying, using a broadband noise light source to output broadband noise optical signals, and then keying the optical power through a power-adjustable laser module. Only under the same power modulation can the lasers be synchronized. At present, the literature (Physical Review L, Vol. 108, 070602, 2012) reports that chaotic synchronization is achieved by injecting continuous light modulated by phase noise into two responding lasers, achieving a key distribution rate of 120 km and 128 kbit / s. The literature (Optics Express, Vol. 31, pp. 42838-42849, 2023) reported that broadband noise light generated by superluminescent diodes was filtered and injected into the responding distributed feedback laser to synchronize chaos, and a special random sequence modulation method was used to achieve 2.55 Gbit / s key generation. However, since the broadband noise signal is still an analog signal and the transmission medium is still limited to single-mode optical fiber, there are still problems such as the transmission distance is limited to hundreds of kilometers and compatibility with the communication process is difficult.

[0008] The above-mentioned chaotic laser-based solutions all use analog signals for transmission. During long-distance transmission, such as thousands of kilometers of optical fiber cables, the channel damage will be more serious. Multiple hardware devices need to be relayed to compensate for the damage of channel dispersion and nonlinearity, which will greatly increase the cost and make it difficult to be compatible with communication systems. At the same time, the use of analog signal transmission will also sacrifice channel capacity. In addition, the transmission in single-mode optical fiber has limited capacity and potential threats to security. Summary of the invention

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

[0010] As another object of the present invention, a method suitable for the device according to the aforementioned object is also provided.

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

[0012] In order to achieve the primary purpose of the present invention, the present invention provides a physical layer security key distribution device in multi-core optical fiber communication, including: 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, wherein the first signal output end of the common source generation module is connected to the signal input end of the local signal receiving module, the second signal output of the common source generation module is connected to 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 to the signal input end of the remote signal receiving module, and the signal output end of the local signal receiving module and the signal output end of the remote signal receiving module are both connected to the post-processing module. The common source generation module is used to generate a multi-wavelength driving signal, and after dividing the multi-wavelength driving signal into two, transmit the signal 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 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 to transmit the multi-wavelength driving signal to the remote signal receiving module; the remote signal receiving module is used 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 respectively transmitted to the remote signal receiving module and the local signal receiving module through a wireless channel, and the post-processing module samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and then discards the inconsistent parts of the two groups of random numbers according to the exchanged keying codes, retains the consistent keys, and obtains consistent random numbers for encryption.

[0013] Furthermore, the common source generation module includes: 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, The output end of the first long cavity Fabry-Perot laser is connected to the optical input end of the intensity modulator, the output end of the first arbitrary waveform generator is connected to the input end of the first gain adjustable electric amplifier, the output end of the first gain adjustable electric amplifier is connected to the electrical input end of the first intensity modulator, the optical output end of the first intensity modulator is connected to the input end of the first erbium-doped fiber amplifier, the output end of the first erbium-doped fiber amplifier is connected to the input end of the fiber Bragg grating, the output end of the fiber Bragg grating is connected to the input end of the optical coupler, the first signal output end of the optical coupler is connected to the signal input end of the local signal receiving module, and the second signal output end of the optical coupler is connected to the signal input end of the multi-core optical fiber link transmission module.

[0014] Furthermore, the multi-core optical fiber link transmission module includes: a first fan-in fan-out device, a seven-core optical fiber, a second fan-in fan-out device, a communication signal transmitter and a communication signal receiver, The second signal output end of the optical coupler in the common source generating module is connected to the fourth input end of the first fan-in and fan-out in the multi-core optical fiber link transmission module, the fourth output end of the first fan-in and fan-out is connected to the input end of the middle core of the seven-core optical fiber, the output end of the middle core of the seven-core optical fiber is connected to the fourth input end of the second fan-in and fan-out, the fourth output end of the second fan-in and fan-out is connected to the signal input end of the remote signal receiving module, the output end of the communication signal transmitter is connected to the first input end of the first fan-in and fan-out, and the first output end of the second fan-in and fan-out is connected to the communication signal receiver.

