Information processing apparatus, QKD network system, information processing method, and program

Abstract

To reduce the processing load in a cryptographic key relay even if the scale of a QKD network is increased.SOLUTION: An information processing apparatus of an embodiment comprises a processing unit that, by a first cryptographic key shared through quantum key delivery between a plurality of first nodes adjacent to each other, using a second cryptographic key transmitted through an encrypted relay to a second node that is one of the plurality of first nodes, establishes an encrypted tunnel communication with the second node, and causes a network interface (IF) unit to transfer a third cryptographic key to the second node through the encrypted tunnel communication.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] An embodiment of the present invention relates to an information processing device, a QKD network system, an information processing method, and a program. [Background technology]

[0002] Quantum Key Distribution (QKD) is a technology that securely shares cryptographic keys between a QKD device that continuously transmits single photons and a QKD device that receives single photons, which are connected by an optical fiber link. The cryptographic keys shared by QKD are guaranteed not to have been intercepted based on the principles of quantum mechanics. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-171530 A [Non-patent literature]

[0004] [Non-Patent Document 1] ITU-T Y.3800, [online], [searched on July 12, 2020], Internet <URL: https: / / www.itu.int / rec / T-REC-Y.3800 / en> Summary of the Invention [Problem to be solved by the invention]

[0005] However, with conventional techniques, it has become increasingly difficult to reduce the processing load in the encryption key relay as the scale of the QKD network increases. [Means for solving the problem]

[0006] An information processing device of an embodiment establishes encrypted tunnel communication with a second node, which is one of a plurality of first nodes, using a first encryption key shared by quantum key distribution between the plurality of adjacent first nodes, and a second encryption key that is encrypted and relayed to the second node, which is one of the plurality of first nodes, and includes a processing unit that causes a network IF (Interface) unit to transfer a third encryption key to the second node via the encrypted tunnel communication. [Brief description of the drawings]

[0007] [Figure 1A] FIG. 1 is a diagram showing an example 1 of the device configuration of a QKDN system according to an embodiment. [Figure 1B] FIG. 2 is a diagram illustrating an example of a key relay according to the embodiment. [Figure 2A] FIG. 13 is a diagram showing a second example of the device configuration of the QKDN system according to the embodiment. [Figure 2B] FIG. 2 is a diagram illustrating an example of a key relay according to the embodiment. [Figure 3A] FIG. 2 is a diagram showing an overview of a first operational example of the QKDN system according to the embodiment. [Figure 3B] FIG. 3B illustrates an example of G-key relay through the encrypted tunnel of FIG. 3A. [Figure 4] FIG. 3C is a diagram showing an example of a packet data format in the G key relay of FIG. 3B. [Figure 5A] FIG. 13 is a diagram showing an overview of a second operation example of the QKDN system according to the embodiment. [Figure 5B] FIG. 5B illustrates an example of G-key relay through the encrypted tunnel of FIG. 5A. [Figure 6] FIG. 2 is a diagram showing an example of the functional configuration of a KM according to the embodiment. [Figure 7] FIG. 11 is a diagram showing an example of updating a packet forwarding table according to the embodiment. [Figure 8] 11 is a flowchart showing an example of the operation of a KM according to the embodiment. [Figure 9A] FIG. 13 is a diagram showing an overview of an operation example of a QKDN system according to a first modified example of an embodiment. [Figure 9B] FIG. 9B illustrates an example of G-key relay through the encrypted tunnel of FIG. 9A. [Figure 10]FIG. 1 is an overall diagram showing an example of a QKDN system according to a first modified example of an embodiment. [Figure 11] FIG. 11 is an overall diagram showing an example of a QKDN system according to a second modified example of an embodiment. [Figure 12] FIG. 2 is a diagram showing an example of the functional configuration of a KM according to the embodiment. [Figure 13] FIG. 2 is a diagram showing an example of the hardware configuration of a QKD device according to an embodiment. [Figure 14] FIG. 2 is a diagram showing an example of the hardware configuration of a KM device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of an information processing device, a QKD network system, an information processing method, and a program will be described in detail with reference to the accompanying drawings.

[0009] In principle, key sharing using QKD has a limited communication distance and can only be used for one-to-one key sharing. By introducing a Key Manager (KM) device in addition to the QKD device, and configuring the KM to hold and manage the keys as well as relay the keys, a QKD network (QKDN) can be configured. This makes it possible to share encryption keys between any two locations in a network with QKD as the link and KM as the node. (See Patent Document 1 and Non-Patent Document 1)

[0010] The shared encryption key is provided from the KM to an external application for use. The QKD device and the KM device may also be implemented as a single device.

[0011] [Example of device configuration] 1A is a diagram showing a first example of the device configuration of a QKDN system 200 according to an embodiment. The QKDN system 200 according to an embodiment includes KMs 1-1 to 1-9, multiple QKDs 2, and multiple applications including applications 3-1 and 3-2.

[0012] Hereinafter, when there is no need to distinguish between KM1-1 to 1-9, they will simply be referred to as KM1. Similarly, when there is no need to distinguish between applications 3-1 and 3-2, they will simply be referred to as application 3.

[0013] In FIG. 1A, the KM device is abbreviated as KM1, the QKD device is abbreviated as QKD2, and the application is abbreviated as App.

[0014] KM1 receives an encryption key from at least one QKD 2. KM1 holds and manages the encryption key, and by relaying the encryption key between KM1, encryption key sharing between any KM1 is realized. Details of the encryption key relay operation are described in, for example, Patent Document 1 and Non-Patent Document 1.

[0015] QKD2 is a QKD device that executes the QKD protocol to generate an encryption key with the opposing QKD2 via QKD. QKD2 is connected to KM1 and provides the encryption key to KM1.

[0016] An application 3 connects to a KM 1, obtains an encryption key from the KM 1, and performs encrypted communication with another application. The application 3 is usually installed at the same site as the KM 1 to which it is connected. Note that multiple applications 3 may be connected to one KM 1.

[0017] KM1 and QKD2 are installed at bases. Bases are areas where physical security is ensured. Nodes equipped with KM1 and QKD2 are sometimes called trusted nodes. By installing trusted nodes at each base, storage of encryption keys and safety in relaying are guaranteed.

[0018] QKDN100 is configured by connecting trusted nodes installed at each location via a QKD link (quantum cryptography communication channel).

[0019] Fig. 1B is a diagram showing an example of key relay in an embodiment. Fig. 1B shows an example of a case where key relay is performed in the configuration of Fig. 1A. In the example of Fig. 1B, an application 3-1 connected to KM 1-2 acquires the same encryption key as an application 3-2 connected to KM 1-8.

[0020] 1A and 1B, KM1-1 to KM1-4, KM1-2 to KM1-4, KM1-3 to KM1-4, KM1-4 to KM1-5, KM1-5 to KM1-6, KM1-6 to KM1-7, KM1-6 to KM1-8, and KM1-6 to KM1-9 are each connected by a QKD link, and encryption keys are shared using the QKD protocol.

[0021] The encryption key shared in this way by the QKD protocol is called the L key (Local key).

[0022] The example in Fig. 1B shows a case where KM1-2 shares an encryption key with KM1-8 via KM1-4, KM1-5, and KM1-6. KM1-2 generates an encryption key (hereinafter referred to as G key (Global key)) that is generated using a random number generator or the like, independently of the L key.

[0023] The random number generating function such as a random number generator may be provided in the KM1, or in an external device connected to the KM1.

[0024] KM1-2 encrypts the G key using a one-time pad with the L key shared among KM1-2 to KM1-4, and transfers the encrypted G key to KM1-4. KM1-4 decrypts the encrypted G key with the same L key used by KM1-2, and restores the G key.

