Centralized quantum key relay network and key distribution method

Abstract

The invention provides a centralized quantum key relay network and a key distribution method. A controller determines a target relay path and target time according to a relay request transmitted by a demand initiating node; and the controller extracts an XOR key with the same relay demand from the XOR keys matched with the target time in the M-2 key pools corresponding to the target relay path, performs bit-by-bit XOR to obtain a relay key, and sends the relay key to the demand initiating node and the demand destination node. The problems of different lengths, different generation times and different consumption conditions of the XOR keys received by the controller from different nodes are considered, an available key link is found in massive key storage, and the problem that in a certain time period, each two links on the link upload enough XOR keys is solved, so that the use efficiency of the XOR keys is improved. And a practical and feasible secret key using method is provided for a centralized relay network.

Description

Technical Field

[0001] The present invention relates to the field of quantum communication, and in particular to a centralized quantum key relay network and a key distribution method. Background Art

[0002] Quantum cryptography technology is based on the quantum key distribution (QKD) protocol and has achieved rapid development in recent years. Unlike traditional cryptography, quantum cryptography is based on quantum mechanics and uses quantum physics properties such as Heisenberg's uncertainty principle and the no-cloning theorem to achieve secure long-distance negotiation of symmetric keys.

[0003] Multiple quantum key distribution nodes can form a quantum key distribution network (QKDN for short). Due to the limited distance between adjacent nodes, quantum key relay distribution is required in long-distance key generation scenarios, and centralized quantum key relay networks came into being.

[0004] In a centralized quantum key relay network, the QKDN controller manages the XOR keys reported by all relay nodes. As the network runs and is used, the amount of XOR keys stored in the QKDN controller will inevitably increase and become difficult to manage. Therefore, how to implement key management in a centralized quantum key relay network so that the QKDN controller can smoothly and quickly select the appropriate XOR key when a key relay request occurs, until enough quantum keys are shared between long-distance network nodes, has become a difficult problem that technicians in this field are concerned about. Summary of the invention

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

[0006] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0007] In a first aspect, an embodiment of the present invention provides a key distribution method for a centralized quantum key relay network, wherein the centralized quantum key relay network comprises: a controller and a plurality of quantum key distribution nodes, wherein the plurality of quantum key distribution nodes comprises at least one relay node, wherein the relay node is a quantum key distribution node connected to at least two quantum links, and the method comprises:

[0008] The controller determines a target relay path and a target time according to a relay request transmitted by a demand initiating node;

[0009] The relay request includes an identifier of a required destination node and a relay requirement, the target relay path is the shortest path in the relay path that satisfies a relay requirement condition, the relay path is a quantum communication path between the required initiating node and the required destination node in the centralized quantum key relay network, the relay requirement condition indicates that there is a target time, 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, and M represents the total number of nodes in the target relay path;

[0010] The controller takes out the XOR key that is the same as the relay demand from the XOR key that matches the target time in the M-2 key pools corresponding to the target relay path, performs bit-by-bit XOR to obtain the relay key, and sends the relay key to the demand initiating node and the demand destination node.

[0011] In a second aspect, an embodiment of the present invention provides a centralized quantum key relay network, the centralized quantum key relay network comprising: 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;

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

[0013] Compared with the prior art, the centralized quantum key relay network and key distribution method provided by the embodiment of the present invention, the controller determines the target relay path and target time according to the relay request transmitted by the demand initiating node; the controller takes out the XOR key that matches the target time from the XOR key in the M-2 key pool corresponding to the target relay path, performs bit-by-bit XOR to obtain the relay key, and sends the relay key to the demand initiating node and the demand destination node. Considering the problem that the XOR key lengths, generation times and consumption conditions received by the controller from different nodes are different, a practical and feasible key usage method is provided for the centralized relay network. By managing the key storage situation separately from the key pool, the workload is reduced when searching for keys, and the key search efficiency is improved. It is possible to find an available key link in the massive key storage, and there is a certain time period in which each two links on the link have uploaded enough XOR keys for use. A guiding scheme is provided for the XOR key management of quantum nodes in quantum networks with centralized control and key relay architecture.

[0014] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

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

[0017] Figure 2 One of the flow charts of the key distribution method for a centralized quantum key relay network provided in an embodiment of the present invention.

[0018] Figure 3 The second flowchart of the key distribution method for a centralized quantum key relay network provided in an embodiment of the present invention.

