A centralized quantum key relay network and key distribution method

Abstract

This invention proposes a centralized quantum key relay network and key distribution method. The controller determines the target relay path and target time based on the relay request transmitted by the requesting node. From the M-2 key pools corresponding to the target relay path, the controller extracts the XOR key matching the target time, performs a bitwise XOR operation to obtain the relay key, and sends the relay key to the requesting node and the requesting destination node. This invention addresses the issue of varying XOR key lengths, generation times, and consumption rates received by the controller from different nodes. It finds a usable key link in the massive key storage, ensuring that within a certain time period, every two links on this link have uploaded sufficient XOR keys for use. This provides a practically feasible key usage method for centralized relay networks.

Description

Technical Field

[0001] This invention relates to the field of quantum communication, and more specifically, to a centralized quantum key relay network and key distribution method. Background Technology

[0002] Quantum cryptography, based on the quantum key distribution (QKD) protocol, has developed rapidly in recent years. Unlike traditional cryptography, quantum cryptography is based on quantum mechanics and utilizes quantum physical properties such as the Heisenberg uncertainty principle and the no-cloning theorem to achieve secure negotiation of symmetric keys over long distances.

[0003] Multiple quantum key distribution nodes can form a quantum key distribution network (QKDN). Due to the limited distance between adjacent nodes, quantum key relay distribution is required in long-distance key generation scenarios, leading to the development of centralized quantum key relay networks.

[0004] In centralized quantum key relay networks (QKDNs), the QKDN controller manages all XOR keys reported by relay nodes. As the network operates and is used, the amount of XOR keys stored in the QKDN controller inevitably increases, becoming difficult to manage. Therefore, how to implement key management in a centralized QKDN so that the QKDN controller can quickly and easily select the appropriate XOR key when a key relay request occurs, and ultimately share sufficient quantum keys among distant network nodes, has become a challenging problem of concern to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a centralized quantum key relay network and key distribution method to improve the above-mentioned problems.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0007] In a first aspect, embodiments of the present invention provide a key distribution method for a centralized quantum key relay network, the centralized quantum key relay network comprising: a controller and multiple quantum key distribution nodes, the multiple quantum key distribution nodes including at least one relay node, the relay node being a quantum key distribution node connected to at least two quantum links, the method comprising:

[0008] The controller initiates a relay request for node transmission based on demand to determine the target relay path and target time;

[0009] The relay request includes the identifier of the destination node and the relay requirement. The target relay path is the shortest path among the relay paths that meets the relay requirement condition. The relay path is the quantum communication path between the request initiating node and the request destination node in the centralized quantum key relay network. The relay requirement condition indicates that there exists a target time, and the key quantity of the XOR key matching the target time in the M-2 key pools corresponding to the target relay path is greater than the relay requirement. M represents the total number of nodes in the target relay path.

[0010] The controller extracts the XOR key that matches the target time from the M-2 key pools corresponding to the target relay path, performs bitwise XOR to obtain the relay key, and sends the relay key to the request initiating node and the request destination node.

[0011] Secondly, embodiments of the present invention provide a centralized quantum key relay network, the centralized quantum key relay network comprising: a controller and multiple quantum key distribution nodes, the multiple quantum key distribution nodes including at least one relay node, the relay node being a quantum key distribution node connected to at least two quantum links;

[0012] The centralized quantum key relay network is used to execute the key distribution method of the centralized quantum key relay network described above.

[0013] Compared to existing technologies, this invention provides a centralized quantum key relay network and key distribution method. The controller determines the target relay path and target time based on the relay request transmitted by the request initiating node. The controller extracts the XOR key matching the target time from the M-2 key pools corresponding to the target relay path, performs a bitwise XOR operation to obtain the relay key, and sends the relay key to the request initiating node and the request destination node. This addresses the issue of different XOR key lengths, generation times, and consumption patterns received by the controller from different nodes, providing a practically feasible key usage method for centralized relay networks. By managing key storage separately from key pools, the workload for key lookup is reduced, and key lookup efficiency is improved. It can find a usable key link in massive key storage, and within a certain time period, every two links on that link have uploaded sufficient XOR keys for use. This provides a guiding scheme for XOR key management in quantum networks with centralized control and key relay architecture.

