Key service routing method and system of quantum satellite network

Abstract

The application discloses a kind of quantum satellite network's key service routing method and system, belong to quantum key distribution network technical field;The method comprises the following steps: step S1: quantum satellite network topology abstraction;Step S2: routing in abstract topology;Step S3: routing in physical topology.The application is advantageous to reduce the number of quantum satellite network routing hops by abstracting dynamic quantum satellite network physical topology into quasi-static topology, avoids the waste of key resources caused by dynamic changes in physical topology, solves the problems of low key resource utilization, high delay in establishing global keys and low service success rate faced by key service routing in existing quantum satellite networks.

Description

Technical Field

[0001] This invention belongs to the field of quantum key distribution network technology, specifically relating to a key service routing method and system for quantum satellite networks. Background Technology

[0002] Quantum Key Distribution (QKD) is a key technology that provides users with information-theoretically secure key distribution, remaining unconditionally secure even with future increases in computing power. Currently, most QKD networks are fiber-optic based; however, due to the significant signal loss in fiber optics, intercontinental QKD communication is difficult to support. Therefore, quantum satellite networks are currently a key technology for realizing intercontinental QKD communication. Key services are a crucial service in quantum satellite networks, encrypting data transmitted between end-to-end users by distributing a certain number of quantum keys. In quantum satellite networks, key service nodes involve source and destination QKD ground station nodes, as well as relay quantum satellite nodes between them. Topology abstraction methods are effective for network routing. Research has been conducted on topology abstraction methods for terrestrial optical networks, but due to the high mobility of satellites, topology abstraction methods based on static physical topology are not applicable to quantum satellite networks. Research also exists on topology abstraction methods for classical satellite networks, but these methods do not address the key characteristics of key services and are therefore also unsuitable for quantum satellite networks. Current routing methods for quantum satellite networks are not based on topology abstraction. These methods suffer from drawbacks such as high latency and low key resource utilization. How to efficiently route key services for quantum satellite networks has become a key issue in building such networks, and this problem remains unsolved.

[0003] Currently, there is no key service routing method based on topology abstraction in quantum satellite networks. This is primarily because most current topology abstraction methods are designed for terrestrial networks, but are unsuitable for the dynamically changing physical topology of satellite networks. Furthermore, topology abstraction methods for classical satellite networks do not consider key resource characteristics and key service attributes, rendering them ineffective for key service routing in quantum satellite networks. Current satellite QKD mostly utilizes a single quantum satellite to implement key services. While a single quantum satellite can meet certain key service requirements, it suffers from high key distribution latency and is increasingly unable to meet the growing key demands. Some research has proposed routing methods for quantum satellite networks, but their key service routing is not based on topology abstraction methods, leading to low key resource utilization or high latency, making it difficult to meet the key service requirements of all-time, all-domain quantum satellite networks. Summary of the Invention

[0004] The purpose of this invention is to provide a key service routing method and system for quantum satellite networks, so as to solve the problems and achieve the effects mentioned in the background art.

[0005] The objective of this invention is achieved as follows: a key service routing method for quantum satellite networks, comprising the following steps: Step S1: Quantum satellite network topology abstraction; Step S2: Routing in the abstract topology; Step S3: Routing in the physical topology.

[0006] Preferably, the quantum satellite network topology abstraction in step S1 includes the following steps: Step S1-1: Set the physical topology sampling interval; Step S1-2: Query the physical distance information, visibility information, and elevation angle information between each node; Step S1-3: Query the QKD protocol supported by the quantum satellite network; Step S1-4: Calculate the key generation rate between each node; Steps S1-5: Query the number of other low-Earth orbit quantum satellites that the low-Earth orbit quantum satellite can support connections to, as well as the number of ground stations; Steps S1-6: Based on the limitation of the number of connections, the low-Earth orbit quantum satellite selects the site that can support the maximum key generation rate to establish a QKD link; Steps S1-7: Add each site with quantum functionality as an abstract node to the abstract topology; Steps S1-8: Update the key pool and query its remaining key quantity; Step S1-9: Set the links corresponding to all key pools with a remaining key quantity greater than 0 to be connected in the abstract topology; Step S1-10: Query the minimum key quantity k required for the key service; Step S1-11: Set the links corresponding to all key pools with remaining key quantity less than k to be disconnected in the abstract topology.

