Administrative system

Abstract

To manage a device apparatus so as to secure the security of communication.SOLUTION: An administrative system comprises: a device apparatus in which an SE having a secure storage region is provided; a KMS server that generates secret data; a relay server that relays a communication between the KMS server and the device apparatus; and an external server that generates a first encryption key used for encryption and a first decryption key used for decryption corresponding to the first encryption key. The first encryption key is notified to the KMS server, the first decryption key is written into the secure storage region of the SE provided in the device apparatus and is stored, the secret data for the device apparatus is generated, first encryption information obtained by encrypting the secret data by using the first encryption key is notified to the device apparatus via the relay server. The device apparatus receives the first encryption information via the relay server, and decodes the first encryption information received by using the first decryption key.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a management system. [Background technology]

[0002] In the field of IoT (Internet of Things), there is a system that aggregates measurement data measured by each of a plurality of devices in a server device. For example, Patent Document 1 discloses a technology for achieving both easy management of agent devices (devices) and security of data transfer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6389575 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a system, it is desirable to be able to manage communications between communication devices in a way that further enhances the security of the communications.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a management system capable of managing devices so as to ensure the security of communications. [Means for solving the problem]

[0006] The management system of the present invention includes a device device provided with an SE having a secure storage area, a KMS server that generates secret data used in communication performed by the device device, a relay server that relays communication between the KMS server and the device device, and an external server that generates a first encryption key used for encryption and a first decryption key used for decryption corresponding to the first encryption key, and notifies the KMS server of the first encryption key, writes and stores the first decryption key in a secure storage area of ​​the SE provided in the device device, the KMS server generates the secret data addressed to the device device, generates first encrypted information by encrypting the secret data using the first encryption key, and notifies the device device of the first encrypted information via the relay server, and the device device receives the first encrypted information via the relay server and decrypts the received first encrypted information using the first decryption key. Effect of the Invention

[0007] According to the present invention, devices can be managed so as to ensure the security of communications. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of the configuration of a management system 1 according to an embodiment. [Diagram 2] FIG. 4 is a diagram illustrating an example of information stored in a key management information storage unit 26 of the embodiment. [Diagram 3] 11 is a diagram illustrating an example of information stored in an SE 31 of the device 30 of the embodiment. FIG. [Figure 4] 4 is a sequence diagram showing a flow of processing performed by the management system 1 of the embodiment. FIG. [Diagram 5] 4 is a sequence diagram showing a flow of processing performed by the management system 1 of the embodiment. FIG. [Figure 6] 4 is a sequence diagram showing a flow of processing performed by the management system 1 of the embodiment. FIG. [Figure 7]FIG. 13 is a block diagram showing an example of the configuration of a management system 1 according to a modified example of the embodiment. [Figure 8] FIG. 11 is a sequence diagram showing a flow of processing performed by a management system 1 in a modified example of the embodiment. [Figure 9] FIG. 11 is a sequence diagram showing a flow of processing performed by a management system 1 in a modified example of the embodiment. [Figure 10] FIG. 11 is a sequence diagram showing a flow of processing performed by a management system 1 in a modified example of the embodiment. [Figure 11] FIG. 11 is a sequence diagram showing a flow of processing performed by a management system 1 in a modified example of the embodiment. [Figure 12A] 13 is a diagram showing an example of information stored in an SE13 of a relay server 10 in a modified example of the embodiment. FIG. [Figure 12B] 13 is a diagram showing an example of information stored in an SE13 of a relay server 10 in a modified example of the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] (Regarding Management System 1) 1 is a block diagram showing an example of the configuration of a management system 1 according to an embodiment. The management system 1 includes, for example, a relay server 10, a KMS server 20, a plurality of devices 30 (devices 30-1, 30-2, ... 30-N), and an external system 40. N is any natural number.

[0011] In the management system 1, the relay server 10, the KMS server 20, and the external system 40 are computers equipped with communication functions, and are communicatively connected via a communication network NW such as the Internet. The relay server 10 and the device 30 are communicatively connected by a wired communication means or a wireless communication means such as LPWA (Low Power Wide Area).

[0012] Furthermore, a plurality of relay servers 10 may be provided in the management system 1. In this case, a plurality of device units 30 are connected to each of the relay servers 10 so as to be able to communicate with each other via wired or wireless communication means.

[0013] The relay server 10 is a computer. The relay server 10 relays communication between the KMS server 20 and the device 30. A PC (personal computer) or the like can be applied as the relay server 10. The relay server 10 receives information (e.g., secret data described later) addressed to the device 30 from the KMS server 20, and transmits the received information to the device 30.

[0014] The KMS server 20 is a computer. An on-premise or cloud server device, a PC, etc. may be used as the KMS server 20. The KMS server 20, as a key management system, enables communication to be performed in the management system 1 using key information, for example, an encryption key EK (Encryption Key). The encryption key EK is, for example, a key used for encryption and decryption in a common key cryptosystem. The common key cryptosystem is an encryption system that uses the same key for encryption and decryption. The KMS server 20 encrypts private data with the encryption key EK, and transmits the encrypted private data together with a destination (a device UUID, described later) to the relay server 10.

[0015] The device 30 is a computer called a device equipped with a secure microcomputer or an IoT device. A PC may be applied as the device 30. The device 30 is equipped with an integrated circuit having a robust structure and tamper resistance that protects information from malicious attacks from the outside. Specifically, the device 30 includes a secure storage area (SE (Secure Element) 31 described later). The SE 31 corresponds to, for example, a SIM (Subscriber Identity Module), an eSIM (Embedded SIM), a TPM (Trusted Platform Module), an HSM (Hardware Security Module), or a SoC (System On Chip). An encryption key EK is stored in advance in the storage area of ​​the SE 31. The private data notified from the KMS server 20 is received via the relay server 10. The device 30 decrypts the received private data using the encryption key EK.

[0016] The external system 40 generates an encryption key EK. For example, the external system 40 generates a different encryption key EK for the relay server 10 or the device 30 connected to the relay server 10 in any group, for example, for each relay server 10, or for each part of the multiple device 30 connected to the relay server 10.

[0017] (Regarding relay server 10) Here, a description will be given of the relay server 10. As shown in Fig. 1, the relay server 10 includes, for example, a device ID generating unit 11 and a relay unit 12.

