Multi-tier user quantum key distribution network and distribution method based on multiple entangled photon sources

Abstract

Disclosed in the present application are a multi-tier user quantum key distribution network and distribution method based on multiple entangled photon sources. By means of introducing multiple entangled photon sources, bandwidth requirements can be effectively dispersed, such that a quantum-entanglement-based quantum secure communication network supporting multiple users becomes possible. During the deployment of second-tier photon sources, the problems of transmission loss and key rate reduction that are caused by excessively long distances between users in the same user group and a central entangled photon source can be effectively mitigated. Under a multi-user-tier framework, the pressure of the central photon source is further reduced, thereby providing the possibility of constructing an entanglement-based secure communication network having more users and a wider range.

Description

Multi-level user quantum key distribution network and distribution method based on multiple entangled light sources Technical Field This 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 multiple entangled light sources. Background Technology Quantum key distribution (QKD), a technique that utilizes the quantum no-cloning principle to guarantee absolute security in communication, has been extensively studied and developed since the first BB84 protocol was proposed in 1984. However, while the BB84 protocol theoretically possesses absolute security, its implementation requires an ideal single-photon source, which remains an experimental challenge. Therefore, subsequent protocols such as E91 and BBM92 have emerged, using entangled light sources as information carriers, thus physically overcoming the security problems caused by imperfect light sources. Existing quantum key distribution technologies based on quantum entanglement typically use a two-photon entangled source to distribute the two photons from the entangled photon pair to two users for quantum key distribution. However, this approach can only meet the needs of point-to-point secure communication. To expand the communication range, researchers have attempted to use high-dimensional or multi-body quantum entanglement, but this method is extremely resource-intensive and the technology is not yet mature. To construct multi-user quantum communication networks, a common approach is to use trusted quantum nodes to extend the network. However, this method reduces the security of quantum key distribution; if any relay point is compromised, the security of the entire network is threatened. Another approach is to use wavelength division multiplexing (WDM) technology, utilizing entangled photon pairs generated by a single central entangled light source for distribution. While this method can achieve fully connected entangled distribution and quantum key distribution for multiple users, its limitation lies in the limited bandwidth of a single entangled light source, making it difficult to generate enough entangled photon pair channels to meet the secure communication requirements of a large number of users. Summary of the Invention This application provides a multi-level user quantum key distribution network and distribution method based on multiple entangled light sources, which improves the security, scalability, efficiency, and fiber optic resource utilization of quantum secure communication networks. To achieve the above objectives, the technical solution of this invention is as follows: In a first aspect, embodiments of the present invention provide a multi-level user quantum key distribution network system based on multiple entangled light sources, comprising: a multi-level entangled light source structure for generating entangled photon pairs, including a first-level multi-channel entangled light source and at least one second-level multi-channel entangled light source; Multiple user groups that receive the entangled photon pairs, with users in each user group divided into Level 1 users and Level 2 users according to a preset user classification method; wherein each user group includes at least one Level 1 user; The primary users perform quantum key distribution through the primary multi-channel entangled light source to achieve fully connected secure communication between the primary users. Within each user group, the secondary users and the primary users within that group perform quantum key distribution through the secondary entangled light source, achieving fully connected secure communication within each corresponding user group. In some possible implementations, both the primary multichannel entangled light source and the secondary multichannel entangled light source distribute entangled photon pairs using wavelength division multiplexing (WDM) technology. In some possible implementations, a primary multi-channel entangled light source is positioned at the center of the network or the center of the user group to provide efficient quantum key distribution services to the primary users. In some possible implementations, a secondary multichannel entangled light source is positioned within a corresponding user group to facilitate the provision of quantum key distribution services within that user group. In some possible implementations, when deploying the secondary multi-channel entangled light source, a band that is not commonly used in telecommunications optical communication and has a slightly higher loss per unit transmission distance is used. In some possible implementations, user groups are divided based on geographical location. In a second aspect, embodiments of the present invention provide a multi-level user quantum key distribution method based on multiple entangled light sources, applied to the multi-level user quantum key distribution network system based on multiple entangled light sources provided in the first aspect, comprising: dividing users into different user groups according to the geographical location of the users; Within each user group, users are divided into Level 1 users and Level 2 users according to a preset user hierarchy; each user group includes at least one Level 1 user. A primary multi-channel entangled light source is deployed at the center of the user group. Quantum key distribution is performed between the primary users through the primary multi-channel entangled light source to achieve fully connected secure communication between the primary users. Within the user groups, quantum key distribution is performed between the secondary users and