Quantum key distribution network, link setting method for key relay, data repeating system, and data repeating method

Abstract

To provide a quantum key distribution network that in a key relay through a plurality of paths in quantum key distribution, is capable of equalizing throughput efficiency as the whole of the plurality of paths.SOLUTION: A quantum key distribution network NWQKD comprises: a plurality of QKD nodes 10 for performing a key relay using quantum key distribution links L and their network; and a QKDN controller 20 that divides the plurality of QKD nodes 10 so as to equalize throughput in the key relay to make a plurality of independent colonies C and sets paths from a colony CS including a QKD node 10S at a start point of the key relay to a colony CR including a QKD node 10R at an end point so that independent keys pass through different colonies C, respectively, for one QKD node 10 not to perform key supply to a plurality of paths.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a quantum key distribution network, a key relay link setting method, a data relay system, and a data relay method. [Background technology]

[0002] A quantum key distribution (QKD) network relays encryption keys at "trusted stations" (QKD nodes) and combines this with one-time pad (OTP) cryptography to enable data transmission with guaranteed information-theoretic security. For example, as shown in FIG. 8, a key K1 serving as an encryption key is distributed from a key sender node N1 to a key receiver node N4 by a key relay using nodes N2 and N3 as relay nodes.

[0003] In the example of FIG. 8, through quantum key distribution, a key K1 is shared between nodes N1 and N2, a key K2 is shared between nodes N2 and N3, and a key K3 is shared between nodes N3 and N4. Then, node N2 transmits the exclusive-OR value of keys K1 and K2 to node N3 via the communication line, and node N3 transmits the exclusive-OR value of keys K1 and K3 to node N4 via the communication line. Node N4 obtains key K1 by calculating the exclusive-OR value of keys K1 and K3 obtained via the communication line and key K3 shared with node N3 in quantum key distribution.

[0004] In this case, some trouble may cause a node to be compromised and the key to be leaked. For example, if node N3 is compromised and the keys K2 and K3 shared by quantum key distribution are leaked, an eavesdropper E can easily derive key K1 from the exclusive-OR value of keys K1 and K3 transmitted via a communication line and the exclusive-OR value of keys K1 and K3. In order to minimize such risks, there is a danger that the security requirements for a node to be a "trusted station" will become infinitely high.

[0005] In view of this, a method is known in which key relay can be performed by relaxing the required level of security for a "trusted station," by distributing multiple keys through multiple different routes. For example, as shown in Figure 9, multiple keys K1 and K2 for generating an encryption key (such as the exclusive OR of keys K1 and K2) are distributed from key sender node N1 to key receiver node N4 via different routes using quantum key distribution. In the example of FIG. 9, the key K1 is key relayed along the route from node N1 to node N2 to node N4, and the key K2 is key relayed along the route from node N1 to node N3 to node N4. In this case, even if node N2 is compromised and keys K1 and K3 are leaked, eavesdropper E cannot obtain the encryption key (such as the exclusive OR of keys K1 and K2) because key K2 is distributed via a different route.

[0006] When this method is used, multiple keys are distributed via different routes, so a condition is required that relay nodes must not participate in key relays on different routes. In addition, such a key relay route is usually searched for using the Dijkstra algorithm to find a route that consumes the least amount of keys (see Non-Patent Documents 1 and 2). [Prior art documents] [Non-patent literature]

[0007] [Patent Document 1] J. Jia, B. Dong, L. KangLe, H. Xie, B. Guo, “Cost-Optimization-Based Quantum Key Distribution over Quantum Key Pool Optical Networks,” Entropy 2023, 25(4), 661. https: / / doi.org / 10.3390 / e25040661 [Non-Patent Document 2] M. Snedovich, “Dikstra's algorithm revisited: the dynamic programming connexion,” Control and cybernetics, vol. 35, pp. 599-620, 2006. Summary of the Invention [Problem to be solved by the invention]