[0018] The device ID generating unit 11 generates a device ID. The device ID is identification information for identifying each of the devices 30 connected to the relay server 10. The device ID generating unit 11 generates a device ID according to the number (for example, N) of the devices 30 connected to the relay server 10. The device ID generating unit 11 transmits the generated device ID to the KMS server 20. The KMS server 20 generates a device UUID for uniquely identifying the device 30 for the device ID notified from the relay server 10, and transmits the correspondence between the device ID and the device UUID and the device UUID associated with the device ID to the relay server 10. The device ID generating unit 11 stores information indicating the correspondence between the device ID and the device UUID in a storage unit (not shown) of the relay server 10. The device ID generating unit 11 may be configured to obtain a device ID from outside by an input operation by a user (human). In this case, for example, the relay server 10 displays an input screen for inputting the device ID on a display unit (not shown). The input screen is provided with, for example, input fields for inputting device IDs according to the number of devices 30 connected to the relay server 10. The user inputs the device IDs in the input fields.

[0019] The relay unit 12 relays the secret data notified by the KMS server 20 to the device 30. For example, the relay unit 12 receives the secret data from the KMS server 20, identifies a device ID associated with the device UUID based on the device UUID indicated as the destination of the received secret data, and transmits the secret data to the device 30 corresponding to the identified device ID.

[0020] (About KMS Server 20) Here, a description will be given of the KMS server 20. As shown in Fig. 1, the KMS server 20 includes, for example, a front-end unit 21, a secret data generation unit 22, an encryption unit 23, a device UUID generation unit 24, a certificate generation unit 25, and a key management information storage unit 26.

[0021] The KMS server 20 may or may not include the front-end unit 21. Also, the function of a CA (Certificate Authority) corresponding to the certificate generation unit 25 may be provided outside the KMS server 20. In this case, the certificate generation unit 25 in the KMS server 20 can be omitted.

[0022] The front-end unit 21 is responsible for connecting the KMS server 20 to the outside. The front-end unit 21 includes, for example, a display that displays the results of processing performed by the KMS server 20 so that an external administrator can visually confirm them, and input devices such as a keyboard and a mouse that allow the administrator to select, edit, and set variables used in processing.

[0023] The private data generation unit 22 generates private data. The private data is data used for communication by the device 30 in the management system 1, and is data for operating the communication safely. For example, the private data is information indicating an authentication key, a signature verification key, a common key, a client certificate, a CA (Certification Authority) certificate, a server certificate, an authentication certificate, etc. The private data generation unit 22 generates private data in response to a request from the relay server 10, and outputs the generated private data to the encryption unit 23.

[0024] The encryption unit 23 manages the encryption key EK. For example, the encryption unit 23 manages the encryption key EK by registering, updating, deleting, or the like the encryption key EK notified from the outside (here, the external system 40) using an API (Application Programming Interface) or a Web API.

[0025] For example, when the external system 40 generates an encryption key EK, it transmits the generated encryption key EK to the KMS server 20 via the communication network NW. The KMS server 20 receives the encryption key EK notified from the external system 40 via a communication unit (not shown) of the KMS server 20 using an API or the like, and outputs the received encryption key EK to the encryption unit 23. In this way, the encryption unit 23 obtains the encryption key EK generated by the external system 40.

[0026] The encryption unit 23 encrypts the secret data generated by the secret data generation unit 22 using the encryption key EK. The encryption unit 23 acquires the secret data from the secret data generation unit 22. The encryption unit 23 acquires the encryption key EK by referring to the storage unit. The encryption unit 23 encrypts the secret data using the encryption key EK. The encryption unit 23 transmits the encrypted secret data (first encrypted data) and information with the device UUID attached to it to the relay server 10 via a communication unit (not shown) of the KMS server 20.

[0027] The device UUID generating unit 24 generates a device UUID. The device UUID is identification information that uniquely identifies the device 30. For example, the device UUID generating unit 24 generates a universally unique identifier (UUID) and assigns the generated UUID to the device UUID, thereby generating a unique device UUID that differs for each device 30. While the device ID is identification information that identifies each of the devices 30 connected to the relay server 10, the device UUID is information that uniquely identifies each of all the devices 30 in the management system 1. The device UUID generating unit 24 may generate a device UUID as identification information that uniquely identifies the relay server 10. This allows the KMS server 20 to manage the device 30 by the device UUID and to manage the relay server 10 by the device UUID.

[0028] The device UUID generation unit 24 acquires the device ID notified from the relay server 10. For example, the relay server 10 generates a device ID corresponding to each of the devices 30 connected to the relay server 10, and transmits the generated device ID to the KMS server 20. The KMS server 20 receives the device ID notified from the relay server 10 by a communication unit (not shown) of the KMS server 20, and outputs the received device ID to the device UUID generation unit 24. In this way, the device UUID generation unit 24 acquires the device ID notified from the relay server 10. The device UUID generation unit 24 generates a device UUID associated with the device ID notified from the relay server 10. The device UUID generation unit 24 transmits the generated device UUID to the relay server 10 as a device UUID associated with the device ID.

[0029] The certificate generating unit 25 functions as a CA (Certification Authority) and generates various electronic certificates in response to requests. For example, the certificate generating unit 25 acquires a public key of a key pair generated by an authentication source device (e.g., the device 30) to be authenticated. The certificate generating unit 25 uses the acquired public key to generate an electronic certificate for authentication in communication between the KMS server 20 and the authentication source device. The certificate generating unit 25 transmits the generated electronic certificate to the authentication source device via a communication unit (not shown) of the KMS server 20.

[0030] FIG. 2 is a diagram showing an example of information stored in the key management information storage unit 26 of the embodiment. The key management information storage unit 26 stores information for managing keys. As shown in FIG. 2, the key management information storage unit 26 stores information indicating, for example, the encryption key EK notified from the external system 40, the device ID and device UUID of the device 30 to which the encryption key EK is applied, and secret data generated for the device 30. In the example of this figure, it is shown that the device UUID (M00001) is associated with the relay server 10 identified by the device ID (1001). In this way, the relay server 10 may be given a device ID or associated with a device UUID as an example of a device. It is also shown that the encryption key EK identified by (EK105) is applied to the device 30 identified by the device ID (0001). It is also shown that the device UUID (010001) is associated with the device ID (0001).