the primary users within the group using the secondary entangled light source, enabling fully connected secure communication within each user group. One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: In this embodiment of the invention, by introducing multiple entangled light sources, bandwidth requirements can be effectively distributed, making it possible to support a quantum entanglement-based quantum secure communication network for multiple users (e.g., more than 10). When deploying secondary light sources, the transmission loss and bit rate reduction caused by excessive distances between users and the central entangled light source within the same user group can be effectively mitigated. Within the multi-user hierarchy, the pressure on the central light source is further reduced, making it possible to construct a larger-scale entanglement-based secure communication network with more users. Attached Figure Description To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 is a schematic diagram of the central entangled light source and network distribution of a quantum communication network that achieves full connectivity for multiple users using entangled light sources and wavelength division multiplexing; Figure 2 is a schematic diagram of a user-based quantum communication network based on entanglement and wavelength division multiplexing. Figure 3 is a schematic diagram of quantum key distribution using a single entangled light source in the prior art; Figure 4 is a schematic diagram of a multi-entangled light source quantum key distribution network; Figure 5 is a schematic diagram of a multi-level user quantum key distribution network system structure based on multiple entangled light sources provided by an embodiment of the present invention; Figure 6 is a schematic flowchart of an embodiment of a multi-level user quantum key distribution method based on multiple entangled light sources according to the present invention. Detailed Implementation The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. In the relevant descriptions of this embodiment, the terms "including," "containing," and "possessing" are all 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 "multiple" refers to two or more; the term "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items, for example, "at least one of a, b, or c", or "at least one of a, b, and c", which can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple; the symbol "A / B" is used to describe the selection relationship of associated objects, generally indicating an "or" relationship. In the following description of the embodiments, the terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. 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 this application. Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Any stated value or intermediate value within a stated range, as well as any other stated value or each smaller range between intermediate values ​​within a range, are also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range. Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe the methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail. To illustrate the technical solution of the present invention, specific embodiments are described below. Quantum key distribution (QKD) leverages the no-cloning principle of quantum mechanics to guarantee absolute security in communication. In 1984, the first QKD protocol, BB84, was proposed. While theoretically absolutely secure, it requires an ideal single-photon source, which cannot yet be fully fabricated experimentally. Using a non-ideal single-photon source introduces security vulnerabilities. Subsequently, in 1991 and 1992, the E91 and BBM92 protocols were proposed, respectively. These protocols use entangled light sources as information carriers, physically overcoming the security issues caused by imperfect light sources. Current technologies typically use two-photon entangled sources, distributing the two photons from an entangled photon pair to two users for QKD. However, such QKD can only satisfy point-to-point secure communication. To achieve multi-user (quantum network) communication, existing methods typically include the following: 1. Quantum networks using quantum memories and entanglement swapping quantum repeaters, but currently the efficiency of quantum memories is very low and has not yet reached the practical stage. 2. Use high-dimensional or multi-body quantum entanglement, but high-dimensional and multi-body quantum entanglement consumes a lot of resources, and the technology is not mature at present. 3. Extending quantum networks using trusted quantum nodes is currently the most common method for implementing quantum secure networks. However, trusted quantum nodes reduce the security of quantum key distribution. 4. One-to-many quantum communication, but using passive beam splitters will significantly reduce the code generation rate; while using active optical switches can improve flexibility, it will also reduce security, and only users between optical switch groups can communicate, and group members cannot communicate directly. 5. A fully connected quantum communication network for multiple users is achieved using entangled light sources and wavelength division multiplexing (WDM), which is currently the most flexible and robust structure. This structure can effectively realize fully connected entangled distribution and quantum key distribution among multiple users. For example, Figure 1 is a schematic diagram of the central entangled light source and network distribution of a quantum communication network that utilizes entangled light sources and wavelength division multiplexing to achieve full connectivity for multiple users. Referring to Figure 1, a schematic diagram of an entangled light source centered at 1550nm illustrates a system designed based on the principle of energy conservation. This system uses 775nm pump light to excite entangled photon pairs. Due to energy conservation, the total energy of these two entangled photons must equal the energy of a single 775nm photon. Therefore, the energies of these two entangled photons are symmetrically distributed on both sides of 1550nm. (The energy of a 1550nm photon is half that of a 775nm photon; the energy of a photon is inversely proportional to wavelength and directly proportional to frequency). We can apply this characteristic to the channel wavelengths specified by the ITU (International Telecommunication Union Standardization Sector). In Figure 1, with 1550nm as the center, the wavelengths on both sides are divided into 12 channels