[0007] Preferably, the routing operation steps in the abstract topology in step S2 are as follows: Step S2-1: Query the key quantity requirements and terminal node information for the key service; Step S2-2: In the abstract topology, perform routing calculations for key services based on the shortest path algorithm and select their key relay paths; Step S2-3: Obtain the minimum remaining key quantity p in the key pool on the key relay path; Step S2-4: Determine if p is greater than the key quantity requirement of the key service. If it is greater, proceed to the next step; otherwise, the key service fails. Step S2-5: Update the key pool by subtracting the key quantity requirement of the key service from the remaining key quantity in the corresponding key pool on the key relay path.

[0008] Preferably, the specific routing operation in the physical topology in step S3 includes the following steps: Step S3-1: Query whether the classic channel can be established for each segment of the key relay path; Step S3-2: For segments where a classical channel cannot be established, query the nearest high-orbit classical satellites to the two nodes of the segment; use the classical channel of the high-orbit classical satellite to assist in the transmission of the encrypted global key; Step S3-3: Based on the retrieved high-orbit classical satellites, establish an end-to-end global key transmission path in the physical topology; Step S3-4: Establish a classic channel and transmit the encrypted global key using the classic channel; The global key is transmitted according to the end-to-end global key transmission path, and encryption and decryption operations are performed at the corresponding nodes according to the key relay path. Step S3-5: Transmission complete, disconnect the classic channel, key service successful.

[0009] A key service routing system for a quantum satellite network includes a key service routing device control module for managing the operation of the entire system, a topology abstraction module for generating and managing the abstract topology of the quantum satellite network, an abstract topology routing module for routing key services on the abstract topology of the quantum satellite network, and a physical topology routing unit for routing key services on the physical topology of the quantum satellite network. The topology abstraction module, abstract topology routing module, and physical topology routing module respectively execute the key service routing method for the quantum satellite network.

[0010] Preferably, the physical topology routing unit includes: Classical Channel Query Unit: Used to query whether a classical channel can be established for each segment of the key relay path; High-orbit satellite query unit: Query the high-orbit classical satellites closest to the node; Connection disconnection unit: used to disconnect the classic channel after transmission is completed; Global key transmission path establishment unit: used to establish an end-to-end global key transmission path in the physical topology; Global Key Transmission Unit: Used to establish a classic channel and transmit the encrypted global key using the classic channel.

[0011] Preferably, the topology abstraction module includes: Topology sampling unit: Used to set the physical topology sampling interval; Abstract topology management unit: used to add and delete nodes and connections in the abstract topology; Key generation rate calculation unit: used to calculate the key generation rate between nodes; Connectivity Restriction Query Unit: Used to query the number of other low-Earth orbit quantum satellites that the low-Earth orbit quantum satellite can connect to, as well as the number of ground stations; QKD Link Management Unit: Controls the low-Earth orbit quantum satellite to select sites that can generate the maximum key generation rate to establish QKD links; Key pool query unit: Query the remaining key quantity in the key pool; QKD Protocol Query Unit: Queries the QKD protocols supported by the quantum satellite network; Node information query unit: used to query the physical distance information, visibility information, elevation angle information between nodes, and whether each node has quantum functionality.

[0012] Preferably, the abstract topology routing module includes: Key service query unit: Query the key quantity requirements and terminal node information for key services; Minimum Remaining Key Quantity Acquisition Unit: Acquires the minimum remaining key quantity in the key pool on the key relay path; Judgment Unit: Determines whether the minimum remaining key quantity in the key pool on the key relay path is greater than the key quantity requirement of the key service; The routing calculation unit performs routing calculations for key services and selects their key relay paths within the abstract topology based on the shortest path algorithm. Key pool update unit: Updates the key pool.