[0025] Next, KM1-4 encrypts the G key using a one-time pad with the L key shared among KM1-4 to KM1-5, and transfers the encrypted G key to KM1-5. KM1-5 decrypts the encrypted G key with the same L key used by KM1-4, and restores the G key.

[0026] Next, KM1-5 encrypts the G key using a one-time pad with the L key shared between KM1-5 and KM1-6, and transfers the encrypted G key to KM1-6. KM1-6 decrypts the encrypted G key with the same L key used by KM1-5, and restores the G key.

[0027] Next, KM1-6 encrypts the G key using a one-time pad with the L key shared among KM1-6 to KM1-8, and transfers the encrypted G key to KM1-8. KM1-8 decrypts the encrypted G key with the same L key used by KM1-6, and restores the G key.

[0028] Through the above steps, KM1-2 and KM1-8 can share the same encryption key (G key). As shown in Figure 1B, this one-time pad (OTP) encryption and decryption is realized by KM1 performing IP communication.

[0029] This one-time pad (OTP) encryption and decryption may be realized by "OTP tunnel communication" using a protocol at a lower layer than IP (for example, Ethernet (registered trademark)). (L-key encryption tunnel)

[0030] The application 3-1 obtains an encryption key (G key) to be shared with the application 3-2 by requesting the encryption key (G key) from KM 1-2. Also, the application 3-2 obtains an encryption key (G key) to be shared with the application 3-1 by requesting the encryption key (G key) from KM 1-8.

[0031] Through the above steps, the application 3-1 and the application 3-2 obtain the same encryption key (G key) and perform encrypted communication.

[0032] In Fig. 1B, the internal communication of KM1 is transmitted as plain text. Furthermore, the communication between KM1 and application 3 is transmitted as plain text or encrypted using TLS (Transport Layer Security) or other methods. In any case, since KM1 and application 3 are installed at the same site, the communication cannot be deciphered by an eavesdropper.

[0033] The above-mentioned configuration of the QKDN100 allows the sharing of an encryption key (G key) between any KM1 on the QKDN100. However, the OTP encryption and decryption process for key relay is performed as many times as the number of KM1 on the relay path. In particular, in a large-scale QKDN100, a large number of key relays increases the processing load of the QKDN system 200 and increases processing delays.

[0034] This causes delays in key relay, and for example, it may not be possible to provide the encryption key (G key) required by application 3 in a timely manner. This is a scalability issue that becomes more pronounced depending on the scale of the QKDN 100. An example where this issue becomes more pronounced is shown in Figure 2A.

[0035] Fig. 2A is a diagram showing a second example of the device configuration of a QKDN system 200-2 according to an embodiment. The example in Fig. 2A shows a large-scale QKDN configured with a Backbone QKDN 100-1, and Access QKDNs 100-2 and 100-3. Note that the illustration of the QKD 2 is omitted in Fig. 2A.

[0036] In Fig. 2A, KM1-2 and 1-13 share an encryption key (G key) used by applications 3-1 and 3-2. In order for KM1-2 and 1-13 to share this encryption key (G key), encryption and decryption processing of the G key is required by eight KM1s (KM1-2, KM1-4, KM1-5, KM1-6, KM1-9, KM1-10, KM1-11, and KM1-13) (see Fig. 2B).

[0037] In addition, in Fig. 2A, an example is shown in which the QKDN100 is composed of three networks, Backbone QKDN100-1, Access QKDN100-2, and 100-3, but this is only one example. As shown in Fig. 1A, even with a single QKDN100, the above problem may occur. Also, the QKDN100 may be composed of three or more networks.

[0038] Hereinafter, when there is no need to distinguish between Backbone QKDN100-1 and Access QKDN100-2 and 100-3, and when referring to QKDNs collectively, they will simply be referred to as QKDN100.

[0039] First, an overview of how the embodiment of the QKDN system 200-2 operates will be provided.

[0040] 3A is a diagram showing an overview of an operation example 1 of the QKDN system 200-2 of the embodiment. As shown in FIG 3A, an "encrypted tunnel" for relaying the G key is established between KM1-5 and KM1-10.

[0041] First, the procedure for establishing an encrypted tunnel will be described.

[0042] Specifically, an encryption key called the M key (Middle Key) is shared between KM1-5 and KM1-10. The M key is generated by KM1 using a random number generator or the like, just like the G key. Then, KM1 shares the M key with any KM1 by encrypting and transmitting the M key with the L key using a one-time pad.

[0043] In FIG. 3A, KM1-5 generate M keys using a random number generator.

[0044] KM1-5 encrypts the M key with a one-time pad using the L key shared with KM1-6 and transfers the encrypted M key to KM1-6. KM1-6 decrypts the encrypted M key with the same L key used by KM1-5, restoring the M key.

[0045] Next, KM1-6 encrypts the M key using a one-time pad with the L key shared among KM1-6 to KM1-9, and transfers the encrypted M key to KM1-9. KM1-9 decrypts the encrypted M key using the same L key as the one used by KM1-6, and restores the M key.

[0046] KM1-9 encrypts the M key with a one-time pad using the L key shared with KM1-10 and transfers the encrypted M key to KM1-10. KM1-10 decrypts the encrypted M key with the same L key used by KM1-9, recovering the M key.

[0047] Through the above steps, KM1-5 and KM1-10 can share the same encryption key (M key).

[0048] As is clear from the above steps, the procedure for sharing the M key is the same as the procedure for sharing the G key. Therefore, the M key and the G key may be shared by substantially the same procedure, or may be shared as the same key.

[0049] The above is the procedure for sharing the M key to realize the encrypted tunnel.

[0050] Next, a method of relaying the G key via the encrypted tunnel (M-key encrypted tunnel) according to the embodiment will be described.

[0051] Fig. 3B is a diagram showing an example of G key relay via the encrypted tunnel (M key encrypted tunnel) of Fig. 3A, and Fig. 4 is a diagram showing an example of a packet data format in the G key relay of Fig. 3B.

[0052] The example in FIG. 3B shows a case where an application 3-1 connected to KM 1-2 shares the same encryption key (G key) with an application 3-2 connected to KM 1-13.

[0053] The following describes a G key relay method by which KM1-2 shares an encryption key (G key) with KM1-13 via KM1-4, KM1-5, KM1-10, and KM1-11.

[0054] First, KM1-2 generates an encryption key (G key) using a random number generation function realized by a random number generator or the like, independently of the L key. KM1-2 encrypts a key relay message addressed to KM1-13, including the G key, using a one-time pad with the L key shared among KM1-2 to KM1-4. KM1-2 then encapsulates an IP packet including the key relay message encrypted with the L key, in an IP packet with the source address of KM1-2 and the destination address of KM1-4, and forwards the encapsulated IP packet to KM1-4.

[0055] KM1-4 decrypts the encrypted key relay message with the same L key used by KM1-2, and decapsulates the IP packet by restoring the key relay message including the G key. Next, KM1-4 encrypts the key relay message including the G key using a one-time pad with the L key shared between KM1-4 and KM1-5. Then, KM1-4 encapsulates the IP packet with the address of KM1-4 as the source and KM1-5 as the destination, toward KM1-5, which is the next-hop toward the destination KM1-13 of the restored key relay message, and forwards the encapsulated IP packet.

[0056] KM1-5 decrypts the encrypted key relay message with the same L key used by KM1-4, and decapsulates the IP packet by recovering the encrypted key relay message containing the G key.