according to the ITU standard. The left side (the shorter wavelength side) of 1550nm is labeled from -6 to -1 from left to right, while the right side (the longer wavelength side) is labeled from +1 to +6 from left to right. According to the principle of energy conservation, photons in channel +1 and channel -1 form an entangled photon pair, and so on, up to +6 and -6, forming a total of 6 entangled photon pairs. In Figure 1, each pair of entangled photons is marked with the same color. Thus, a system containing 6 pairs of entangled photons is obtained, each pair strictly obeying the law of energy conservation and having a clear wavelength correspondence. The principle of quantum communication based on entanglement and wavelength division multiplexing can be seen in Figure 2. Figure 2 is a schematic diagram of a user-based quantum communication network using entanglement and wavelength division multiplexing. In the entangled network shown in Figure 2, each user receives photons from three channels of an entangled light source. This design ensures that each user can find at least one pair of entangled photons in its received photons for secure communication with other users. However, for a fully connected entangled network with N users, theoretically, N(N-1) independent communication channels are needed, i.e., N(N-1) / 2 pairs of entangled photons, to ensure secure communication between any two users. However, a significant drawback of this approach is that the required number of photon pairs increases 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. On the other hand, researchers have proposed a quantum communication network based on entanglement and wavelength division multiplexing (WDM), and successfully demonstrated quantum communication between four users. Theoretically, fully connected entangled quantum key distribution for N users can be achieved through wavelength division multiplexing of wide-bandwidth degenerate entangled photons. However, this requires N(N-1) dense wavelength division multiplexing (DWDM) ITU channels (see Figure 2) and the generation of N(N-1) / 2 entangled photon pairs at different frequencies using a single entangled light source device (see Figure 1). However, this approach is difficult to implement when N is large. While beam splitters can increase the number of users N, they significantly reduce the communication code rate, especially within a city-wide area, where the code generation rate may fall below 1000 bits per second. Furthermore, conventional fully connected entangled networks typically employ a star topology, placing the entangled light source at the central node. However, in real-world applications, the network structure for quantum key distribution users is far more complex than this. Figure 3 illustrates a schematic diagram of quantum key distribution using a single entangled light source in the prior art. Figure 3 shows a schematic diagram of quantum key distribution in a single entangled light source quantum key distribution network with 10 users. In cities, since secure communication users are often clustered in areas, to maximize the average key distribution rate, the entangled light source is usually placed at the center of all users' locations to avoid a significant drop in the key distribution rate due to users being too far from the center. In Figure 3, a total of [number] channels are required, therefore theoretically 45 pairs of entangled photons are needed, which usually exceeds the capability of a single entangled source. Figure 4 illustrates a schematic diagram of a multi-entangled light source quantum key distribution network. As shown in Figure 4, the network is divided into three user groups. One user group has only a single 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 the 6-user group, the number of entangled photon channels required by its secondary multi-channel entangled light source is [value missing], which is 15 pairs of entangled photons. For the 3-user group, the number of entangled photon channels required by its secondary multi-channel entangled light source is [value missing], which is 3 pairs of entangled photons. The central entangled light source needs to provide an additional 54 entangled photon channels (i.e., [value missing]), which is 27 pairs of entangled photons. Based on this, embodiments of the present invention provide a multi-level user quantum key distribution network and distribution method based on multiple entangled light sources, which improves the security, scalability, efficiency, and fiber optic resource utilization of quantum secure communication networks. Figure 5 is a schematic diagram of a multi-level user quantum key distribution network system based on multiple entangled light sources provided by an embodiment of the present invention. Referring to Figure 5, the aforementioned multi-level user quantum key distribution network system 500 based on multiple entangled light sources may include: The multi-level entangled light source structure 501 for generating entangled photon pairs includes a first-level multi-channel entangled light source 5011 and at least one second-level multi-channel entangled light source 5012; Multiple user groups 502 receive entangled photon pairs. Users in each user group 502 are divided into Level 1 users 5021 and Level 2 users 5022 according to a preset user classification method. Each user group 502 includes at least one Level 1 user 5021. Quantum key distribution is performed between Level 1 users 5021 through Level 1 multi-channel entangled light source 5011, enabling fully connected secure communication between Level 1 users 5021. Within each user group 502, secondary users 5022 and primary users 5021 within the group perform quantum key distribution through secondary entangled light source 5012, achieving fully connected secure communication within each corresponding user group 502. Among them, the primary multi-channel entangled light source 5011 serves as the core of the entire network. The primary multi-channel entangled light source 5011 is responsible for generating entangled photon pairs, which are then distributed to different communication channels. The primary multi-channel entangled light source 5011 can have high brightness and multi-channel output capabilities, enabling fully connected secure communication between multiple primary users 5021. Within each user group 502, the secondary multi-channel entangled light source 5012 is responsible for providing entangled photon pairs to secondary users 5022 and primary users 5021 within the group, thereby achieving fully connected and secure