[0015] Furthermore, the local signal receiving module includes: a first programmable optical filter, a first polarization controller, a first Mach-Zehnder interferometer, a second arbitrary waveform generator, a second gain adjustable electric amplifier, a second long cavity Fabry-Perot laser, a first photodetector, The first signal output end of the optical coupler in the common source generating module is connected to 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 to the input end of the first polarization controller, the output end of the first polarization controller is connected to the optical input end of the first Mach-Zehnder interferometer, the output end of the second arbitrary waveform generator is connected to the input end of the second gain adjustable electric 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 electric amplifier is connected to the electrical input end of the first Mach-Zehnder interferometer, the optical output end of the first Mach-Zehnder interferometer is connected to the input end of the second long cavity Fabry-Perot laser, the output end of the second long cavity Fabry-Perot laser is connected to the input end of the first photodetector, and the output end of the first photodetector is connected to the input end of the digital oscilloscope.

[0016] Furthermore, 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 input signal voltage of the second arbitrary waveform generator, and the state of the second long cavity Fabry-Perot laser changes with the phase output of the first Mach-Zehnder interferometer.

[0017] Furthermore, the remote signal receiving module includes a dispersion compensating optical fiber, a second programmable optical filter, a second polarization controller, a second Mach-Zehnder interferometer, a third arbitrary waveform generator, a third gain adjustable electric amplifier, a third long cavity Fabry-Perot laser, a second photodetector, The fourth output end of the second fan-in and fan-out device in the multi-core optical fiber link transmission module is connected to the input end of the dispersion compensating optical fiber in the remote signal receiving module, the output end of the dispersion compensating optical fiber is connected to the input end of the second programmable optical filter, the output end of the second programmable optical filter is connected to the input end of the second polarization controller, the output end of the second polarization controller is connected to the optical input end of the second Mach-Zehnder interferometer, the output end of the third arbitrary waveform generator is connected to the input end of the third gain adjustable electric amplifier, and the output of the third arbitrary waveform generator is also sent to the local signal receiving end through a wireless channel, the output end of the third gain adjustable electric amplifier is connected to the electrical input end of the second Mach-Zehnder interferometer, the optical output end of the second Mach-Zehnder interferometer is connected to the input end of the third long cavity Fabry-Perot laser, the output end of the third long cavity Fabry-Perot laser is connected to the input end of the second photodetector, and the output end of the second photodetector is connected to the input end of the digital oscilloscope.

[0018] Furthermore, 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 input signal voltage of the third arbitrary waveform generator, and the state of the third long cavity Fabry-Perot laser changes with the phase output of the second Mach-Zehnder interferometer.

[0019] In order to achieve another object of the present invention, a physical layer security key distribution method in multi-core optical fiber communication is also provided. The method is based on the physical layer security key distribution device in multi-core optical fiber communication, and comprises the following steps: The common source generation module generates a multi-wavelength driving signal, and divides the multi-wavelength driving signal into two 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; The local signal receiving module and the remote signal receiving module respectively select signals of the same wavelength from the first signal and the second signal, 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 respectively transmitted to the remote signal receiving module and the local signal receiving module through a wireless channel; The post-processing module samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and then discards inconsistent parts of the two groups of random numbers according to the exchanged key codes, retains consistent keys, and obtains consistent random numbers for encryption.

[0020] Furthermore, the same wavelength is Inside.