[0013] Compared with the prior art, the present invention has the following improvements and advantages: 1. By abstracting the dynamic physical topology of the quantum satellite network into a quasi-static topology, it is beneficial to reduce the routing hops of the quantum satellite network, avoid the waste of key resources caused by dynamic changes in the physical topology, and solve the problems of low key resource utilization, high latency in establishing global keys, and low service success rate faced by key service routing in existing quantum satellite networks.

[0014] 2. The dynamic physical topology is abstracted into a quasi-static topology and routing is performed within it. At the same time, the encrypted global key is transmitted using the classical channels of high-orbit classical satellites with wide coverage, thereby achieving efficient key service routing. Attached Figure Description

[0015] Figure 1 This is an overall flowchart of the method of the present invention.

[0016] Figure 2 This is a flowchart illustrating the topology abstraction of the quantum satellite network in this invention.

[0017] Figure 3 This is a flowchart of routing in the abstract topology of this invention.

[0018] Figure 4 This is a flowchart of routing in the physical topology of this invention.

[0019] Figure 5 This is a block diagram of the system of the present invention.

[0020] Figure 6 This is a diagram showing the key service routing settings according to an embodiment of the present invention. Detailed Implementation

[0021] The invention will be further summarized below with reference to the accompanying drawings.

[0022] See Figure 1 , 2 A key service routing method for a quantum satellite network, comprising the following steps: Step S1: Quantum Satellite Network Topology Abstraction; The specific operations for quantum satellite network topology abstraction are as follows: Step S1-1: Set the physical topology sampling interval; the sampling interval refers to the time interval for sampling the physical topology to obtain the discrete topology. Step S1-2: Query the physical distance information, visibility information, and elevation angle information between each node; the nodes include low-Earth orbit quantum satellites and ground stations.

[0023] Step S1-3: Query the QKD protocol supported by the quantum satellite network; Step S1-4: Calculate the key generation rate between each node; the key generation rate is affected by the physical distance between nodes, visibility, elevation angle, QKD protocol, etc.

[0024] Steps S1-5: Query the number of other low-Earth orbit quantum satellites and ground stations that the low-Earth orbit quantum satellite can support connection to; due to the limitations of satellite payload, the number of quantum transceivers it can carry is limited, and a satellite can only establish QKD connections with a limited number of other stations at the same time, namely low-Earth orbit quantum satellites or ground stations.

[0025] Steps S1-6: Based on the limitation of the number of connections, the low-Earth orbit quantum satellite selects the site that can support the maximum key generation rate to establish a QKD link; in order to generate the most key resources, the low-Earth orbit quantum satellite only connects to the site that can support the maximum key generation rate within the topology sampling interval, and injects the generated key resources into the key pool, which refers to the storage space used to store the keys.

[0026] Steps S1-7: Add each station with quantum functionality as an abstract node to the abstract topology; key pools can only be established between stations with quantum functionality.

[0027] Steps S1-8: Update the key pool and query its remaining key quantity; Step S1-9: Set the links corresponding to all key pools with a remaining key quantity greater than 0 to be connected in the abstract topology; as long as there are key pools with key surplus between nodes, these local keys can be used to relay the global key through the classic channel.

[0028] Step S1-10: Query the minimum key quantity k required for the key service; Step S1-11: Set the links corresponding to all key pools with remaining key quantity less than k to be disconnected in the abstract topology. This is because if the remaining key quantity of a key pool is less than k, then the key pool for that link cannot meet the needs of any key service, so it is set to be disconnected to improve the success rate of key services.