[0008] Conventional methods for relaying multiple keys over multiple different routes use Dijkstra's algorithm to sequentially search for optimal routes, under the condition that relay nodes do not participate in key relays over different routes. This causes a problem in that the performance of the entire system is limited to the route with the worst throughput among the multiple routes searched. Therefore, an object of the present invention is to provide a quantum key distribution network, a key relay link setting method, a data relay system, and a data relay method that are capable of equalizing the throughput efficiency across multiple routes in a multiple-route key relay in quantum key distribution. [Means for solving the problem]

[0009] In order to solve the above problems, the quantum key distribution network of the present invention is a quantum key distribution network that distributes multiple keys for generating a common encryption key independently by quantum key distribution, and includes: a quantum key distribution link and a multiple node that performs key relay through the network; and a controller that manages the network. The controller divides the multiple nodes into a multiple independent node aggregates so as to equalize throughput in the key relay, and sets a route from a node aggregate including a start node of the key relay to a node aggregate including an end node such that one node does not supply keys to multiple routes via different node aggregates for each key, and performs key relay from the start node to the end node via different routes set by the controller for each key, and the start node and the end node generate the common encryption key by exclusive ORing or concatenating the multiple keys.

[0010] According to this configuration, the quantum key distribution network distributes multiple keys for generating encryption keys independently along different routes from a node collection including a start node to a node collection including an end node in a node collection divided so as to equalize throughput. In this case, since the node group is divided to equalize the throughput, even if the quantum key distribution network relays multiple keys via different routes, the throughput of quantum key distribution for each key will be equalized.

[0011] In order to solve the above-mentioned problems, the present invention provides a key relay link setting method for independently distributing multiple keys in a quantum key distribution network composed of quantum key distribution links and multiple nodes that perform key relay through the network, wherein a controller that manages the quantum key distribution network divides the multiple nodes into multiple independent node aggregates so as to equalize the throughput in the key relay, and sets a route from a node aggregate including a start node of the key relay to a node aggregate including an end node thereof via different node aggregates for each key, so that one node does not supply keys to multiple routes.

[0012] According to this method, in a node collection divided to equalize throughput, key relay links can be set up for multiple keys on different routes from a node collection including a starting node to a node collection including an end node. As a result, the key relay link setting method can set up independent key relay links for multiple keys so that the throughput is approximately equal.

[0013] In order to solve the above-mentioned problems, a data relay system according to the present invention is a data relay system that receives an encryption key through a quantum key distribution network including a plurality of nodes that relay keys through the quantum key distribution links and the network, and a controller that performs network management to divide the plurality of nodes into a plurality of independent node aggregates so as to equalize throughput in the key relay, and to set a route from a node aggregate including a start node of the key relay to a node aggregate including an end node, via different node aggregates for each of a plurality of keys for generating an encryption key, so that a single node does not supply keys to multiple routes. The data relay system relays data in a communication network and is provided with an encryption key through the quantum key distribution network, the data relay system comprising: a transmitting device that corresponds to the start node and encrypts original data with the encryption key, distributes the data into a plurality of shares by a secret sharing scheme, and transmits the distributed data; a relay device that corresponds to a node that serves as a different route for each of the multiple keys, and relays the multiple shares; and a receiving device that corresponds to the end node, receives the multiple shares, restores the data by a secret sharing scheme, and decrypts the original data with the encryption key.

[0014] According to this configuration, the data relay system relays a plurality of keys for generating encryption keys in a quantum key distribution network via a node group divided so as to equalize the throughput, thereby equalizing the throughput of the entire key relay. Also, the data relay system relays data using secret shared shares corresponding to the key relay routes with equalized throughput, thereby enabling efficient restoration of original data from each share.