[0021] In order to achieve another purpose of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored. When the computer-stored program is executed by a processor, the physical layer security key distribution method in multi-core optical fiber communication is implemented.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The present invention drives lasers at two locations 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 signal through the scrambling effect of the fiber grating; after negotiating the selection of wavelengths, the two parties in the confidential communication can use a programmable optical filter to filter the multi-wavelength digital signal so as to select the corresponding wavelength. Since the combination of wavelengths satisfies the characteristics of permutation and combination and different wavelengths are basically unrelated, a large key space can be provided under the condition that there are enough wavelengths available for selection. At the same time, after selecting a consistent wavelength, the state of the laser needs to be randomly keyed. Only when the two lasers output the same state can a consistent signal be output for key extraction. Since the phase change also has a key space, the two modes are cascaded for modulation, 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. Due to the physical mechanism of the multi-core optical fiber, it is difficult for an eavesdropper to eavesdrop on the information of the middle core. Since the common source uses a digital signal, the communication signal can be used as a driver for transmission, the light source is reduced, the system complexity can be reduced, and the combination with communication is also achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of a physical layer security key distribution device in multi-core optical fiber communication according to embodiment 1 of the present invention; Figure 2 This is a common source signal spectrum diagram of Example 1 of the present invention; Figure 3 A timing diagram of digital signals included in each wavelength of Embodiment 1 of the present invention; Figure 4 This is a timing diagram of a scrambled digital signal according to Embodiment 1 of the present invention; Figure 5 This is a timing diagram of a portion of synchronous output signals intercepted by a response laser according to Embodiment 1 of the present invention, wherein Alice and Bob are the communicating parties; Figure 6 This is an overview of 15 Nist random number tests in Example 1 of the present invention; Figure 7 This is a flow chart of a physical layer security key distribution method in multi-core optical fiber communication according to embodiment 2 of the present invention.

[0024] Description of Figure Numbers: 1. Common source generation module; 101. First long cavity Fabry-Perot laser; 102. Intensity modulator; 104. First arbitrary waveform generator; 103. First gain adjustable electric amplifier; 105. First erbium-doped fiber amplifier; 106. Fiber Bragg grating; 107. Optical coupler; 2. Multi-core fiber link transmission module; 201. First fan-in fan-out; 202. Seven-core optical fiber; 203. Second fan-in fan-out; 204. Communication signal transmitter; 205. Communication signal receiver; 3. Local signal receiving module; 301. First programmable optical filter; 302. First polarization controller; 303 , first Mach-Zehnder interferometer; 305, second arbitrary waveform generator; 304, second gain adjustable electric amplifier; 307, second long cavity Fabry-Perot laser; 306, first photodetector; 4, remote signal receiving module; 401, dispersion compensation optical fiber; 402, second programmable optical filter; 403, second polarization controller; 404, second Mach-Zehnder interferometer; 406, third arbitrary waveform generator; 405, third gain adjustable electric amplifier; 408, third long cavity Fabry-Perot laser; 407, second photodetector; 501, post-processing module (501) DETAILED DESCRIPTION The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0028] Example 1 like Figure 1 As shown, a physical layer security key distribution device in a multi-core optical fiber communication of a preferred embodiment of an embodiment of the present invention 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, wherein a first signal output end of the common source generating module 1 is connected to a signal input end of the local signal receiving module 3, a second signal output end of the common source generating module 1 is connected to a signal input end of the multi-core optical fiber link transmission module 2, a signal output end of the multi-core optical fiber link transmission module 2 is connected to a signal input end of the remote signal receiving module 4, a signal output end of the local signal receiving module 3 and a signal output end of the remote signal receiving module 4 are both connected to the post-processing module 501, The common source generation module 1 is used to generate a multi-wavelength driving signal, and after dividing the multi-wavelength driving signal into two, transmit it 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 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 to transmit the multi-wavelength driving signal to the remote signal receiving module 4; the remote signal receiving module 4 is used 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 respectively transmitted to the remote signal receiving module 4 and the local signal receiving module 3 through a wireless channel, 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 discards the inconsistent parts of the two groups of random numbers according to the exchanged keying codes, retains the consistent keys, and obtains consistent random numbers for encryption.

[0029] 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 inject the optical signal into the intensity modulator 102, and the output signal of the first arbitrary waveform generator 104 can be an NRZ signal or a high-order QPSK or PAM4 signal, etc. After the intensity of the electrical signal is amplified by the first gain adjustable electrical amplifier 103, it is injected into the intensity modulator 102 to simulate a multi-wavelength communication signal. Figure 2 is the spectrum of the common source signal, Figure 3 The timing of the digital signal contained in each wavelength.

[0030] like Figure 1 As 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 To adjust the timing of the scrambled digital signal, the scrambled signal is injected into the optical coupler 107, and then one output end of the optical coupler 107 is injected into the first programmable optical filter 301 in the local signal receiving module to retain the signal locally, and the second output end of the optical coupler 107 is injected into the fourth input end of the first fan-in and fan-out device 201 in the multi-core optical fiber link transmission module to prepare for sending to a remote location.

