Quantum key distribution method, system and device for co-channel transmission

Abstract

The present disclosure provides a co-channel transmission quantum key distribution method, system and device, which can be applied to the technical field of information security. The co-channel transmission quantum key distribution method is applied to a receiving end of a quantum key distribution system, and includes: in response to obtaining a composite optical signal sent by a sending end, performing wave separation processing on the composite optical signal to obtain a first quantum optical signal, a synchronization optical signal and a classical optical signal; performing quantum state measurement on the first quantum optical signal to obtain a second quantum optical signal in a determined state; performing clock synchronization processing on the second quantum optical signal by using the synchronization optical signal to obtain a third quantum optical signal; performing signal rejection on the third quantum optical signal by using preset time position information to obtain a fourth quantum optical signal; and performing key negotiation based on the classical optical signal and the fourth quantum optical signal to obtain a target key.

Description

Technical Field

[0001] This disclosure relates to the field of information security technology, and more specifically, to a quantum key distribution method, system, and device for co-channel transmission. Background Technology

[0002] Quantum key distribution (QKD) technology utilizes the uncertainty principle and the no-cloning theorem of quantum mechanics to achieve secure key sharing. With the development of quantum technology, an increasing number of enterprises are adopting QKD for information encryption and protection. Currently, QKD technology has wide applications in financial systems, e-commerce, and government systems.

[0003] In realizing the concept disclosed herein, the inventors discovered that there are many interference signals in the quantum optical signal during the quantum key distribution process in related technologies, resulting in low efficiency of quantum key distribution. Summary of the Invention

[0004] In view of this, the present disclosure provides a quantum key distribution method, system and device for co-channel transmission.

[0005] One aspect of this disclosure provides a quantum key distribution method for co-channel transmission, applied at the receiver end of a quantum key distribution system, comprising: in response to acquiring a composite optical signal transmitted by a transmitter, performing wavelength division processing on the composite optical signal to obtain a first quantum optical signal, a synchronization optical signal, and a classical optical signal; performing quantum state measurement on the first quantum optical signal to obtain a second quantum optical signal in a defined state; performing clock synchronization processing on the second quantum optical signal using the synchronization optical signal to obtain a third quantum optical signal; performing signal elimination on the third quantum optical signal using preset time position information to obtain a fourth quantum optical signal; and performing key negotiation based on the classical optical signal and the fourth quantum optical signal to obtain a target key.

[0006] According to an embodiment of this disclosure, the above-described quantum key distribution method for co-channel transmission further includes: in response to an initialization request, determining the preset time position information based on the initialization optical signal sent by the transmitting end.

[0007] According to embodiments of this disclosure, determining the preset time position information based on the initialization optical signal transmitted by the transmitting end in response to an initialization request includes: acquiring the initialization optical signal transmitted by the transmitting end in response to the initialization request; performing wavelength division processing on the initialization optical signal to obtain an initialization synchronization optical signal and an initialization classical optical signal; obtaining the time position information of the initialization synchronization optical signal and the time position information of the initialization classical optical signal based on the quantum state measurement results of the initialization synchronization optical signal and the initialization classical optical signal, respectively; and obtaining the preset time position information based on the time position information of the initialization synchronization optical signal and the time position information of the initialization classical optical signal.

[0008] According to embodiments of this disclosure, the above-mentioned method of using preset time and position information to remove signals from the third quantum optical signal to obtain a fourth quantum optical signal includes: determining a target wavelength band corresponding to the initialization synchronization optical signal and the initialization classical optical signal based on the preset time and position information; and removing the optical signal corresponding to the target wavelength band from the third quantum optical signal to obtain the fourth quantum optical signal.

[0009] According to embodiments of this disclosure, the key negotiation process based on the classical optical signal and the fourth quantum optical signal to obtain the target key includes: determining the basis vector of the transmitting end based on the classical optical signal; determining the sieved key from the fourth quantum optical signal based on the basis vector of the transmitting end and the basis vector of the receiving end; calculating the bit error rate of the sieved key; performing error correction processing on the sieved key if the bit error rate of the sieved key is less than a preset value to obtain an intermediate target key; and amplifying the intermediate target key based on the error correction processing result to obtain the target key.

[0010] Another aspect of this disclosure provides a quantum key distribution system for co-channel transmission, comprising: a transmitter for generating a quantum optical signal, a negotiation optical signal, and a classical optical signal, and transmitting a composite optical signal obtained by combining the quantum optical signal, the negotiation optical signal, and the classical optical signal to a receiver; a channel for transmitting the composite optical signal; and a receiver for performing wavelength division processing on the received composite optical signal to obtain a first quantum optical signal, performing quantum state measurement on the first quantum optical signal obtained by wavelength division, removing the synchronization optical signal and the classical optical signal from the first quantum optical signal using preset time and position information to obtain a fourth quantum optical signal, and performing key negotiation based on the classical optical signal and the fourth quantum optical signal to obtain a target key.

[0011] According to embodiments of this disclosure, the transmitting end includes: a quantum state preparation module for generating a single-photon quantum optical signal using a first clock signal, wherein the single-photon quantum optical signal is a signal at the single-photon level; a synchronous light generation module for generating a synchronous optical signal using a second clock signal; a first classical communication transceiver module for generating a classical optical signal using a third clock signal; a first wavelength division multiplexer for performing a multiplexing process on the quantum optical signal, the synchronous optical signal, and the classical optical signal to obtain a composite optical signal; and a first electronic control system for outputting the first clock signal, the second clock signal, and the third clock signal, wherein the first clock signal, the second clock signal, and the third clock signal are synchronous clocks, and the first clock signal, the second clock signal, and the third clock signal are coherent.

[0012] According to an embodiment of this disclosure, the quantum state preparation module is used to generate a quantum optical signal using a first clock signal, including: triggering a laser using the first clock signal to generate an optical pulse signal; performing quantum state modulation on the optical pulse signal using a quantum state modulation unit to obtain an intermediate optical pulse signal; and performing optical attenuation processing on the intermediate optical pulse signal using an optical attenuator to obtain the quantum optical signal; wherein the optical attenuator includes at least one of a fixed optical attenuator and an electrically controlled optical attenuator.

