Multi-level user quantum key distribution network and distribution method based on multi-entangled light sources

Abstract

The present application discloses a multi-level user quantum key distribution network and distribution method based on multiple entangled light sources. By introducing multiple entangled light sources, the bandwidth demand can be effectively dispersed, making it possible to support a quantum secure communication network based on quantum entanglement for multiple users. When arranging the secondary light source, the transmission loss and code rate reduction problems caused by the long distance between users in the same user group and the central entangled light source can be effectively alleviated. Under the framework of the multi-user level, the pressure on the central light source is further reduced, which makes it possible to build a secure communication network based on entanglement with more users and a larger range.

Description

Technical Field

[0001] The present application relates to the field of quantum communication technology, and in particular to a multi-level user quantum key distribution network and distribution method based on multi-entangled light sources. Background Art

[0002] Quantum key distribution (QKD), as a technology that uses the quantum non-cloning principle to ensure the absolute security of communication, has been widely studied and developed since the first BB84 protocol was proposed in 1984. However, although the BB84 protocol has absolute security in theory, its implementation requires an ideal single-photon source, which is still a challenge in experiments. Therefore, subsequent protocols such as E91 and BBM92 have emerged, which use entangled light sources as information carriers, thereby physically overcoming the security issues caused by the imperfection of the light source.

[0003] Existing quantum key distribution technology based on quantum entanglement usually uses a two-photon entangled source to distribute the two photons in the entangled photon pair to two users for quantum key distribution. However, this solution can only meet the needs of point-to-point confidential communication. In order to expand the communication range, researchers have tried to use high-dimensional or multi-body quantum entanglement, but this method consumes a lot of resources and the technology is not yet mature.

[0004] In order to build a multi-user quantum communication network, a common method is to use trusted quantum nodes to expand the network. However, this method reduces the security of quantum key distribution. Once any relay point is compromised, the security of the entire network will be threatened. Another method is to use wavelength division multiplexing technology to distribute entangled photon pairs generated by a single central entangled light source. Although this method can achieve fully connected entanglement distribution and quantum key distribution for multiple users, its limitation is that the bandwidth of a single entangled light source is limited, and it is difficult to generate enough entangled photon pair channels to meet the confidential communication needs of a large number of users. Summary of the invention

[0005] The embodiments of the present application improve the security, scalability, efficiency and optical fiber resource utilization of the quantum secure communication network by providing a multi-level user quantum key distribution network and distribution method based on multiple entangled light sources.

[0006] In order to achieve the above object, the technical solution of the embodiment of the present invention is:

[0007] In a first aspect, an embodiment of the present invention provides a multi-level user quantum key distribution network system based on a multi-entangled light source, comprising: a multi-level entangled light source structure for generating entangled photon pairs, comprising a primary multi-channel entangled light source and at least one secondary multi-channel entangled light source;

[0008] A plurality of user groups receiving the entangled photon pairs, wherein the users in each of the user groups are divided into primary users and secondary users by a preset user classification method; wherein each of the user groups includes at least one primary user;

[0009] The first-level users perform quantum key distribution through the first-level multi-channel entangled light source to achieve fully connected confidential communication between the first-level users;

[0010] In each of the user groups, the secondary users and the primary users in the group perform quantum key distribution through the secondary entangled light source, thereby achieving fully connected confidential communication within each corresponding user group.

[0011] In some possible implementations, both the primary multi-channel entangled light source and the secondary multi-channel entangled light source distribute entangled photon pairs through wavelength division multiplexing technology.

[0012] In some possible implementations, the primary multi-channel entangled light source is disposed at the center of the network or the center of the user group, so as to provide efficient quantum key distribution services for the primary users.

[0013] In some possible implementations, the secondary multi-channel entangled light source is disposed within a corresponding user group so as to provide a quantum key distribution service within the corresponding user group.

[0014] In some possible implementations, when deploying the secondary multi-channel entangled light source, a band that is not commonly used in telecommunication optical communications and has a slightly higher loss per unit transmission distance is used for arrangement.

[0015] In some possible implementations, user groups are divided based on geographic locations.