[0031] The storage unit (including the key management information storage unit 26) of the KMS server 20 is configured by a storage medium such as a flash memory, an EEPROM (Electrically Erasable Programmable Read Only Memory), a RAM (Random Access read / write Memory), a ROM (Read Only Memory), or a combination of these. The storage unit of the KMS server 20 stores programs for executing various processes in the KMS server 20, and temporary data used when executing various processes.

[0032] In addition, the functional units (including the front-end unit 21, the secret data generation unit 22, the encryption unit 23, the device UUID generation unit 24, and the certificate generation unit 25) of the KMS server 20 are realized by having a CPU (Central Processing Unit) and / or a GPU (Graphics Processing Unit) that the KMS server 20 has as hardware execute a program.

[0033] (Regarding device 30) Here, the device 30 will be described. As shown in FIG. 1, the device 30 includes, for example, an SE 31. The SE 31 is an integrated circuit having a function for improving security of communication. The SE 31 includes a secure storage area. The secure storage area is a storage area configured to make it difficult for information stored in the storage area to be read or tampered with. The SE 31 may also include functions for improving security of communication, such as a function for authenticating a communication destination device, an encryption function, and a decryption function.

[0034] An encryption key EK is written and stored in the SE 31 in advance. For example, when the device is shipped from a factory, the encryption key EK generated by the external system 40 and notified to the KMS server 20 is transmitted to a manager at the factory. The manager at the factory writes and stores the encryption key EK notified from the external system 40 in the SE 31. The SE 31 with the encryption key EK written therein is incorporated into the device 30, whereby the device 30 is manufactured and shipped.

[0035] Furthermore, the SE31 acquires encrypted private data notified by the KMS server 20 and decrypts the encrypted private data. The KMS server 20 generates private data in response to a request from the device 30 or the like, encrypts the generated private data using the encryption key EK, and notifies the encrypted private data to the device 30 via the relay server 10. The device 30 decrypts the encrypted private data received via the relay server 10 using the encryption key EK.

[0036] The SE31 stores the decrypted private data in a secure storage area of ​​the SE31. Alternatively, the SE31 may re-encrypt the decrypted private data using an individual key KEK. The individual key KEK here is an individual encryption key that is different for each device 30. Here, the external system 40 generates an encryption key EK for each group, and an encryption key EK having the same information is written to each of the devices 30 in the group. For this reason, if the encryption key EK is leaked from the KMS server 20 or another device 30 in the same group for some reason, the possibility that the private data received by the device 30 will be stolen increases. In response to this, by re-encrypting the private data using the individual key KEK, the possibility that the private data will be stolen can be reduced even if the encryption key EK is leaked.

[0037] For example, the SE31 generates the individual key KEK. The SE31 may generate the individual key KEK by any method, for example, a key derivation function (KDF, Key Define Function) or the like can be used. The SE31 stores the generated individual key KEK in a secure storage area of ​​the SE31.

[0038] The SE31 re-encrypts the decrypted private data using the individual key KEK. The SE31 stores the private data re-encrypted with the individual key KEK. Here, the SE31 may store the private data re-encrypted with the individual key KEK in a normal storage area, i.e., a storage area that is not the secure storage area of ​​the SE31.

[0039] Fig. 3 is a diagram showing an example of information stored in the secure storage area of ​​SE31. As shown in Fig. 3, the secure storage area of ​​SE31 stores information corresponding to items such as an encryption key EK, decrypted private data, and an individual key. In the example of this figure, it is shown that an encryption key EK identified by (EK105) is written in the secure storage area of ​​SE31. It is also shown that decrypted private data (Data_a1) and an individual key (KEK01) generated by SE31 are stored in the secure storage area of ​​SE31.

[0040] In addition, "enc(Data_a1)EK105", which is the secret data encrypted with the encryption key EK, may be stored in a normal storage area of ​​the SE31 or the device 30. In addition, "enc(Data_a1)KEK01", which is the secret data re-encrypted with an individual key, may be stored in a normal storage area of ​​the E31 or the device 30.

[0041] (Processing flow performed by management system 1) Here, the flow of processing performed by the management system 1 of the embodiment will be described with reference to Fig. 4 to Fig. 6. Fig. 4 to Fig. 6 are sequence diagrams showing the flow of processing performed by the management system 1 of the embodiment.

[0042] In this embodiment, processing is carried out according to each of the following four scenes SN (scenes SN1 to SN4). Scene SN1: Writing the encryption key EK to SE31 Scene SN2: A scene in which the encryption key EK is registered with the KMS server 20 Scene SN3: KMS server 20 generates secret data Scene SN4: A scene in which the device 30 acquires secret data

[0043] FIG. 4 shows a process flow corresponding to scenes SN1 and SN2. First, in scene SN1, the external system 40 generates an encryption key EK (step S1). The external system 40 notifies the writing device 300 of the generated encryption key EK (step S2). The writing device 300 is a writer that writes information to the SE 31. The external system 40 notifies the manufacturer of the device 30 of the encryption key EK by using a notification means such as an email, or by storing the encryption key EK in a file sharing system or a portable storage medium such as a USB memory. The manufacturer of the device 30 sets the notified encryption key EK in the writing device 300. As a result, the encryption key EK is notified to the writing device 300. The writing device 300 writes and stores the encryption key EK in a secure storage area in the SE 31 of the device 30 (step S3). For example, a manufacturer of the device 30 connects the SE 31 to the writing device 300 and operates the writing device 300 to perform writing, thereby writing and storing the encryption key EK in a secure storage area in the SE 31.

[0044] Next, in scene SN2, the external system 40 and the KMS server 20 prepare for authentication (step S4). For example, the external system 40 generates a key pair for authentication, and transmits the public key of the generated key pair to the KMS server 20. The KMS server 20 generates an electronic certificate (public key certificate) for authentication, using the public key received from the external system 40. The KMS server 20 transmits the generated electronic certificate to the external system 40. The external system 40 stores the electronic certificate received from the KMS server 20 in a storage unit (not shown) of the external system 40. This completes preparation for authentication.

[0045] Any method may be adopted for notifying the KMS server 20 of the public key for authentication generated by the external system 40. For example, the external system 40 may notify the KMS server 20 via the communication network NW, or may notify the person in charge of the KMS server 20 of the public key using a notification means such as email.