[0013] According to embodiments of this disclosure, the receiving end includes: a second wavelength division multiplexer for performing wavelength division processing on the composite optical signal acquired from the receiving end to obtain a first quantum optical signal, a synchronization optical signal, and a classical optical signal; a quantum state measurement module for performing quantum state measurement on the first quantum optical signal to obtain a second quantum optical signal in a defined state; a synchronization optical processing module for performing clock synchronization processing on the second quantum optical signal to obtain a third quantum optical signal; a second electronic control system for recording the second quantum optical signal and using preset time and position information to perform signal rejection on the third quantum optical signal to obtain a fourth quantum optical signal; and a second classical communication transceiver module for performing key negotiation based on the classical optical signal and the fourth quantum optical signal to obtain a target key.

[0014] Another aspect of this disclosure provides an electronic device comprising:

[0015] One or more processors;

[0016] Memory, used to store one or more computer programs.

[0017] The aforementioned one or more processors execute the aforementioned one or more computer programs to implement the steps of the aforementioned method.

[0018] Another aspect of this disclosure provides a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implement the steps of the above-described method.

[0019] Another aspect of this disclosure provides a computer program product, including a computer program or instructions that, when executed by a processor, implement the steps of the above-described method.

[0020] According to the quantum key distribution method, system, and device for co-channel transmission provided in this disclosure, by performing wavelength division processing on the composite optical signal, a first quantum optical signal, a synchronization optical signal, and a classical optical signal can be obtained. Quantum measurement of the first quantum optical signal yields a second quantum optical signal in a deterministic state. Clock synchronization processing of the second quantum optical signal using the synchronization optical signal yields a third quantum optical signal. With clock synchronization at the transmitting and receiving ends, signal elimination of the third quantum optical signal using preset time position information yields a fourth quantum optical signal. Key negotiation based on the classical optical signal and the fourth quantum optical signal yields the target key. By eliminating the signal from the third quantum optical signal, interference between the synchronization optical signal and the classical optical signal in the third quantum optical signal can be reduced, and the increase in spectral spacing is avoided, thus not increasing the transmission loss of the classical optical signal, thereby reducing the cost of use and improving the efficiency of quantum key distribution. Attached Figure Description

[0021] The above and other objects, features, and advantages of this disclosure will become clearer from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0022] Figure 1 This diagram illustrates an application scenario of a quantum key distribution method using co-channel transmission according to embodiments of the present disclosure.

[0023] Figure 2 A flowchart illustrating a quantum key distribution method using co-channel transmission according to an embodiment of the present disclosure is shown schematically.

[0024] Figure 3 A flowchart illustrating a quantum key distribution method using co-channel transmission according to yet another embodiment of this disclosure is shown schematically;

[0025] Figure 4 A schematic block diagram of a quantum key distribution system with co-channel transmission according to an embodiment of the present disclosure is shown.

[0026] Figure 5 This schematically illustrates the structure of the transmitter of a quantum key distribution system with co-channel transmission according to an embodiment of the present disclosure;

[0027] Figure 6This schematically illustrates the structure of a quantum state preparation module in a quantum key distribution system with co-channel transmission according to an embodiment of the present disclosure;

[0028] Figure 7 This schematically illustrates the structure of a receiver in a quantum key distribution system with co-channel transmission according to an embodiment of the present disclosure;

[0029] Figure 8 A schematic diagram of a quantum key distribution system with co-channel transmission according to an embodiment of the present disclosure is shown.

[0030] Figure 9 A schematic diagram of a quantum key distribution system with co-channel transmission according to yet another embodiment of the present disclosure is shown.

[0031] Figure 10 A schematic diagram illustrates the structure of a quantum key distribution system with co-channel transmission according to yet another embodiment of this disclosure; and

[0032] Figure 11 A block diagram of an electronic device suitable for implementing a quantum key distribution method for co-channel transmission according to an embodiment of the present disclosure is shown schematically. Detailed Implementation

[0033] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0034] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0035] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0036] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0037] In the technical solution disclosed herein, the user information (including but not limited to user personal information, user image information, user device information, such as location information) and data (including but not limited to data used for analysis, stored data, and displayed data) involved are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, storage, use, processing, transmission, provision, disclosure, and application of related data all comply with relevant laws, regulations, and standards, necessary confidentiality measures have been taken, and they do not violate public order and good morals. Corresponding operation entry points are provided for users to choose to authorize or refuse.

[0038] In scenarios involving automated decision-making using personal information, the methods, devices, and systems provided in this disclosure all offer users corresponding entry points for choosing to agree to or reject the automated decision-making results. If the user chooses to reject, the process proceeds to the expert decision-making stage. Here, "automated decision-making" refers to the activity of automatically analyzing and evaluating an individual's behavioral habits, interests, or economic, health, and credit status through computer programs, and then making a decision. Here, "expert decision-making" refers to the activity of making decisions by personnel who specialize in a particular field, possess specialized experience, knowledge, and skills, and have reached a certain level of professional expertise.

[0039] In the process of developing this disclosure, it was discovered that commercial quantum key distribution systems in related technologies mainly use two optical fibers. One fiber transmits quantum signals as a quantum channel, while the other fiber uses traditional optical communication to transmit post-processing information and synchronization clocks required for the quantum key distribution protocol as a classical optical channel. The network architecture for key distribution using two optical fibers is complex and has low fiber utilization, which is detrimental to large-scale practical application. Transmitting quantum light and classical light through a shared channel in the quantum key distribution system can reduce the construction cost of quantum secure communication networks, which is beneficial to the practical application and promotion of quantum secure communication technology.

[0040] Furthermore, related technologies also include co-channel quantum key distribution network architectures. Co-channel quantum key distribution network architectures primarily employ wavelength division multiplexing (WDM). Light propagating in optical fibers undergoes Raman scattering. Since optical fibers are molten silica, their Raman scattering is broadband, still contributing noise to quantum light in the frequency domain. Although the influence of classical light on quantum light can be suppressed by increasing spectral spacing and reducing the transmission power of classical light, the low-loss band bandwidth of communication optical fibers is limited. Increasing spectral spacing increases the transmission loss of classical light, and the reduction in optical power also limits the co-channel transmission distance. In addition, high-isolation WDM devices require custom-designed components, resulting in high costs. Alternatively, spatial division multiplexing (SDM) and co-channel technologies based on few-mode fibers can be used. However, SDM and few-mode fiber-based technologies are subject to many limitations due to the type of optical fiber channel used; practical underground dark fiber optics rarely use multi-core or few-mode fibers.