[0057] Next, KM1-5 identifies that the next-hop of the restored key relay message toward destination KM1-13 is KM1-10, and encrypts the key relay message including the G key (third encryption key) by one-time pad with the M key (second encryption key) shared among KM1-5 to KM1-10. KM1-5 encapsulates the IP packet encrypted with the M key (an example of a first communication packet) as an IP packet (an example of a second communication packet) with KM1-5 as the sender and KM1-10 as the destination. KM1-5 then transfers the encapsulated IP packet to KM1-6, which is the next-hop addressed to KM1-10.

[0058] KM1-6 and KM1-10, acting as relay KMs, forward the encapsulated IP packet, thereby forwarding the encapsulated IP packet to KM1-10.

[0059] KM1-10 decrypts the encrypted key relay message with the same M key used by KM1-5, and decapsulates the IP packet by recovering the encrypted key relay message containing the G key.

[0060] Next, KM1-10 encrypts the key relay message including the G key using a one-time pad with the L key shared among KM1-10 to KM1-11, and transfers the encrypted key relay message to KM1-11.

[0061] KM1-11 decrypts the encrypted relay message with the same L key used by KM1-10, and recovers the key relay message containing the G key. Next, KM1-11 encrypts the key relay message containing the G key using a one-time pad with the L key shared among KM1-11 to KM1-13, and transfers the encrypted key relay message to KM1-13.

[0062] KM1-13 decrypts the encrypted key relay message with the same L key used by KM1-11, restores the key relay message containing the G key, and obtains the G key from the key relay message.

[0063] Through the above steps, KM1-2 and KM1-13 can share the same encryption key (G key).

[0064] In the above-mentioned encryption key (G key) relay step, the encryption of the G key between KM1-5 to KM1-10 is performed using the M key, which is different from conventional operation. In conventional operation, when KM1-2 relays an encryption key with KM1-13, it was necessary for eight KM1s (KM1-2, KM1-4, KM1-5, KM1-6, KM1-9, KM1-10, KM1-11, and KM1-13) to encrypt and decrypt the G key.

[0065] On the other hand, in the G key relay method of the embodiment, when KM1-2 relays the encryption key (G key) with KM1-13, the G key is encrypted and decrypted by six KM1s (KM1-2, KM1-4, KM1-5, KM1-10, KM1-11 and KM1-13), simplifying the encryption key relay procedure.

[0066] 3B, in the embodiment, KM1-6 and KM1-9 may also operate as IP routers and transfer G key data (key relay message) encrypted with the M key. However, KM1-6 and KM1-9 are not involved in the encryption and decryption of the G key.

[0067] Also, as shown in FIG. 4, the subject to be encrypted may be the entire IP packet including the G-key data contained in the payload, or may be only the G-key data contained in the payload.

[0068] As shown in FIG. 3B, KM1, which is the starting point of the key relay using the encrypted tunnel with the M key, is called Ingress KM, and KM1, which is the ending point of the key relay using the encrypted tunnel with the M key, is called Egress KM.

[0069] This key relay using the M-key encrypted tunnel (M-key encrypted tunnel) can tunnel not only a single-route G-key relay but also multiple-route G-key relays. Figures 5A and 5B show an example of tunneling multiple-route G-key relays.

[0070] Fig. 5A is a diagram showing an overview of an operation example 2 of the QKDN system of the embodiment. In the example of Fig. 5A, not only the G key relay between KM1-2 connected to application 3-1 and KM1-13 connected to application 3-2, but also the G key relay between KM1-1 connected to application 3-3 and KM1-12 connected to application 3-4, and the G key relay between KM1-3 connected to application 3-5 and KM1-14 connected to application 3-6 are transferred by an encrypted tunnel using the M key between KM1-5, which is the Ingress KM, and KM1-10, which is the Egress KM. This makes it possible to improve the efficiency of multiple G key relays.

[0071] Fig. 5B is a diagram showing an example of a G key relay via the encrypted tunnel (M key encrypted tunnel) of Fig. 5A. In the example of Fig. 5B, the M key encrypted tunnel is used for the transfer of three G key relays: a G key shared by applications 3-1 and 3-2, a G key shared by applications 3-3 and 3-4, and a G key shared by applications 3-5 and 3-6. Due to space limitations, applications 3-3 to 3-6 are omitted from Fig. 5B.

[0072] In this way, this embodiment can simplify the system processing procedure and processing load for relaying the encryption key (G key) in the QKDN 100, and reduce the processing load and processing delay associated with the G key relay. Furthermore, the G key relay not only reduces the processing load and processing delay of a single G key relay path (FIG. 3A), but also exerts its effect on multiple G key relay paths (FIG. 5A).

[0073] In particular, by setting up a G key relay via an encrypted tunnel using the M key of the embodiment for an important G key relay between KM1s through which many key relays pass, it is possible to improve the efficiency and processing delay of G key relay operation throughout the system.

[0074] Here, the effects of the embodiment will be summarized again. 1.The processing load of the G key relay can be reduced. 2. The processing delay (latency) of the G key relay can be reduced. 3. By completing key relay in advance between the Ingress KM and the Egress KM, it is possible to reduce the impact of congestion caused by a reduction in L keys, etc.

[0075] 4. Considering the total processing load of the M key relay performed in advance between the Ingress KM and Egress KM and the G key relay (via an encrypted tunnel using the M key) performed upon request from application 3, there is no difference from the conventional method. However, by performing the M key relay in advance, the encryption / decryption load on KM1 performing the G key relay is distributed over time, making it possible to level out the processing load.

[0076] 5. By completing the M key relay in advance between the Ingress KM and Egress KM, which are the main routes, it is possible to prepare for the occurrence of G key relay on multiple routes. In other words, the processing delay of G key relay on multiple routes can be reduced.

[0077] [Example of functional configuration] 6 is a diagram showing an example of the functional configuration of the KM1 of the embodiment. The KM1 of the embodiment includes a processing unit 11, a network IF unit 12, a random number generation unit 13, and a memory unit .

[0078] The processing unit 11 is realized by at least one processing device, and executes the processing of KM1. This processing device includes, for example, a control device and an arithmetic device, and is realized by analog or digital circuits, etc. The processing device may be a central processing unit (CPU), a general-purpose processor, a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0079] The processing unit 11 includes a control unit 111 , a tunnel establishment processing unit 112 , a transfer unit 113 , an encryption unit 114 , and a decryption unit 115 .

[0080] When the KM1 operates as an Ingress KM or an Egress KM, the control unit 111 determines whether to establish an M key encrypted tunnel and whether to terminate the M key encrypted tunnel.

[0081] The tunnel establishment processing unit 112 performs M key encrypted tunnel establishment processing when KM1 operates as an Ingress KM or Egress KM. For example, the tunnel establishment processing unit 112 requests another KM1 (second node) to establish M key encrypted tunnel communication, and establishes M key encrypted tunnel communication with the other KM1 in response to a response from the other KM1. Also, for example, when the tunnel establishment processing unit 112 receives a request to establish M key encrypted tunnel communication from another KM1 (second node), if the tunnel establishment processing unit 112 returns a response indicating approval to the other KM1, it establishes M key encrypted tunnel communication with the other KM1.

[0082] When KM1 operates as an Ingress KM, the transfer unit 113 transfers the G key via the M key encrypted tunnel. When KM1 operates as an Egress KM, the transfer unit 113 receives the G key via the M key encrypted tunnel. When KM1 operates as a relay KM, the transfer unit 113 transfers traffic (simple data forwarding without OTP encryption). The transfer and reception performed by the transfer unit 113 is performed via the network IF unit 12, which will be described later.