[0016] In a second aspect, an embodiment of the present invention provides a multi-level user quantum key distribution method based on a multi-entangled light source, which is applied to the multi-level user quantum key distribution network system based on a multi-entangled light source provided in the first aspect, including: dividing users into different user groups according to their geographical locations;

[0017] In each user group, users are divided into primary users and secondary users by a preset user classification method; wherein each user group includes at least one primary user;

[0018] A primary multi-channel entangled light source is deployed at the center of the user group, and quantum key distribution between the primary users is performed through the primary multi-channel entangled light source to achieve full-connectivity confidential communication between the primary users;

[0019] In the user group, quantum key distribution is performed between the secondary users and the primary users in the group through the secondary entangled light source, so that fully connected confidential communication is achieved within each corresponding user group.

[0020] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0021] In the embodiment of the present invention, by introducing multiple entangled light sources, the bandwidth demand can be effectively dispersed, making it possible to support a quantum secure communication network based on quantum entanglement for multiple users (for example, more than 10). When arranging the secondary light source, the transmission loss and code rate reduction problems caused by the long distance between users in the same user group and the central entangled light source can be effectively alleviated. Under the framework of the multi-user level, the pressure on the central light source is further reduced, making it possible to build a secure communication network based on entanglement with more users and a larger range. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention, the accompanying drawings required for use in the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0023] Figure 1 Schematic diagram of the central entangled light source and network distribution for realizing a multi-user fully connected quantum communication network using entangled light sources and wavelength division multiplexing;

[0024] Figure 2 Provide users with a schematic diagram of a quantum communication network based on entanglement and wavelength division multiplexing;

[0025] Figure 3 A schematic diagram of quantum key distribution of a single entangled light source in the prior art;

[0026] Figure 4 This is a schematic diagram of a multi-entangled light source quantum key distribution network;

[0027] Figure 5 A schematic diagram of the structure of a multi-level user quantum key distribution network system based on multi-entangled light sources provided for the implementation of the present invention;

[0028] Figure 6 The present invention is a flowchart of a method for distributing quantum keys to multiple users based on multiple entangled light sources in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] In the relevant description of this embodiment, the terms "including, containing, having" and the like are open terms and are generally understood to include but not be limited to; the term "at least one" is generally understood to mean one or more, where "plurality" refers to two or more; the term "at least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items, for example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively; the symbol "A / B" is used to describe the selection relationship of associated objects, generally indicating an "or" relationship before and after.

[0031] In the following description of the present embodiment, the terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0032] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0033] Those skilled in the art will appreciate that the numerical ranges in the embodiments of the present application are to be construed as also specifically disclosing each intermediate value between the upper and lower limits of the scope. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded in the scope.

[0034] Unless otherwise specified, the technical / scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to these may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0035] In order to illustrate the technical solution of the present invention, specific embodiments are provided below for illustration.

[0036] Quantum key distribution uses the principle of quantum non-cloning to ensure the absolute security of communication. In 1984, the first quantum key distribution protocol, the BB84 protocol, was proposed. Although this protocol is absolutely safe in theory, it requires an ideal single-photon source, which cannot be fully prepared experimentally. The use of non-ideal single-photon sources will cause certain security loopholes. Subsequently, in 1991 and 1992, the E91 and BBM92 protocols were proposed respectively. These two protocols use entangled light sources as information carriers, which physically overcome the security issues caused by the imperfection of the light source. Existing technologies usually use a two-photon entangled source to distribute the two photons in the entangled photon pair to two users for quantum key distribution. However, such quantum key distribution can only meet point-to-point confidential communication.

[0037] To achieve multi-person (quantum network) communication, the existing methods usually include the following:

[0038] 1. Quantum repeater-type quantum network using quantum memory and entanglement exchange, but the efficiency of quantum memory is currently very low and has not yet reached the practical stage.

[0039] 2. Use high-dimensional or multi-body quantum entanglement, but high-dimensional and multi-body quantum entanglement consumes a lot of resources and the current technology is not mature.