[0029] Step S2: Routing in the abstract topology; The routing operation steps in the abstract topology are as follows: Step S2-1: Query the key quantity requirements and terminal node information for the key service; Step S2-2: In the abstract topology, perform routing calculations for key services based on the shortest path algorithm and select its key relay path; the key relay path refers to the path between source and destination terminal nodes that encrypts and relays the global key hop by hop, and the global key can be shared between source and destination terminal nodes based on this path.

[0030] Step S2-3: Obtain the minimum remaining key amount p of the key pool on the key relay path; the minimum remaining key amount of the key pool on the key relay path refers to the minimum value of the remaining key amount on all links in the key relay path.

[0031] Step S2-4: Determine if p is greater than the key quantity requirement of the key service. If it is greater, proceed to the next step; otherwise, the key service fails. Step S2-5: Update the key pool by subtracting the key quantity requirement of the key service from the remaining key quantity in the corresponding key pool on the key relay path.

[0032] Step S3: Routing in the physical topology; The specific operations for routing in the physical topology include the following steps: Step S3-1: Query whether the classic channel of each segment on the key relay path can be established; the segment on the key relay path refers to the point-to-point link between two adjacent nodes in the key relay path.

[0033] Step S3-2: For segments where a classical channel cannot be established, query the nearest high-orbit classical satellites to the two nodes of the segment; use the classical channel of the high-orbit classical satellite to assist in the transmission of the encrypted global key; Step S3-3: Based on the retrieved high-orbit classical satellites, establish an end-to-end global key transmission path in the physical topology; the end-to-end global key transmission path refers to the transmission path of the global key in the classical channel, which includes the high-orbit classical satellites. Step S3-4: Establish a classic channel and transmit the encrypted global key using the classic channel; The local key is transmitted according to the end-to-end global key transmission path, and encryption and decryption operations are performed at the corresponding nodes according to the key relay path. Step S3-5: Transmission complete, disconnect the classic channel, key service successful.

[0034] like Figure 5 As shown, a key service routing system for a quantum satellite network includes a key service routing device control module, a topology abstraction module, an abstract topology routing module, and a physical topology routing module. The key service routing device control module is responsible for the operation of the entire device, while the topology abstraction module, the abstract topology routing module, and the physical topology routing module respectively execute the key service routing method for the quantum satellite network.

[0035] The topology abstraction module is used to generate and manage the abstract topology of the quantum satellite network. Specifically, it includes a topology sampling unit, an abstract topology management unit, a key generation rate calculation unit, a connection limit query unit, a QKD link management unit, a key pool query unit, a QKD protocol query unit, and a node information query unit. The topology sampling unit sets the physical topology sampling interval; the abstract topology management unit adds and deletes nodes and connections in the abstract topology; the key generation rate calculation unit calculates the key generation rate between nodes; the connection limit query unit queries the number of other low-Earth orbit quantum satellites and ground stations that the low-Earth orbit quantum satellite can connect to; the QKD link management unit controls the low-Earth orbit quantum satellite to select the site that can generate the maximum key generation rate to establish a QKD link; the key pool query unit queries the remaining key quantity in the key pool; the QKD protocol query unit queries the QKD protocols supported by the quantum satellite network; and the node information query unit queries the physical distance information, visibility information, elevation angle information, and whether each node has quantum functionality between nodes.

[0036] The abstract topology routing module is used to route key services on the abstract topology of the quantum satellite network. Specifically, it includes a key service query unit, a minimum remaining key quantity acquisition unit, a judgment unit, a route calculation unit, and a key pool update unit. The key service query unit queries the key quantity requirements and terminal node information for key services; the minimum remaining key quantity acquisition unit obtains the minimum remaining key quantity in the key pool along the key relay path; the judgment unit determines whether the minimum remaining key quantity in the key pool along the key relay path exceeds the key quantity requirements of the key service; the route calculation unit performs route calculations for key services based on the shortest path algorithm within the abstract topology and selects the key relay path; and the key pool update unit updates the key pool.