[0015] In order to solve the above-mentioned problems, a data relay method according to the present invention provides a quantum key distribution network including a plurality of nodes that relay keys through the quantum key distribution links and the network, and a controller that performs network management to divide the plurality of nodes into a plurality of independent node aggregates so as to equalize throughput in the key relay, and to set a route from a node aggregate including a start node of the key relay to a node aggregate including an end node, so that a single node does not supply keys to a plurality of routes via different node aggregates for a plurality of keys for generating an encryption key, the data relay method relaying data in a communication network, in which the encryption key is supplied through the quantum key distribution network, a transmitting device corresponding to the start node encrypts original data with the encryption key and distributes the data into a plurality of shares by a secret sharing scheme, distributes the plurality of shares to each relay device corresponding to a node on a different route for the plurality of keys and relays the data through the communication network, and a receiving device corresponding to the end node receives the plurality of shares and restores the data by a secret sharing scheme, and decrypts the original data with the encryption key.

[0016] According to this method, in a quantum key distribution network, the data relay method relays a plurality of keys for generating encryption keys via a node group divided so as to equalize the throughput, thereby equalizing the throughput of the entire key relay. Also, the data relay method relays shares of secretly shared data in accordance with key relay routes with equalized throughput, thereby enabling efficient restoration of original data from each share. Effect of the Invention

[0017] According to the present invention, in key relay of multiple keys on different routes in quantum key distribution, it is possible to equalize the throughput efficiency across the multiple routes. [Brief description of the drawings]

[0018] [Figure 1]1 is a configuration diagram showing an overall configuration of a quantum key distribution network according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is an explanatory diagram for explaining a colony (node ​​collection). [Diagram 3] FIG. 1 is an explanatory diagram for explaining an example of a key relay. [Figure 4] FIG. 13 is an explanatory diagram for explaining a key relay via a colony. [Diagram 5] FIG. 2 is a sequence diagram showing an operation of key relaying a plurality of keys in the quantum key distribution network according to the first embodiment of the present invention. [Figure 6] FIG. 11 is a configuration diagram showing the overall configuration of a data relay system according to a second embodiment of the present invention. [Figure 7] 7 is an explanatory diagram for explaining a process of distributing and relaying data in the data relay system of FIG. 6. FIG. [Figure 8] FIG. 1 is an explanatory diagram for explaining a key relay in conventional quantum key distribution. [Figure 9] FIG. 1 is an explanatory diagram for explaining a key relay that transmits multiple keys via different routes in conventional quantum key distribution. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] [Quantum key distribution network configuration] First, referring to FIG. 1, a quantum key distribution network (QKDN) NW according to a first embodiment of the present invention will be described. QKD The configuration of the quantum key distribution network NW QKD FIG. Here, the quantum key distribution network NW QKD The encryption key (key K) provided by the U Secret communication is carried out from the transmitting device 1 to the receiving device 2 above.

[0020] The transmitter 1 is connected to a quantum key distribution network NW QKD (Here, QKD node 10 S) encrypts the data (one-time pad encryption) with an encryption key (key K) supplied from the encryption device 1 and transmits the encrypted data to the receiving device 2 via secret communication.

[0021] The receiving device 2 transmits the encrypted data received from the transmitting device 1 to the quantum key distribution network NW QKD (Here, QKD node 10 R ) to decrypt the data using the encryption key (key K). The common encryption key (key K) provided to the transmitter 1 and the receiver 2 is transmitted through the quantum key distribution network NW QKD QKD Node 10 S From QKD Node 10 R The key is then distributed to the recipient by the key relay. The transmitting device 1 and the receiving device 2 are connected to the corresponding QKD node 10 (10 S ,10 R ) may be integrated into the device.

[0022] Quantum key distribution network QKD This system distributes multiple keys for generating encryption keys independently using quantum key distribution. As shown in Figure 1, the quantum key distribution network NW QKD The system includes a quantum key distribution link (QKD link) L and a plurality of QKD nodes 10 that share keys in the network, and a QKDN controller 20 that manages the network and notifies the QKD nodes 10 of key relay path information.

[0023] [QKD Node] A QKD node (node) 10 shares a key, which is a random number sequence, via a QKD link L by quantum key distribution. As shown in FIG. 3, the QKD node 10 includes a key management device 11 and a quantum key distribution module (QKD module) 12.