[0019] Figure 4 The third flow chart of the key distribution method for the centralized quantum key relay network provided in the embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0023] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0024] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0025] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0027] Please refer to Figure 1 , Figure 1 A schematic diagram of the architecture of a centralized quantum key relay network provided for an embodiment of the present invention. The centralized quantum key relay network includes: a controller (also referred to as QKDNC) and multiple quantum key distribution nodes. Among them, the quantum key distribution node is deployed with a QKD device for quantum key distribution and a KM device for managing the keys of the QKD device. All quantum key distribution nodes are connected to the controller in communication to form a full network connection topology diagram. The controller is used to control and manage the centralized quantum key relay network to achieve routing control and resource scheduling of each node and link. The controller maintains time synchronization with each quantum key distribution node.

[0028] It should be noted that Figure 1 8 quantum key distribution nodes are shown in FIG. 1 , but this is not a limitation. The number of quantum key distribution nodes can be greater or less than 8. All quantum key distribution nodes are connected to the controller in communication. Figure 1 Some connections are omitted to make the presentation clearer.

[0029] The multiple quantum key distribution nodes include at least one relay node, and the relay node is a quantum key distribution node connected to at least two quantum links.

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

[0031] It should be noted that the multiple quantum key distribution nodes also include user nodes, which are quantum key distribution nodes connected to the business system. The user nodes can receive communication requirements transmitted by the business system and send keys to the business system.

[0032] Figure 1 Ki(K1-K8) in represents the quantum key generated by the i-th quantum link at a certain moment. The relay node is used to perform XOR on the related quantum keys of the same generation time in pairs to obtain the XOR key, and transmit the characteristic information of the XOR key to the controller. Among them, the related quantum key is the quantum key generated by the quantum link connected to the relay node, and the characteristic 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 controller is used to store the XOR key in combination with the characteristic information of the XOR key.

[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) shown 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, and the XOR keys obtained after pairwise XOR include K1⊕K2, K1⊕K3 and K2⊕K3. The generation time of the XOR key is the same as the generation time of the relevant quantum key, and the identifier of the quantum key distribution node can be but is not limited to the node ID.

[0034] Among them, the relay nodes corresponding to the XOR keys K1⊕K2, K1⊕K3 and K2⊕K3 are all quantum key distribution nodes 2. The generation time corresponding to the XOR keys K1⊕K2, K1⊕K3 and K2⊕K3 is the generation time of the quantum keys K1, K2 and K3. The nodes on the quantum link related to the XOR key K1⊕K2 are quantum key distribution nodes 1 and quantum key distribution nodes 6, the nodes on the quantum link related to the XOR key K1⊕K3 are quantum key distribution nodes 1 and quantum key distribution nodes 3, and the nodes on the quantum link related to the XOR key K2⊕K3 are quantum key distribution nodes 6 and quantum key distribution nodes 3.

[0035] The embodiment of the present invention provides a key distribution method for a centralized quantum key relay network, which can be applied to but not limited to the centralized quantum key relay network mentioned above. Figure 2 , Figure 2 One of the flow diagrams of the key distribution method of the centralized quantum key relay network provided by the embodiment of the present invention. The key distribution method of the centralized quantum key relay network includes: S10 and S20, which are specifically described as follows.

[0036] S10, the controller determines a target relay path and a target time according to a relay request of a demand-initiated node transmission.

[0037] Among them, the relay request includes the identification of the required destination node and the relay demand, and the demand initiating node and the demand destination node are both quantum key distribution nodes in the centralized quantum key relay network.

[0038] The target relay path is the shortest path in the relay path that meets the relay demand condition. The relay path is the quantum communication path between the demand initiating node and the demand destination node in the centralized quantum key relay network. The relay demand condition indicates that there is 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 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, 1≤i≤N-2, and i is initially 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, and 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 takes out the XOR key that is the same as the relay demand from the XOR key that matches the target time in the M-2 key pools corresponding to the target relay path, performs bit-by-bit XOR to obtain the relay key, and sends the relay key to the demand initiating node and the demand destination node.

[0041] The key distribution method for a centralized quantum key relay network provided in an embodiment of the present invention takes into account the problems of different lengths, different generation times, and different consumption of XOR keys received by the controller from different nodes, and provides a practical key usage method for a centralized relay network. By managing the key storage situation separately from the key pool, the workload is reduced when searching for keys, and the key search efficiency is improved. It is possible to find an available key link in a massive key storage, and there is a certain time period in which every two links on the link have uploaded enough XOR keys for use. A guidance scheme is provided for the XOR key management of quantum nodes in a quantum network with centralized control and key relay architecture.