[0037] The physical topology routing unit is used to route key services on the physical topology of the quantum satellite network. Specifically, it includes a classical channel query unit, a high-orbit satellite query unit, a connection disconnection unit, a global key transmission path establishment unit, and a global key transmission unit. The classical channel query unit queries whether classical channels can be established for each segment of the key relay path; the high-orbit satellite query unit queries the nearest high-orbit classical satellite to the node; the connection disconnection unit disconnects the classical channel after transmission is complete; the global key transmission path establishment unit establishes an end-to-end global key transmission path in the physical topology; and the global key transmission unit establishes a classical channel and transmits the encrypted global key using this classical channel.

[0038] like Figure 6 The image shown is a preferred embodiment of the present invention.

[0039] First, set the physical topology sampling interval to 1 minute; query the physical distances between nodes: 300 km (1−4), 350 km (1−5), 400 km (4−5), 450 km (2−5), 250 km (2−6), 350 km (3−6), 400 km (3−7), 400 km (6−7), 48500 km (1−8), 50000 km (2−8), 49500 km (3−8), 47500 km (4−8), 46500 km (5−8), 46000 km (6−8), 47000 km (7-8); Visibility information: Visible (1-4), Visible (1-5), Visible (4-5), Visible (2-5), Visible (2-6), Visible (3-6), Visible (3-7), Visible (6-7), Visible (1-8), Visible (2-8), Visible (3-8), Visible (4-8), Visible (5-8), Visible (6-8), Visible (7-8), the rest are not visible; Elevation information: 10 degrees (1-4), 15 degrees (1-5), 8 degrees (4-5), 13 degrees (2-5), 18 degrees (2-6), 14 degrees (3-6), 9 degrees (3-7), 12 degrees (6-7), 7 degrees (1-8), 5 degrees (2-8), 7 degrees (3-8), 9 degrees (4-8), 3 degrees (5-8), 6 degrees (6-8), 9 degrees (7-8); Search for the BB84 protocol of the QKD protocol supported by the quantum satellite network; Calculate the key generation rates between nodes: 80 kbps (1−4), 74 kbps (1−5), 70 kbps (4−5), 65 kbps (2−5), 90 kbps (2−6), 76 kbps (3−6), 68 kbps (3−7), 69 kbps (6−7); The query shows the number of other low-Earth orbit quantum satellites that the low-Earth orbit quantum satellite can connect to, as well as the number of ground stations: 4 (low-Earth orbit satellite → low-Earth orbit satellite) and 4 (low-Earth orbit satellite → ground station). Based on the limitation on the number of connections, the low-Earth orbit quantum satellite selects the sites that can generate the maximum key generation rate to establish QKD connections (1-4, 1-5, 4-5, 2-5, 2-6, 3-6, 3-7, 6-7); sites with quantum functionality: nodes 1-7, and node 8 without quantum functionality; are added as abstract nodes to the abstract topology; the key pool is updated and the remaining key quantity is queried: 5500 kbit (1-4), 5300 kbit (1-5), 5200 kbit (2-5), 5100 kbit (2-6), 5050 kbit (3-6), 5550 kbit (3-7), 5300 kbit (4-5), 5200 kbit (4-6), 4900 kbit (4-7), 4950 kbit (5-6), 5500 kbit (5-7), 5250 kbit (6-7)). In the abstract topology, set the links corresponding to all key pools with a remaining key quantity greater than 0 as connected: Connect (1-4), Connect (1-5), Connect (2-5), Connect (2-6), Connect (3-6), Connect (3-7), Connect (4-5), Connect (4-6), Connect (4-7), Connect (5-6), Connect (5-7), Connect (6-7); The minimum key quantity required for querying key services. k (1000 kbit); All remaining key amounts less than k The link corresponding to the key pool is set to disconnect in the abstract topology; update the abstract topology.