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the architecture of a centralized quantum key relay network provided in an embodiment of the present invention.

[0017] Figure 2 This is one of the flowcharts illustrating a key distribution method for a centralized quantum key relay network provided in an embodiment of the present invention.

[0018] Figure 3 This is the second flowchart illustrating the key distribution method for a centralized quantum key relay network provided in this embodiment of the invention.

[0019] Figure 4 This is the third flowchart illustrating the key distribution method for a centralized quantum key relay network provided in this embodiment of the invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0024] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0025] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the architecture of a centralized quantum key relay network provided in an embodiment of the present invention. The centralized quantum key relay network includes a controller (also called a QKDNC) and multiple quantum key distribution nodes. Each quantum key distribution node deploys a QKD device for quantum key distribution and a KM device for managing the keys of the QKD devices. All quantum key distribution nodes are communicatively connected to the controller, forming a network topology. The controller is used to control and manage the centralized quantum key relay network, realizing routing control and resource scheduling for each node and link. The controller maintains time synchronization with each quantum key distribution node.

[0028] It should be noted that, Figure 1 The diagram shows eight quantum key distribution nodes, but this is not a limitation; the number of quantum key distribution nodes can be greater or less than eight. All quantum key distribution nodes are communicatively connected to the controller. Figure 1 Some links have been omitted to make the content clearer.

[0029] Multiple quantum key distribution nodes include at least one relay node, which is a quantum key distribution node that connects at least two quantum links.

[0030] Please refer to Figure 1 Quantum key distribution nodes 2, 3, 4, 6, and 7 are all relay nodes. Taking quantum key distribution node 2 as an example, the quantum links it connects to include the link between quantum key distribution node 1 and quantum key distribution node 2, the link between quantum key distribution node 2 and quantum key distribution node 3, and the link between quantum key distribution node 2 and quantum key distribution node 6.

[0031] It should be noted that multiple quantum key distribution nodes also include user nodes. User nodes are quantum key distribution nodes connected to the business system. They can receive communication requests transmitted by the business system and distribute keys to the business system.

[0032] Figure 1 In this context, Ki(K1-K8) represents the quantum key generated by the i-th quantum link at a certain moment. Relay nodes are used to XOR related quantum keys generated at the same time with each other to obtain the XOR key, and then transmit the characteristic information of the XOR key to the controller. The related quantum keys are those generated by the quantum links connected to the relay nodes, and the characteristic information of the XOR key includes the XOR key itself, the identifier of the relay node, the identifiers of the nodes on the quantum links associated with the XOR key, and the generation time of the XOR key. The controller stores the XOR key in conjunction with its characteristic information.

[0033] It should be noted that once a quantum link is formed, it will continuously generate quantum keys. Figure 1 Taking the relay node (quantum key distribution node 2) as an example, at a certain moment, the relevant quantum keys corresponding to quantum key distribution node 2 are quantum key K1, quantum key K2, and quantum key K3. The XOR keys obtained by XORing each pair of quantum keys include K1⊕K2, K1⊕K3, and K2⊕K3. The generation time of the XOR keys is the same as the generation time of the relevant quantum keys. The identifier of the quantum key distribution node can be, but is not limited to, a node ID.

[0034] In this context, the relay nodes corresponding to the XOR keys K1⊕K2, K1⊕K3, and K2⊕K3 are all quantum key distribution node 2. The generation times of the XOR keys K1⊕K2, K1⊕K3, and K2⊕K3 are the generation times of the quantum keys K1, K2, and K3, respectively. The nodes on the quantum link associated with the XOR key K1⊕K2 are quantum key distribution nodes 1 and 6; the nodes on the quantum link associated with the XOR key K1⊕K3 are quantum key distribution nodes 1 and 3; and the nodes on the quantum link associated with the XOR key K2⊕K3 are quantum key distribution nodes 6 and 3.