[0024] The key management device 11 holds the keys generated by the QKD module 12, and supplies the keys to applications (the transmitting device 1, the receiving device 2, etc.) as necessary. The key management device 11 also executes key relay according to route information notified from the QKDN controller 20.

[0025] The QKD module 12 transmits and receives photon pulses to and from the QKD modules 12 of other QKD nodes 10 via the QKD link L, which is an optical fiber, and shares keys by extracting a safe and error-free random number sequence of a predetermined data length by key distillation. Note that quantum key distribution is a well-known technology, and therefore a detailed description thereof will be omitted here.

[0026] [QKDN Controller] The QKDN controller (controller) 20 controls the quantum key distribution network NW QKD This is responsible for network management. The QKDN controller 20 requests the QKD node 10 to generate a shared key via a communication line (not shown), and notifies the QKD node 10 of route information indicating the order of the nodes in the key relay.

[0027] The QKDN controller 20 sets a route from a colony C including a start node (QKD node 10) of the key relay to a colony C including an end node (QKD node 10) such that each of a plurality of keys passes through different colonies C.

[0028] (colony) Now, colony C will be described with reference to FIG. The colonies C are multiple independent node aggregates obtained by dividing all the QKD nodes 10 so as to equalize the throughput in the key relay. Here, "independent" means that one colony C does not belong to multiple node aggregates.

[0029] Note that equalizing the throughput means that predetermined criteria such as geographical factors, key supply amount, etc. are roughly equalized. Here, the geographical factor is, for example, a division criterion for dividing colonies C so that the distances between colonies C are approximately equal. This works in the direction of making the path distances roughly equal when key relay is performed for multiple keys via different paths. Also, the key supply amount is a division criterion based on, for example, the number of QKD modules 12 that can supply keys belonging to colony C. This reduces the delay in key generation on each path when key relay is performed for multiple keys via different paths, and works to perform key relay efficiently. The division criteria do not have to be one criterion, and a plurality of criteria may be combined according to weights based on the priority. Colony C is defined in advance by dividing colony C according to such a division criterion.

[0030] The inside of colony C is a network in which QKD modules 12 are connected by QKD links L. The QKD nodes 10 that are the end points (edges) between colonies C are determined in advance. For example, as shown in FIG. 2, the QKD nodes 10 at the east, west, south, and north ends of colonies C are E ,10 W ,10 S ,10 N are four end points connecting to other colonies. This number of end points is merely an example, and two, three, or five or more end points may be defined. Colony C performs key relay between colonies between their endpoints, and within the colony, it performs key relay from the input endpoint to the output endpoint of the key.

[0031] (Key Relay) An example of a typical key relay will now be described with reference to FIG. A From QKD Node 10 D Up to 10 QKD nodes B ,10 C As relay nodes, one key K AB This will be explained using an example of relaying. QKD Node 10 A and 10 B QKD Module 12 A and 12 B1 between the key K AB Share. QKD Node 10 A Key management device 11 A QKD Module 12 A The key K generated by AB This key K is stored in a storage device (not shown). AB is provided to an application (for example, the transmitting device 1 (FIG. 1)) as needed.

[0032] QKD Node 10 B and 10 C QKD Module 12 B2 and 12 C1 between the key K BC Share. QKD Node 10 B Key management device 11 B QKD Module 12 B1 The key K generated by AB and QKD module 12 B2 The key K generated by BC The key management device 11 performs an exclusive OR (XOR) with B is the result of the operation (K AB (XOR)K BC ) is notified as route information from the QKDN controller 20 to the link destination (QKD node 10 C ) via a communication line.

[0033] QKD Node 10 C and 10 D QKD Module 12 C2 and 12 D between the key K CD Share. QKD Node 10 C Key management device 11 C QKD Module 12 C1 The key K generated by BC and QKD module 12 C2 The key K generated byCD The key management device 11 performs an exclusive OR (XOR) with C is further calculated as the result (K BC (XOR)K CD ) and QKD node 10 B Key management device 11 B The calculation result (K AB (XOR)K BC ) and the exclusive OR (XOR) is calculated. C is the result of the operation (K AB (XOR)K CD ) is notified as route information from the QKDN controller 20 to the link destination (QKD node 10 D ) via a communication line.