[0083] Furthermore, the transfer unit 113 uses the L key (first encryption key) shared with the adjacent KM1 (first node) to encrypt and relay-transmit to the adjacent KM1 the M key (second encryption key) used for the M key encrypted tunnel or the G key (third encryption key) used for encrypted communication of application 3. Note that in the encrypted relay transmission performed by the transfer unit 113, encryption using the L key is performed by the encryption unit 114, which will be described later, and relay transmission of the encrypted M key or encrypted G key is performed via the network IF unit 12, which will be described later.

[0084] The encryption unit 114 uses the L key or the M key to encrypt data including the G key.

[0085] The decryption unit 115 uses the L key or the M key to decrypt the encrypted data including the G key.

[0086] The network IF unit 12 connects to the QKD network 100 and transmits and receives data. The random number generation unit 13 generates an encryption key (G key) independently of the L key. For example, the random number generation unit 13 is realized by a random number generator or the like.

[0087] The memory unit 14 accumulates the L key (first encryption key), the M key (second encryption key), and the G key (third encryption key). The memory unit 14 is realized by a storage medium such as a hard disk drive (HDD), an optical disk, a memory card, or a random access memory (RAM).

[0088] Note that the example of the functional configuration shown in FIG. 5 is just an example and may be changed as appropriate. For example, the memory unit 14 may exist outside KM1. Also, for example, the control unit 111 does not have to be included in KM1 itself and may exist in another device within the QKDN system 200, for example.

[0089] The operation outline of KM1 in the QKDN system 200-2 in FIG. 3A is organized. Note that in the following example, the case where the object to be encrypted is only the G key data included in the payload, rather than the entire IP packet including the G key data included in the payload, will be described.

[0090] 1. The transfer units 113 of the Ingress KM (KM1-5) and the Egress KM (KM1-10) share the M key in advance via the network IF unit 12. Note that since the generation method and the sharing method of the M key and the G key are the same, they are substantially the same as data.

[0091] 2. The tunnel establishment processing units 112 of the Ingress KM and the Egress KM establish an M key encrypted tunnel (OTP encrypted tunnel) using the M key. As a result, the transfer units 113 of the Ingress KM and the Egress KM can directly transfer the G key by OTP communication via the network IF unit 12, and thus become virtual adjacent KMs.

[0092] 3. The control unit 111 of the Ingress KM (KM1-5) is requested by the control unit 111 of KM1-4 on the Access QKDN100-2 for G key relay. <Processing of KM1-5> (a) The decryption unit 115 decrypts the received encrypted G key data with the L key shared with the source KM1 of the received encrypted G key data by OTP. (b) The transfer unit 113 refers to the routing path information of the G key relay and identifies the destination KM1. In the example of Fig. 3A, for instance, when the destination KM1 is KM1-13, the transfer will be via the M key encrypted tunnel. Therefore, the IP packet becomes an encapsulated IP packet when the destination KM1 is set to the Egress KM (KM1-10 which becomes the virtual next hop). (c) The encryption unit 114 encrypts the G key included in the payload with the M key shared with the Egress KM, and the transfer unit 113 transfers the encapsulated IP packet including the encrypted G key to the Egress KM via the network IF unit 12. Note that the Ingress KM transfers the encapsulated IP packet with the destination being the Egress KM, and this IP packet may be transferred via KM1-6, KM1-9, etc. as an IP router. Here, KM1-6 and KM1-9 are referred to as transfer KMs.

[0093] 4. The KM1 (transfer KM) on the Backbone QKDN100-1 only performs transfer according to the routing path information without decrypting the encapsulated IP packet.

[0094] 5. The transfer unit 113 of the Egress KM (KM1-10) receives the encapsulated IP packet destined for KM1-10 including the encrypted G key via the network IF unit 12. <Processing of KM1-10> (a) The transfer unit 113 unpacks the encapsulated IP packet and extracts the inner IP packet. Then, the decryption unit 115 decrypts the encrypted G key in the inner IP packet using the M key shared with the source Ingress KM. (b) The transfer unit 113 refers to the routing path information of the G key relay based on the destination information of the inner IP packet and identifies the destination next hop KM. In the example of Fig. 3A, for instance, when the destination KM1 is KM1-13, it becomes KM1-11 on the Access QKDN100-3. (c) The encryption unit 114 encrypts the G key with the L key shared with KM1-11, and the transfer unit 113 transfers the IP packet containing the encrypted G key in its payload to KM1-11 via the network IF unit 12.

[0095] The details of the processing after passing through the M key encrypted tunnel, that is, the reception processing and forwarding processing of KM1-11 and the reception processing of KM1-13, are the same as those explained with reference to FIG. 3B, and therefore will be omitted here.

[0096] The following describes, in order, the decision to establish or stop an encrypted tunnel, the encrypted tunnel establishment process, forwarding to an encrypted tunnel, forwarding and receiving from an encrypted tunnel, and forwarding of encrypted tunnel traffic.

[0097] [Encryption tunnel establishment / termination decision] The decision to establish or stop an encrypted tunnel is made by the control unit 111 of the Ingress KM and Egress KM.

[0098] The control unit 111 judges whether or not to establish an M-key encrypted tunnel with a specific KM1 on the QKDN 100. Specific examples of the judgment method are shown in the following items 1 to 4.

[0099] 1. The control unit 111 controls the establishment of an M key encrypted tunnel between KM1s designated by a network administrator, or the termination of an M key encrypted tunnel. For example, the designation by the network administrator is made by setting information of the KM1s, etc.

[0100] 2. The control unit 111 controls the establishment of an M key encrypted tunnel or the termination of an M key encrypted tunnel in response to an instruction from a network management manager (e.g., QKDN Manager) present on the QKDN system 200-2. For example, the function of the network management manager may be provided in the control unit 111 of any of multiple KM1s present on the QKDN system 200-2.

[0101] Also, for example, a management device having a function of a network management manager may be provided on the QKDN system 200-2, and the control unit 111 of each KM1 may control the establishment of an M key encrypted tunnel or the termination of an M key encrypted tunnel according to an instruction from the management device. An example of a configuration including a management device will be described later in the second modified example of the embodiment (FIG. 11).

[0102] 3. A specific example of establishing an encrypted tunnel: (a) When G key sharing is performed at a frequency equal to or higher than a certain frequency on a certain path, the tunnel establishment processing unit 112 establishes an M key encrypted tunnel on the path in response to an instruction from the control unit 111. For example, when G key sharing is performed at a frequency equal to or higher than a certain frequency, it is determined whether or not the requested amount of G key (third encryption key) shared with another KM1 (second node) per unit time (for example, 1 minute, 1 hour, 1 day, etc.) is larger than a first amount.

[0103] (b) In response to an instruction from the control unit 111, the tunnel establishment processing unit 112 establishes an M-key encrypted tunnel on a partial route that is used in common by a plurality of G-key shared routes.

[0104] (c) In response to an instruction from the control unit 111, the tunnel establishment processing unit 112 establishes an M-key encrypted tunnel between the partial QKDNs 100-i to 100-j that frequently communicate in the QKDN 100 that is composed of n partial QKDNs 100-1 to 100-n.

[0105] (d) When the accumulated amount of the M key (second encryption key) used in the M key encrypted tunnel becomes greater than the first amount and transmission of the G key via the M key encrypted tunnel becomes possible, the tunnel establishment processing unit 112 establishes an M key encrypted tunnel in accordance with an instruction from the control unit 111.