[0035] This invention provides a key distribution method for a centralized quantum key relay network, which can be applied to, but is not limited to, the centralized quantum key relay network described above. Please refer to [reference needed]. Figure 2 , Figure 2 This is one of the flowcharts illustrating a key distribution method for a centralized quantum key relay network provided in an embodiment of the present invention. The key distribution method for a centralized quantum key relay network includes S10 and S20, which are described in detail below.

[0036] S10, the controller initiates a relay request for node transmission based on demand to determine the target relay path and target time.

[0037] The relay request includes the identifier of the destination node and the relay requirement. Both the request initiating node and the request destination node are quantum key distribution nodes in a centralized quantum key relay network.

[0038] The target relay path is the shortest path among the relay paths that satisfies the relay demand condition. The relay path is the quantum communication path between the demand initiating node and the demand destination node in a centralized quantum key relay network. The relay demand condition means that there exists a target time, and the number of XOR keys matching the target time in the M-2 key pools corresponding to the target relay path is greater than the relay demand. M represents the total number of nodes in the target relay path.

[0039] The i-th key pool corresponding to the target relay path corresponds to the i-th node, the (i+1)-th node, and the (i+2)-th node in the target relay path, where 1 ≤ i ≤ N-2, and i is initially set to 1. The i-th key pool in the target relay path is used to store the XOR key uploaded by the (i+1)-th node in the target relay path that matches the target relay path. The peer nodes of the XOR key in the i-th key pool are the i-th node and the (i+2)-th node in the target relay path.

[0040] S20, the controller extracts the XOR key that matches the target time from the M-2 key pools corresponding to the target relay path, performs bitwise XOR to obtain the relay key, and sends the relay key to the request initiating node and the request destination node.

[0041] The key distribution method for centralized quantum key relay networks provided in this invention addresses the issue of varying XOR key lengths, generation times, and consumption patterns received by the controller from different nodes, offering a practically feasible key usage method for centralized relay networks. By managing key storage separately from the key pool, the workload for key lookup is reduced, improving key search efficiency. It enables the retrieval of a usable key link from a massive key storage, ensuring that within a certain timeframe, every two links on that link have uploaded sufficient XOR keys for use. This provides guidance for XOR key management in quantum networks with centralized control and key relay architectures.

[0042] Based on the preceding text, regarding the content of S10, this embodiment of the invention also provides an optional implementation method, please refer to the following. S10, the step of the controller initiating a relay request for node transmission according to demand to determine the target relay path and target time, includes: S101, S102, S104, S105, S106, S107, S108, S109 and S110, which are described in detail below.

[0043] S101, the controller uses the shortest relay path between the request initiating node and the request destination node as the suspected target path.

[0044] The shortest relay path refers to the relay path with the fewest nodes, or the relay path with the shortest corresponding optical fiber link length. A relay path is the quantum communication path between the request initiating node and the request destination node in a centralized quantum key relay network.

[0045] S102, the controller determines the generation time of the earliest generated XOR key in the first key pool of the suspected target path as the suspected target time.

[0046] The first key pool corresponds to the first, second, and third nodes in the suspected target path. The first key pool of the suspected target path is used to store the XOR key uploaded by the second node in the suspected target path that matches the suspected target path. The peer nodes of the XOR key in the first key pool are the first and third nodes in the suspected target path, and the first node is the request initiating node.

[0047] Taking a relay path consisting of quantum key distribution nodes 1, 2, 3, 4, and 5 as an example, where quantum key distribution node 1 is the request initiating node (node ​​1) and quantum key distribution node 5 is the request destination node, the first key pool of the suspected target path is used to store the XOR key K1⊕K3 uploaded by quantum key distribution node 2. The peer nodes of the XOR key K1⊕K3 are quantum key distribution nodes 1 and 3.

[0048] S104, the controller determines whether the amount of the i-th key is greater than or equal to the relay demand. If yes, proceed to S105; otherwise, proceed to S108.