[0034] QKD Node 10 D Key management device 11 D QKD Node 10 C The calculation result (K AB (XOR)K CD ) and QKD module 12 D The key K generated by CD The key management device 11 performs an exclusive OR (XOR) with D is the result of the operation (K AB ) is stored in a storage device (not shown). AB is provided to an application (for example, the receiving device 2 (FIG. 1)) as needed. This key relay allows the key K AB QKD Node 10 A From QKD Node 10 D Up to 10 QKD nodes B ,10 C is forwarded as a relay node. Returning to FIG. 1, the explanation of the QKDN controller 20 will be continued.

[0035] As a method for setting up a link for a key relay, the QKDN controller 20 sets up the key relay illustrated in FIG. 3 as a link for a starting QKD node (here, the QKD node 10 S ) containing colony C Sfrom the destination node (here, QKD node 10 R ) containing colony C R The route is set to pass through a different colony C for each of the multiple keys.

[0036] The multiple keys referred to here are keys (sub-keys) used to generate an encryption key that the QKD node 10 supplies to applications such as the transmitting device 1, and the original key can only be reproduced from all of the sub-keys. For example, if a start node generates a key K of a certain bit length by exclusive-ORing three keys (sub-keys) K1, K2, and K3 of the same bit length as key K, the end node can only reproduce key (encryption key) K by obtaining the three keys K1, K2, and K3 and calculating the exclusive-OR. Also, for example, if a key K of a certain bit length is generated at a starting node by concatenating three keys (subkeys) K1, K2, and K3 whose bit lengths are shorter than that of key K, then at the end node, key (encryption key) K can only be reproduced by obtaining and concatenating the three independent keys K1, K2, and K3.

[0037] The QKDN controller 20 sets up routes so that such multiple keys are relayed independently via different colonies C, and notifies the QKD node 10 of the route information. The QKDN controller 20 regards the colony C as one node, and sets different routes for each of a plurality of keys, so that one QKD node 10 does not supply keys to a plurality of routes. At this time, each colony C can only participate in one route of key relay. Also, colony C is a one-input, one-output system that inputs and outputs only one key (subkey). Within colony C, multiple key relays are performed by each QKD node 10.

[0038] When setting a route between colonies C, the QKDN controller 20 sets a route that uses the least amount of keys based on the key supply amount of the entire colonies C. The input / output end point of a colony C is, for example, the QKD node 10 that is closest to another colony C that is the connection destination of the route.

[0039] These routes may be determined in advance if the starting point and the end point are known, or may be searched for in real time by the QKDN controller 20. This allows multiple keys to be relayed over multiple different routes, for example as shown in FIG.

[0040] In the example in Figure 4, the starting colony C S From the end point, Colony C R Until now, multiple keys K1, K2, and K3 have different key relay routes RR K1 ,RR K2 ,RR K3 The key will be relayed via Key Relay Route RR K1 The key relay function is a set of multiple colonies C K1 The key relay route RR K2 The key relay function is a set of multiple colonies C K2 The key relay route RR K3 The key K3 is relayed by multiple colonies C. K3 It is composed of: This enables the QKDN controller 20 to relay multiple keys through different key relay routes RR, thereby ensuring information-theoretic security. Furthermore, since colony C is a node group divided so as to equalize the throughput, the efficiency of key relay can be roughly equalized regardless of which key relay route RR is used.

[0041] [Quantum key distribution network operation] Next, referring to FIG. 5 (referring to FIG. 1 and FIG. 3 as appropriate), the quantum key distribution network NW QKD Here, the operation of key relaying, via multiple routes, multiple keys for generating an encryption key used when transmitting encrypted data from the transmitting device 1 to the receiving device 2 will be described.

[0042] In step S1, the QKDN controller 20 requests the multiple QKD modules 12 of the QKD node 10 to generate a key to be shared between the opposing QKD modules 12 via a QKD link L that has been connected in advance.