communication within the group. The secondary entangled light source 5012 can be flexibly configured according to the size and needs of the user group 502, effectively reducing the bandwidth pressure on the primary entangled light source 5011. In some embodiments, user groups 502 can be divided based on geographical location. This division allows for more efficient utilization of entangled photon pairs generated by entangled light sources, improving system communication efficiency and security. Users within each user group 502 are divided into primary users 5021 and secondary users 5022 according to a preset user hierarchy. Primary users typically have higher communication priority or greater communication needs, while secondary users may have relatively lower priority or only need to communicate under specific circumstances. Secondary users 5022 primarily communicate with other users within their group, but can also indirectly communicate with primary users 5021 in other groups through primary users 5021 within their group. Specifically, the preset user classification method can be determined based on various factors to ensure the system's efficiency, security, and flexibility. For example, it can include the following classification methods: Based on security requirements: Users are categorized according to their level of communication security needs. For example, users with extremely high security requirements (such as government agencies and financial institutions) can be classified as Level 1 users, while users with slightly lower security requirements (such as ordinary enterprises and individual users) can be classified as Level 2 users. Based on communication frequency: Users are categorized according to the frequency of their communication. Users who communicate frequently are classified as Level 1 users, while those with lower communication frequencies are classified as Level 2 users. This categorization helps optimize network resource allocation and ensures that users with high-frequency communication receive better service quality. User-based access control: Users are categorized according to their permissions within the network. Users with high privileges (such as network administrators and heads of key departments) can be classified as Level 1 users, while users with lower privileges can be classified as Level 2 users. This hierarchical approach helps in achieving secure system management and access control. In practical applications, the preset user classification method can be dynamically adjusted based on specific application scenarios, network scale, user needs, and other factors. Furthermore, to maintain system flexibility and scalability, the classification method may need continuous optimization and improvement as the system evolves. During quantum key distribution, primary users 5021 distribute quantum keys among themselves using entangled photon pairs generated by a primary multi-channel entangled light source 5011. Each primary user 5021 receives photons from multiple channels of the primary entangled light source 5011 and identifies entangled photon pairs with other primary users 5021. Within each user group 502, secondary users 5022 and primary users 5021 within the group perform quantum key distribution using entangled photon pairs generated by the secondary entangled light source 5012. In this way, each user can find at least one pair of entangled photons in their received photons for secure communication with other users. This achieves fully connected secure communication within user group 502, improving the system's communication efficiency and security. Simultaneously, the deployment of the secondary entangled light source 5012 further alleviates the bandwidth pressure of a single light source. In this embodiment of the invention, the introduction of a multi-level entangled light source expands the number of users and the communication rate of the quantum secure communication network, making it possible to support a larger-scale user network. The user group and hierarchical configuration allows the network to more flexibly adapt to the complex and ever-changing user needs in the real world. The second-level entangled light source 5012 can be deployed in less frequently used telecommunication optical communication bands, further alleviating the bandwidth limitation problem of a single light source and improving the utilization rate of optical fiber resources. In summary, the 500 multi-level user quantum key distribution network system based on multi-entangled light sources achieves efficient and secure quantum communication through its multi-level entangled light source structure, user group division and user hierarchical method, and efficient quantum key distribution mechanism. In some embodiments, both the primary multichannel entangled light source and the secondary multichannel entangled light source distribute entangled photon pairs using wavelength division multiplexing (WDM) technology. Specifically, a first-stage multi-channel entangled light source generates multiple entangled photon pairs. Each photon pair has two photons assigned different wavelength tags. These entangled photon pairs with specific wavelengths are then combined into the same optical fiber via a wavelength division multiplexer for transmission. Similarly, a second-stage multi-channel entangled light source follows a similar principle, generating and distributing entangled photon pairs with different wavelength tags. At the receiving end, these mixed entangled photon pairs with different wavelengths can be accurately separated using a wavelength division multiplexer and sent to different detection channels for subsequent quantum information processing or measurement. The entangled photon pair distribution method based on wavelength division multiplexing (WDM) 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. Furthermore, WDM technology makes it easier to expand entangled light sources. By adding more wavelength channels, the number of entangled photon pairs can be easily increased, thus meeting more complex and demanding quantum communication tasks. Simultaneously, since photons of different wavelengths do not interfere with each other during transmission, this distribution method also possesses good stability and anti-interference capabilities, providing strong guarantees for the reliability and security of quantum communication. In some embodiments, a primary multi-channel entangled light source is positioned at the center of the network or the center of a user group to provide efficient quantum key distribution services to primary users.