[0106] 4. Specific example of stopping an encrypted tunnel: (a) When the accumulated amount of M keys used in the M key encrypted tunnel becomes smaller than the second amount and the transmission of G keys via the M key encrypted tunnel can no longer be performed, the tunnel establishment processing unit 112 stops the encrypted tunnel in response to an instruction from the control unit 111.

[0107] (b) When it is determined that the frequency with which the M key encrypted tunnel is used falls below a certain level and that the effect of improving processing efficiency by establishing and using the M key encrypted tunnel is not obtained, the tunnel establishment processing unit 112 stops the M key encrypted tunnel in response to an instruction from the control unit 111. For example, when the consumption of the M keys used in the M key encrypted tunnel decreases and falls below a certain level, it is determined that the frequency with which the M key encrypted tunnel is used falls below a certain level.

[0108] (c) If the requested amount per unit time (e.g., one minute, one hour, one day, etc.) of the G key (third encryption key) shared by the M key encrypted tunnel with another KM1 (second node) is smaller than the second amount, the tunnel establishment processing unit 112 stops the M key encrypted tunnel communication in response to an instruction from the control unit 111.

[0109] [Encryption tunnel establishment process] The encrypted tunnel establishment is a process that takes place between the Ingress KM and the Egress KM.

[0110] Establishing an encrypted tunnel corresponds to agreeing to generate and store the M key between a specified Ingress KM and Egress KM, and setting up a virtual next hop at the Ingress KM and Egress KM to transmit G key data through an encrypted tunnel using the M key.

[0111] For example, signaling processing may be performed between the Ingress KM and the Egress KM to establish an encrypted tunnel. For example, a packet instructing the establishment of an M key tunnel may be transmitted from the Ingress KM to the Egress KM by IKE (Internet Key Exchange), which is a signaling protocol used in IPsec. Then, the Egress KM may receive the packet instructing the establishment of an M key tunnel and respond to the Ingress KM to start tunnel operation. At this time, peer authentication may be performed between the Ingress KM and the Egress KM, and negotiation may be performed regarding a packet transfer method, encryption method, data authentication method, and the like for realizing the M key encrypted tunnel.

[0112] Also, for example, KM1 for establishing an M-key encrypted tunnel on QKDN system 200-2 may be specified by configuration information of KM1, and the encrypted tunnel may be established without executing a specific signaling protocol such as that described above.

[0113] To establish an encrypted tunnel, a certain number of M keys (=G keys) must be stored between the Ingress KM and the Egress KM. If a certain number of M keys (=G keys) have not been stored, the transfer unit 113 first shares the M keys (=G keys) between the Ingress KM and the Egress KM via the network IF unit 12 in the manner of a normal G key relay.

[0114] The tunnel establishment processing unit 112 performs settings for performing OTP encryption / decryption using the G key (=M key) shared as described above. The OTP encryption / decryption may be realized as an M-key cryptographic tunnel using a virtual interface. For example, by setting multiple virtual interfaces for one physical interface, it becomes possible to use one physical interface for multiple purposes.

[0115] In addition, IP packet forwarding settings may be added so that the Ingress KM and the Egress KM communicate as virtual next hops. As a specific example, in the Ingress KM where the M-key encrypted tunnel is established, the packet forwarding table is updated so that encrypted communication using the M-key is performed in the G-key relay addressed to the Egress KM. An example of the packet forwarding table in KM1-5 is shown in Figure 7.

[0116] 7 is a diagram showing an example of updating the packet forwarding table (for KM1-5) in the embodiment. Before the M key encrypted tunnel is established (FIG. 2A), for example, when the destination address is the address of KM1-12, the next-hop IP address of KM1-5 is KM1-6. In this case, the G key forwarded to KM1-12 is encrypted with the L key shared between KM1-5 and KM1-6, and is forwarded by being encapsulated in an IP packet addressed to KM6.

[0117] On the other hand, after the M key encrypted tunnel has been established (FIG. 5A), for example, when the destination address is the address of KM1-12, the next-hop IP address of KM1-5 becomes KM1-10 (virtual next-hop). In this case, the G key transferred to KM1-12 is encrypted with the M key shared between KM1-5 and KM1-10, and transferred by being encapsulated in an IP packet addressed to KM10.

[0118] [Transfer to encrypted tunnel] The transfer to the encryption tunnel is performed by the transfer unit 113 of the Ingress KM (KM1-5 in FIG. 3A) via the network IF unit 12.

[0119] The transfer unit 113 receives the G key data to be key-relayed from KM1-4 on the Access QKDN100-2 via the network IF unit 12.

[0120] The decryption unit 115 decrypts the G key with the L key shared with KM1-4 on Access QKDN100-2, which is the transfer source of the G key data.

[0121] The forwarding unit 113 refers to the routing route information and identifies the forwarding destination node as the Egress KM (KM1-10 in FIG. 3A).

[0122] The encryption unit 114 encrypts the G key with the M key shared with the Egress KM, and the transfer unit 113 transfers the G key encrypted with the M key to the Egress KM via the network IF unit 12 (key relay using an encrypted tunnel with the M key). The transfer destination of the G key encrypted with the M key may be a virtual interface set in the Egress KM when the M key encrypted tunnel is established.

[0123] The M key and the G key may be stored in any manner. For example, the memory unit 14 may store the M key used to establish the M key encrypted tunnel in a separate database (storage area) or may store the M key together with the general G key.

[0124] [Receive from encrypted tunnel] Reception from the encrypted tunnel is performed by the transfer unit 113 of the Ingress KM (KM1-10 in FIG. 3A) via the network IF unit 12.

[0125] The transfer unit 113 receives the G key data encrypted with the M key from the Ingress KM (KM1-5 in FIG. 3A) via the network IF unit 12 by the virtual interface set when the M key encrypted tunnel was established.

[0126] The decryption unit 115 decrypts the G key data encrypted with the M key, using the M key shared with the Ingress KM. Specifically, the decryption unit 115 identifies the source KM from the source of the IP packet containing the decrypted G key data, and identifies the decryption key used to decrypt the data (IP packet). That is, the decryption unit 115 determines whether to perform decryption with the M key or to perform decryption with the normal L key, which is not the decryption of the M key encrypted tunnel communication, according to the source KM.

[0127] The M key shared with the Ingress KM is associated with, for example, a virtual interface through which the G key data encrypted with the M key is received, or with a source KM (KM1-5 in FIG. 3A), and is stored in the memory unit 14. Also, for example, a normal L key is associated with a source KM and is stored in the memory unit 14.

[0128] The transfer unit 113 refers to the routing path information, identifies the transfer destination KM as KM1 on the Access QKDN100-3, and the encryption unit 114 encrypts the G key data with the L key shared with the transfer destination KM. Then, the transfer unit 113 transfers the encrypted G key data to the transfer destination KM via the network IF unit 12.

[0129] [Forwarding encrypted tunnel traffic] The encrypted tunnel traffic is forwarded by the forwarding unit 113 of the relay KM (KM1-6 and KM1-9 in FIGS. 2A and 3A) via the network IF unit 12.

[0130] The transfer unit 113 receives an IP packet of M key encrypted tunnel traffic via the network IF unit 12. The transfer unit 113 judges whether the received IP packet is M key encrypted tunnel traffic or not. The transfer unit 113 performs different transfer processing depending on whether the received IP packet is M key encrypted tunnel traffic or not.