[0046] Any method may be adopted for notifying the external system 40 of the electronic certificate generated by the KMS server 20. For example, the KMS server 20 may notify the external system 40 via the communication network NW, or may notify the person in charge of the external system 40 of the electronic certificate using a notification means such as email.

[0047] The external system 40 and the KMS server 20 perform authentication (step S5). For example, the external system 40 and the KMS server 20 perform authentication by PKI (Public Key Infrastructure) using the key pair and the electronic certificate generated in step S4. The authentication method may be authentication by TLS (Transport Layer Security), or authentication by SSL (Secure Sockets Layer), etc. Also, one-sided authentication or mutual authentication may be used. Also, if it is determined that the communication partner is a legitimate device as a result of the authentication, communication with the communication partner may be started, and encrypted communication may be performed with the communication partner. For example, if the authenticating device can authenticate that the communication partner is a legitimate device, it generates a session key and transmits the generated session key to the communication partner. The communication partner receives the session key, and transmits information encrypted using the received session key to the authenticating device. This allows encrypted communication using the session key to be performed.

[0048] The external system 40 transmits the encryption key EK to the KMS server 20 in accordance with the result of the authentication (step S6). For example, if the external system 40 determines as a result of the authentication that the KMS server 20 is a legitimate device, it transmits the encryption key EK to the KMS server 20 and requests it to register the encryption key EK. The KMS server 20 stores the encryption key EK received from the external system 40 in the storage unit of the KMS server 20 (step S7). As a result, the encryption key EK is registered in the KMS server 20.

[0049] 5 shows a process flow corresponding to scene SN3. Scene SN3 is made up of scene SN30 and scene SN31. Scene SN30 is a process performed when a new device is registered, that is, when a new device 30 is added to the management system 1, a device ID is assigned to the added device 30, and a device UUID is associated with the device 30. Scene SN31 is a process performed when secret data is generated for a device 30 to which a device ID and a device UUID have already been assigned.

[0050] First, in scene SN30, the KMS server 20 and relay server 10 prepare for authentication (step S8). The process flow for preparing for authentication is the same as that of step S4. That is, the relay server 10 generates a key pair for authentication and transmits the public key of the generated key pair to the KMS server 20. The KMS server 20 generates an electronic certificate for authentication (public key certificate) using the public key received from the relay server 10. The KMS server 20 transmits the generated electronic certificate to the relay server 10. The relay server 10 stores the electronic certificate received from the KMS server 20 in a storage unit (not shown) of the relay server 10. This completes the preparation for authentication.

[0051] Any method may be adopted for notifying the KMS server 20 of the public key for authentication generated by the relay server 10. For example, the external system 40 may notify the KMS server 20 via the communication network NW, or the public key may be notified to a person in charge of the KMS server 20 using a notification means such as email.

[0052] Any method may be adopted for notifying the relay server 10 of the digital certificate generated by the KMS server 20. For example, the KMS server 20 may notify the external system 40 via the communication network NW, or may notify the person in charge of the relay server 10 of the digital certificate by using a notification means such as email.

[0053] The relay server 10 generates a device ID (step S9). The relay server 10 generates a device ID to identify each of the devices 30 that it relays, i.e., the devices 30 connected to the relay server 10. For example, when N devices 30 (30-1 to 30-N) are connected to the relay server 10, the relay server 10 generates N device IDs that are different from each other.

[0054] The relay server 10 and the KMS server 20 associate the device ID with the device UUID (step S10). The relay server 10 and the KMS server 20 perform authentication. For example, the relay server 10 and the KMS server 20 perform authentication by PKI using the key pair and the electronic certificate generated in step S8. If the relay server 10 determines that the KMS server 20 is a legitimate device as a result of the authentication, the relay server 10 transmits the device ID to the KMS server 20 and requests that it associate the device ID with the device UUID. The KMS server 20 generates a device UUID according to the device ID received from the relay server 10. The KMS server 20 associates the generated device UUID with the device ID and stores it in the storage unit of the KMS server 20. The KMS server 20 transmits information associating the device ID with the device UUID to the relay server 10. As a result, the device ID is associated with the device UUID.

[0055] On the other hand, in the scene SN31, when the relay server 10 generates secret data for the device 30 according to the status of the device 30, the relay server 10 and the KMS server 20 perform authentication (step S11). For example, the relay server 10 and the KMS server 20 perform authentication by PKI using the key pair and the electronic certificate generated in step S8. When the relay server 10 determines that the KMS server 20 is a legitimate device as a result of the authentication, the relay server 10 transmits to the KMS server 20 the device UUID of the device 30 and information indicating the type of secret data to be generated, and notifies the KMS server 20 to generate secret data (step S12). In response to the request from the relay server 10, the KMS server 20 generates secret data (step S13) and encrypts the generated secret data using the encryption key EK (step S14). The KMS server 20 transmits the secret data encrypted with the encryption key EK to the relay server 10 (step S15).

[0056] In step S12, the relay server 10 may notify the KMS server 20 to generate each of the multiple pieces of secret data. By the relay server 10 collectively managing the devices 30 connected to itself, each device 30 does not need to individually request the KMS server 20 to generate secret data. This makes it possible to reduce the processing load of the devices 30.

[0057] FIG. 6 shows a process flow corresponding to scene SN4. First, the relay server 10 and the device 30 prepare for authentication (step S16). The relay server 10 and the device 30 perform an authentication method that does not use an electronic certificate, for example, challenge-and-response authentication. In this case, the relay server 10 and the device 30 store encryption information, for example, the same key information or password, used to authenticate the other device in advance. The encryption information here may be generated by any method. For example, the KMS server 20 generates encryption information, and the generated encryption information is stored in the relay server 10 in advance by an input operation by a user (human). Also, the encryption information is stored in the device 30 when the device is manufactured. This completes the preparation for authentication. Note that, in step S16, authentication using an electronic certificate may be performed, but since the relay server 10 often does not have a function for generating an electronic certificate, in this case, instead of the relay server 10, the KMS server 20 generates an electronic certificate used for authentication between the device 30 and the relay server 10.