[0043] In step S2, the multiple QKD modules 12 of the QKD node 10 generate a shared key by transmitting and receiving photon pulses via the QKD link L and extracting a secure and error-free random number sequence of a predetermined data length by key distillation. At this time, the QKD node 10 generates multiple keys for each QKD link L according to the number of the multiple QKD modules 12.

[0044] In step S3, the multiple QKD modules 12 of the QKD node 10 supply the multiple keys they have generated to the key management device 11. In step S4, the key management device 11 stores the key provided in step S3 in a storage device (not shown).

[0045] In step S5, the QKDN controller 20 detects the originating QKD node 10 corresponding to the transmitting device 1. S Colony C containing S , the end QKD node 10 corresponding to the receiving device 2 R Colony C containing R Up to this point, route information is set so that a single QKD node 10 does not supply keys to multiple routes via different colonies for each of the multiple keys. In step S6, the QKDN controller 20 notifies the key management device 11 of the QKD node 10 of the route information set in step S5. In step S7, key management device 11 of QKD node 10 holds the route information notified in step S6.

[0046] In step S8, the transmitting device 1 requests a key from the key management device 11 of the corresponding start-point QKD node 10. Here, the transmitting device 1 requests from the key management device 11 a key K which is the exclusive OR of three keys (sub-keys) K1, K2, and K3, as shown in the example of FIG.

[0047] In step S9, the receiving device 2 requests a key from the key management device 11 of the corresponding end point QKD node 10. Here, like the transmitting device 1, the receiving device 2 requests from the key management device 11 a key K which is the exclusive OR of three keys (subkeys) K1, K2, and K3. In step S10, the key management device 11 combines the multiple keys stored in step S4. In this example, as shown in FIG. 4, the key management device 11 calculates the exclusive OR of the three keys K1, K2, and K3 to generate an encryption key (key K) shared with the receiving device 2. In step S11, the key management device 11 supplies the combined encryption key (key K) to the transmission device 1.

[0048] In step S12, the key management device 11 executes key relay via different paths for each of the multiple keys used to generate the encryption keys in step S10, in accordance with the path information held in step S7. In the example of FIG. 4, the key management device 11 transmits the keys K1, K2, and K3 used to generate the encryption key K via different key relay routes RR K1 ,RR K2 ,RR K3 This performs key relay. This allows the key management device 11 of the end point QKD node 10 corresponding to the receiving device 2 to obtain multiple keys via different key relay paths.

[0049] In step S13, the key management device 11 combines the multiple keys acquired in step S12. Here, as an example of Fig. 4, the key management device 11 calculates the exclusive OR of the three keys K1, K2, and K3 to generate an encryption key (key K) shared with the transmission device 1. In step S14, the key management device 11 supplies the combined encryption key (key K) to the receiving device 2.

[0050] This allows the sending device 1 and the receiving device 2 to use a common encryption key to send and receive encrypted data using one-time pad encryption. In this case, multiple keys are relayed through a predetermined route so as to equalize the throughput in the key relay. QKD In this way, a single key relay does not cause a large delay, and the encryption key used by the receiving device 2 can be efficiently supplied.

[0051] [Data Relay System Configuration] Next, a configuration of a data relay system 100 according to a second embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 shows the quantum key distribution network NW described in Fig. 1. QKD FIG. 1 is a configuration diagram showing an example of a data relay system 100 configured as above. Quantum key distribution network QKD Since the configuration is the same as that described in FIG. 1, the description will be omitted.

[0052] Here, the data relay system 100 is a user network NW which is an existing communication network (such as the Internet). U Data is distributed from the transmitting device 1B to the receiving device 2B by a secret sharing scheme, and the distributed shares are relayed via the relay device 3 along different routes. The share path from the transmitter 1B to the receiver 2B is established through the quantum key distribution network NW QKD In this embodiment, the key relay path is the same as that in the QKDN controller 20, and is managed collectively.