[0041] In view of this, embodiments of the present disclosure provide a quantum key distribution method for co-channel transmission, applied to the receiver of a quantum key distribution system, comprising: in response to acquiring a composite optical signal transmitted by a transmitter, performing wavelength division processing on the composite optical signal to obtain a first quantum optical signal, a synchronization optical signal, and a classical optical signal; performing quantum state measurement on the first quantum optical signal to obtain a second quantum optical signal in a determined state; performing clock synchronization processing on the second quantum optical signal using the synchronization optical signal to obtain a third quantum optical signal; using preset time position information to perform signal elimination on the third quantum optical signal to obtain a fourth quantum optical signal; and performing key negotiation based on the classical optical signal and the fourth quantum optical signal to obtain a target key.

[0042] Figure 1 The diagram illustrates an application scenario of a quantum key distribution method using co-channel transmission according to an embodiment of the present disclosure.

[0043] like Figure 1 As shown, application scenario 100 according to this embodiment may include a terminal device 101, a second terminal device 102, a third terminal device 103, a network 104, and a server 105. The network 104 serves as a medium for providing a communication link between the first terminal device 101, the second terminal device 102, the third terminal device 103, and the server 105. The network 104 may include various connection types, such as wired or wireless communication links, or fiber optic cables, etc.

[0044] Users can use the first terminal device 101, the second terminal device 102, and the third terminal device 103 to interact with the server 105 via the network 104 to receive or send messages, etc. Various communication client applications can be installed on the first terminal device 101, the second terminal device 102, and the third terminal device 103, such as shopping applications, web browser applications, search applications, instant messaging tools, email clients, social media platform software, etc. (for example only).

[0045] The first terminal device 101, the second terminal device 102, and the third terminal device 103 can be various electronic devices with displays and support web browsing, including but not limited to smartphones, tablets, laptops, and desktop computers.

[0046] Server 105 can be a server that provides various services, such as a backend management server that supports websites browsed by users using the first terminal device 101, the second terminal device 102, and the third terminal device 103 (this is just an example). The backend management server can analyze and process data such as received user requests, and feed back the processing results (such as web pages, information, or data obtained or generated according to user requests) to the terminal devices.

[0047] It should be noted that the co-channel quantum key distribution method provided in this disclosure can generally be executed by server 105. Correspondingly, the co-channel quantum key distribution system provided in this disclosure can generally be located in server 105. The co-channel quantum key distribution method provided in this disclosure can also be executed by a server or server cluster that is different from server 105 and capable of communicating with the first terminal device 101, the second terminal device 102, the third terminal device 103, and / or server 105. Correspondingly, the co-channel quantum key distribution system provided in this disclosure can also be located in a server or server cluster that is different from server 105 and capable of communicating with the first terminal device 101, the second terminal device 102, the third terminal device 103, and / or server 105.

[0048] It should be understood that Figure 1 The number of terminal devices, networks, and servers shown is merely illustrative. Depending on implementation needs, any number of terminal devices, networks, and servers can be included.

[0049] The following will be based on Figure 1 The described scene, through Figures 2-6 The quantum key distribution method for co-channel transmission in the embodiments is described in detail.

[0050] Figure 2A flowchart illustrating a quantum key distribution method using co-channel transmission according to an embodiment of the present disclosure is shown schematically.

[0051] like Figure 2 As shown, the co-channel quantum key distribution method is applied to the receiver of a quantum key distribution system. The method 200 includes operations S210~S250.

[0052] In operation S210, in response to acquiring the composite optical signal sent by the transmitter, the composite optical signal is subjected to wavelength division processing to obtain the first quantum optical signal, the synchronization optical signal and the classical optical signal.

[0053] In operation S220, the quantum state of the first quantum optical signal is measured to obtain the second quantum optical signal in a definite state.

[0054] In operation S230, the second quantum optical signal is clock-synchronized using the synchronization optical signal to obtain the third quantum optical signal.

[0055] In operation S240, the third quantum optical signal is eliminated using preset time and position information to obtain the fourth quantum optical signal.

[0056] In operation of S250, key negotiation is performed based on classical optical signals and fourth quantum optical signals to obtain the target key.

[0057] According to embodiments of this disclosure, the composite optical signal can be obtained by multiplexing the quantum optical signal, classical optical signal, and synchronization optical signal from the transmitting end. After receiving the composite optical signal from the transmitting end, the receiving end can use a second wavelength division multiplexer to perform wavelength division processing on the composite optical signal to obtain the first quantum optical signal, the synchronization optical signal, and the classical optical signal.

[0058] According to embodiments of this disclosure, a quantum optical signal can characterize a signal on the order of a single photon. Because a quantum optical signal contains only a single photon, it possesses low power characteristics. A first quantum optical signal can characterize a quantum optical signal that is crosstalked to a synchronous optical signal and a classical optical signal. The synchronous optical signal and the classical optical signal obtained by wave division are also crosstalked to by quantum optical signals, but because the power of the quantum optical signal is low, the crosstalk of quantum optical signals in the synchronous optical signal and the classical optical signal obtained by wave division can be ignored.

[0059] According to embodiments of this disclosure, by performing quantum state measurement on a first quantum optical signal, a second quantum optical signal in a definite state can be obtained. Before the measurement, it can be in a superposition of multiple possible states. The quantum state measurement can destroy the superposition state, causing it to collapse into one of the multiple possible states.

[0060] According to embodiments of this disclosure, a synchronization optical signal can characterize a synchronization clock signal for optical transmission. The clocks of the transmitting and receiving ends can be synchronized based on the synchronization optical signal. A third quantum optical signal can be obtained by using the synchronization optical signal to perform clock synchronization processing on a second quantum optical signal.

[0061] According to embodiments of this disclosure, a fourth quantum optical signal can be obtained by using preset time and position information to remove measurement results corresponding to the synchronization optical signal and the classical optical signal from the third quantum optical signal. The fourth quantum optical signal can characterize the measurement results corresponding to the quantum optical signal.

[0062] According to embodiments of this disclosure, key negotiation can be performed based on classical optical signals and fourth quantum optical signals to obtain a symmetrical target key for the transmitter and receiver. Key negotiation may include basis pairing, error calculation, error correction, and amplification operations.