[0058] The relay server 10 and the device 30 perform authentication (step S17). For example, the device 30 transmits a challenge code CC to the relay server 10. The challenge code CC may be any information. For example, the device 30 generates a random number and transmits the generated random number to the relay server 10 as the challenge code CC. When the device 30 receives the challenge code CC from the relay server 10, it encrypts the received challenge code CC using encryption information held in advance. Any method can be used for the encryption here. For example, the device 30 encrypts the challenge code CC by generating a hash value using the challenge code CC and the encryption information. The device 30 transmits the encrypted challenge code CC to the relay server 10 as a response to the challenge code CC. When the relay server 10 receives a response from the device 30, it decrypts the received response using encryption information held in advance. The decryption here is a method corresponding to the encryption performed by the device 30. For example, the relay server 10 generates a hash value using the challenge code CC and the encryption information. If the generated hash value matches the hash value received as a response, the relay server 10 determines that the device 30 is an authorized device. In the above, a case has been described in which the relay server 10 performs "one-sided authentication" to authenticate the device 30. In the above, if the device 30 can be authenticated as a legitimate device, the device 30 may perform "mutual authentication" by authenticating the relay server 10 using a similar method. Also, if the communication counterpart can be authenticated as a legitimate device, encrypted communication is performed in subsequent communication. For example, if the authenticating device can authenticate the communication counterpart as a legitimate device, it generates a session key and transmits the generated session key to the communication counterpart. The communication counterpart receives the session key and transmits information encrypted using the received session key to the authenticating device. This enables encrypted communication using the session key. If the relay server 10 determines that the device 30 is a legitimate device as a result of the authentication, it transmits private data encrypted with the encryption key EK to the device 30 (step S18). At this time, the relay server 10 transmits the device ID corresponding to the device 30 to the device 30 together with the private data encrypted with the encryption key EK. This allows the device 30 to be assigned the device ID generated by the relay server 10.

[0059] The device device 30 stores the device ID notified from the relay server 10 in the storage unit (step S19). Here, the storage area in which the device ID is stored may be a secure storage area or a normal storage area. The device device 30 decrypts the secret data encrypted with the encryption key EK (step S20). The device device 30 generates an individual key KEK and stores the generated individual key KEK in the secure storage area of ​​the SE31 (step S21). The device device 30 re-encrypts the decrypted secret data using the individual key KEK (step S22). The device device 30 stores the re-encrypted secret data in the storage unit. Here, the storage area in which the re-encrypted secret data is stored may be a secure storage area or a normal storage area.

[0060] In the above embodiment, the case where the external system 40 generates the encryption key EK has been described as an example. However, this is not limited to this. In the management system 1, a system or device other than the external system 40, for example, the KMS server 20, may be configured to generate the encryption key EK.

[0061] In the above-described embodiment, the encryption key EK is a common key. However, the encryption key EK is not limited to a common key. The encryption key EK may be any encryption key that can be used for encryption and decryption. For example, the encryption key EK may be a set of encryption key and decryption key. In this case, the external system 40 generates information of a set of EKenc used for encryption and EKdec used for decryption as the encryption key EK. The external system 40 notifies the KMS server 20 of the EKenc used for encryption. The external system 40 writes and stores the EKdec used for decryption in a secure storage area in the SE31 of the device 30.

[0062] As described above, the management system 1 of the embodiment includes the device device 30, the KMS server 20, the relay server 10, and the external system 40. The device device 30 is provided with an SE31 having a secure storage area. The KMS server 20 generates secret data for keeping the device device 30 secret. The relay server 10 relays communication between the KMS server 20 and the device device 30. The external system 40 generates an encryption key EK (a first encryption key used for encryption). The management system 1 writes and stores the encryption key EK (a first decryption key used for decryption corresponding to the first encryption key) in a secure storage area of ​​the SE31 provided in the device device 30. The management system 1 notifies the KMS server 20 of the encryption key EK (the first encryption key). The KMS server 20 generates secret data addressed to the device device 30. The KMS server 20 encrypts the generated private data using an encryption key EK (first encryption key) to generate private data encrypted with the encryption key EK (first encrypted information). The KMS server 20 notifies the device 30 of the private data encrypted with the encryption key EK (first encrypted information) via the relay server 10. The device 30 receives the private data encrypted with the encryption key EK (first encrypted information) via the relay server 10. The device 30 decrypts the received private data encrypted with the encryption key EK (first encrypted information) using the encryption key EK (first decryption key).

[0063] As a result, in the management system 1 of the embodiment, the secret data can be encrypted with the encryption key EK and then notified to the device 30. This reduces the possibility that the secret data will be intercepted during transmission. Furthermore, in the device 30, the encryption key EK for decryption is written to a secure storage area. This reduces the possibility that the encryption key EK will be leaked to the outside. This allows the secret data to be safely notified to the device 30, and the device can be managed so that the security of communication is ensured.

[0064] In the management system 1 of the embodiment, the relay server 10 generates a device ID (ID for identifying the device 30 that it relays). The relay server 10 notifies the KMS server 20 of the generated device ID. The KMS server 20 generates a device UUID for uniquely identifying the device 30 based on the device ID notified from the relay server 10. The KMS server 20 notifies the relay server 10 of the generated device UUID. When the KMS server 20 generates secret data, the KMS server 20 notifies the relay server 10 of information in which the device UUID is added to the secret data (first encryption information) encrypted with the encryption key EK. The device 30 transmits the corresponding device ID and the secret data (first encryption information) encrypted with the encryption key EK to the device 30 corresponding to the device UUID included in the information received from the KMS server 20. The device 30 stores the device ID included in the information received from the relay server 10 as the device ID assigned to itself.

[0065] As a result, the relay server 10 can make the KMS server 20 generate a device UUID corresponding to the device ID, and even if duplicate device IDs are generated in multiple relay servers 10, it is possible to uniquely identify each of the devices 30 by associating the device UUIDs. Furthermore, even if the KMS server 20 does not know the detailed situation such as which device 30 is connected to which relay server 10, it can uniquely identify each of the devices 30 for which secret data needs to be generated in the management system 1. Therefore, it is possible to correctly generate desired secret data to be used for the desired device 30.