[0053] The transmitting device 1B is connected to the quantum key distribution network NW QKDThe original data is encrypted (one-time pad encryption) using an encryption key (key K) supplied from, the encrypted data is distributed into multiple data (shares) using a secret sharing scheme, and each share is transmitted to the receiving device 2B via a different route. A common secret sharing scheme may be used. For example, the transmission device 1B uses a (k, n) threshold scheme as the secret sharing scheme, distributes encrypted data into n shares, and makes it impossible to restore the original data with k-1 shares. The colony C corresponding to the transmitting device 1B performs key relay by passing multiple keys for generating encryption keys through different routes. The transmitting device 1B generates shares from the encrypted data (encrypted original data) in the same number as the keys for generating the encryption keys.

[0054] The receiver 2B receives the multiple shares via the relay device 3, restores the encrypted data using the secret sharing scheme, and transmits the data to the quantum key distribution network NW. QKD The original data is restored by decrypting the encrypted data using the encryption key (key K) supplied from the

[0055] The relay device 3 relays the distributed shares between the transmitting device 1 B and the receiving device 2 B. The relay device 3 may also function as a shareholder that stores the received shares and distributes them upon request. The transmitting device 1B, the receiving device 2B, and the relay device 3 are each a part of a quantum key distribution network NW QKD The QKD nodes 10 correspond to the QKD nodes 10 belonging to different colonies C. Incidentally, the transmitting device 1B, the relay device 3 and the receiving device 2B may each be integrated with the corresponding QKD node 10 as a device.

[0056] [Data relay method of data relay system] The data relay method of the data relay system 100 will be specifically described with reference to FIG. Here, like the key relay route explained in Figure 4, the starting colony C S From the end point, Colony C RUntil now, multiple keys K1, K2, and K3 have different key relay routes RR K1 ,RR K2 ,RR K3 The key will be relayed via The key relay of the keys K1, K2, and K3 is the same as the key relay described in FIG.

[0057] User network NW U Above is the starting colony C. S A transmitter 1B is arranged corresponding to a QKD node (not shown) belonging to colony C R A receiving device 2B is disposed corresponding to a QKD node (not shown) belonging to the

[0058] In addition, the relay device 31 that relays the share s1 relays the key K1 via a key relay route RR K1 The relay device 32 that relays the share s2 is arranged corresponding to a QKD node (not shown) that belongs to the colony C that corresponds to the key K2. K2 The relay device 33 that relays the share s3 is arranged corresponding to a QKD node (not shown) that belongs to the colony C corresponding to the key K3. K3 1. The QKD nodes 111 and 112 are arranged corresponding to the QKD nodes (not shown) belonging to the colony C corresponding to the colony C.

[0059] The transmitter 1B is the starting colony C. S The original data d is encrypted (one-time pad encryption) using the encryption key K supplied by a QKD node belonging to the QKD node. The transmission device 1B distributes the encrypted data, which has been encrypted with the encryption key K, into three shares (shares s1 to s3) by a secret sharing scheme.

[0060] Then, the transmitting device 1B sends the key relay route RR K1 Colony C relays key K1 K1 The share s1 is relayed by the relay device 31 installed corresponding to the share s1. In addition, the transmitting device 1B transmits the key relay route RR K2The share s2 is relayed by a relay device 32 installed in correspondence with the colony that relays the key K2. In addition, the transmitting device 1B transmits the key relay route RR K3 The share s3 is relayed by a relay device 33 installed in correspondence with the colony that relays the key K3.

[0061] The receiving device 2B receives the relayed three shares (shares s1 to s3) and generates the original encrypted data by the secret sharing scheme. R By being supplied with an encryption key (key K) from a QKD node belonging to, the encrypted data is decrypted and restored data d' is generated by restoring the original data d. This allows the data relay system 100 to transmit data in a distributed manner using a secret sharing scheme while equalizing the throughput of a plurality of key relay paths. Each share is relayed along a different path corresponding to the key relay path, so even if an incident occurs at the QKD node corresponding to a certain share, the data can be restored. In this way, the data relay system 100 includes a quantum key distribution network NW QKD By using the key relay based on the IEEE 802.11 standard and secret sharing of data using one-time pad cryptography, it is possible to realize information-theoretically secure and highly efficient data relay.