[0040] 3. Use trusted quantum nodes to expand the quantum network, which is currently the most commonly used method to implement quantum security networks. However, trusted quantum nodes reduce the security of quantum key distribution.

[0041] 4. One-to-many quantum communication, but the use of passive beam splitters will significantly reduce the coding rate; and the use of active optical switch switches can improve flexibility, but it will also reduce security, and only users between optical switch groups can communicate, and group members cannot communicate directly.

[0042] 5. Using entangled light sources and wavelength division multiplexing to realize a multi-user fully connected quantum communication network, which is also the most flexible and robust structure at present. This structure can effectively realize fully connected entanglement distribution and quantum key distribution among multiple users.

[0043] For example, Figure 1 Schematic diagram of the central entangled light source and network distribution for a multi-user fully connected quantum communication network using entangled light sources and wavelength division multiplexing.

[0044] See also Figure 1 As shown, the schematic diagram of the entangled light source centered on 1550nm shows a system designed based on the principle of energy conservation. The system uses 775nm pump light to stimulate the production of entangled photon pairs. Due to the conservation of energy, the total energy of the two entangled photons must be equal to the energy of a 775nm photon. Therefore, the energy of the two entangled photons will be symmetrically distributed on both sides of 1550nm. (The energy of a 1550nm photon is equal to half the energy of a 775nm photon, and the energy of a photon is inversely proportional to the wavelength and directly proportional to the frequency). We can apply this feature to the channel wavelength specified by ITU (International Telecommunication Union Standardization Department). Figure 1 In the 1550nm spectrum, the wavelengths on both sides are divided into 12 channels according to the ITU standard, with the left side of 1550nm (the shorter wavelength side) marked from left to right as -6 to -1, and the right side (the longer wavelength side) marked from left to right as +1 to +6. According to the principle of energy conservation, the photons in the +1 channel and the -1 channel form a pair of entangled photons, and so on until +6 and -6, forming a total of 6 pairs of entangled photon pairs. Figure 1 In the experiment, the color of each pair of entangled photons is marked the same. In this way, a system containing 6 pairs of entangled photons is obtained, each pair of photons strictly follows the law of conservation of energy and has a clear wavelength correspondence.

[0045] The principle of quantum communication based on entanglement and wavelength division multiplexing can be found in Figure 2 As shown, Figure 2 A schematic diagram of a quantum communication network based on entanglement and wavelength division multiplexing is provided for users. Figure 2 In the entangled network shown, each user receives photons from three channels of the entangled light source. This design ensures that each user can find at least one entangled photon pair among the photons it receives for confidential communication with other users. However, for a fully connected entangled network with N users, theoretically N(N-1) independent communication channels, i.e., N(N-1) / 2 pairs of entangled photon pairs, are required to ensure confidential communication between any two users.

[0046] However, a significant drawback of this scheme is that the number of photon pairs required rises rapidly as the number of users N increases. This rapid growth poses a challenge to the practical deployment and maintenance of large-scale entangled networks, especially in the context of limited resources and high technical complexity.

[0047] On the other hand, relevant technicians proposed a quantum communication network based on entanglement and wavelength division multiplexing, and successfully demonstrated quantum communication between four users. Through the wavelength division multiplexing of wide-bandwidth degenerate entangled photons, it is theoretically possible to achieve full-connected entangled quantum key distribution for N users, but this requires the use of N (N-1) dense wavelength division multiplexing (DWDM) ITU channels (reference Figure 2 As shown), and an entangled light source device is required to generate N(N-1) / 2 entangled photon pairs of different frequencies (reference Figure 1 However, when N is large, this solution is difficult to implement.

[0048] The use of beam splitters can expand the number of users N, but greatly reduce the communication code rate, especially within the city area, the code rate may be less than 1000 bits per second. In addition, the previous fully connected entangled network usually adopts a star structure by default, placing the entangled light source at the central node of the star structure. However, in real life, the network structure of quantum key distribution users is much more complicated than this.