[0049] Here, the i-th key quantity represents the number of XOR keys in the i-th key pool that match the suspected target time. The i-th key pool corresponds to the i-th node, the (i+1)-th node, and the (i+2)-th node in the suspected target path, where 1 ≤ i ≤ N-2, i is initially 1, and N represents the total number of nodes in the suspected target path. The i-th key pool of the suspected target path is used to store the XOR keys uploaded by the (i+1)-th node in the suspected target path that match the suspected target path. The peer nodes of the XOR keys in the i-th key pool are the i-th node and the (i+2)-th node in the suspected target path.

[0050] Continuing with the example of a relay path consisting of quantum key distribution nodes 1, 2, 3, 4, and 5, where the suspected target path is i=2, the second key pool is used to store the XOR key K3⊕K5 uploaded by quantum key distribution node 3 (the third node in the suspected target path) that matches the suspected target path. The peer nodes of the XOR key in the second key pool are quantum key distribution nodes 2 and 4.

[0051] Execute S105 when the amount of key i is greater than or equal to the relay requirement; execute S108 when the amount of key i is less than the relay requirement.

[0052] S105, the controller determines whether the (i+2)th node is the destination node of the demand. If the (i+2)th node is the destination node of the demand, then execute S106; if the (i+2)th node is not the destination node of the demand, then execute S107.

[0053] It should be understood that to determine whether i = N - 2 is true, if it is true, then i + 2 = N, and the i + 2nd node is the target node of the demand; otherwise, the i + 2nd node is not the target node of the demand.

[0054] S106, the controller determines the suspected target path as the final target relay path and the suspected target time as the final target time.

[0055] S107, the controller sets i = i + 1.

[0056] After S107, S104, the step of the controller determining whether the i-th key quantity is greater than or equal to the relay demand quantity, is repeated.

[0057] S108, the controller determines whether there is still an XOR key in the first key pool of the suspected target path that was generated later than the suspected target time. If there is an XOR key that was generated later than the suspected target time, then proceed to S109; if there is no XOR key that was generated later than the suspected target time, then proceed to S110.

[0058] S109, the controller determines the generation time of the XOR key in the first key pool that is later than and closest to the original suspected target time as the new suspected target time.

[0059] After S109, S104 is repeated, in which the controller determines whether the amount of the i-th key is greater than or equal to the relay demand.

[0060] S110, after removing the original suspected target path, the shortest relay path between the request initiating node and the request destination node is taken as the new suspected target path.

[0061] After S110, S102 is executed again, in which the controller determines the generation time of the earliest generated XOR key in the first key pool of the suspected target path as the suspected target time.

[0062] In an optional implementation, after S102, the step of the controller initiating a relay request for node transmission based on demand to determine the target relay path and target time further includes: S103, which is described in detail below.

[0063] S103, the controller determines whether there is an XOR key in the i-th key pool that matches the suspected target time.

[0064] If an XOR key matching the suspected target time exists, then S104 is executed, and the controller determines whether the amount of the i-th key is greater than or equal to the relay demand. If no XOR key matching the suspected target time exists, then S108 is executed, and the controller determines whether there is still an XOR key in the first key pool of the suspected target path whose generation time is later than the suspected target time.

[0065] Relay nodes are used to perform pairwise XOR operations on related quantum keys generated at the same time to obtain an XOR key, and then transmit the characteristic information of the XOR key to the controller. The related quantum keys are those generated by the quantum links connected to the relay nodes, and the characteristic information of the XOR key includes the XOR key itself, the identifier of the relay node, the identifiers of the nodes on the quantum links associated with the XOR key, and the time when the XOR key was generated. Based on this, regarding how the controller manages the XOR keys uploaded by the relay nodes to facilitate retrieval during key distribution, this embodiment of the invention also provides an optional implementation method, please refer to [reference needed]. Figure 3 , Figure 3 This is the second schematic flowchart of the key distribution method for a centralized quantum key relay network provided in this embodiment of the invention. The key distribution method for a centralized quantum key relay network further includes steps S30 and S40, which are described in detail below.

[0066] S30, when receiving the feature information of the XOR key uploaded by the relay node, the controller stores the XOR keys of the same relay node and the same nodes on the quantum link related to the XOR key in the same key pool, and marks the generation time of the XOR key.