[0131] As a specific example 1 of a method for determining whether or not the traffic is M-key encrypted tunnel traffic, there is a method for determining whether or not the destination IP address of a received IP packet is addressed to the own device. Specifically, whether or not the destination IP address is addressed to the own device can be determined from the received IP packet, as shown in Fig. 4. When the destination of the received IP address is addressed to the own device, the decryption unit 115 decrypts the IP packet with the L key since it is not an IP packet of M-key encrypted tunnel traffic. On the other hand, when the destination of the received IP address is not the own device, the decryption unit 115 transfers the IP packet to the destination as it is without decrypting or encrypting the IP packet since it is an IP packet of M-key encrypted tunnel traffic.

[0132] As a second specific example of a method for determining whether or not traffic is M-key encrypted tunnel traffic, there is a method using the type of destination IP address of the received IP packet. In this case, IP addresses for transferring M-key encrypted tunnel traffic (i.e., IP addresses that do not encrypt / decrypt using the L key) and IP addresses for normal key relay (i.e., IP addresses that encrypt / decrypt using the L key) are distinguished and used.

[0133] As a third specific example of a method for determining whether or not the traffic is M-key encrypted tunnel traffic, a method using the protocol number of data included in a received IP packet can be mentioned. In this case, the protocol number of an IP packet carrying M-key encrypted tunnel traffic and the protocol number of an IP packet carrying normal G-key relay traffic are operated separately. For example, it is possible to insert a protocol number into an IP packet by IPIP (IP over IP), L2TP / IPsec, GRE, etc.

[0134] When the received IP packet is M key encrypted tunnel traffic, the decryption unit 115 does not perform OTP decryption using the L key. The transfer unit 113 performs a transfer process for the M key encrypted tunnel traffic. Specifically, when the transfer unit 113 transmits an IP packet of the M key encrypted tunnel traffic via the network IF unit 12, the transfer unit 113 transfers the IP packet as a router. Furthermore, when the transfer unit 113 transfers an IP packet of the M key encrypted tunnel traffic via the network IF unit 12, the transfer unit 113 may set identification information (e.g., a protocol number) indicative of the fact that the IP packet is tunnel traffic in the IP packet.

[0135] [Examples of information processing methods] Fig. 8 is a flowchart showing an example of the operation of the KM 1 in the embodiment. The example in Fig. 8 shows an example of the operation when the KM 1-10 in Fig. 3A operates as a relay KM, an Ingress KM, or an Egress KM.

[0136] First, the forwarding unit 113 receives reception data (IP packets) from the source KM1 via the network IF unit 12 (step S1). Next, the forwarding unit 113 determines whether the destination KM of the data received in step S1 is the own device (step S2).

[0137] If the destination KM is not the own device (step S2, No), the transfer unit 113, as a relay KM, transfers the received data as it is via the network IF unit 12 (step S7).

[0138] If the destination KM is the own device (step S2, Yes), the decryption unit 115 identifies a decryption key from the received data and decrypts the received data with the decryption key (step S3). Specifically, the decryption unit 115 identifies the source KM1 from the source address included in the received data, thereby identifying the decryption key to be used for decryption.

[0139] For example, if the sender's KM1 is KM1-5, the M key shared with KM1-5 is identified as the decryption key used for decryption. If the sender's KM1 is KM1-8, the L key shared with KM1-8 is identified as the decryption key used for decryption. If the sender's KM1 is KM1-9, the L key shared with KM1-9 is identified as the decryption key used for decryption. If the sender's KM1 is KM1-11, the L key shared with KM1-11 is identified as the decryption key used for decryption.

[0140] Next, the forwarding unit 113 refers to the IP packet forwarding table and identifies the next hop IP address of the received data (step S4).

[0141] Next, the encryption unit 114 identifies an encryption key from KM1 of the destination corresponding to the next hop IP address, and encrypts the received data with the encryption key (step S5).

[0142] For example, if destination KM1 is KM1-5, the M key shared with KM1-5 is identified as the encryption key used for encryption. For another example, if destination KM1 is KM1-8, the L key shared with KM1-8 is identified as the encryption key used for encryption. For another example, if destination KM1 is KM1-9, the L key shared with KM1-9 is identified as the encryption key used for encryption. For another example, if destination KM1 is KM1-11, the L key shared with KM1-11 is identified as the encryption key used for encryption.

[0143] Next, the transfer unit 113 transfers the received data encrypted in step S5 to the destination KM1 specified by the next hop IP address via the network IF unit 12 (step S6).

[0144] As described above, in KM1 (an example of an information processing device) of the embodiment, the processing unit 11 establishes M key encrypted tunnel communication with the second node, using the M key (second encryption key) encrypted and relayed to the second node, which is one of the multiple KM1s, by the L key (first encryption key) shared by quantum key distribution between multiple adjacent KM1s (first nodes). Then, the processing unit 11 causes the network IF unit 12 to transfer the G key (third encryption key) to the second node by the M key encrypted tunnel communication.

[0145] As a result, according to the KM1 of the embodiment, even if the scale of the QKD network increases, the processing load in the encryption key (G key) relay can be reduced. For example, an encrypted tunnel using the M key is preferably set up between KM1s with higher communication frequency. Examples of KM1s with higher communication frequency include KM1s that correspond to gateways of the QKDN100 (for example, KM1-5 and KM1-10 in the example of FIG. 2A).

[0146] When performing G-key relay across QKDNs 100s with different key sharing and relaying methods, setting up an encrypted tunnel using an M key in advance corresponds to hiding the key relay method in the corresponding QKDNs 100. For example, in the example of Fig. 2A, setting up an M-key encrypted tunnel in advance in KM1-5 and KM1-10 corresponds to hiding the Backbone QKDN 100-1.

[0147] (First Modification of the Embodiment) Next, a first modified example of the embodiment will be described. In the description of the first modified example, the same description as in the embodiment will be omitted, and only the differences from the embodiment will be described. In the first modified example, a case will be described in which an M key encrypted tunnel using an M key is established between ends KM1 with which a connected application 3 frequently communicates.

[0148] Fig. 9A is a diagram showing an outline of an example of the operation of the QKDN system 200-2 according to the first modified example of the embodiment. Fig. 9B is a diagram showing an example of the G key relay via the M key encrypted tunnel in Fig. 9A.

[0149] The KM 1-1 provides an encryption key (G key) to the application 3-1. Similarly, the KM 1-12 provides an encryption key (G key) to the application 3-2.

[0150] In addition, KM1-1 and KM1-12 can easily autonomously make the decision to establish or terminate the M key encrypted tunnel as described above in 3. Specific example (a) of establishing an encrypted tunnel, "When G key sharing is performed at a certain frequency on a specific route." In other words, KM1-1 and KM1-12 can autonomously make the decision to establish or terminate the M key encrypted tunnel without receiving instructions from an external QKDN manager.

[0151] 10 is an overall view showing an example of a QKDN system 200-2 according to the first modification of the embodiment. As shown in FIG.

[0152] In the example of Figure 10, the processing unit 11 of KM1-1 provides the G key (third encryption key) shared via an encrypted tunnel using the M key, or the G key (third encryption key) shared by a normal key relay using the L key, to the connected application 3 (e.g., application 3-3).

[0153] The application 3-3 uses the G key received from KM 1-1 to encrypt a communication message (plain text) to the destination application 3-4, and transmits the encrypted message via the encrypted communication network 101 to the application 3-4.

[0154] The encryption method used by the application 3-3 may be OTP, AES (Advanced Encryption Standard), or any other encryption method. The encrypted communication network 101 may be realized on the same network as the QKDN 100 in which the KM 1 realizes key relay, or may be configured as a separate network.

[0155] (Modification 2 of the embodiment) Next, a second modification of the embodiment will be described. In the description of the second modification, the same description as in the embodiment will be omitted, and only the differences from the embodiment will be described. In the second modification, a case will be described in which the KM1 further has a function of receiving plaintext data from the application 3, encrypting the plaintext data with the G key, and transmitting the ciphertext to the application 3 of the communication destination, and a function of decrypting the ciphertext.