[0049] like Figure 3 As shown, Figure 3 Schematic diagram of quantum key distribution of a single entangled light source in existing technology. Figure 3 The diagram shows the quantum key distribution when there are 10 users in the original single entangled light source quantum key distribution network. In cities, since confidential communication users are often gathered in units of regions, in order to maximize the average key distribution coding rate, the entangled light source is usually placed at the center of all users to avoid a significant drop in the relevant coding rate due to users being too far away from the center. Figure 3 In total channels, so theoretically 45 pairs of entangled photons are needed, which is usually beyond the capabilities of a single entangled source.

[0050] Figure 4 shows a schematic diagram of a multi-entangled light source quantum key distribution network, see Figure 4 As shown in Figure 1, the network is divided into three user groups, one of which has only one user and does not require a secondary multi-channel entangled light source; the other two user groups contain 6 and 3 users respectively, each equipped with a secondary multi-channel entangled light source. For a user group of 6 users, the number of entangled photon channels required for its secondary multi-channel entangled light source is , that is, 15 pairs of entangled photons are needed. For a user group of 3 users, the number of entangled photon channels required for the secondary multi-channel entangled light source is , that is, 3 pairs of entangled photons are needed. The central entangled light source needs to provide an additional 54 entangled photon channels (i.e. ), that is, 27 pairs of entangled photons.

[0051] Based on this, the embodiments of the present invention provide a multi-level user quantum key distribution network and distribution method based on multi-entangled light sources, which improves the security, scalability, efficiency and optical fiber resource utilization of the quantum secure communication network.

[0052] Figure 5 A schematic diagram of the structure of a multi-level user quantum key distribution network system based on multi-entangled light sources provided for the implementation of the present invention, see Figure 5 As shown, the multi-level user quantum key distribution network system 500 based on multi-entangled light sources may include:

[0053] A multi-level entangled light source structure 501 for generating entangled photon pairs, comprising a primary multi-channel entangled light source 5011 and at least one secondary multi-channel entangled light source 5012;

[0054] A plurality of user groups 502 receiving entangled photon pairs, wherein users in each user group 502 are divided into primary users 5021 and secondary users 5022 by a preset user classification method; wherein each user group 502 includes at least one primary user 5021;

[0055] The first-level users 5021 perform quantum key distribution through the first-level multi-channel entangled light source 5011, thereby achieving fully connected confidential communication between the first-level users 5021;

[0056] In each user group 502 , the secondary user 5022 and the primary user 5021 in the group perform quantum key distribution through the secondary entangled light source 5012 , thereby achieving fully connected confidential communication within each corresponding user group 502 .

[0057] Among them, the primary multi-channel entangled light source 5011 is the core of the entire network. The primary multi-channel entangled light source 5011 is responsible for generating entangled photon pairs, which are distributed to different communication channels. The primary multi-channel entangled light source 5011 can have high brightness and multi-channel output capabilities, and can support fully connected confidential communications between multiple primary users 5021.

[0058] The secondary multi-channel entangled light source 5012 is inside each user group 502. The secondary multi-channel entangled light source 5012 is responsible for providing entangled photon pairs to the secondary users 5022 and the primary users 5021 in the group to achieve full-connected confidential communication within the group. The secondary entangled light source 5012 can be flexibly configured according to the scale and needs of the user group 502, effectively reducing the bandwidth pressure of the primary entangled light source 5011.

[0059] In some embodiments, user groups 502 can be divided based on geographic location. By dividing user groups, entangled photon pairs generated by entangled light sources can be more effectively utilized to improve the communication efficiency and security of the system. Users in each user group 502 are divided into primary users 5021 and secondary users 5022 according to a preset user classification method. Among them, primary users usually have higher communication priorities or greater communication needs, while secondary users may be users with relatively lower priorities or who only need to communicate under specific circumstances. Secondary users 5022 mainly communicate with other users in their group, but can also communicate indirectly with primary users 5021 of other groups through primary users 5021 in the group.