[0042] Based on the above, regarding the content in S10, the embodiment of the present invention also provides an optional implementation, please refer to the following. S10, the controller determines the target relay path and target time according to the relay request transmitted by the demand initiating node, including: S101, S102, S104, S105, S106, S107, S108, S109 and S110, which are specifically described as follows.

[0043] S101: The controller takes the shortest relay path between the demand initiating node and the demand destination node as a suspected target path.

[0044] The shortest relay path refers to the relay path with the smallest number of nodes on the path, or the relay path with the shortest optical fiber link length corresponding to the path. The relay path is the quantum communication path between the demand initiating node and the demand destination node in the 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] Among them, the first key pool corresponds to the first node, the second node and the third node 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 counterpart nodes of the XOR key in the first key pool are the first node and the third node in the suspected target path, and the first node is the demand initiating node.

[0047] Take the relay path composed of quantum key distribution node 1, quantum key distribution node 2, quantum key distribution node 3, quantum key distribution node 4 and quantum key distribution node 5 as an example, where quantum key distribution node 1 is the demand initiating node (first node) and quantum key distribution node 5 is the demand 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, and the peer nodes of the XOR key K1⊕K3 are quantum key distribution node 1 and quantum key distribution node 3.

[0048] S104, the controller determines whether the i-th key quantity is greater than or equal to the relay requirement quantity. If yes, execute S105; if no, execute S108.

[0049] Among them, the i-th key quantity represents the key quantity of the XOR key that matches the suspected target time in the i-th key pool, and 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, 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 key that matches the suspected target path uploaded by the i+1-th node in the suspected target path, and 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 suspected target path.

[0050] Continuing with the relay path composed of quantum key distribution node 1, quantum key distribution node 2, quantum key distribution node 3, quantum key distribution node 4 and quantum key distribution node 5 as an example, when i is 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, and the counterpart nodes of the XOR key in the second key pool are quantum key distribution node 2 and quantum key distribution node 4.

[0051] When the i-th key amount is greater than or equal to the relay requirement, S105 is executed; when the i-th key amount is less than the relay requirement, S108 is executed.

[0052] S105, the controller determines whether the i+2th node is a required destination node. If the i+2th node is a required destination node, S106 is executed; if the i+2th node is not a required destination node, S107 is executed.

[0053] It should be understood that it is determined whether i=N-2 is established. If yes, it means that i+2=N, and the i+2th node is the required destination node; otherwise, the i+2th node is not the required destination node.

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

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

[0056] After S107, S104 is repeatedly executed, and the controller determines whether the i-th key amount is greater than or equal to the relay requirement amount.

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

[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 repeatedly executed, and the controller determines whether the i-th key amount is greater than or equal to the relay demand amount.

[0060] S110, after removing the original suspected target path, the controller uses the shortest relay path between the demand initiating node and the demand destination node as a new suspected target path.

[0061] After S110, S102 is repeatedly executed, 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 controller determines the target relay path and target time according to the relay request of the demand-initiating node transmission, and further includes: S103, which is described in detail as follows.

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

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

[0065] The relay node is used to perform XOR on related quantum keys of the same generation time in pairs to obtain an XOR key, and transmit the characteristic information of the XOR key to the controller. The related quantum key is a quantum key generated by a quantum link connected to the relay node, and the characteristic 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. On this basis, regarding how the controller manages the XOR key uploaded by the relay node to facilitate its retrieval during the key distribution process, the embodiment of the present invention also provides an optional implementation method, please refer to Figure 3 , Figure 3 The second flow chart of the key distribution method of the centralized quantum key relay network provided by the embodiment of the present invention. The key distribution method of the centralized quantum key relay network also includes: S30 and S40, which are specifically described as follows.

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

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

[0068] In an optional implementation, the XOR keys in the key pool are sorted according to generation time.

[0069] S40, the controller updates the XOR key index according to the characteristic information of the XOR key uploaded by the relay node.

[0070] The updated 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 quantity. The key pool pointer is used to indicate the location where the XOR key is stored, so as to indicate the location where the XOR key is retrieved from the key pool.

[0071] It should be understood that the corresponding key pool can be determined through the identification of the relay node corresponding to the XOR key and the identification of the node on the quantum link related to the XOR key, and the key call and calculation judgment can be performed through the key pool pointer corresponding to the XOR key and the corresponding key amount.