[0063] According to embodiments of this disclosure, by performing wavelength division processing on the composite optical signal, a first quantum optical signal, a synchronization optical signal, and a classical optical signal can be obtained. Quantum measurement of the first quantum optical signal yields a second quantum optical signal in a defined state. Clock synchronization processing of the second quantum optical signal using the synchronization optical signal yields a third quantum optical signal. With clock synchronization at the transmitting and receiving ends, signal elimination of the third quantum optical signal using preset time position information yields a fourth quantum optical signal. Key negotiation based on the classical optical signal and the fourth quantum optical signal yields a target key. By eliminating signals from the third quantum optical signal, interference between the synchronization optical signal and the classical optical signal in the third quantum optical signal can be reduced, and the increase in spectral spacing is avoided, thus not increasing the transmission loss of the classical optical signal. This reduces the cost of use and improves the efficiency of quantum key distribution.

[0064] According to embodiments of this disclosure, the above-described quantum key distribution method for co-channel transmission further includes: in response to an initialization request, determining preset time and location information based on an initialization optical signal sent by the transmitter.

[0065] According to embodiments of this disclosure, a quantum key distribution system using a common-channel transmission quantum key distribution method can be initialized based on an initialization request.

[0066] According to embodiments of this disclosure, in response to an initialization request, the initialization optical signal transmitted by the transmitting end may include a synchronization optical signal and a classic optical signal. In response to the initialization request, preset time and position information is determined based on the initialization optical signal transmitted by the transmitting end.

[0067] According to embodiments of this disclosure, an initialization request can be used to determine preset time and position information based on the initialization signal sent by the transmitter. When the preset time and position information is determined, interference between classical optical signals and synchronization optical signals in the third quantum optical signal can be reduced by signal elimination of the third quantum optical signal.

[0068] According to embodiments of this disclosure, in response to an initialization request, determining preset time position information based on an initialization optical signal transmitted by a transmitter includes: acquiring the initialization optical signal transmitted by the transmitter in response to the initialization request; performing wavelength division processing on the initialization optical signal to obtain an initialization synchronization optical signal and an initialization classical optical signal; obtaining time position information of the initialization synchronization optical signal and the initialization classical optical signal respectively based on quantum state measurement results for the initialization synchronization optical signal and the initialization classical optical signal; and obtaining preset time position information based on the time position information of the initialization synchronization optical signal and the initialization classical optical signal.

[0069] According to embodiments of this disclosure, in response to an initialization request, an initialization optical signal transmitted by the transmitter can be obtained. By performing wavelength division multiplexing on the initialization optical signal using a first wavelength division multiplexer, an initialization synchronization optical signal and an initialization classical optical signal can be obtained.

[0070] According to embodiments of this disclosure, the time position information of the initialization synchronization optical signal and the time position information of the initialization classical optical signal can be obtained based on the quantum state measurement results of the initialization synchronization optical signal and the initialization classical optical signal, respectively.

[0071] According to embodiments of this disclosure, the preset time position information can characterize the time position information for initializing the synchronization optical signal and the time position information for initializing the classical optical signal. Therefore, the preset time position information can be obtained based on the time position information for initializing the synchronization optical signal and the time position information for initializing the classical optical signal.

[0072] According to embodiments of this disclosure, an initial classical optical signal and an initial synchronization optical signal are obtained by performing wavelength division processing on the initialization optical signal. Based on the quantum state detection results of the initial classical optical signal and the initial synchronization optical signal, the time position information of the initial synchronization optical signal and the time position information of the initial classical optical signal can be obtained. The preset time position information is then determined. When the preset time position information is determined, the interference between the classical optical signal and the synchronization optical signal in the third quantum optical signal can be reduced by signal elimination of the third quantum optical signal.

[0073] According to embodiments of this disclosure, a fourth quantum optical signal is obtained by signal elimination from a third quantum optical signal using preset time and position information. This includes: determining a target wavelength band corresponding to the initialized synchronization optical signal and the initialized classical optical signal based on the preset time and position information; and eliminating the optical signal corresponding to the target wavelength band from the third quantum optical signal to obtain the fourth quantum optical signal.

[0074] According to embodiments of this disclosure, based on preset time and location information, target wavelengths corresponding to the initialization synchronization optical signal and the initialization classical optical signal can be determined. Once the target wavelengths corresponding to the initialization synchronization optical signal and the initialization classical optical signal are determined, the optical signal corresponding to the target wavelength can be removed from the third quantum optical signal to obtain the fourth quantum optical signal.

[0075] According to embodiments of this disclosure, by removing the target bands corresponding to the initialization synchronization optical signal and the initialization classical optical signal from the third quantum optical signal, the interference of the classical optical signal and the synchronization optical signal on the quantum optical signal is reduced, and the use of expensive high-isolation wavelength division multiplexers is avoided, thereby reducing costs.

[0076] According to embodiments of this disclosure, key negotiation processing based on classical optical signals and fourth quantum optical signals to obtain a target key includes: determining the basis vectors of the transmitting end based on the classical optical signal; determining the filtered key from the fourth quantum optical signal based on the basis vectors of the transmitting end and the receiving end; calculating the bit error rate of the filtered key; performing error correction processing on the filtered key if the bit error rate is less than a preset value to obtain an intermediate target key; and amplifying the intermediate target key based on the error correction result to obtain the target key.

[0077] According to embodiments of this disclosure, the basis vectors of the transmitting end can be determined based on classical optical signals. The basis vectors of the transmitting end can be the modulation basis of the transmitting end. The basis vectors of the receiving end can be the measurement basis of the receiving end.

[0078] According to embodiments of this disclosure, a sieved key can be determined from a fourth quantum optical signal based on the basis vectors of the transmitting end and the receiving end. When the basis vectors of the transmitting end and the receiving end are the same, the identical basis vectors of the transmitting end and the receiving end can be determined as the sieved key; different basis vectors of the transmitting end and the receiving end are discarded.

[0079] According to embodiments of this disclosure, the bit error rate (BER) of the filtered key can characterize the probability that the filtered keys at the sending and receiving ends are inconsistent. The BER of the filtered key can be obtained by calculating its BER. If the BER of the filtered key is greater than or equal to a preset value, it indicates that the channel may be insecure, and the current communication is cancelled. If the BER of the filtered key is less than the preset value, error correction processing can be performed on the filtered key to obtain an intermediate target key. Error correction processing of the filtered key can utilize methods such as low-density parity check (LDPC).