[0060] Specifically, the preset user classification method can be determined based on a variety of factors to ensure the efficiency, security and flexibility of the system. For example, the following classification methods may be included:

[0061] Based on security requirements: Users are classified according to their communication security requirements. For example, users with extremely high security requirements (such as government agencies, financial institutions, etc.) can be classified as first-level users, while users with slightly lower security requirements (such as ordinary enterprises, individual users, etc.) can be classified as second-level users.

[0062] Based on communication frequency: Users are classified according to their communication frequency. Frequently communicating users can be classified as primary users, while users with lower communication frequency can be classified as secondary users. This classification method helps optimize network resource allocation and ensures that users with high communication frequency can obtain better service quality.

[0063] Based on user rights: Users are classified according to their rights in the network. Users with high rights (such as network administrators, key department heads, etc.) can be classified as first-level users, while users with lower rights can be classified as second-level users. This classification method helps to achieve system security management and access control.

[0064] In actual applications, the preset user classification method can be dynamically adjusted according to specific application scenarios, network scale, user needs, etc. At the same time, in order to maintain the flexibility and scalability of the system, the classification method may also need to be continuously optimized and improved as the system develops.

[0065] When performing quantum key distribution, the first-level users 5021 perform quantum key distribution through the entangled photon pairs generated by the first-level multi-channel entangled light source 5011. Each first-level user 5021 receives photons from multiple channels of the first-level entangled light source 5011, and finds entangled photon pairs with other first-level users 5021.

[0066] Within each user group 502, the secondary user 5022 and the primary user 5021 within the group perform quantum key distribution through the entangled photon pairs generated by the secondary entangled light source 5012. In this way, each user can find at least one pair of entangled photon pairs in the photons it receives, which is used for confidential communication with other users. In this way, fully connected confidential communication within the user group 502 is achieved, improving the communication efficiency and security of the system. At the same time, through the deployment of the secondary entangled light source 5012, the bandwidth pressure of a single light source is further alleviated.

[0067] In the embodiment of the present invention, by introducing a multi-level entangled light source, the number of users and the communication rate of the quantum secure communication network are expanded, making it possible to support a larger user network. The setting of user groups and classification enables the network to more flexibly adapt to the complex and changeable user needs in the real world. The secondary entangled light source 5012 can be arranged in an uncommon telecommunication optical communication band, further alleviating the bandwidth limitation problem of a single light source and improving the utilization rate of optical fiber resources.

[0068] In summary, the multi-level user quantum key distribution network system 500 based on multi-entangled light sources realizes efficient and secure quantum communication through a multi-level entangled light source structure, user group division and user grading method, and an efficient quantum key distribution mechanism.

[0069] In some embodiments, both the primary multi-channel entangled light source and the secondary multi-channel entangled light source distribute entangled photon pairs through wavelength division multiplexing (WDM) technology.

[0070] Specifically, the first-level multi-channel entangled light source generates multiple entangled photon pairs, and the two photons in each photon pair are assigned different wavelength labels. These entangled photon pairs with specific wavelengths are then combined into the same optical fiber for transmission through a wavelength division multiplexer. Similarly, the second-level multi-channel entangled light source also follows a similar principle to generate and distribute entangled photon pairs with different wavelength labels. At the receiving end, through the wavelength division multiplexer, these mixed entangled photon pairs of different wavelengths can be accurately separated and sent to different detection channels for subsequent quantum information processing or measurement.

[0071] The distribution method of entangled photon pairs based on wavelength division multiplexing technology not only improves the integration and flexibility of quantum communication systems, but also provides strong technical support for building large-scale, multi-node quantum networks. In addition, wavelength division multiplexing technology also makes it easier to expand entangled light sources. By adding more wavelength channels, the number of entangled photon pairs can be easily increased, thereby meeting more complex and more demanding quantum communication tasks. At the same time, since photons of different wavelengths do not interfere with each other during transmission, this distribution method also has good stability and anti-interference capabilities, providing a strong guarantee for the reliability and security of quantum communication.

[0072] In some embodiments, a primary multi-channel entangled light source is disposed at a network center or a central location of a user group so as to provide efficient quantum key distribution services for primary users.