[0156] Fig. 11 is an overall view showing an example of a QKDN system 200-3 according to the second modified example of the embodiment. In the example of Fig. 11, the processing unit 11 of the KM 1-1 encrypts plaintext data received from the application 3-3 with the G key, and transmits this ciphertext via the encrypted communication network 101 to the application 3-4 of the communication destination.

[0157] Furthermore, the processing unit 11 of KM 1-12 decrypts the ciphertext received via the encrypted communication network 101 with the G key shared with KM 1-1, and transmits the resulting plaintext to the application 3-4.

[0158] 11, a management device 4 having a network management manager function that controls the establishment and termination of M key encrypted tunnel communication is provided on the encrypted communication network 101. The control unit 111 of each KM1 may control the establishment of an M key encrypted tunnel or the termination of an M key encrypted tunnel according to instructions from the management device 4. The management device 4 receives instructions to start and terminate M key encrypted tunnel communication, for example, from an administrator of the QKDN system 200-3. The management device 4 may be provided other than on the encrypted communication network 101. For example, it may be provided on the QKDN 100.

[0159] [Example of functional configuration] 12 is a diagram showing an example of the functional configuration of the KM1 of the embodiment. The KM1 of the modified example 2 includes a processing unit 11, a network IF unit 12, a random number generation unit 13, and a memory unit .

[0160] The processing unit 11 includes a control unit 111, a tunnel establishment processing unit 112, a transfer unit 113, a first encryption unit 114, a first decryption unit 115, a second encryption unit 116, and a second decryption unit 117. The control unit 111, the tunnel establishment processing unit 112, the first encryption unit 114, and the first decryption unit 115 are similar to the control unit 111, the tunnel establishment processing unit 112, the encryption unit 114, and the decryption unit 115 of the embodiment, and therefore a description thereof will be omitted.

[0161] The second encryption unit 116 generates ciphertext by encrypting the plaintext data received from the application 3 with the G key (third encryption key) shared with the destination KM1.

[0162] The second decryption unit 117 generates plaintext data by decrypting the ciphertext received via the encrypted communication network 101 with the G key (third encryption key) shared with the sender KM1.

[0163] The transfer unit 113 of variant example 2 further receives plaintext data from application 3, transfers ciphertext generated by the second encryption unit 116, receives ciphertext sent from the source KM1, and transfers plaintext data generated by the second decryption unit 117 via the network IF unit 12.

[0164] As in the first modification, the encryption method used for encrypting and decrypting the plaintext data may be OTP, AES, or any other encryption method. The encrypted communication network 101 may be realized on the same network as the QKDN 100 in which the KM1 realizes the key relay, or may be configured as a separate network.

[0165] Finally, an example of the hardware configuration of the KM device (KM1) and QKD device (QKD2) of the embodiment, and the management device 4 of the second modification will be described.

[0166] [Example of hardware configuration] 13 is a diagram showing an example of a hardware configuration of the QKD2 of the embodiment. The QKD2 of the embodiment includes a control device 301, a main memory device 302, an auxiliary memory device 303, a display device 304, an input device 305, a quantum communication IF (Interface) 306, and a classical communication IF307.

[0167] The control device 301 , the main memory device 302 , the auxiliary memory device 303 , the display device 304 , the input device 305 , the quantum communication IF 306 and the classical communication IF 307 are connected via a bus 310 .

[0168] The control device 301 executes a program read from the auxiliary storage device 303 to the main storage device 302. The main storage device 302 is a memory such as a ROM (Read Only Memory) and a RAM. The auxiliary storage device 303 is a HDD, a memory card, or the like.

[0169] The display device 304 displays the status of the QKD2, etc. The input device 305 accepts input from a user. The display device 304 and the input device 305 may be realized by a touch panel or the like having a display function and an input function. The display device 304 and the input device 305 may not be provided in the QKD2. In this case, for example, the display function and the input function of an external terminal connected to the QKD2 are used.

[0170] The quantum communication IF 306 is an interface for connecting to a QKD link through which photons are transmitted, and the classical communication IF 307 is an interface for connecting to a transmission line through which control signals and the like are transmitted.

[0171] 14 is a diagram showing an example of the hardware configuration of the KM 1 of the embodiment. The KM 1 of the embodiment includes a control device 401, a main memory device 402, an auxiliary memory device 403, a display device 404, an input device 405, and a communication IF 406.

[0172] The control device 401 , the main memory device 402 , the auxiliary memory device 403 , the display device 404 , the input device 405 and the communication IF 406 are connected via a bus 410 .

[0173] The control device 401 executes a program read from the auxiliary storage device 403 to the main storage device 402. The main storage device 402 is a memory such as a ROM and a RAM. The auxiliary storage device 403 is a HDD, a memory card, or the like.

[0174] The display device 404 displays the status of KM1, etc. The input device 405 accepts input from the user. The display device 404 and the input device 405 may be realized by a touch panel or the like having a display function and an input function. The display device 404 and the input device 405 may not be provided in KM1. In this case, for example, the display function and the input function of an external terminal connected to KM1 are used.

[0175] The communication IF 406 is an interface for connecting to a transmission line.

[0176] The hardware configuration of the management device 4 in the second modification is similar to the hardware configuration of the KM 1 shown in FIG.

[0177] The programs executed by the KM1 and QKD2 in the embodiments are provided as a computer program product stored in an installable or executable format on a computer-readable storage medium such as a CD-ROM, memory card, CD-R, or DVD (Digital Versatile Disc).

[0178] Furthermore, the programs executed by the KM 1 and QKD 2 of the embodiment may be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network.

[0179] Furthermore, the programs executed by the KM 1 and QKD 2 in the embodiment may be configured to be provided via a network such as the Internet without being downloaded.

[0180] Furthermore, the programs executed by the KM 1 and QKD 2 of the embodiment may be configured to be provided by being pre-installed in a ROM or the like.

[0181] The program executed by the KM1 in the embodiment has a modular configuration including functions that can be realized by the program among the functional configuration of the KM1. The functions realized by the program are loaded into the main memory device 402 by the control device 401 reading the program from a storage medium such as the auxiliary memory device 403 and executing it. In other words, the functions realized by the program are generated on the main memory device 402.

[0182] Some or all of the functions of the KM1 may be realized by hardware such as an integrated circuit (IC). The IC is, for example, a processor that executes dedicated processing.

[0183] Furthermore, when multiple processors are used to realize the respective functions, each processor may realize one of the respective functions, or may realize two or more of the respective functions.

[0184] Furthermore, the KM1 and QKD2 may operate in any manner. For example, the KM1 and QKD2 may operate as a QKDN system 200 that realizes encrypted communications in a cloud system on a network.

[0185] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0186] (Additional Note) The above-described embodiments can be summarized as the following technical solutions.

[0187] Technical proposal 1 establishing encrypted tunnel communication with a second node, which is one of the first nodes, by using a first encryption key shared by quantum key distribution between the first nodes and adjacent first nodes, and a second encryption key that is encrypted and relayed to the second node, which is one of the first nodes; a processing unit that causes a network IF (Interface) unit to transfer a third encryption key to the second node through the encrypted tunnel communication; An information processing device comprising:

[0188] Technical proposal 2 the information processing device is one of the first nodes, the processing unit encrypts and relays the second encryption key to a first node adjacent to the information processing device by using a first encryption key shared with the first node adjacent to the information processing device; An information processing device according to technical proposal 1.