[0080] According to embodiments of this disclosure, the intermediate target key can be amplified based on the error correction processing result of the filtered key to obtain the target key. During the error correction process, the communication between the sending and receiving ends reflects the nature of the key to some extent, i.e., it leaks information about the intermediate target key. Therefore, it is necessary to amplify the intermediate key to obtain the target key. Amplifying the intermediate key represents amplifying the amount of information not leaked during the error correction process, resulting in a more secure target key.

[0081] According to embodiments of this disclosure, a sieved key can be determined from the fourth quantum optical signal based on the basis vectors of the transmitting end and the receiving end. Error rate calculation is performed on the sieved key. If the error rate of the sieved key is less than a preset value, the channel is characterized as secure. Error correction processing can be performed on the sieved key to obtain an intermediate target key. Based on the error correction processing result of the sieved key, the intermediate key is amplified. This amplifies the undisclosed information portion of the intermediate target key, thereby improving the security of the target key.

[0082] Figure 3 A flowchart illustrating a quantum key distribution method for co-channel transmission according to yet another embodiment of the present disclosure is shown.

[0083] like Figure 3 As shown, the quantum key distribution method using co-channel transmission is applied to the receiver of a quantum key distribution system. The method 300 includes operations S301 to S311.

[0084] In operation S301, in response to the initialization request, the initialization optical signal sent by the transmitter is obtained.

[0085] In operation S302, the initial optical signal is subjected to wavelength division processing to obtain the initial synchronization optical signal and the initial classical optical signal.

[0086] In operation S303, based on the quantum state measurement results of the initial synchronization optical signal and the initial classical optical signal respectively, the time position information of the initial synchronization optical signal and the time position information of the initial classical optical signal are obtained.

[0087] In operation S304, the preset time and position information is obtained based on the time and position information of the initial synchronization optical signal and the initial classic optical signal.

[0088] In operation S305, based on preset time and location information, the target band corresponding to the initialization synchronization optical signal and the initialization classic optical signal is determined.

[0089] In operation S306, the optical signal corresponding to the target band is removed from the third quantum optical signal to obtain the fourth quantum optical signal.

[0090] In operation of S307, the basis vector of the transmitting end is determined based on the classical optical signal.

[0091] In operation S308, the sieved key is determined from the fourth quantum optical signal based on the basis vectors at the transmitting end and the receiving end.

[0092] In operation S309, the error rate of the sieved key is calculated.

[0093] In operation S310, if the error rate of the filtered key is less than a preset value, error correction processing is performed on the filtered key to obtain the intermediate target key.

[0094] In operation S311, based on the error correction results of the sieved key, the intermediate target key is amplified to obtain the target key.

[0095] According to embodiments of this disclosure, by using preset time information, optical signals corresponding to the target wavelength can be removed from the third quantum optical signal to obtain a fourth quantum optical signal, thereby reducing interference from classical optical signals and synchronization optical signals in the quantum optical signal. Key negotiation is then performed based on the fourth quantum optical signal and the classical optical signal, improving the efficiency of quantum key distribution and the security of the distributed target key.

[0096] Based on the aforementioned quantum key distribution method using co-channel transmission, this disclosure also provides a quantum key distribution system using co-channel transmission. The following will be combined with... Figure 4 The system is described in detail.

[0097] Figure 4 A schematic block diagram of a quantum key distribution system with co-channel transmission according to an embodiment of the present disclosure is shown.

[0098] like Figure 4 As shown, the quantum key distribution system 400 with co-channel transmission in this embodiment includes a transmitter 410, a channel 420, and a receiver 430.

[0099] According to an embodiment of this disclosure, the transmitting end 410 can be used to generate a quantum optical signal, a negotiated optical signal, and a classical optical signal, and use a first wavelength division multiplexer to send the composite optical signal obtained by combining the quantum optical signal, the negotiated optical signal, and the classical optical signal to the receiving end 430.

[0100] According to embodiments of this disclosure, the transmitting end 410 and the receiving end 430 are connected via a channel 420. The channel 420 is used to transmit a composite optical signal. A first composite optical signal can be transmitted from the transmitting end 410 to the receiving end 430 via the channel 420. The channel 420 can be an optical fiber or space-based system.

[0101] According to embodiments of this disclosure, the receiver 430 can be used to perform wavelength division multiplexing on the received composite optical signal using a second wavelength division multiplexer to obtain a first quantum optical signal, a classical optical signal, and a synchronization optical signal. Quantum state measurement is performed on the first quantum optical signal obtained by wavelength division, and using preset time and position information, the synchronization optical signal and the classical optical signal in the first quantum optical signal are removed to obtain a fourth quantum optical signal. Key negotiation is then performed based on the classical optical signal and the fourth quantum optical signal to obtain the target key.

[0102] According to embodiments of this disclosure, a second quantum optical signal in a defined state can be obtained by measuring the quantum state of a first quantum optical signal. A third quantum optical signal can be obtained by clock synchronization processing of the second quantum optical signal using a synchronization optical signal. Clock synchronization between the transmitter 410 and the receiver 430 can be achieved using the synchronization optical signal. By using preset time position information, signal rejection can be performed on the third quantum optical signal to remove interference signals, resulting in a fourth quantum optical signal. The interference signals can characterize the crosstalk between the synchronization optical signal and the classical optical signal in the quantum optical measurement module caused by insufficient isolation of the second wavelength division multiplexer.

[0103] According to embodiments of this disclosure, a target key is obtained through key negotiation based on classical optical signals and fourth quantum optical signals. The transmitting and receiving ends can obtain the target key, which is symmetrical on both sides.

[0104] According to embodiments of this disclosure, the transmitting end performs multiplexing of the generated quantum optical signal, classical optical signal, and synchronous optical signal to obtain a composite optical signal, and transmits the composite optical signal to the receiving end through a channel. The receiving end performs wavelength division multiplexing on the received composite optical signal to obtain a first quantum optical signal, a classical optical signal, and a synchronous optical signal. Due to insufficient isolation of the second wavelength division multiplexer, the first quantum optical signal is interfered with the classical optical signal and the synchronous optical signal. In order to reduce the interference of the classical optical signal and the synchronous optical signal in the first quantum optical signal, the classical optical signal and the synchronous optical signal are removed from the first quantum optical signal according to preset time position information, thereby obtaining a fourth quantum optical signal. Key negotiation is performed based on the classical optical signal and the fourth quantum optical signal to obtain the target key, thereby reducing the interference in the first quantum optical signal and reducing the cost of the quantum key distribution system with co-channel transmission.