[0073] It can be understood that by placing the first-level multi-channel entangled light source in a central position, it can be ensured that all first-level users can receive entangled photon pairs from the light source at a shorter transmission distance, thereby maximizing the average key distribution rate. Specifically, the first-level multi-channel entangled light source can distribute multiple entangled photon pairs of different wavelengths to each first-level user at the same time through wavelength division multiplexing technology. Since the light source is located in the center, the transmission distance between each user and the light source is relatively short, so the problems of transmission loss and code rate reduction can be effectively alleviated. In addition, this centralized layout also helps to simplify the network structure and reduce network complexity and maintenance costs.

[0074] In some embodiments, the secondary multi-channel entangled light source is disposed within the corresponding user group to facilitate providing quantum key distribution services within the corresponding user group.

[0075] Similarly, by placing the secondary entangled light source inside the group, the distance that the entangled photon pairs travel during transmission can be effectively shortened, thereby reducing transmission losses and increasing communication code rates. This design not only improves the flexibility and reliability of the network, but also enables users in the same group to more efficiently use entangled photon pairs for confidential communications, thereby meeting the communication needs between different users in the group. In addition, since the secondary entangled light sources deployed in the group are relatively independent, the scale of the user network can be further expanded and the communication performance of the network can be improved without increasing the burden on the central light source.

[0076] In some embodiments, when deploying a secondary multi-channel entangled light source, a band that is not commonly used in telecommunication optical communications and has a slightly higher loss per unit transmission distance is used for arrangement.

[0077] Understandably, the deployment of secondary entangled light sources in the same group is arranged in a band that is not commonly used in telecommunication optical communications and has a slightly higher loss per unit transmission distance due to the relatively short transmission distance. This not only further alleviates the problem of bandwidth limitation of a single light source, but also enables these high-brightness entangled photons to have the potential to coexist and transmit with existing classical communication light in the same optical fiber when transmitting in an uncommon band, thereby improving the utilization rate of optical fiber resources.

[0078] In some embodiments, a hybrid solution using a primary multi-channel entangled light source and partially trusted nodes of a regional user group may also be adopted. The specific implementation of the solution may include:

[0079] In the network architecture, the primary entangled light source is still retained as the core part, which is responsible for generating and distributing entangled photon pairs to maintain the basic communication needs of the network. However, in order to cope with the challenges brought by large-scale user access and complex network structure, the solution introduces some trusted nodes within the regional user group. These partially trusted nodes are set inside or around each user group, playing the role of relaying and forwarding, assisting the primary entangled light source to distribute entangled photon pairs to a wider user group. With the participation of these nodes, the network can cover more users while maintaining high communication efficiency.

[0080] Understandably, although this hybrid solution sacrifices the inherent security of pure quantum entangled networks to a certain extent, because some trusted nodes may become potential attack points, this sacrifice is acceptable compared to the significant increase in the number of users and the enhanced network scalability it brings. Especially in practical application scenarios, users have higher demands for communication efficiency and network coverage. Therefore, by comprehensively considering the balance between security and scalability, this hybrid solution of a central entangled light source and partially trusted nodes of regional user groups provides a feasible path for the future development of quantum secure communication networks.

[0081] In an embodiment of the present invention, by introducing multiple entangled light sources, the bandwidth demand can be effectively dispersed, making it possible to support a quantum secure communication network based on quantum entanglement for more than 10 users. When arranging the secondary light source, the transmission loss and code rate reduction caused by the long distance between users in the same user group and the central entangled light source can be effectively alleviated. Utilize the potential of uncommon bands: deploy secondary entangled light sources in the same group. Since the relative transmission distance is relatively short, you can choose to arrange bands that are not commonly used in telecommunication optical communications and have slightly higher unit transmission distance losses. Doing so not only further alleviates the problem of bandwidth limitation of a single light source, but also enables these high-brightness entangled photons to have the potential to coexist and transmit in the same optical fiber with existing classical communication light when transmitting in uncommon bands, thereby improving the utilization rate of optical fiber resources. Under the framework of multi-user levels, the pressure on the central light source is further reduced, which provides the possibility of building a secure communication network based on entanglement with more users and a larger range.