[0067] by Figure 1 For example, the upload nodes for XOR keys K1⊕K2, K1⊕K3, and K2⊕K3 are all quantum key distribution node 2, but the nodes on the quantum links related to the XOR keys are different. XOR keys K1⊕K2, K1⊕K3, and K2⊕K3 correspond to different key pools. XOR keys K1⊕K2 generated at different times are stored in the same key pool, and their generation times are marked.

[0068] In one alternative implementation, the XOR keys in the key pool are sorted according to their generation time.

[0069] S40, the controller updates the XOR key index based on the feature information of the XOR key uploaded by the relay node.

[0070] The updated information includes the identifier of the relay node corresponding to the XOR key, the identifier of the node on the quantum link associated with the XOR key, the generation time of the XOR key, the key pool pointer corresponding to the XOR key, and the corresponding key quantity. The key pool pointer indicates its storage location, facilitating the retrieval of the XOR key from the key pool.

[0071] It should be understood that the corresponding key pool can be determined by the identifier of the relay node corresponding to the XOR key and the identifier of the node on the quantum link related to the XOR key. Key calls and calculations can be performed by the key pool pointer corresponding to the XOR key and the corresponding key quantity.

[0072] Optionally, the XOR key index is used as a reference file for determining the suspected target time, determining whether the i-th key quantity is greater than or equal to the relay demand, and determining whether there is an XOR key in the i-th key pool that matches the suspected target time; the XOR key index can also be used as a reference file in S10 to control the relay request initiated by the node to determine the target relay path and target time according to the demand.

[0073] Optionally, when executing S101 or S110, the shortest relay path between the request initiating node and the request destination node can be found by combining the XOR key index; or, the shortest relay path between the request initiating node and the request destination node can be found after excluding the original suspected target path.

[0074] When executing S102 or S109, the generation time of the earliest generated XOR key in the first key pool of the suspected target path can be found by combining the XOR key index; or, the generation time of the XOR key in the first key pool whose generation time is later than and closest to the original suspected target time can be found.

[0075] When executing S103, the XOR key index can be used to determine whether there is an XOR key in the i-th key pool that matches the suspected target time.

[0076] When executing S104, the amount of the i-th key can be determined by combining the XOR key index.

[0077] When executing S108, the XOR key index can be used to determine whether there is still an XOR key in the first key pool of the suspected target path that was generated later than the suspected target time.

[0078] Building upon the preceding text, this invention also provides an optional implementation method for how relay nodes upload the XOR key. Please refer to [link / reference needed]. Figure 4 , Figure 4 This is the third flowchart illustrating the key distribution method for a centralized quantum key relay network provided in this embodiment of the invention. The key distribution method for a centralized quantum key relay network further includes steps S50 and S70, which are described in detail below.

[0079] S50, the relay node stores the quantum key generated by the quantum link connected to it in the corresponding node key pool and records the generation time of the quantum key.

[0080] It should be noted that multiple node key pools are set up in the relay node, and different node key pools correspond to different quantum links. Taking quantum key distribution node 2 as an example, quantum key distribution node 2 has a node key pool with 1 corresponding to quantum key K1, a node key pool with 1 corresponding to quantum key K2, and a node key pool with 1 corresponding to quantum key K3.

[0081] S70, when the relay node is uploading the XOR key, it takes a preset number of quantum keys with the same generation time from the key pool of each node according to the order of generation time, performs pairwise XOR on the quantum keys in different node key pools to obtain the XOR key, and transmits the feature information of the XOR key to the controller.

[0082] The preset quantity here can be pre-set or issued by the controller to the relay nodes. Optionally, according to the generation time (starting from the earliest generation time), a preset number of quantum keys with the same generation time are taken from the key pool of each node.

[0083] by Figure 1 Taking the relay node (quantum key distribution node 2) as an example, at a certain moment, the relevant quantum keys corresponding to quantum key distribution node 2 are quantum key K1, quantum key K2, and quantum key K3. The XOR keys obtained by XORing each pair of these quantum keys include K1⊕K2, K1⊕K3, and K2⊕K3. The characteristic information of the XOR keys includes the XOR key itself, the identifier of the relay node, the identifier of the node on the quantum link associated with the XOR key, and the generation time of the XOR key.