[0072] Optionally, 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; the XOR key index can be used as S10 to control the reference file for determining the target relay path and target time based on the relay request transmitted by the demand-initiating node.

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

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

[0075] When executing S103 , it may be determined whether there is an XOR key matching the suspected target time in the i-th key pool in combination with the XOR key index.

[0076] When executing S104, the i-th key amount may be determined in combination with the XOR key index.

[0077] When executing S108, it can be determined in combination with the XOR key index whether there is any XOR key in the first key pool of the suspected target path whose generation time is later than the suspected target time.

[0078] Based on the above, regarding how the relay node uploads the XOR key, the embodiment of the present invention also provides an optional implementation method, please refer to Figure 4 , Figure 4 The third flow chart of the key distribution method of the centralized quantum key relay network provided by the embodiment of the present invention. The key distribution method of the centralized quantum key relay network also includes: S50 and S70, which are specifically described as follows.

[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 in the relay node, and different quantum links correspond to different node key pools. Taking quantum key distribution node 2 as an example, quantum key distribution node 2 has a node key pool corresponding to 1 for quantum key K1, a node key pool corresponding to 1 for quantum key K2, and a node key pool corresponding to 1 for quantum key K3.

[0081] S70, when the relay node uploads the XOR key, it takes a preset number of quantum keys with the same generation time from each node key pool 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 characteristic information of the XOR key to the controller.

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

[0083] by Figure 1 Taking the relay node (quantum key distribution node 2) shown 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, and the XOR keys obtained after pairwise XOR include K1⊕K2, K1⊕K3 and K2⊕K3. The characteristic 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.

[0084] Optionally, the key distribution method of the centralized quantum key relay network also includes: one or more steps of S61, S62 and S63, which are specifically described as follows.

[0085] S61: When the interval between the time of the last XOR key upload and the time of the last XOR key upload is greater than a preset time length, the relay node determines that the XOR key upload needs to be performed.

[0086] Alternatively, S62, when the amount of keys in the node key pool inside the relay node is greater than a preset storage threshold, the relay node determines that XOR key upload is required.

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

[0088] In the embodiment of the present invention, the relay demand quantity may be preset or uploaded by the demand initiating node.

[0089] The embodiment of the present 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, the multiple quantum key distribution nodes include at least one relay node, and the relay node is a quantum key distribution node connected to at least two quantum links.

[0090] The centralized quantum key relay network is used to execute the key distribution method of the centralized quantum key relay network mentioned 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 method flow embodiment to achieve the corresponding technical effect. For the sake of brief description, for parts not mentioned in this embodiment, please refer to the corresponding content in the above embodiment.

[0092] In summary, the embodiment of the present invention provides a centralized quantum key relay network and key distribution method, in which the controller determines the target relay path and target time according to the relay request transmitted by the demand initiating node; the controller takes out the XOR key that matches the target time from the XOR key in the M-2 key pool corresponding to the target relay path, performs bit-by-bit XOR to obtain the relay key, and sends the relay key to the demand initiating node and the demand destination node. Considering the problem that the XOR key lengths, generation times, and consumption conditions received by the controller from different nodes are different, a practical and feasible key usage method is provided for the centralized relay network. By managing the key storage situation separately from the key pool, the workload is reduced when searching for keys, and the key search efficiency is improved. It is possible to find an available key link in the massive key storage, and there is a certain time period in which each two links on the link have uploaded enough XOR keys for use. A guidance scheme is provided for the XOR key management of quantum nodes in quantum networks with centralized control and key relay architecture.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0094] It will be apparent to those skilled in the art that the 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 the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A key distribution method for a centralized quantum key relay network, characterized in that: The centralized quantum key relay network includes: a controller and a plurality of quantum key distribution nodes, the plurality of quantum key distribution nodes include at least one relay node, the relay node is a quantum key distribution node connected to at least two quantum links, and the method includes: The controller determines a target relay path and a target time according to a relay request transmitted by a demand initiating node; The relay request includes an identifier of a required destination node and a relay requirement, the target relay path is the shortest path in the relay path that satisfies a relay requirement condition, the relay path is a quantum communication path between the required initiating node and the required destination node in the centralized quantum key relay network, the relay requirement condition indicates that there is a target time, 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, and M represents the total number of nodes in the target relay path; The controller takes out the XOR key that is the same as the relay demand from the XOR key that matches the target time in the M-2 key pools corresponding to the target relay path, performs bit-by-bit XOR to obtain the relay key, and sends the relay key to the demand initiating node and the demand destination node.