[0073] Understandably, by placing the primary multi-channel entangled light source at the center, it is possible to ensure that all primary users can receive entangled photon pairs from the light source with a shorter transmission distance, thereby maximizing the average key distribution rate. Specifically, the primary multi-channel entangled light source, through wavelength division multiplexing (WDM) technology, can simultaneously distribute multiple entangled photon pairs of different wavelengths to each primary user. Because the light source is located at the center, the transmission distance between each user and the light source is relatively short, thus effectively mitigating transmission loss and rate degradation issues. Furthermore, this centralized layout helps simplify the network structure, reducing network complexity and maintenance costs. In some embodiments, a secondary multichannel entangled light source is located within a corresponding user group to facilitate the provision of quantum key distribution services within that user group. Similarly, by placing the second-order entangled light source within the cluster, the distance between entangled photon pairs during transmission can be effectively shortened, thereby reducing transmission loss and increasing the communication rate. This design not only improves the network's flexibility and reliability but also enables users within the same cluster to more efficiently utilize entangled photon pairs for secure communication, thus meeting the communication needs of different users within the cluster. Furthermore, since the second-order entangled light sources deployed within the cluster are relatively independent, the scale of the user network and the network's communicability can be further expanded without increasing the burden on the central light source. In some embodiments, when deploying a secondary multi-channel entangled light source, a band that is not commonly used in telecommunications optical communication and has a slightly higher loss per unit transmission distance is used for the arrangement. Understandably, deploying secondary entangled light sources within the same group, especially in bands less commonly used in telecommunications optical communication where the transmission distance is relatively short, is preferable. This approach not only further alleviates the bandwidth limitations of a single light source but also enables these high-brightness entangled photons to coexist and transmit in the same optical fiber as existing classical communication light when transmitting in less frequently used bands, thereby improving the utilization rate of optical fiber resources. In some embodiments, a hybrid scheme using a single-level multi-channel entangled light source and partially trusted nodes in a regional user group can also be adopted. Specific implementations of this scheme may include: In the network architecture, the primary entangled light source remains as the core component, responsible for generating and distributing entangled photon pairs to maintain the network's basic communication needs. However, to address the challenges posed by large-scale user access and complex network structures, this scheme introduces partially trusted nodes within regional user groups. These partially trusted nodes are positioned within or around each user group, acting as relays and forwarders to assist the primary entangled light source in distributing entangled photon pairs to a wider range of users. Through the participation of these nodes, the network can cover more users while maintaining high communication efficiency. Understandably, while this hybrid approach sacrifices some of the inherent security of a purely quantum entangled network—as some trusted nodes could 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. This is especially true in practical applications where users have higher demands for communication efficiency and network coverage. Therefore, by comprehensively considering the balance between security and scalability, this hybrid approach of a central entangled light source and partially trusted nodes in a regional user group provides a feasible path for the future development of quantum secure communication networks. In this embodiment of the invention, by introducing multiple entangled light sources, bandwidth requirements can be effectively distributed, making it possible to support quantum entanglement-based secure communication networks with more than 10 users. When deploying secondary light sources, the transmission loss and rate reduction caused by excessive distances between users and the central entangled light source within the same user group can be effectively mitigated. The potential of less frequently used bands is utilized: deploying secondary entangled light sources within the same group allows for the selection of bands less commonly used in telecommunications optical communication, which have slightly higher loss per unit transmission distance, due to their relatively short transmission distances. This not only further alleviates the bandwidth limitation of a single light source but also enables these high-brightness entangled photons to coexist and transmit with existing classical communication light in the same optical fiber when transmitting in less frequently used bands, thereby improving the utilization rate of optical fiber resources. Within the