[0084] Optionally, the key distribution method for centralized quantum key relay networks also includes one or more steps from S61, S62, and S63, which are described in detail below.

[0085] S61, when the interval between the last XOR key upload and the previous XOR key upload time is greater than a preset time, the relay node determines that an XOR key upload is required.

[0086] Alternatively, in step S62, if the number of keys in the node key pool within the relay node exceeds a preset storage threshold, it is determined that an XOR key upload is required.

[0087] Alternatively, in S63, when the relay node receives the XOR key upload instruction from the controller, it determines that an XOR key upload is required.

[0088] In this embodiment of the invention, the relay demand can be preset or uploaded by the demand initiating node.

[0089] This invention also provides a centralized quantum key relay network, such as... Figure 1 As shown, the centralized quantum key relay network includes: a controller and multiple quantum key distribution nodes, including at least one relay node, which is a quantum key distribution node connected to at least two quantum links.

[0090] Centralized quantum key relay networks are used to implement the key distribution method of centralized quantum key relay networks described above.

[0091] It should be noted that the centralized quantum key relay network provided in this embodiment can execute the method flow shown in the above-described method flow embodiment to achieve the corresponding technical effects. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the above-described embodiments.

[0092] In summary, this invention provides a centralized quantum key relay network and key distribution method. The controller determines the target relay path and target time based on the relay request transmitted by the request initiating node. The controller extracts the XOR key matching the target time from the M-2 key pools corresponding to the target relay path, performs bitwise XOR operations to obtain the relay key, and sends the relay key to the request initiating node and the request destination node. This addresses the issue of different XOR key lengths, generation times, and consumption patterns received by the controller from different nodes, providing a practically feasible key usage method for centralized relay networks. By managing key storage separately from key pools, the workload for key lookup is reduced, and key lookup efficiency is improved. It can find a usable key link in massive key storage, and within a certain time period, every two links on that link have uploaded enough usable XOR keys. This provides a guiding scheme for XOR key management in quantum networks with centralized control and key relay architectures.

[0093] The above description is merely a preferred 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 principles of the present invention should be included within the scope of protection of the present invention.

[0094] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for key distribution in a centralized quantum key relay network, characterized by, The centralized quantum key relay network comprises a controller and a plurality of quantum key distribution nodes, the plurality of quantum key distribution nodes comprising at least one relay node, the relay node being a quantum key distribution node connected with at least two quantum links, and the method comprises the following steps: The controller determines a target relay path and a target time according to a relay request transmitted by a demand initiator; The relay request comprises an identifier of a demand destination node and a relay demand quantity, the target relay path is a shortest path in a relay path that meets a relay demand quantity condition, the relay path is a quantum communication path between the demand initiator and the demand destination node in the centralized quantum key relay network, the relay demand quantity condition indicates that there is a target time, and key quantities of exclusive or keys in M-2 key pools corresponding to the target relay path and matching the target time are all greater than the relay demand quantity, M representing a total number of nodes in the target relay path; The controller takes out the same exclusive or keys as the relay demand quantity from the exclusive or keys in the M-2 key pools corresponding to the target relay path and matching the target time, performs bit-by-bit exclusive or to obtain a relay key, and sends the relay key to the demand initiator and the demand destination node; The step of determining a target relay path and a target time according to a relay request transmitted by a demand initiator comprises the following steps: The controller takes the shortest relay path between the demand initiator and the demand destination node as a suspected target path; The controller determines a generation time of an exclusive or key generated earliest in a first key pool of the suspected target path as a suspected target time, the first key pool corresponding to a first node, a second node and a third node in the suspected target path; The controller determines whether an ith key quantity is greater than or equal to the relay demand quantity, the ith key quantity representing a key quantity of an exclusive or key in an ith key pool and matching the suspected target time, the ith key pool corresponding to an ith node, an ith+1 node and an ith+2 node in the suspected target path, and i being initially 1; When the ith key quantity is greater than or equal to the relay demand quantity, the controller determines whether the ith+2 node is the demand destination node; If the ith+2 node is the demand destination node, the controller determines the suspected target path as a final target relay path and determines the suspected target time as a final target time; If the ith+2 node is not the demand destination node, the controller sets i=i+1 and repeats the step of determining whether the ith key quantity is greater than or equal to the relay demand quantity; When the ith key quantity is less than the relay demand quantity, the controller determines whether there is an exclusive or key generated later than the suspected target time in the first key pool of the suspected target path. If there is an XOR key later than the suspected target time, the controller determines the generation time of the XOR key in the first key pool of the suspected target path as the new suspected target time, and repeats the step of determining whether the i-th key amount is greater than or equal to the relay demand amount.