[0105] Figure 5 The diagram schematically illustrates the structure of the transmitter of a quantum key distribution system with co-channel transmission according to an embodiment of the present disclosure.

[0106] like Figure 5 As shown, the transmitting end 410 includes a quantum state preparation module 411, a synchronous light generation module 412, a first classical communication transceiver module 413, a first electronic control system 414, and a first wavelength division multiplexer 415.

[0107] According to an embodiment of this disclosure, the transmitting end 410 includes: a quantum state preparation module 411 for generating a quantum optical signal using a first clock signal; a synchronous optical generation module 412 for generating a synchronous optical signal using a second clock signal; a first classical communication transceiver module 413 for generating a classical optical signal using a third clock signal; a first wavelength division multiplexer 415 for performing multiplexing of the quantum optical signal, the synchronous optical signal, and the classical optical signal to obtain a composite optical signal; and a first electronic control system 414 for outputting the first clock signal, the second clock signal, and the third clock signal.

[0108] According to embodiments of this disclosure, the first clock signal, the second clock signal, and the third clock signal are synchronous clocks, and are correlated with each other. The first electronic control system 414 can be used to output the first clock signal, the second clock signal, and the third clock signal.

[0109] According to embodiments of this disclosure, the quantum optical signal can be a signal at the single-photon level. Triggered by a first clock signal output by the electronic control system 414, the quantum state preparation module 411 can generate the quantum optical signal. The quantum state preparation module 411 may include a laser, a quantum state modulation unit, and an optical attenuator.

[0110] According to embodiments of this disclosure, the synchronization optical generation module 412 can generate a synchronization optical signal when triggered by the second clock signal output by the electronic control system 414. The synchronization optical signal enables clock synchronization between the transmitting and receiving ends. When triggered by the third clock signal output by the electronic control system 414, the first classical communication transceiver module 412 can generate a classical optical signal.

[0111] According to embodiments of this disclosure, the quantum optical signal, the synchronization optical signal, and the classical optical signal have different wavelengths. A first wavelength division multiplexer 415 can perform multiplexing of the quantum optical signal, the synchronization optical signal, and the classical optical signal to obtain a composite optical signal. The composite optical signal obtained by multiplexing the quantum optical signal, the synchronization optical signal, and the classical optical signal can be transmitted in the same channel.

[0112] According to embodiments of this disclosure, the first clock signal, the second clock signal, and the third clock signal can be synchronous clocks, and the first clock signal, the second clock signal, and the third clock signal are coherent. The coherence between the first clock signal, the second clock signal, and the third clock signal can indicate that the first clock signal, the second clock signal, and the third clock signal have the same frequency or have a stable phase difference.

[0113] According to embodiments of this disclosure, under the drive of the electronic control system, the quantum state preparation module can generate a quantum optical signal, the synchronous optical generation module can generate a synchronous optical signal, the first classical communication transceiver module can generate a classical optical signal, and the first wavelength division multiplexer can perform multiplexing of the quantum optical signal, the synchronous optical signal and the classical optical signal to obtain a composite optical signal, and transmit the composite optical signal to the receiving end through the channel, thereby avoiding the separation of the quantum channel and the classical optical channel and reducing costs.

[0114] Figure 6 The diagram schematically illustrates the structure of a quantum state preparation module for a co-channel quantum key distribution system according to an embodiment of the present disclosure.

[0115] like Figure 6 As shown, the quantum state preparation module 411 includes a laser 4111, a quantum state modulation unit 4112, and an optical attenuator 4113.

[0116] According to an embodiment of this disclosure, a quantum state preparation module 411 is used to generate a quantum optical signal using a first clock signal, including: triggering a laser 4111 with the first clock signal to generate an optical pulse signal; performing quantum state modulation on the optical pulse signal using a quantum state modulation unit 4112 to obtain an intermediate optical pulse signal; and performing optical attenuation processing on the intermediate optical pulse signal using an optical attenuator 4113 to obtain a quantum optical signal.

[0117] According to an embodiment of this disclosure, when triggered by a first clock signal, the laser 4111 can generate optical pulses. The optical pulses can be generated in gain-switching mode or by continuous optical chopping.

[0118] According to embodiments of this disclosure, an intermediate optical pulse signal can be obtained by using a quantum state modulation unit 4112 to perform quantum state modulation on a quantum optical signal. The modulation method for quantum state modulation of the optical pulse may include, but is not limited to, phase encoding, polarization encoding, path encoding, and timestamp encoding.

[0119] According to embodiments of this disclosure, a quantum optical signal can be obtained by using an optical attenuator 4113 to attenuate an intermediate optical pulse signal. The optical attenuator 4113 may include at least one of a fixed optical attenuator and an electrically controlled optical attenuator. If the attenuation of one optical attenuator can attenuate the light to the level of a single photon, only one type of optical attenuator can be used. If the attenuation of one optical attenuator cannot attenuate the light to the level of a single photon, two types of optical attenuators can be used.

[0120] According to embodiments of this disclosure, triggering the laser via an electronic control system can generate an optical pulse signal. Quantum state modulation of the optical pulse signal in a quantum state modulation unit can obtain an intermediate optical pulse signal. Optical attenuation of the intermediate optical pulse signal can obtain a quantum optical signal. Triggering the laser with a first clock signal different from the second and third clock signals reduces the interference of classical optical signals and synchronous optical signals on the quantum optical signal.

[0121] Figure 7 The schematic diagram illustrates the structure of a receiver in a quantum key distribution system with co-channel transmission according to an embodiment of the present disclosure.

[0122] like Figure 7 As shown, the receiver 430 includes a second wavelength division multiplexer 431, a quantum state measurement module 432, a synchronous optical processing module 433, a second electronic control system 434, and a second classical communication transceiver module 435.