[0066] Moreover, in the management system 1 of the embodiment, the encryption key EK (first encryption key and first decryption key) is a common key used for encryption and decryption in a common key cryptosystem. The same encryption key EK (common key) is written and stored in a plurality of device units 30. As a result, in the management system 1 of the embodiment, the key information used for encryption and decryption can be made common using the common key cryptosystem, and it is possible to reduce the effort of key management compared to managing keys for encryption and decryption separately. Moreover, it is only necessary to write the same encryption key EK to the SE31, and there is no need to write individual keys. This makes it possible to reduce the effort of writing.

[0067] Furthermore, in the management system 1 of the embodiment, the KMS server 20 generates secret data based on a request from the relay server 10. The relay server 10 issues a notification requesting the KMS server 20 to generate secret data to be used for the corresponding device 30 by specifying a device UUID. As a result, in the management system 1 of the embodiment, the relay server 10 can collectively manage the generation of secret data to be used for the device 30 connected thereto. As a result, it is not necessary for each device 30 to individually request the KMS server 20 to generate secret data. This makes it possible to reduce the processing load of the device 30.

[0068] In the management system 1 of the embodiment, the device unit 30 generates an individual key KEK (first individual key used for encryption). The device unit 30 stores the generated individual key KEK (first individual key) in a secure storage area of ​​the SE31 provided in the device unit 30. The device unit 30 re-encrypts the secret data decrypted using the EK (second key information) using the individual key KEK (first individual key). In this way, the management system 1 of the embodiment can re-encrypt using the individual key and safely store the secret data. By changing the secret data encrypted using the encryption key EK and storing the re-encrypted secret data using the individual key, even if the encryption key EK is leaked, the possibility that the secret data will be decrypted and intercepted by a third party can be reduced.

[0069] (Modification of the embodiment) Here, a modified example of the embodiment will be described. This modified example differs from the above-mentioned embodiment in that the relay server 10 includes an SE, and that secret data is encrypted using an individual key KEK2 that differs for each device 30 instead of the encryption key EK. In the following description, the differences from the above-mentioned embodiment will be mainly described, and the same reference numerals will be used to denote the same points as the above-mentioned embodiment, and the description thereof will be omitted.

[0070] Fig. 7 is a block diagram showing a configuration example of a management system 1 in a modified example of the embodiment. As shown in Fig. 7, the relay server 10 of the management system 1 includes an SE 13. The SE 13 has a configuration equivalent to that of the SE 31. That is, the SE 13 is an integrated circuit having a robust structure that protects information from malicious attacks from the outside and is tamper-resistant, and includes a secure storage area. The SE 13 corresponds to, for example, a SIM, an eSIM, a TPM, an HSM, or an SoC.

[0071] 8 to 11 are sequence diagrams showing the flow of processes performed by the management system 1 in the modified example of the embodiment.

[0072] Fig. 8 shows a process flow corresponding to scenes SN1 and SN2. The processes shown in steps S101 to S107 in Fig. 8 are similar to steps S1 to S7 in Fig. 4. Therefore, the description thereof will be omitted.

[0073] 9 shows a process flow corresponding to scene SN3. This differs from the above-described embodiment in that authentication is performed using the SE13 included in the relay server 10, and that an individual key individual to the device 30 is generated by the KMS server 20.

[0074] First, the KMS server 20 and the relay server 10 perform authentication using the SE 13 of the relay server 10 (step S108). The flow of the authentication process is the same as that of step S5. The processes shown in steps S109 to S110 are the same as those shown in steps S9 to S10, in which a device ID is generated and the generated device ID is associated with a device UUID.

[0075] Here, the KMS server 20 performs a process of registering the individual key KEK2 in the device 30 (step S111). The individual key KEK2 here is key information used to encrypt private data when notifying the device 30 via the relay server 10, and is key information that differs for each device 30 that is the notification destination. The process of the relay server 10 registering the individual key KEK2 will be described in detail later.

[0076] On the other hand, in scene SN31, when the relay server 10 generates private data for the device 30, the relay server 10 and the KMS server 20 perform authentication (step S112). The process shown in step S112 is equivalent to step S5.

[0077] If the relay server 10 determines that the KMS server 20 is a legitimate device as a result of the authentication, it notifies the KMS server 20 of a request to generate secret data (step S113). The KMS server 20 generates secret data in response to the request from the relay server 10 (step S114), and encrypts the generated secret data using the individual key KEK2 corresponding to the device 30 to which the notification is to be sent (step S115). The KMS server 20 transmits the secret data encrypted with the individual key KEK2 to the relay server 10 (step S116).

[0078] 10 shows a process flow corresponding to scene SN4. First, the relay server 10 and the device 30 prepare for authentication (step S117) and perform authentication (step S118). The process flow for preparing for authentication and performing authentication is the same as steps S17 to S18.

[0079] When the relay server 10 determines that the device 30 is a valid device as a result of the authentication, the relay server 10 transmits the private data encrypted with the individual key KEK2 to the device 30 (step S119). The device 30 stores the device ID notified from the relay server 10 in the storage unit (step S120). The device 30 decrypts the private data encrypted with the individual key KEK2 (step S121). The device 30 generates the individual key KEK and stores the generated individual key KEK in a secure storage area of ​​the SE31 (step S122). The device 30 re-encrypts the private data decrypted in step S121 using the individual key KEK (step S123). The device 30 stores the re-encrypted private data in the storage unit. Here, the storage area in which the re-encrypted private data is stored may be a secure storage area or a normal storage area.

[0080] FIG. 11 shows the flow of the process corresponding to step S111, that is, the process in which the KMS server 20 registers the individual key KEK2.

[0081] First, the relay server 10 and the KMS server 20 perform authentication and perform encrypted communication using a session key (step S130). The flow of the authentication process is the same as that of step S105. If the relay server 10 determines that the KMS server 20 is a valid device as a result of the authentication, it generates a session key and transmits it to the KMS server 20, and performs subsequent communication by encrypted communication using the session key. The relay server 10 sends a notification requesting the KMS server 20 to generate an individual key for each device 30 (step S131).

[0082] The KMS server 20 generates the pre-individual key KEK2_a in response to the request from the relay server 10 (step S132). The pre-individual key KEK2_a is information that serves as a parameter for generating the individual key KEK2. Any method may be adopted as a method for generating the pre-individual key KEK2_a. For example, a HASH value may be calculated from a combination of a device ID and a random number, and a specific number of bytes at the beginning of the calculated HASH value may be set as the pre-individual key KEK2_a. As the HASH value applied here, SHA (Secure Hash Algorithm) 256, SHA512, or the like may be applied. The KMS server 20 encrypts the generated pre-individual key KEK2_a using the encryption key EK (step S133).

