Portable device, management server, management system, decryption method, key management method and program

Abstract

We provide technology that contributes to improving the security of shared keys used to encrypt confidential information. [Solution] A portable device comprising an internal memory unit that stores an encrypted encryption key obtained by encrypting an encryption key with an embedded key, a removable external memory unit that stores an encrypted common key obtained by encrypting a common key with the encrypted encryption key, a reading unit that reads confidential information encrypted with the common key, and a decryption unit that decrypts the confidential information with the common key, wherein the decryption unit decrypts the encrypted common key with the encrypted encryption key to obtain the common key used when decrypting the confidential information.

Description

[Technical field]

[0001] The present disclosure relates to a portable device, a management server, a management system, a decryption method, a key management method, and a program. [Background technology]

[0002] There is a system in which information stored in a non-contact IC card is read by two devices located at separate locations, and the user's actions are restricted. For example, in Patent Document 1, an entrance / exit management device creates a common key and transmits it to a copy machine. When a user enters or leaves a facility, the entrance / exit management device reads information from the non-contact IC card, and if the information contains entry authority information, it encrypts the information with a common key to create encrypted information and overwrites the information on the non-contact IC card. A user who has the entry authority enters a room and has the IC card reader / writer of the copy machine read the non-contact IC card. The copy machine attempts to decrypt the read information based on the common key previously obtained from the entrance / exit management device. Then, the copy machine controls the usage of the copy machine based on the result of the decryption, thereby preventing unauthorized use. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-033437 A Summary of the Invention [Problem to be solved by the invention]

[0004] The following analysis was performed by the inventors of the present disclosure.

[0005] According to the technology disclosed in Patent Document 1, it is necessary to transmit the common key created by the entrance / exit management device outside the room to the copy machine inside the room and store it in the copy machine. In other words, the common key needs to be held by the entrance / exit management device and the copy machine. If either one of them is illegally accessed or the device itself is stolen, the common key may be leaked, which is not a sufficient security measure.

[0006] The present disclosure has been made in consideration of the above circumstances, and has as one of its objectives to provide a technique that contributes to improving the security of a common key used to encrypt confidential information. [Means for solving the problem]

[0007] According to a first aspect of the present disclosure, a built-in storage unit for storing an encrypted encryption key obtained by encrypting an encryption key with an embedded key; a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encryption key; a reading unit that reads confidential information encrypted with the common key; a decryption unit that decrypts the confidential information using the common key; an authentication unit that performs authentication using the decrypted confidential information; an output unit that outputs a signal according to a result of the authentication; Equipped with The decryption section may be a portable device that decrypts the encrypted common key with the encrypted encryption key to obtain the common key used for decrypting the confidential information.

[0008] According to a second aspect of the present disclosure, an encryption key generation unit that generates an encryption key; a key encryption unit that encrypts a key used for encryption; a server storage unit that stores an embedded key; A server communication unit that transmits and receives a key to and from an external device, The key encryption unit When the encryption key is generated, the encryption key is encrypted with the embedded key to generate an encrypted encryption key, and the encrypted encryption key is transmitted to the external device via the server communication unit; A management server is provided which, upon obtaining the common key, obtains the encrypted encryption key from the external device, encrypts the common key with the encrypted encryption key to generate an encrypted common key, stores the encrypted common key in the server memory unit, and transmits the encrypted common key to the external device via the server communication unit.

[0009] According to a third aspect of the present disclosure, A management system including a management server and a portable device, The management server includes: an encryption key generation unit that generates an encryption key; a key encryption unit that encrypts a key used for encryption; a server storage unit that stores an embedded key; a server communication unit for transmitting and receiving a key between the portable device and the server communication unit; The key encryption unit When the encryption key is generated, the encryption key is encrypted with the embedded key to generate an encrypted encryption key, and the encrypted encryption key is transmitted to the portable device via the server communication unit; when the common key is acquired, the encryption key is acquired from the portable device, and the common key is encrypted with the encryption key to generate an encrypted common key, which is stored in the server storage unit and transmitted to the portable device via the server communication unit; The portable device comprises: an internal storage unit that stores the encryption key received from the management server; a removable external storage unit that stores the encrypted common key received from the management server; a reading unit that reads confidential information encrypted with the common key; a decryption unit that decrypts the confidential information with the common key, There is provided a management system in which the decryption unit decrypts the encrypted common key with the encrypted encryption key to obtain the common key used when decrypting the confidential information.

[0010] According to a fourth aspect of the present disclosure, A method for decrypting confidential information encrypted with a common key in a portable device including an internal storage unit that stores an encrypted encryption key obtained by encrypting an encryption key with an embedded key, and a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encrypted encryption key, the method comprising: a computer of the portable device, Decrypting the encrypted common key with the encrypted encryption key to obtain the common key; The secret information is decrypted using the obtained common key. death, performing authentication using the decrypted confidential information; Outputting a signal according to the result of the authentication A decoding method is provided.