[0040] Routing in the abstract topology. Query the key service's key quantity requirement of 1000 kbit and terminal node information: Node 1, Node 3; calculate the route for the key service in the abstract topology based on the shortest path algorithm and select its key relay path (1−5−6−3); obtain the minimum remaining key quantity in the key pool on the key relay path. p (4950 kbit); Judgment p Does it exceed the key quantity requirement of the key service? Update the key pool: 4300 kbit (1−5), 3950 kbit (5−6), 4050 kbit (3−6).

[0041] In the physical topology, routing is performed. The classical channel for each segment of the key relay path is queried to determine if it can be established: (1-5), (5-6), (6-3). For segments (5-6) where a classical channel cannot be established, the two nodes closest to that segment are queried: node 5 and node 6; the nearest high-orbit classical satellites are Node 8 and Node 8. Based on the high-orbit classical satellite Node 8, an end-to-end global key transmission path (1-5-8-6-3) is established in the physical topology. Establish a classic channel: establish (1-5), establish (5-8), establish (8-6), establish (6-3), and transmit the encrypted global key using the classic channel (key). 1-5 Å key 5-6 (5®8), Key 1-5 Å key 5-6 (8®6), (Key) 1-5 Å key 5-6 )Å key 5-6 (6) Key 1-5 Å key 3-6 (6®3), (Key) 1-5 Å key 3-6 )Å key 3-6 (3)); Transmission complete. Disconnect the classic channel: disconnect (1-5), disconnect (5-8), disconnect (8-6), disconnect (6-3). Key service successful.

[0042] Working principle: The key service routing device of the quantum satellite network is implemented in the centralized management system of the network by abstracting the physical topology using key pool technology and routing within it, and by using the classical channel of high-orbit satellites to achieve low-latency transmission of encrypted global keys. The specific process is as follows: The quantum satellite network operator calls the key service routing device of the quantum satellite network through the centralized management system, executes the key service routing method of the quantum satellite network, meets the key quantity requirements of the key service of the quantum satellite network, and updates the state of the quantum satellite network after the routing is completed.

[0043] By considering the use of key pool technology for topology abstraction, the encrypted global key is transmitted using classical channels of high-orbit classical satellites with wide coverage. The proposed key service routing method for quantum satellite networks is implemented through topology abstraction, routing within the abstract topology, and routing within the physical topology. The proposed key service routing device for quantum satellite networks is used to implement the key service routing method in a centralized manner. This invention abstracts the dynamic physical topology of quantum satellite networks into a quasi-static topology, which helps reduce the routing hop count of quantum satellite networks and avoids the waste of key resources caused by dynamic changes in the physical topology to a certain extent. It solves the problems of low key resource utilization, high latency in establishing the global key, and low service success rate faced by key service routing in existing quantum satellite networks.