[0083] The KMS server 20 generates the individual key KEK2 (step S134). The KMS server 20 generates the individual key KEK2 by executing a specific algorithm using the encryption key EK and the pre-individual key KEK2_a. The specific algorithm here may be set arbitrarily, but is an algorithm that can be shared between the KMS server 20 and the device 30. For example, the individual key KEK2 can be information obtained by sequentially combining the encryption key EK and the pre-individual key KEK2_a. The KMS server 20 stores the generated individual key KEK2 in a storage unit of the KMS server 20.

[0084] The KMS server 20 transmits the pre-individual key KEK2_a encrypted with the encryption key EK to the relay server 10 (step S135). The relay server 10 relays the pre-individual key KEK2_a encrypted with the encryption key EK received from the KMS server 20, and transmits it to the device 30 (step S136).

[0085] The device apparatus 30 decrypts the pre-individual key KEK2_a, which has been encrypted with the encryption key EK and received via the relay server 10, using the encryption key EK stored in the SE31 to obtain the pre-individual key KEK2_a (step S137). The device apparatus 30 generates the individual key KEK2 by executing a specific algorithm using the encryption key EK and the pre-individual key KEK2_a stored in the SE31. The specific algorithm here is an algorithm equivalent to the algorithm used by the KMS server 20 to generate the individual key KEK2. The device apparatus 30 stores the generated individual key KEK2 in a secure storage area of ​​the SE31 (step S138).

[0086] Furthermore, the device apparatus 30 generates an individual key KEK3. The individual key KEK3 is key information for re-encrypting data received from the KMS server 20 or the device apparatus 30, similar to the individual key KEK. As a method for generating the individual key KEK3, the device apparatus 30 can use a key derivation function (KDF, Key Define Function) or the like, similar to the individual key KEK. The individual key KEK3 may be the same key information as the individual key KEK, or may be different key information. The device apparatus 30 stores the generated individual key KEK3 in a secure storage area of ​​the SE31 (step S139).

[0087] On the other hand, the relay server 10 generates an individual key KEK4. The individual key KEK4 is key information for re-encrypting data received by the relay server 10. The relay server 10 stores the generated individual key KEK4 in a secure storage area of ​​the SE 13 (step S140). The relay server 10 transmits the device UUID to the KMS server 20, and requests the KMS server 20 to generate an individual key KEK5 to be used for communication between the relay server 10 and the device unit 30 corresponding to the device UUID (step S141).

[0088] The KMS server 20 generates an individual key KEK5 in response to the request from the relay server 10 (step S142). Any method may be adopted as a method for generating the individual key KEK5. For example, the KMS server 20 generates the individual key KEK5 using a HASH value calculated from a combination of the device UUID and a random number. The KMS server 20 encrypts the generated individual key KEK5 using the individual key KEK2 generated for the device unit 30 corresponding to the notified device UUID (step S143).

[0089] The KMS server 20 transmits the individual key KEK5 encrypted using the individual key KEK2 and the individual key KEK5 itself to the relay server 10 (step S144). Here, in step S130, the relay server 10 and the KMS server 20 perform authentication and then perform encrypted communication using the session key. Therefore, the information that the KMS server 20 transmits to the relay server 10 (here, the individual key KEK5 encrypted using the individual key KEK2 and the individual key KEK5 itself) is encrypted using the session key.

[0090] Of the information received from the KMS server 20 (individual key KEK5 encrypted using individual key KEK2 and individual key KEK5 itself), the relay server 10 decrypts individual key KEK5 itself using the session key, then re-encrypts it with individual key KEK4, and stores individual key KEK5 re-encrypted with individual key KEK4 in a secure memory area of ​​SE13 (step S145).

[0091] The relay server 10 relays the individual key KEK5 encrypted using the individual key KEK2 received from the KMS server 20, and transmits it to the device apparatus 30 (step S146). More specifically, the relay server 10 decrypts the information to be relayed to the device apparatus 30 (individual key KEK5 encrypted using the individual key KEK2) among the information received from the KMS server 20 (individual key KEK5 encrypted using the individual key KEK2 and the individual key KEK5 itself), using the session key, and transmits the decrypted information (individual key KEK5 encrypted using the individual key KEK2) to the device apparatus 30.

[0092] The device apparatus 30 decrypts the individual key KEK5, which has been encrypted using the individual key KEK2 and received via the relay server 10, using the individual key KEK2 stored in the SE31 to obtain the individual key KEK5 (step S147). The device apparatus 30 re-encrypts the individual key KEK5 using the individual key KEK3 stored in the SE31 to generate the individual key KEK5 re-encrypted using the individual key KEK3. The device apparatus 30 stores the generated individual key KEK5 re-encrypted using the individual key KEK3 in a secure storage area of ​​the SE31 (step S148).

[0093] Here, in step S140, the relay server 10 may divide the multiple devices 30 connected to the relay server 10 into several groups and generate an individual key KEK4 for each group. In this case, in step S145, the relay server 10 re-encrypts the individual key KEK5 with the individual key KEK4 for each group, and stores the re-encrypted individual key KEK5 in a secure storage area of ​​the SE13.

[0094] Fig. 12 (Fig. 12A and Fig. 12B) is a diagram showing an example of information stored in a secure storage area of ​​the SE13 in the relay server 10. Fig. 12A shows an example in which the devices 30 connected to the relay server 10 are not divided into groups. Fig. 12B shows an example in which the devices 30 connected to the relay server 10 are divided into three groups (groups GR01 to GR03).

[0095] As shown in the upper part of Fig. 12A, for example, information corresponding to individual key KEK4 (denoted as "KEK" in the example of Fig. 12A) is stored in the secure storage area of ​​SE13. In the example of this figure, it is shown that (F1l511...) is stored as individual key KEK4.

[0096] Also, as shown in the lower part of Fig. 12A, the secure storage area of ​​SE13 or the storage unit (normal storage area) of relay server 10 stores information corresponding to items such as the device ID and individual key KEK5 (relay SV-device authentication key in the example of Fig. 12A). In the example of this figure, it is shown that information obtained by encrypting individual key KEK5 generated for device ID (iot01) with individual key KEK4 (F1l511...) is (s5aogv...). Also, it is shown that information obtained by encrypting individual key KEK5 generated for device ID (pc02) with individual key KEK4 (F1l511...) is (wr2fg...).