[0011] According to a fifth aspect of the present disclosure, A method for decrypting confidential information encrypted with the common key in a management server including a server storage unit that stores an embedded key and an encrypted common key obtained by encrypting a common key with an encrypted encryption key obtained by encrypting a generated encryption key with the embedded key, and a server communication unit that acquires the encrypted encryption key from an external device, the method comprising: obtaining the encryption key from the external device via the server communication unit; Decrypting the encrypted common key with the encrypted encryption key to obtain the common key; A decryption method is provided for decrypting the confidential information using the obtained common key.

[0012] According to a sixth aspect of the present disclosure, A key management method in a management system including a management server including an encryption key generation unit that generates an encryption key, and a portable device including an internal storage unit and a removable external storage unit, comprising: the management server generates an encrypted encryption key by encrypting the generated encryption key with an embedded key, and transmits the encrypted encryption key to the portable device; the portable device stores the encryption key transmitted from the management server in the built-in storage unit; the management server acquires the encrypted encryption key from the portable device, encrypts a common key using the encrypted encryption key to generate an encrypted common key, stores the encrypted common key, and transmits the encrypted common key to the portable device; The portable device stores the encrypted common key transmitted from the management server in the external storage unit.

[0013] According to a seventh aspect of the present disclosure, A computer includes an internal storage unit that stores an encrypted encryption key obtained by encrypting an encryption key with an embedded key, and a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encrypted encryption key. a step of decrypting the encrypted common key with the encrypted encryption key to obtain the common key; using the obtained common key to decrypt confidential information that has been encrypted in advance with the common key; performing authentication using the decrypted confidential information; outputting a signal according to a result of the authentication; A program for executing the above is provided.

[0014] According to an eighth aspect of the present disclosure, A computer includes a server storage unit that stores an embedded key and an encrypted common key obtained by encrypting a common key with an encrypted encryption key obtained by encrypting a generated encryption key with the embedded key, and a server communication unit that acquires the encrypted encryption key from an external device, obtaining the encryption key from the external device via the server communication unit; a step of decrypting the encrypted common key with the encrypted encryption key to obtain the common key; A program for executing a procedure for decrypting confidential information that has been encrypted in advance with the common key by using the obtained common key is provided.

[0015] These programs can be recorded in a computer-readable storage medium. The storage medium can be a non-transitory medium such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present disclosure can also be embodied as a computer program product. Effect of the Invention

[0016] The present disclosure can contribute to improving the security of a common key used to encrypt confidential information. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2A is an overall configuration diagram of an example of a management system of the present disclosure, and FIG. 2B is a functional block diagram of an example of a card reader of the present disclosure. [Diagram 2] FIG. 2 is a diagram for explaining a storage location of a key according to the present disclosure. [Diagram 3] FIG. 2A is a functional block diagram of an example of a management server according to the present disclosure, and FIG. 2B is a diagram for explaining an example of information stored in a server storage unit of the management server. [Figure 4] 1A and 1B are diagrams for explaining an example of an operation permission table and an entry management table, respectively, according to the present disclosure, and FIG. 1C and 1D are diagrams for explaining an example of an authentication table, respectively, according to the present disclosure. [Diagram 5] FIG. 2 is a functional block diagram of an example of a card reader of the present disclosure. [Figure 6] 11 is a flowchart of an example of a key management process of the present disclosure. [Figure 7] 13 is a flowchart of an example of an operation authentication process of the present disclosure. [Figure 8] 13 is a flowchart of an example of an entry management process of the present disclosure. [Figure 9] FIG. 2 is a functional block diagram of an example of a card reader of the present disclosure. [Figure 10] FIG. 2 is a configuration diagram showing an example of a hardware configuration of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that the reference symbols in the drawings are added to each element for convenience as an example to facilitate understanding, and are not intended to limit the present disclosure to the illustrated embodiment. In addition, the connecting lines between blocks in the drawings and the like referred to in the following description include both bidirectional and unidirectional. A unidirectional arrow is a schematic representation of the flow of a main signal (data), and does not exclude bidirectionality. In addition, in the following description, "A and / or B" is used to mean A or B, or A and B.

[0019] <<First embodiment>> An overview of this embodiment will be described. FIG. 1(a) is a diagram for explaining an overview of this embodiment. A card reader 200, which is a portable device of this embodiment, is included in a management system 100 that manages entry to each area 620 such as a room. The card reader 200 is placed in front of the door of each area 620 and manages locking and unlocking of the door. The area 620 having the door in which the card reader 200 is placed is also called the management area 620 of the card reader 200. The management system 100 may also include a management server 300 and an electric lock 400 in addition to the card reader 200.