[0123] According to embodiments of this disclosure, the receiving end 430 includes: a second wavelength division multiplexer 431, which can be used to perform wavelength division processing on the composite optical signal acquired from the receiving end 430 to obtain a first quantum optical signal, a synchronization optical signal, and a classical optical signal. Due to insufficient isolation of the second wavelength division multiplexer 431, crosstalk between classical and synchronization optical signals may enter the quantum state measurement module; therefore, the input to the quantum state measurement module is the first quantum optical signal. The quantum state measurement module 432 can be used to perform quantum state measurement on the first quantum optical signal to obtain a second quantum optical signal in a defined state. The synchronization optical processing module 433 can be used to perform clock synchronization processing on the second quantum optical signal to obtain a third quantum optical signal. The second electronic control system 434 can be used to record the second quantum optical signal and, using preset time and position information, to remove signals from the third quantum optical signal to obtain a fourth quantum optical signal. The second classical communication transceiver module 435 can be used to perform key negotiation based on the classical optical signal and the fourth quantum optical signal to obtain a target key.

[0124] According to embodiments of this disclosure, the synchronous light processing module 433 can realize the functions of synchronous light signal detection, signal shaping and level conversion.

[0125] Figure 8 A schematic diagram of a quantum key distribution system for co-channel transmission according to an embodiment of the present disclosure is shown.

[0126] like Figure 8 As shown, the down-frequency synchronization clock output by the first electronic control system 414 is input to the synchronization light generation module 412. The synchronization light generation module 412 can convert the down-frequency synchronization clock from an electrical signal to an optical signal. The synchronization light signal is transmitted to the synchronization light processing module 433 after passing through the first wavelength division multiplexer 415, channel 420, and second wavelength division multiplexer 431. The synchronization light processing module 433 may include a synchronization light measurement unit 4331 and a frequency multiplier 4332. The synchronization light measurement unit 4331 can measure the synchronization light signal output by the second wavelength division multiplexer 431 to realize the conversion of optical signal to electrical signal and obtain the synchronization light signal measurement result. The frequency multiplier 4332 can realize the frequency multiplication of the down-frequency clock to obtain a synchronization clock with the same frequency as the transmitter 430.

[0127] Figure 9 A schematic diagram of a quantum key distribution system for co-channel transmission according to yet another embodiment of the present disclosure is shown.

[0128] like Figure 9As shown, the atomic clock disciplined clock output by the first electronic control system 414 is input to the synchronization light generation module 412. The synchronization light generation module 412 can convert the atomic clock disciplined clock from an electrical signal to a synchronization light signal in the form of an optical signal. The synchronization light signal is transmitted to the synchronization light processing module 433 after passing through the first wavelength division multiplexer 415, channel 420 and the second wavelength division multiplexer 431. The synchronization light processing module 433 may include a synchronization light measurement unit 4331 and an atomic clock unit. The synchronization light measurement unit can measure the synchronization light signal output by the second wavelength division multiplexer to realize the conversion of optical signal to electrical signal and obtain the synchronization light signal measurement result. The atomic clock unit can realize the calibration of the disciplined clock to obtain a synchronization clock with the same frequency as the transmitting end.

[0129] Figure 10 A schematic diagram of a quantum key distribution system for co-channel transmission according to yet another embodiment of the present disclosure is shown.

[0130] like Figure 10 As shown, the classical optical signal output by the first electronic control system 414 is input to the first classical communication transceiver 413. The first classical communication transceiver 413 can transmit and receive the classical optical signal. After passing through the first wavelength division multiplexer 415, channel 420 and the second wavelength division multiplexer 431, the classical optical signal is transmitted to the second classical communication transceiver 435. The clock data recovery module 4333 can recover the synchronous clock from the classical optical signal.

[0131] According to embodiments of this disclosure, any plurality of modules in the transmitter 410, channel 420, and receiver 430 may be combined into one module, or any one of these modules may be split into multiple modules. Alternatively, at least a portion of the functionality of one or more of these modules may be combined with at least a portion of the functionality of other modules and implemented in one module. According to embodiments of this disclosure, at least one of the transmitter 410, channel 420, and receiver 430 may be at least partially implemented as hardware circuitry, such as a field-programmable gate array (FPGA), a programmable logic array (PLA), a system-on-a-chip, a system-on-a-substrate, a system-on-package, an application-specific integrated circuit (ASIC), or any other reasonable means of integrating or packaging circuitry, or implemented in software, hardware, or firmware, or in any suitable combination of any of these three implementation methods. Alternatively, at least one of the transmitter 410, channel 420, and receiver 430 may be at least partially implemented as a computer program module, which, when run, can perform corresponding functions.

[0132] Figure 11 A block diagram of an electronic device suitable for implementing a quantum key distribution method for co-channel transmission according to an embodiment of the present disclosure is shown schematically.

[0133] like Figure 11 As shown, an electronic device 1100 according to an embodiment of the present disclosure includes a processor 1101, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1102 or a program loaded from a storage portion 1108 into a random access memory (RAM) 1103. The processor 1101 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 1101 may also include onboard memory for caching purposes. The processor 1101 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0134] RAM 1103 stores various programs and data required for the operation of electronic device 1100. Processor 1101, ROM 1102, and RAM 1103 are interconnected via bus 1104. Processor 1101 performs various operations of the method flow according to embodiments of the present disclosure by executing programs in ROM 1102 and / or RAM 1103. It should be noted that the programs may also be stored in one or more memories other than ROM 1102 and RAM 1103. Processor 1101 may also perform various operations of the method flow according to embodiments of the present disclosure by executing programs stored in said one or more memories.

[0135] According to embodiments of this disclosure, the electronic device 1100 may further include an input / output (I / O) interface 1105, which is also connected to a bus 1104. The electronic device 1100 may also include one or more of the following components connected to the I / O interface 1105: an input section 1106 including a keyboard, mouse, etc.; an output section 1107 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1108 including a hard disk, etc.; and a communication section 1109 including a network interface card such as a LAN card, modem, etc. The communication section 1109 performs communication processing via a network such as the Internet. A drive 1110 is also connected to the I / O interface 1105 as needed. A removable medium 1111, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on the drive 1110 as needed so that computer programs read from it can be installed into the storage section 1108 as needed.

[0136] This disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into the device / apparatus / system. The computer-readable storage medium carries one or more programs that, when executed, implement the method according to the embodiments of this disclosure.

[0137] According to embodiments of this disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, such as including, but not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this disclosure, the computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. For example, according to embodiments of this disclosure, the computer-readable storage medium may include ROM 1102 and / or RAM 1103 and / or one or more memories other than ROM 1102 and RAM 1103 described above.

[0138] Embodiments of this disclosure also include a computer program product comprising a computer program containing program code for performing the methods shown in the flowchart. When the computer program product is run on a computer system, the program code is used to enable the computer system to implement the quantum key distribution method for co-channel transmission provided in embodiments of this disclosure.