2. The key distribution method of a centralized quantum key relay network according to claim 1, wherein, The step of determining the target relay path and the target time according to the relay request transmitted by the demand initiating node includes: If there is no XOR key later than the suspected target time, the controller determines the shortest relay path between the demand initiating node and the demand destination node as the new suspected target path, and repeats the step of determining the generation time of the XOR key in the first key pool of the suspected target path as the suspected target time.

3. The key distribution method for a centralized quantum key relay network according to claim 1, wherein, The step of determining the target relay path and the target time according to the relay request transmitted by the demand initiating node further includes: The controller determines whether there is an XOR key matching the suspected target time in the i-th key pool; If there is an XOR key matching the suspected target time, the controller determines whether the i-th key amount is greater than or equal to the relay demand amount; If there is no XOR key matching the suspected target time, the controller determines whether there is an XOR key later than the suspected target time in the first key pool of the suspected target path.

4. The key distribution method of a centralized quantum key relay network according to claim 3, wherein, The relay node is configured to XOR the relevant quantum keys of the same generation time to obtain an XOR key, and transmit the feature information of the XOR key to the controller; wherein the relevant quantum keys are quantum keys generated by quantum links connected to the relay node, and the feature information of the XOR key includes the XOR key, the identifier of the relay node, the identifier of the node on the quantum link related to the XOR key, and the generation time of the XOR key. The method further includes: Upon receiving the feature information of the XOR key uploaded by the relay node, the controller stores the XOR keys of the same relay node and the same node on the quantum link related to the XOR key in the same key pool, and marks the generation time of the XOR key. The controller updates the XOR key index according to the feature information of the XOR key uploaded by the relay node, wherein the update content includes the identifier of the relay node corresponding to the XOR key, the identifier of the node on the quantum link related to the XOR key, the generation time of the XOR key, the key pool pointer corresponding to the XOR key, and the corresponding key amount.

5. The key distribution method of a centralized quantum key relay network according to claim 4, wherein The XOR key index is used as a reference file for determining the suspected target time, determining whether the i-th key amount is greater than or equal to the relay demand amount, and determining whether there is an XOR key matching the suspected target time in the i-th key pool.

6. The key distribution method of a centralized quantum key relay network according to claim 4, wherein, The method further includes: The relay node stores the quantum keys generated by the quantum links connected thereto in the corresponding node key pool, and records the generation time of the quantum keys. The relay node takes a preset number of quantum keys with the same generation time from each node key pool in the order of generation time when uploading the XOR key, XORs the quantum keys in different node key pools two by two to obtain the XOR key, and transmits feature information of the XOR key to the controller.

7. The key distribution method of a centralized quantum key relay network according to claim 6, wherein, The method further comprises: The relay node determines that the XOR key upload is needed when the interval from the last XOR key upload time is greater than a preset time length; Or, the relay node determines that the XOR key upload is needed when the number of keys in the node key pool inside the relay node is greater than a preset storage threshold; Or, the relay node determines that the XOR key upload is needed when an XOR key upload instruction is received from the controller.

8. A centralized quantum key relay network, characterized by, The centralized quantum key relay network comprises a controller and a plurality of quantum key distribution nodes, the plurality of quantum key distribution nodes comprising at least one relay node, the relay node being a quantum key distribution node connected to at least two quantum links; The centralized quantum key relay network is used to perform the key distribution method of the centralized quantum key relay network in any one of claims 1-7.

Images