[0020] Before describing the card reader 200 of this embodiment, a brief description will be given of the management server 300. The management server 300, for example, manages ID information that is permitted to enter each area 620. The management server 300 is connected to each card reader 200 via a network 610 such as a LAN, and transmits ID information that is permitted to enter each area 620 to each card reader 200.

[0021] The management server 300 of this embodiment also holds a prepared embedded key. It also generates an encryption key to be used within the management system 100. It then encrypts the generated encryption key with the embedded key to generate an encrypted encryption key, and transmits the encrypted encryption key to each card reader 200. In other words, the management server 300 does not hold an encryption key or an encrypted encryption key in its own device.

[0022] Furthermore, when the management server 300 is given the common key, it obtains the encryption key from the card reader 200, encrypts the common key with the encryption key, and generates an encrypted common key. The management server 300 holds the generated encrypted common key in its own device and transmits it to the card reader 200.

[0023] The card reader 200 reads encrypted confidential information (encrypted confidential information 501) from an IC card 500 carried by each user, decrypts it, extracts ID information, and manages entry into the management area 620 of the own device.

[0024] To achieve this, the card reader 200 of this embodiment includes a reading unit 210, a decryption unit 220, an interface (IF) 230, and an internal storage unit 240, as shown in FIG. 1(b).

[0025] The built-in storage unit 240 is a storage unit built into the card reader 200, and is configured with a readable and writable storage medium such as a static random access memory (SRAM). The built-in storage unit 240 stores an encrypted encryption key 712 obtained by encrypting an encryption key with an embedded key 711. The encrypted encryption key 712 is transmitted from the management server 300, for example, by encrypted communication or the like.

[0026] The IF 230 is an interface that accesses the external storage unit 231. The card reader 200 of this embodiment can access a removable external storage unit 231, such as an SD card, via the IF 230. The card reader 200 may include, as the IF 230, a direct memory slot into which an SD card can be directly inserted. The IF 230 may also be a Universal Serial Bus (USB) port.

[0027] The external storage unit 231 stores an embedded key 711 and an encrypted common key 713. The embedded key 711 is distributed in advance. The encrypted common key 713 is transmitted from the management server 300, for example, by encrypted communication.

[0028] The reading unit 210 reads the encrypted confidential information 501 recorded in the IC card 500. The encrypted confidential information 501 is confidential information encrypted with a common key prepared in advance. The confidential information includes a user ID that uniquely identifies a user who owns the IC card 500. The reading unit 210 performs short-distance wireless communication with an IC chip in the IC card 500 to obtain the encrypted confidential information 501. For example, near field communication (NFC) is used as the short-distance wireless communication.

[0029] The decryption unit 220 decrypts the encrypted confidential information 501 read by the reading unit 210 with a common key. The decryption unit 220 of this embodiment calculates a common key using the encrypted common key 713 stored in the external storage unit 231 and the encrypted encryption key 712 stored in the internal storage unit 240, and decrypts the encrypted confidential information 501. The decryption unit 220 obtains the common key by decrypting the encrypted common key 713 with the encrypted encryption key 712.

[0030] A list of storage destinations for each type of key is shown in Fig. 2. As shown in this figure, the embedded key 711 is stored in the storage unit of the management server 300 and the external storage unit 231 of the card reader 200. An encrypted encryption key 712 encrypted with the embedded key 711 is stored in the built-in storage unit 240 of the card reader 200. An encrypted common key 713, which is a common key encrypted with the encrypted encryption key 712, is stored in the external storage unit 231 of the card reader 200 and the management server 300.

[0031] As described above, the card reader 200 of this embodiment reads the encrypted confidential information 501 encrypted with a common key in the IC card 500, decrypts it, and extracts the user ID. At this time, the system-specific embedded key 711 and encryption key for encrypting the common key are prepared, and the common key is encrypted and stored using these. That is, the common key required for decrypting the encrypted confidential information 501 is not stored as it is in the card reader 200. In addition, the encrypted encryption key 712 and the encrypted common key 713 required for obtaining the common key are stored separately in the built-in storage unit 240 and the external storage unit 231.

[0032] As described above, according to this embodiment, the common key necessary for decrypting confidential information can be safely stored by not storing the common key as is. Furthermore, security is further increased by distributing the storage locations of the information necessary for decrypting the common key. In other words, removable storage media are generally prone to being stolen. However, according to this embodiment, even if stolen, it cannot be decrypted.

[0033] In particular, one of the pieces of information required to decrypt the common key is stored in a removable external storage unit 231 such as an SD card. For example, if the external storage unit 231 is removed from the card reader 200 during times when no one is entering the room, such as on holidays or at night, the key information will not be leaked even if the card reader 200 itself, which is a portable device that can be easily carried around, is stolen.