[0189] Technical proposal 3 The information processing device communicates with at least one application; the processing unit provides the third encryption key to the application. An information processing device according to technical proposal 1 or 2.

[0190] Technical proposal 4 The information processing device communicates with at least one first application; the processing unit generates encrypted data by encrypting plaintext data received from the first application with the third encryption key; causing the network IF unit to transfer the encrypted data to a second node; An information processing device according to technical proposal 1 or 2.

[0191] Technical proposal 5 the processing unit sends a first communication packet including data obtained by encrypting the third encryption key with the second encryption key, the first communication packet having a source address of the information processing device; encapsulating the second communication packet with the address of the second node as the destination; causing the network IF unit to transfer the second communication packet to the second node; An information processing device according to any one of technical proposals 1 to 4.

[0192] Technical plan 6 the processing unit requests the second node to establish the encrypted tunnel communication; Establishing an encrypted tunnel communication with the second node in response to a response from the second node; An information processing device according to any one of technical proposals 1 to 5.

[0193] Technical proposal 7 the processing unit, when receiving a request for establishing the encrypted tunnel communication from the second node, establishes the encrypted tunnel communication with the second node if the processing unit returns a response indicating approval to the second node. An information processing device according to any one of technical proposals 1 to 6.

[0194] Technical proposal 8 a memory unit that stores the first encryption key, the second encryption key, and the third encryption key; the processing unit establishes the encrypted tunnel communication when a storage amount of the second encryption key shared with the second node is greater than a first amount; If the storage amount is smaller than a second amount, terminating the encrypted tunnel communication. An information processing device according to any one of technical proposals 1 to 7.

[0195] Technical proposal 9 the processing unit controls establishment and termination of the encrypted tunnel communication with the second node in response to an instruction from a management device that controls establishment and termination of the encrypted tunnel communication. An information processing device according to any one of technical proposals 1 to 8.

[0196] Technical proposal 10 the processing unit establishes the encrypted tunnel communication when a requested amount per unit time of the third encryption key shared with the second node is greater than a first amount; If the requested amount is smaller than a second amount, terminating the encrypted tunnel communication. An information processing device according to any one of technical proposals 1 to 9.

[0197] Technical proposal 11 A plurality of first nodes including the information processing device according to any one of technical proposals 1 to 10 and the second node; generating the first encryption key by quantum key distribution; A plurality of quantum key distribution (QKD) devices each providing the generated first encryption key to any one of the plurality of first nodes; A first application that receives the third encryption key from the information processing device according to technical proposal 1 or 2; a second application that receives the third encryption key from the second node; A QKD network system comprising:

[0198] Technical proposal 12 An information processing device establishes encrypted tunnel communication with a second node, which is one of the first nodes, by using a first encryption key shared between the first nodes and adjacent first nodes through quantum key distribution, and a second encryption key that is encrypted and relayed to the second node, which is one of the first nodes; the information processing device transferring a third encryption key to the second node through the encrypted tunnel communication; An information processing method comprising:

[0199] Technical proposal 13 On the computer, establishing encrypted tunnel communication with a second node, which is one of the first nodes, by using a first encryption key shared by quantum key distribution between the first nodes and adjacent first nodes, and a second encryption key that is encrypted and relayed to the second node, which is one of the first nodes; transferring a third encryption key to the second node through the encrypted tunnel communication; program. [Explanation of symbols]

[0200] 1 KM 2. QKD 3. Applications 4 Management device 11 Processing section 12 Network Interface Section 13 Random Number Generator 14 Memory section 100 QKD 101 Crypto communication network 111 Control section 112 Tunnel establishment processing unit 113 Transfer Department 114 Encryption section (1st encryption section) 115 Decoding unit (first decoding unit) 116 2nd encryption section 117 Second Decoding Unit 301 Control device 302 Main storage 303 Auxiliary storage device 304 Display device 305 Input Device 306 Quantum Communication Interface 307 Classic Communication IF 310 Bus 401 Control device 402 Main storage 403 Auxiliary storage 404 Display device 405 Input Device 406 Communication Interface 410 Bus

Claims

1. establishing encrypted tunnel communication with a second node, the second node being one of the first nodes, by using a first encryption key shared by quantum key distribution between the first nodes adjacent to each other, and a second encryption key that is encrypted and relayed to the second node, the second encryption key being one of the first nodes; a processing unit that causes a network IF (Interface) unit to transfer a third encryption key to the second node through the encrypted tunnel communication; An information processing device comprising:

2. the information processing device is one of the first nodes, the processing unit encrypts and relays the second encryption key to the first node adjacent to the information processing device by using a first encryption key shared with the first node adjacent to the information processing device; The information processing device according to claim 1 .

3. The information processing device communicates with at least one application; the processing unit provides the third encryption key to the application.

3. The information processing device according to claim 1 or 2.

4. The information processing device communicates with at least one first application; the processing unit generates encrypted data by encrypting plaintext data received from the first application with the third encryption key; causing the network IF unit to transfer the encrypted data to the second node; 3. The information processing device according to claim 1 or 2.

5. the processing unit sends a first communication packet including data obtained by encrypting the third encryption key with the second encryption key, the first communication packet having a source address of the information processing device; encapsulating the second communication packet with the address of the second node as the destination; causing the network IF unit to transfer the second communication packet to the second node; 3. The information processing device according to claim 1 or 2.

6. the processing unit requests the second node to establish the encrypted tunnel communication; Establishing an encrypted tunnel communication with the second node in response to a response from the second node; 3. The information processing device according to claim 1 or 2.

7. the processing unit, when receiving a request for establishing the encrypted tunnel communication from the second node, returns a response indicating approval to the second node, and establishes the encrypted tunnel communication with the second node.

3. The information processing device according to claim 1 or 2.

8. a memory unit that stores the first encryption key, the second encryption key, and the third encryption key; the processing unit establishes the encrypted tunnel communication when a storage amount of the second encryption key shared with the second node is greater than a first amount; If the amount of storage is less than a second amount, terminating the encrypted tunnel communication.

3. The information processing device according to claim 1 or 2.

9. the processing unit controls establishment and termination of encrypted tunnel communication with the second node in response to an instruction from a management device that controls establishment and termination of the encrypted tunnel communication.

3. The information processing device according to claim 1 or 2.

10. the processing unit establishes the encrypted tunnel communication when a requested amount per unit time of the third encryption key shared with the second node is greater than a first amount; If the requested amount is smaller than a second amount, terminating the encrypted tunnel communication.

3. The information processing device according to claim 1 or 2.

11. A plurality of first nodes including the information processing device according to claim 1 or 2 and the second node; generating the first encryption key by quantum key distribution; a plurality of quantum key distribution (QKD) devices each providing the generated first cryptographic key to any one of the plurality of first nodes; a first application that receives the third encryption key from the information processing device according to claim 1; a second application that receives the third encryption key from the second node; A QKD network system comprising:

12. A step in which an information processing device establishes encrypted tunnel communication with a second node, which is one of the first nodes, by using a first encryption key shared between the first nodes and adjacent first nodes through quantum key distribution, and a second encryption key that is encrypted and relayed to the second node, which is one of the first nodes; the information processing device transferring a third encryption key to the second node through the encrypted tunnel communication; An information processing method comprising:

13. On the computer, establishing encrypted tunnel communication with a second node, which is one of the first nodes, by using a first encryption key shared by quantum key distribution between the first nodes adjacent to each other and a second encryption key that is encrypted and relayed to the second node, which is one of the first nodes; transferring a third encryption key to the second node through the encrypted tunnel communication; program.

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