[0044] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A key service routing method for a quantum satellite network, characterized in that: The method includes the following steps: Step S1: Quantum satellite network topology abstraction; Step S1-1: Set the physical topology sampling interval; Step S1-2: Query the physical distance information, visibility information, and elevation angle information between each node; Step S1-3: Query the QKD protocol supported by the quantum satellite network; Step S1-4: Calculate the key generation rate between each node; Steps S1-5: Query the number of other low-Earth orbit quantum satellites that the low-Earth orbit quantum satellite can support connections to, as well as the number of ground stations; Steps S1-6: Based on the limitation of the number of connections, the low-Earth orbit quantum satellite selects the site that can support the maximum key generation rate to establish a QKD link; Steps S1-7: Add each site with quantum functionality as an abstract node to the abstract topology; Steps S1-8: Update the key pool and query its remaining key quantity; Step S1-9: Set the links corresponding to all key pools with a remaining key quantity greater than 0 to be connected in the abstract topology; Step S1-10: Query the minimum key amount required for the key service. k ; Step S1-11: Set the links corresponding to all key pools with remaining key quantity less than k to be disconnected in the abstract topology; Step S2: Route in the abstract topology. The operation steps are as follows: Step S2-1: Query the key quantity requirements and terminal node information for the key service; Step S2-2: In the abstract topology, perform routing calculations for key services based on the shortest path algorithm and select their key relay paths; Step S2-3: Obtain the minimum remaining key quantity p in the key pool on the key relay path; Step S2-4: Determine if p is greater than the key quantity requirement of the key service. If it is greater, proceed to the next step; otherwise, the key service fails. Step S2-5: Update the key pool by subtracting the key quantity requirement of the key service from the remaining key quantity in the corresponding key pool on the key relay path. Step S3: Routing in the physical topology, specifically including the following steps: Step S3-1: Query whether the classic channel can be established for each segment of the key relay path; Step S3-2: For segments where a classical channel cannot be established, query the nearest high-orbit classical satellites to the two nodes of the segment; use the classical channel of the high-orbit classical satellite to assist in the transmission of the encrypted global key; Step S3-3: Based on the retrieved high-orbit classical satellites, establish an end-to-end global key transmission path in the physical topology; Step S3-4: Establish a classic channel and transmit the encrypted global key using the classic channel; The global key is transmitted according to the end-to-end global key transmission path, and encryption and decryption operations are performed at the corresponding nodes according to the key relay path. Step S3-5: Transmission complete, disconnect the classic channel, key service successful.

2. A key service routing system for a quantum satellite network, characterized in that: The key service routing system includes the key service routing method for the quantum satellite network as described in claim 1; The key service routing system includes a key service routing device control module responsible for the operation of the entire system, a topology abstraction module for generating and managing the abstract topology of the quantum satellite network, an abstract topology routing module for routing key services on the abstract topology of the quantum satellite network, and a physical topology routing module for routing key services on the physical topology of the quantum satellite network. The topology abstraction module, abstract topology routing module, and physical topology routing module respectively execute the key service routing method for the quantum satellite network.

3. The key service routing system for a quantum satellite network according to claim 2, characterized in that: The physical topology routing module includes: Classical Channel Query Unit: Used to query whether a classical channel can be established for each segment of the key relay path; High-orbit satellite query unit: Query the high-orbit classical satellites closest to the node; Connection disconnection unit: used to disconnect the classic channel after transmission is completed; Global key transmission path establishment unit: used to establish an end-to-end global key transmission path in the physical topology; Global Key Transmission Unit: Used to establish a classic channel and transmit the encrypted global key using the classic channel.

4. The key service routing system for a quantum satellite network according to claim 2, characterized in that: The topology abstraction module includes: Topology sampling unit: Used to set the physical topology sampling interval; Abstract topology management unit: used to add and delete nodes and connections in the abstract topology; Key generation rate calculation unit: used to calculate the key generation rate between nodes; Connectivity Restriction Query Unit: Used to query the number of other low-Earth orbit quantum satellites that the low-Earth orbit quantum satellite can connect to, as well as the number of ground stations; QKD Link Management Unit: Controls the low-Earth orbit quantum satellite to select sites that can generate the maximum key generation rate to establish QKD links; Key pool query unit: Query the remaining key quantity in the key pool; QKD Protocol Query Unit: Queries the QKD protocols supported by the quantum satellite network; Node information query unit: used to query the physical distance information, visibility information, elevation angle information between nodes, and whether each node has quantum functionality.

5. A key service routing system for a quantum satellite network according to claim 2, characterized in that: The abstract topology routing module includes: Key service query unit: Query the key quantity requirements and terminal node information for key services; Minimum Remaining Key Quantity Acquisition Unit: Acquires the minimum remaining key quantity in the key pool on the key relay path; Judgment Unit: Determines whether the minimum remaining key quantity in the key pool on the key relay path is greater than the key quantity requirement of the key service; The routing calculation unit performs routing calculations for key services and selects their key relay paths within the abstract topology based on the shortest path algorithm. Key pool update unit: Updates the key pool.

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