[0097] As shown in the upper part of Fig. 12B, the secure storage area of ​​SE13 stores, for example, information corresponding to an individual key KEK4 for each group (denoted as "KEK" in the example of Fig. 12B). In the example of this figure, it is shown that (f1511a...) is stored as the individual key KEK4 generated for group ID (GR01). It is also shown that (7manda...) is stored as the individual key KEK4 generated for group ID (GR02).

[0098] As shown in the lower part of Figure 12B, the secure memory area of ​​SE13 or the memory unit (normal memory area) of relay server 10 stores information corresponding to items such as group ID, device ID, and individual key KEK5 (in the example of Figure 12B, relay SV-device authentication key).

[0099] In the example of this figure, it is shown that the information obtained by encrypting the individual key KEK5 generated for the device ID (iot01) belonging to the group ID (GR01) with the individual key KEK4 (f1511a...) is (s5aogv...). It is also shown that the information obtained by encrypting the individual key KEK5 generated for the device ID (ito02) belonging to the group ID (GR01) with the individual key KEK4 (f1511a...) is (f7mnv...). It is also shown that the information obtained by encrypting the individual key KEK5 generated for the device ID (pc02) belonging to the group ID (GR02) with the individual key KEK4 (7manda...) is (wr2fg...).

[0100] As described above, in the management system 1 according to the modified example of the embodiment, the encryption key EK is a common key. The KMS server 20 generates an individual key KEK2 (second individual key). The individual key KEK2 is an individual key that differs for each device device 30. The KMS server 20 generates the individual key KEK2 by executing a specific algorithm using a pre-individual key KEK2_a generated individually for each device device 30 and the encryption key EK. The KMS server 20 generates second encrypted information by encrypting the pre-individual key KEK2_a using the encryption key EK. The KMS server 20 notifies the device device 30 of the second encrypted information via the relay server 10. The device device 30 receives the second encrypted information via the relay server 10. The device device 30 decrypts the received second encrypted information using the encryption key EK, and generates the individual key KEK2 by executing a specific algorithm using the decrypted pre-individual key KEK2_a and the encryption key EK. The device 30 stores the individual key KEK2 in a secure storage area of ​​the SE31. The KMS server 20 generates secret data addressed to the device 30, and generates third encrypted information by encrypting the secret data using the individual key KEK2. The KMS server 20 notifies the device 30 of the third encrypted information via the relay server 10. The device 30 receives the third encrypted information via the relay server 10. The device 30 decrypts the received third encrypted information using the individual key KEK2.

[0101] As a result, in the management system 1 according to the modified embodiment, the secret data can be encrypted using an individual key KEK2 that differs for each device 30. Therefore, it is possible to manage the devices so as to ensure the security of communication.

[0102] The management system 1 in the above-mentioned embodiment may be realized in whole or in part by a computer. In that case, a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the function. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also include a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in that case. The above-mentioned program may be a program for realizing a part of the above-mentioned function, or may be a program that can realize the above-mentioned function in combination with a program already recorded in the computer system, or may be a program that is realized using a programmable logic device such as an FPGA.

[0103] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included. [Explanation of symbols]

[0104] 1. Management system 10…Relay server 11...Device ID generation section 20…KMS server 22...Secret data generation section 23...Encryption section 24…Device UUID generation section 30...Device equipment 31…SE 40…External system

Claims

1. A device provided with an SE having a secure storage area; A KMS server that generates secret data used in communication by the device; A relay server that relays communication between the KMS server and the device; an external server that generates a first encryption key used for encryption and a first decryption key used for decryption corresponding to the first encryption key; Equipped with storing the first encryption key in the KMS server and storing the first decryption key in a secure storage area of ​​the SE provided in the device; the KMS server generates the secret data addressed to the device, generates first encrypted information by encrypting the secret data using the first encryption key, and notifies the device of the first encrypted information via the relay server; the device receives the first encrypted information via the relay server, and decrypts the received first encrypted information using the first decryption key. Management system.

2. The relay server generates a device ID for identifying the device that it relays, and notifies the KMS server of the generated device ID; The KMS server generates a device UUID that uniquely identifies the device based on the device ID, and notifies the relay server of the generated device UUID; When the KMS server generates the secret data, the KMS server notifies the relay server of information in which the first encrypted information is added with the device UUID; The relay server transmits the corresponding device ID and the first encrypted information to the device device corresponding to the device UUID included in the information received from the KMS server; The device stores the device ID included in the information received from the relay server as the device ID assigned to the device. The management system according to claim 1 .

3. the first encryption key and the first decryption key are common keys used for encryption and decryption in a common key cryptosystem, and the same common key is applied to the multiple devices; The management system according to claim 1 .

4. The KMS server generates the secret data based on a request from the relay server; The relay server issues a notification to the KMS server requesting the KMS server to generate the secret data to be used for the corresponding device by specifying the device UUID. The management system according to claim 2.

5. The device comprises: generating a first individual key to be used for encryption, and storing the generated first individual key in a secure storage area of ​​the SE provided therein; re-encrypting the secret data decrypted using the first decryption key using the first individual key; The management system according to claim 1 .

6. the first encryption key and the first decryption key are common keys used for encryption and decryption in a common key cryptosystem, The KMS server generates a second individual key by executing a specific algorithm using a pre-individual key generated individually for each of the devices and the common key, generates second encryption information by encrypting the pre-individual key using the common key, and notifies the device of the second encryption information via the relay server; the device receives the second encrypted information via the relay server, decrypts the received second encrypted information using the common key, executes the algorithm using the decrypted pre-individual key and the common key to generate the second individual key, and writes and stores the second individual key in a secure storage area of ​​the SE; The communication between the KMS server and the device is performed using the second individual key. The management system according to claim 1 .

7. the KMS server generates the secret data addressed to the device, generates third encrypted information by encrypting the secret data using the second individual key, and notifies the device of the third encrypted information via the relay server; The device receives the third encrypted information via the relay server, and decrypts the received third encrypted information using the second individual key. The management system according to claim 6.

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