[0031] like Figure 1 As shown, in the multi-core optical fiber link transmission module 2, the two output ends of the optical coupler 107 are injected into the fourth input end of the first fan-in fan-out device 201 in the multi-core link transmission module, and the signal enters the middle core of the seven-core optical fiber 202 to start transmission. After being transmitted to the remote end, the signal will enter the fourth input end of the second fan-in fan-out device 203 from the middle core of the seven-core optical fiber 202 to be ready to be received 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 optical fiber 202 through an input end of the fan-in fan-out device for transmission. After the outer core is output, the receiving end uses the communication signal receiver 205 to receive the communication signal, so as to simulate the normal communication between users in the key distribution process. The communicating parties communicate normally in the outer core, and the inner core is used to transmit a common digital signal source, which is used to control the synchronization of the response laser in the key distribution system, and can achieve parallel with the key distribution system during the communication process.

[0032] like Figure 1As shown, in the local signal receiving module 3, the signal is first injected from an output end 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, and then the signal after the wavelength selection is injected into the first polarization controller 302 for controlling the signal to be injected into the laser as linear polarization, and then 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, and 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, wherein the keying code generated by the second arbitrary waveform generator 305 will be transmitted to the remote end through the wireless channel, and then the signal with the controlled phase will be injected into the second long cavity Fabry-Perot laser 307.

[0033] Specifically, since the laser is sensitive to phase, different injected signal phases 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 and then enter the post-processing module 501 for sampling and quantization.

[0034] 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 and fan-out device 203 in the multi-core optical fiber link transmission module to the dispersion compensation optical fiber 401 in the remote signal receiving module to compensate for the dispersion of the seven-core optical fiber, and then the signal is connected to the second programmable optical filter 402 to select the wavelength of the signal. Here, it is necessary to select a wavelength consistent with the local end. If it is inconsistent, the signals of both parties will be unrelated.

[0035] like Figure 1 As shown, the signal after wavelength selection is injected into the second polarization controller 403 to control the signal as a linear polarization injection 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 will output a random NRZ signal, and the second Mach-Zehnder interferometer 404 will output signals with different phases according to the signal voltage change of the third arbitrary waveform generator 406. Here, the output signal of the third arbitrary waveform generator 406 may be inconsistent with the output signal of the second arbitrary waveform generator 305, because the remote end will send the key code to the local end through the wireless channel, so as to realize the exchange of the key code between the two in the wireless channel.

[0036] Specifically, the phase-controlled signal is injected into the third long-cavity Fabry-Perot laser 408. Under the same phase injection, the two lasers will output synchronized signals, and under different phase injection, the two lasers will be out of sync. 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 timing diagram of the partial synchronous output signal intercepted by the laser, Alice and Bob are the communicating parties, and then enter the post-processing module 501 for sampling and quantization. The local and remote sites will select the random number generated when the same key code is used through the exchanged key code, and discard the random number generated when the key code is different. Finally, the communicating parties will obtain a consistent key for encryption. At the same time, the collected 10 Mbit signal is quantized and the same keying part is retained. Finally, a 2.25 Mbit key is generated when the bit error rate is 1.4e-3, which is lower than the hard decision threshold of 3.8e-3. When the key rate is not limited by the device, the high-speed key generation of Gbit / s can be achieved. Figure 6 To pass the 15-item Nist random number test, the P-value must be greater than 0.01.

[0037] It can be seen from the specific embodiments that the present invention proposes a high-speed physical layer key distribution method and system that is compatible with an optical fiber communication system. The communicating parties select the wavelength of a common multi-wavelength digital signal source, and then key the state of the laser through a Mach-Zehnder interferometer. Due to the multi-wavelength characteristics of the long-cavity Fabry-Perot laser and the large key space of phase changes, it is difficult for eavesdroppers to crack the parameters that ensure security. Furthermore, transmission is performed in the middle core of a seven-core optical fiber, and an additional physical layer protection can be applied. Finally, the communicating parties extract a consistent key through the synchronized laser output of a consistent signal, and encrypt the signal for transmission in the outer core of the seven-core optical fiber, thereby realizing a secure and confidential communication process of the system. This solution provides important value for future secure encrypted communications based on semiconductor lasers.