multi-user hierarchy, the pressure on the central light source is further reduced, making it possible to build entanglement-based secure communication networks with more users and a wider coverage area. Based on the same inventive concept, this application also provides a multi-level user quantum key distribution method based on multiple entangled light sources, applied to the aforementioned multi-level user quantum key distribution network system based on multiple entangled light sources. Figure 6 is a schematic flowchart of an embodiment of the multi-level user quantum key distribution method based on multiple entangled light sources according to the present invention. Referring to Figure 6, the method may include: S601 divides users into different user groups based on their geographical location; S602, within each user group, users are divided into Level 1 users and Level 2 users according to a preset user hierarchy method; wherein each user group includes at least one Level 1 user; S603 deploys a first-level multi-channel entangled light source at the center of the user group, and performs quantum key distribution between first-level users through the first-level multi-channel entangled light source to achieve fully connected secure communication between first-level users; S604, within a user group, uses a secondary entangled light source to distribute quantum keys between secondary users and primary users within the group, achieving fully connected secure communication within each corresponding user group. In some possible implementations, both the first-level multichannel entangled light source and the second-level multichannel entangled light source distribute entangled photon pairs using wavelength division multiplexing (WDM) technology. In some possible implementations, a primary multi-channel entangled light source is positioned at the center of the network or the user group to provide efficient quantum key distribution services to primary users. In some possible implementations, a secondary multichannel entangled light source is located within the corresponding user group to facilitate the provision of quantum key distribution services within that user group. In some possible implementations, when deploying a secondary multi-channel entangled light source, a band that is not commonly used in telecommunications optical communication and has a slightly higher loss per unit transmission distance is used. In some possible implementations, user groups are divided based on geographical location. The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments. The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A multi-level user quantum key distribution network system based on multiple entangled light sources, characterized in that, include: A multi-level entangled light source structure for generating entangled photon pairs includes a first-level multi-channel entangled light source and at least one second-level multi-channel entangled light source; Multiple user groups receive the entangled photon pairs. Users within each user group are divided into Level 1 users and Level 2 users according to a preset user hierarchy. Each user group includes at least one Level 1 user. The Level 1 users perform quantum key distribution through the Level 1 multi-channel entangled light source to achieve fully connected secure communication among themselves. Within each user group, the Level 2 users and the Level 1 users within that group perform quantum key distribution through the Level 2 multi-channel entangled light source to achieve fully connected secure communication within each corresponding user group.

2. The multi-level user quantum key distribution network system based on multiple entangled light sources according to claim 1, characterized in that, Both the primary multi-channel entangled light source and the secondary multi-channel entangled light source distribute entangled photon pairs using wavelength division multiplexing (WDM) technology.

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

4. The multi-level user quantum key distribution network system based on multiple entangled light sources according to claim 3, characterized in that the secondary multi-channel entangled light source is set inside the corresponding user group so as to provide quantum key distribution services within the corresponding user group.

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

6. A multi-level user quantum key distribution method based on multiple entangled light sources, applied to the multi-level user quantum key distribution network system based on multiple entangled light sources as described in any one of claims 1 to 5, characterized in that, include: Users are divided into different user groups based on their geographical location; Within each user group, users are divided into Level 1 users and Level 2 users according to a preset user hierarchy. Each user group includes at least one Level 1 user. A Level 1 multi-channel entangled light source is deployed at the center of each user group to perform quantum key distribution among the Level 1 users, achieving fully connected secure communication among them. Within each user group, a Level 2 entangled light source is used to perform quantum key distribution among the Level 2 users and the Level 1 users within that group, achieving fully connected secure communication within each corresponding user group.

Images