2. The key distribution method of a centralized quantum key relay network according to claim 1, characterized in that: The step of the controller determining a target relay path and a target time according to a relay request transmitted by a demand initiating node comprises: The controller uses the shortest relay path between the demand initiating node and the demand destination node as a suspected target path; 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; wherein the first key pool corresponds to the first node, the second node and the third node in the suspected target path; The controller determines whether the i-th key quantity is greater than or equal to the relay demand quantity, wherein the i-th key quantity represents the key quantity of the XOR key that matches the suspected target time in the i-th key pool, 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, and i is initially 1; When the i-th key amount is greater than or equal to the relay demand amount, the controller determines whether the i+2-th node is the demand destination node; If the i+2th node is the required destination node, the controller determines the suspected target path as the final target relay path, and determines the suspected target time as the final target time; If the i+2th node is not the required destination node, the controller sets i=i+1 and repeats the step of determining whether the i-th key quantity is greater than or equal to the relay required quantity.

3. The key distribution method of a centralized quantum key relay network as claimed in claim 2, characterized in that: The step of the controller determining a target relay path and a target time according to a relay request transmitted by a demand initiating node comprises: When the i-th key amount is less than the relay requirement, the controller determines whether there is an XOR key in the first key pool of the suspected target path whose generation time is later than that of the suspected target; If there is an XOR key that is later than the suspected target time, 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, and repeats the step of the controller determining whether the i-th key amount is greater than or equal to the relay demand amount.

4. The key distribution method of a centralized quantum key relay network as claimed in claim 3, characterized in that: The step of the controller determining a target relay path and a target time according to a relay request transmitted by a demand initiating node comprises: If there is no XOR key later than the suspected target time, the controller uses the shortest relay path between the demand initiation node and the demand destination node as the new suspected target path after removing the original suspected target path, and repeats the step of determining the generation time of the earliest generated XOR key in the first key pool of the suspected target path as the suspected target time.

5. The key distribution method of a centralized quantum key relay network as claimed in claim 3, characterized in that: The controller determines the target relay path and target time according to the relay request transmitted by the demand initiating node, and 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 that matches 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 any XOR key generated later than the suspected target time in the first key pool of the suspected target path.

6. The key distribution method of a centralized quantum key relay network as claimed in claim 5, characterized in that: The relay node is used to perform XOR on related quantum keys of the same generation time in pairs to obtain an XOR key, and transmit characteristic information of the XOR key to the controller; wherein the related quantum key is a quantum key generated by a quantum link connected to the relay node, and the characteristic information of the XOR key includes the XOR key, an identifier of the relay node, an identifier of a node on the quantum link related to the XOR key, and a generation time of the XOR key; The method further comprises: Upon receiving characteristic information of the XOR key uploaded by the relay node, the controller stores the XOR keys of the nodes on the quantum link with the same relay node and the same 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 characteristic 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.

7. The key distribution method of a centralized quantum key relay network as claimed in claim 6, characterized in that: The XOR key index is used as a reference file to determine the suspected target time, determine whether the i-th key amount is greater than or equal to the relay requirement, and determine whether there is an XOR key matching the suspected target time in the i-th key pool.

8. The key distribution method of a centralized quantum key relay network according to claim 6, characterized in that: The method further comprises: 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; When uploading the XOR key, the relay node takes a preset number of quantum keys with the same generation time from each node key pool 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 characteristic information of the XOR key to the controller.

9. The key distribution method of a centralized quantum key relay network as claimed in claim 8, characterized in that: The method further comprises: The relay node determines that the XOR key needs to be uploaded when the interval between the time of the last XOR key upload and the time of the last XOR key upload is greater than a preset time length; Alternatively, when the amount of keys in the node key pool inside the relay node is greater than a preset storage threshold, the relay node determines that XOR key upload is required; Alternatively, when the relay node receives the XOR key upload instruction sent by the controller, it determines that the XOR key upload needs to be performed.

10. A centralized quantum key relay network, characterized in that: The centralized quantum key relay network includes: a controller and a plurality of quantum key distribution nodes, wherein the plurality of quantum key distribution nodes include at least one relay node, and the relay node is a quantum key distribution node connected to at least two quantum links; The centralized quantum key relay network is used to execute the key distribution method of the centralized quantum key relay network described in any one of claims 1 to 9.

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