[0038] Example 2 like Figure 7 As shown, a physical layer security key distribution method in multi-core optical fiber communication according to an embodiment of the present invention includes: S1: The common source generation module generates a multi-wavelength driving signal, and divides the multi-wavelength driving signal into two 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; S2: The local signal receiving module and the remote signal receiving module select signals with the same wavelength from the first signal and the second signal respectively. and generating a first sequence and a first key code, a second sequence and a second key code according to the selected signal, wherein the first key code and the second key code are transmitted to the remote signal receiving module and the local signal receiving module respectively through a wireless channel; S3: The post-processing module samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and then discards inconsistent parts of the two groups of random numbers according to the exchanged key codes, retains consistent keys, and obtains consistent random numbers for encryption.

[0039] The method of this embodiment is based on the device of Embodiment 1. Therefore, the options proposed in Embodiment 1 are applicable to this embodiment and will not be described in detail here.

[0040] Example 3 An embodiment of the present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer-stored program is executed by a processor, the physical layer security key distribution method in multi-core optical fiber communication is implemented.

[0041] In summary, the embodiments of the present invention provide a physical layer security key distribution device, method and storage medium in multi-core optical fiber communication, which drives the lasers at two locations 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 signal through the scrambling effect of the fiber grating; after negotiating the selection of wavelengths, the two parties in the confidential communication can use programmable optical filters to filter the multi-wavelength digital signals so as to select the corresponding wavelength. Since the combination of wavelengths satisfies the characteristics that different wavelengths are basically unrelated to each other in the permutation combination, under the condition that there are enough wavelengths available for selection, , it can have a huge key space. At the same time, after selecting a consistent wavelength, it is also necessary to randomly key the state of the laser. Only when the two lasers output the same state can they output a consistent signal for key extraction. Since the phase change also has a key space, the two methods are cascaded for modulation, and the security of the system has been significantly improved. It also uses space division multiplexing technology, the middle core is used for key generation, and the outer core is used for communication. Due to the physical mechanism of multi-core optical fiber, it is difficult for eavesdroppers to eavesdrop on the information of the middle core. Since the public source uses a digital signal, the communication signal can be used as a drive for transmission. Reducing the light source can reduce the complexity of the system and also achieve integration with communication.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A physical layer security key distribution device in multi-core optical fiber communication, characterized in that: 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), wherein a first signal output end of the common source generating module (1) is connected to a signal input end of the local signal receiving module (3), a second signal output end of the common source generating module (1) is connected to a signal input end of the multi-core optical fiber link transmission module (2), a signal output end of the multi-core optical fiber link transmission module (2) is connected to a signal input end of the remote signal receiving module (4), and a signal output end of the local signal receiving module (3) and a signal output end of the remote signal receiving module (4) are both connected to the post-processing module (501). The common source generation module (1) is used to generate a multi-wavelength drive signal, and after dividing the multi-wavelength drive signal into two, transmit the signal to the local signal receiving module (3) and the multi-core optical fiber link transmission module (2) through a first signal output terminal and a second signal output terminal respectively; the local signal receiving module (3) is used to generate a first sequence and a first key code according to the multi-wavelength drive signal drive; 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 generate a second sequence and a second key code according to the multi-wavelength drive signal drive; the first key code and the second key 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 to obtain two groups of random numbers, and then discards inconsistent parts of the two groups of random numbers according to the exchanged key codes, retains a consistent key, and obtains a consistent random number for encryption.

2. A physical layer security key distribution device in multi-core optical fiber communication according to claim 1, characterized in that The common source generation 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 to the optical input end of the intensity modulator (102), the output end of the first arbitrary waveform generator (104) is connected to the input end of the first gain adjustable electric amplifier (103), the output end of the first gain adjustable electric amplifier (103) is connected to the electrical input end of the first intensity modulator (102), the optical output end of the first intensity modulator (102) is connected to the input end of the first erbium-doped fiber amplifier (105), the output end of the first erbium-doped fiber amplifier (105) is connected to the input end of the fiber Bragg grating (106), the output end of the fiber Bragg grating (106) is connected to the input end of the optical coupler (107), the first signal output end of the optical coupler (107) is connected to the signal input end of the local signal receiving module (3), and the second signal output end of the optical coupler (107) is connected to the signal input end of the multi-core optical fiber link transmission module (2).