[0062] As explained above, the quantum key distribution network NW QKD By introducing the concept of a colony into the above and equalizing the throughput and key relay efficiency of each route, the present invention can equalize the throughput and key relay efficiency of the entire system. In addition, the present invention can lower the security requirements for a QKD node to be a "trusted station," and the quantum key distribution network NW QKD This will accelerate the realization of key supply business using this technology. [Explanation of symbols]

[0063] N.W. QKDQuantum Key Distribution Network N.W. U User network (communication network) 1. Transmitting device 2. Receiving device 10 QKD nodes (nodes) 11 Key management device 12 QKD Module 20 QKDN Controller (Controller) C Colony (node ​​cluster) L QKD link (quantum key distribution link) RR Key Relay Route 100 Data Relay System 1B Transmitter 2B Receiver 3. Repeater s1,s2,s3 Share

Claims

1. A quantum key distribution network that distributes a plurality of keys for generating a common encryption key independently by quantum key distribution, A plurality of nodes that relay keys through a quantum key distribution link and the network; A controller for performing network management, the controller divides the plurality of nodes into a plurality of independent node aggregates so as to equalize throughput in the key relay, and sets a route from a node aggregate including a start node of the key relay to a node aggregate including an end node thereof so that a single node does not supply keys to a plurality of routes via different node aggregates for each key; a quantum key distribution network, characterized in that a key relay is performed for each of the keys from the start node to the end node along different routes set by the controller, and the start node and the end node generate the common encryption key by exclusive-ORing or concatenating the multiple keys.

2. A method for setting up a link for a key relay that distributes multiple keys independently in a quantum key distribution network that is composed of quantum key distribution links and multiple nodes that perform key relay through the network, comprising: A controller that performs network management of the quantum key distribution network, A link setting method for a key relay, characterized in that the multiple nodes are divided into multiple independent node collections so as to equalize the throughput in the key relay, and a route from a node collection including a starting node of the key relay to a node collection including an ending node is set so as to pass through different node collections for each key, so that one node does not supply keys to multiple routes.

3. A data relay system relays data in a communication network by receiving encryption keys from a quantum key distribution network including: quantum key distribution links and a plurality of nodes that relay keys through the network; and a controller that divides the plurality of nodes into a plurality of independent node aggregates so as to equalize throughput in the key relay, and that sets a route from a node aggregate including a start node of the key relay to a node aggregate including an end node via different node aggregates for each of a plurality of keys for generating an encryption key, such that one node does not supply keys to a plurality of routes, a transmitting device corresponding to the starting node, encrypting original data with the encryption key, distributing the data into a plurality of shares by a secret sharing scheme, and transmitting the data; a relay device that corresponds to a node that is a different path for each of the plurality of keys and relays the plurality of shares; a receiving device corresponding to the end node, receiving the shares, restoring the shares by a secret sharing scheme, and decrypting the original data with the encryption key; A data relay system comprising:

4. A data relay method for relaying data in a communication network, in which encryption keys are supplied through a quantum key distribution network including: quantum key distribution links and a plurality of nodes that relay keys through the network; and a controller that performs network management by dividing the plurality of nodes into a plurality of independent node aggregates so as to equalize throughput in the key relay, and setting a route from a node aggregate including a start node of the key relay to a node aggregate including an end node via different node aggregates for each of a plurality of keys for generating an encryption key, such that one node does not supply keys to a plurality of routes, the data relay method comprising: A transmitting device corresponding to the starting node encrypts the original data with the encryption key and distributes the data into a plurality of shares by a secret sharing scheme; distributing the plurality of shares to relay devices corresponding to nodes on different paths for the plurality of keys, and relaying the shares through the communication network; A data relay method, comprising: a receiving device corresponding to the end node receiving the plurality of shares, restoring the shares by a secret sharing scheme, and decrypting the original data with the encryption key.

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