[0082] Based on the same inventive concept, an embodiment of the present application also provides a multi-level user quantum key distribution method based on multi-entangled light sources, which is applied to the above-mentioned multi-level user quantum key distribution network system based on multi-entangled light sources. Figure 6 FIG. 1 is a flow chart of an embodiment of a multi-level user quantum key distribution method based on multi-entangled light sources in an embodiment of the present invention, see Figure 6 As shown, the method may include:

[0083] S601, dividing users into different user groups according to their geographical locations;

[0084] S602, dividing users into primary users and secondary users in each user group by a preset user classification method; wherein each user group includes at least one primary user;

[0085] S603, deploying a primary multi-channel entangled light source at the user group center, distributing quantum keys between primary users through the primary multi-channel entangled light source, and realizing fully connected confidential communication between primary users;

[0086] S604: within the user group, quantum key distribution is performed between the secondary users and the primary users in the group through the secondary entangled light source, so as to realize fully connected confidential communication within each corresponding user group.

[0087] In some possible implementations, both the primary multi-channel entangled light source and the secondary multi-channel entangled light source distribute entangled photon pairs through wavelength division multiplexing technology.

[0088] In some possible implementations, the primary multi-channel entangled light source is set at the center of the network or the center of the user group to provide efficient quantum key distribution services for the primary users.

[0089] In some possible implementations, the secondary multi-channel entangled light source is disposed within the corresponding user group to facilitate providing quantum key distribution services within the corresponding user group.

[0090] In some possible implementations, when deploying a secondary multi-channel entangled light source, a band that is not commonly used in telecommunication optical communications and has a slightly higher loss per unit transmission distance is used for arrangement.

[0091] In some possible implementations, user groups are divided based on geographic locations.

[0092] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0093] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A multi-level user quantum key distribution network system based on multi-entangled light sources, characterized in that: include: A multi-level entangled light source structure for generating entangled photon pairs, comprising a primary multi-channel entangled light source and at least one secondary multi-channel entangled light source; A plurality of user groups receiving the entangled photon pairs, wherein users in each of the user groups are divided into primary users and secondary users by a preset user classification method; wherein each of the user groups includes at least one primary user; The first-level users perform quantum key distribution through the first-level multi-channel entangled light source to achieve fully connected confidential communication between the first-level users; In each of the user groups, the secondary users and the primary users in the group perform quantum key distribution through the secondary multi-channel entangled light source, thereby achieving fully connected confidential communication within each corresponding user group.

2. The multi-level user quantum key distribution network system based on multi-entangled light sources according to claim 1 is characterized in that: The primary multi-channel entangled light source and the secondary multi-channel entangled light source both distribute entangled photon pairs through wavelength division multiplexing technology.

3. The multi-level user quantum key distribution network system based on multi-entangled light sources according to claim 2 is characterized in that: The primary multi-channel entangled light source is arranged at the center of the network or the center of the user group, so as to provide efficient quantum key distribution services for the primary users.

4. According to claim 3, the multi-level user quantum key distribution network system based on multi-entangled light sources is characterized in that the secondary multi-channel entangled light sources are arranged inside the corresponding user groups to provide quantum key distribution services within the corresponding user groups.

5. The multi-level user quantum key distribution network system based on multi-entangled light sources according to claim 4 is characterized in that: The user groups are divided based on geographical locations.

6. A multi-level user quantum key distribution method based on a multi-entangled light source, applied to the multi-level user quantum key distribution network system based on a multi-entangled light source according to any one of claims 1 to 5, characterized in that: include: Divide users into different user groups based on their geographic locations; In each user group, users are divided into primary users and secondary users by a preset user classification method; wherein each user group includes at least one primary user; A primary multi-channel entangled light source is deployed at the center of the user group, and quantum key distribution between the primary users is performed through the primary multi-channel entangled light source to achieve full-connectivity confidential communication between the primary users; Within the user group, quantum key distribution is performed between the secondary users and the primary users within the group through the secondary entangled light source, so that fully connected confidential communication is achieved within each corresponding user group.

Images