3. The physical layer security key distribution device in multi-core optical fiber communication according to claim 2, characterized in that: The multi-core optical fiber link transmission module (2) comprises: a first fan-in fan-out device (201), a seven-core optical 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 to the fourth input end of the first fan-in fan-out device (201) in the multi-core optical fiber link transmission module (2); the fourth output end of the first fan-in fan-out device (201) is connected to the input end of the middle core (202) of the seven-core optical fiber; the output end of the middle core (202) of the seven-core optical fiber is connected to 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 to the signal input end of the remote signal receiving module (4); the output end of the communication signal transmitter (204) is connected to 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 to the communication signal receiver (205).

4. The physical layer security key distribution device in multi-core optical fiber communication according to claim 2, characterized in that: 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 to 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 to the input end of the first polarization controller (302), the output end of the first polarization controller (302) is connected to the optical input end of the first Mach-Zehnder interferometer (303), the output end of the second arbitrary waveform generator (305) is connected to the input end of the second gain adjustable electric amplifier (304), and the second arbitrary waveform generator (3 05) 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 to the electrical input end of the first Mach-Zehnder interferometer (303), the optical output end of the first Mach-Zehnder interferometer (303) is connected to 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 to the input end of the first photodetector (306), and the output end of the first photodetector (306) is connected to the input end of the digital oscilloscope (501).

5. The physical layer security key distribution device in multi-core optical fiber communication according to claim 4, characterized in that: 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 device in multi-core optical fiber communication according to claim 3, characterized in that: The remote signal receiving module (4) comprises a dispersion compensating 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 photodetector (407). The fourth output end of the second fan-in fan-out device (203) in the multi-core optical fiber link transmission module (2) is connected to the input end of the dispersion compensation optical fiber (401) in the remote signal receiving module, the output end of the dispersion compensation optical fiber (401) is connected to the input end of the second programmable optical filter (402), the output end of the second programmable optical filter (402) is connected to the input end of the second polarization controller (403), the output end of the second polarization controller (403) is connected to the optical input end of the second Mach-Zehnder interferometer (404), the output end of the third arbitrary waveform generator (406) is connected to the output end of the third gain adjustable electric amplifier (405), and the output end of the third arbitrary waveform generator (406) is connected to the output end of the third gain adjustable electric amplifier (405). The output of the third arbitrary waveform generator (406) is also sent to the local signal receiving end (3) through a wireless channel, the output end of the third gain adjustable electric amplifier (405) is connected to the electric input end of the second Mach-Zehnder interferometer (404), the optical output end of the second Mach-Zehnder interferometer (404) is connected to 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 to the input end of the second photodetector (407), and the output end of the second photodetector (407) is connected to the input end of the digital oscilloscope (501).

7. The physical layer security key distribution device in multi-core optical fiber communication according to claim 6, characterized in that: 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 distributing physical layer security keys in multi-core optical fiber communication, the method being based on a device for distributing physical layer security keys in multi-core optical fiber communication according to any one of claims 1 to 7, characterized in that: The following steps are involved: The common source generation module generates a multi-wavelength driving signal, and divides the multi-wavelength driving signal into two 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; The local signal receiving module and the remote signal receiving module respectively select signals of the same wavelength from the first signal and the second signal, 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 respectively transmitted to the remote signal receiving module and the local signal receiving module through a wireless channel; The post-processing module samples and quantizes the first sequence and the second sequence to obtain two groups of random numbers, and then discards inconsistent parts of the two groups of random numbers according to the exchanged key codes, retains consistent keys, and obtains consistent random numbers for encryption.

9. A method for distributing physical layer security keys in multi-core optical fiber communication according to claim 8, characterized in that: The same wavelength Inside.

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

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