[0139] When the computer program is executed by the processor 1101, it performs the functions defined in the system / apparatus of this disclosure embodiments. According to embodiments of this disclosure, the systems, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0140] In one embodiment, the computer program may rely on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may also be transmitted and distributed in the form of signals over a network medium, and may be downloaded and installed via the communication section 1109, and / or installed from the removable medium 1111. The program code contained in the computer program can be transmitted using any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination thereof.

[0141] In such an embodiment, the computer program can be downloaded and installed from a network via communication section 1109, and / or installed from removable medium 1111. When the computer program is executed by processor 1101, it performs the functions defined in the system of this disclosure embodiment. According to embodiments of this disclosure, the systems, devices, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0142] According to embodiments of this disclosure, program code for executing the computer programs provided in embodiments of this disclosure can be written in any combination of one or more programming languages. Specifically, these computational programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C", or similar programming languages. The program code can execute entirely on a user's computing device, partially on a user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0143] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0144] Those skilled in the art will understand that the features described in the various embodiments of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0145] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A quantum key distribution method using co-channel transmission, applied at the receiver of a quantum key distribution system, characterized in that, include: In response to acquiring the composite optical signal transmitted by the transmitting end, the composite optical signal is subjected to wavelength division processing to obtain a first quantum optical signal, a synchronization optical signal, and a classical optical signal; The first quantum optical signal is subjected to quantum state measurement to obtain a second quantum optical signal in a definite state; The second quantum optical signal is clock-synchronized using the aforementioned synchronous optical signal to obtain the third quantum optical signal; In response to the initialization request, a preset time and position information is determined based on the initialization optical signal sent by the transmitter. Based on the preset time and position information, a target band corresponding to the initialization synchronization optical signal and the initialization classical optical signal in the initialization optical signal is determined. The optical signal corresponding to the target band is removed from the third quantum optical signal to obtain the fourth quantum optical signal. The target key is obtained by key negotiation based on the classical optical signal and the fourth quantum optical signal.

2. The method according to claim 1, characterized in that, The step of determining the preset time and location information based on the initialization optical signal sent by the transmitting end in response to the initialization request includes: In response to the initialization request, the initialization optical signal sent by the sending end is obtained; The initial optical signal is subjected to wavelength division processing to obtain an initial synchronization optical signal and an initial classical optical signal; Based on the quantum state measurement results of the initial synchronization optical signal and the initial classical optical signal, respectively, the time position information of the initial synchronization optical signal and the time position information of the initial classical optical signal are obtained; and The preset time and position information is obtained based on the time and position information of the initial synchronization optical signal and the initial classic optical signal.

3. The method according to claim 1, characterized in that, The key negotiation process based on the classical optical signal and the fourth quantum optical signal to obtain the target key includes: Based on the classical optical signal, determine the basis vector of the transmitting end; Based on the basis vectors of the transmitting end and the receiving end, the sieved key is determined from the fourth quantum optical signal; The error rate of the screened key is obtained by calculating the error rate of the screened key. If the bit error rate of the filtered key is less than a preset value, the filtered key is subjected to error correction processing to obtain the intermediate target key; Based on the error correction results of the filtered key, the intermediate target key is amplified to obtain the target key.

4. A quantum key distribution system for co-channel transmission, characterized in that, include: The transmitting end is used to generate quantum optical signals, negotiated optical signals and classical optical signals, and to send the composite optical signal obtained by combining the quantum optical signals, negotiated optical signals and classical optical signals to the receiving end. A channel for transmitting the composite optical signal; The receiving end is used to perform wavelength division processing on the received composite optical signal, perform quantum state measurement on the first quantum optical signal obtained by wavelength division, use preset time and position information to remove the synchronization optical signal and classical optical signal in the first quantum optical signal to obtain the fourth quantum optical signal, and perform key negotiation based on the classical optical signal and the fourth quantum optical signal to obtain the target key. The receiving end includes: The second wavelength division multiplexer is used to perform wavelength division processing on the composite optical signal obtained from the receiving end to obtain the first quantum optical signal, the synchronization optical signal and the classical optical signal; A quantum state measurement module is used to perform quantum state measurement on the first quantum optical signal to obtain a second quantum optical signal in a defined state. A synchronous optical processing module is used to perform clock synchronization processing on the second quantum optical signal to obtain a third quantum optical signal; The second electronic control system is used to record the second quantum optical signal and, in response to an initialization request, determine preset time and position information based on the initialization optical signal sent by the transmitter, and determine the target band corresponding to the initialization synchronization optical signal and the initialization classical optical signal in the initialization optical signal based on the preset time and position information; and remove the optical signal corresponding to the target band from the third quantum optical signal to obtain the fourth quantum optical signal. The second classical communication transceiver module is used to perform key negotiation based on the classical optical signal and the fourth quantum optical signal to obtain the target key.

5. The system according to claim 4, characterized in that, The transmitting end includes: A quantum state preparation module is used to generate a quantum optical signal using a first clock signal, wherein the quantum optical signal is a signal on the order of a single photon; The synchronization light generation module is used to generate a synchronization light signal using a second clock signal; The first classical communication transceiver module is used to generate classical optical signals using a third clock signal; The first wavelength division multiplexer is used to perform multiplexing processing on the quantum optical signal, the synchronous optical signal and the classical optical signal to obtain a composite optical signal; A first electronic control system is used to output a first clock signal, a second clock signal, and a third clock signal, wherein the first clock signal, the second clock signal, and the third clock signal are synchronous clocks, and the first clock signal, the second clock signal, and the third clock signal are correlated.

6. The system according to claim 5, characterized in that, The quantum state preparation module is used to generate a quantum optical signal using a first clock signal, including: The laser is triggered using the first clock signal to generate an optical pulse signal; The optical pulse signal is quantum-modulated using a quantum state modulation unit to obtain an intermediate optical pulse signal; The intermediate optical pulse signal is attenuated using an optical attenuator to obtain the quantum optical signal; wherein the optical attenuator includes at least one of a fixed optical attenuator and an electrically controlled optical attenuator.

7. An electronic device, comprising: One or more processors; Memory, used to store one or more computer programs. The characteristic feature is that the one or more processors execute the one or more computer programs to implement the steps of the method according to any one of claims 1 to 3.

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