[0034] According to the card reader 200 of this embodiment, it is possible to improve the security of the common key used for encrypting confidential information.

[0035] <<Second embodiment>> Next, a second embodiment of the present disclosure will be described. This embodiment is an embodiment in which the first embodiment is embodied in more detail. In this embodiment, configurations having the same names as those in the first embodiment basically have the same functions as those in the first embodiment. Hereinafter, this embodiment will be described with a focus on the differences from the first embodiment.

[0036] The management system 100 of this embodiment has a configuration basically similar to that of the first embodiment, and manages entry to each area 620 such as a room. As shown in Fig. 1(a), the management system 100 includes a management server 300, a card reader 200 arranged in front of the door of each area 620, and an electric lock 400 for the door of each area 620.

[0037] The management server 300 and each card reader 200 are connected via a network 610 such as a LAN. A server-connected card reader 301 is connected to the management server 300 by wire or wirelessly. This server-connected card reader 301 reads encrypted confidential information 501 recorded on an IC card 500. The card reader 200 and the electronic lock 400 are also connected by wire or wirelessly.

[0038] A user who is an administrator of the entire management system 100 accesses the management server 300 and registers persons permitted to enter each area 620. Here, information (data) indicating whether or not entry is permitted is registered in association with a user ID. The registered data is distributed to the card readers 200 of each area 620 via a LAN. Each card reader 200 reads the encrypted confidential information 501 in the IC card 500 of the person who wishes to enter, and determines whether or not the user ID included in the confidential information is registered as a person permitted to enter. If the person is a person permitted to enter, an unlocking signal is output to the connected electric lock 400. The electric lock 400 receives the unlocking signal and unlocks, for example, by contact movement. This unlocks the door for entering the area 620.

[0039] [Management Server] The management server 300 manages users who are permitted to enter each area 620. Specifically, the management is performed by a user ID given to each user.

[0040] Each user is assigned a unique user ID in advance. The user ID is included in the confidential information. The confidential information is encrypted with a common key prepared in advance, and is recorded in the IC card 500 as encrypted confidential information 501. The user is authenticated using the IC card 500.

[0041] To achieve this, the management server 300 of this embodiment includes an encryption key generation unit 310, a key encryption unit 320, a server communication unit 330, a server interface (IF) 340, a server authentication unit 350, and a server storage unit 360, as shown in FIG. 3(a).

[0042] The encryption key generation unit 310 generates an encryption key.

[0043] The key encryption unit 320 encrypts a key used for encryption. In this embodiment, the encryption key is encrypted using an embedded key 711 to generate an encrypted encryption key 712. The common key is also encrypted using the encrypted encryption key 712 to generate an encrypted common key 713. The common key is obtained from the common key storage medium 302 via the server IF 340.

[0044] The server communication unit 330 transmits and receives various information including keys to and from external devices. In this embodiment, keys are transmitted and received between the card reader 200 and the server communication unit 330 through encrypted communication. Specifically, an encrypted encryption key 712 and an encrypted common key 713 are transmitted to the card reader 200. In this embodiment, information related to an entry management table 364 (described later) is also transmitted to the card reader 200. The entry management table 364 is transmitted, for example, every time it is updated.

[0045] Furthermore, the management server 300 of this embodiment does not hold the encrypted encryption key 712. Therefore, when the encrypted encryption key 712 is necessary, the management server 300 requests the encrypted encryption key 712 from the card reader 200 via the server communication unit 330. Furthermore, the management server 300 receives the encrypted encryption key 712 transmitted from the card reader 200 in response to the request via the server communication unit 330.

[0046] The server IF 340 is a connection interface for various external devices. For example, it is a USB interface. In this embodiment, the server IF 340 is connected to a server connection card reader 301, a common key storage medium 302, an input / output device 303, etc., and transmits and receives data to and from these devices. The server IF 340 may be equipped with multiple types of interfaces.

[0047] For example, the server IF 340 receives encrypted confidential information 501 recorded on an IC card 500, which has been read by the server-connected card reader 301. It also reads a common key from a common key storage medium 302. It also receives information input via an input device of the input / output device 303, and outputs information processed by the management server 300 via an output device. In this embodiment, an operation permission table 363 and an entry management table 364, which will be described later, are generated when a user inputs necessary information via an input device.

[0048] The server authentication unit 350 authenticates the user. In this embodiment, if information permitting operation is stored in an operation permission table 363 (described later) in association with the user ID, the authentication is deemed successful, and operation of the management server 300 is permitted.

[0049] The server storage unit 360 stores information generated by the management server 300, information required for processing, etc. In this embodiment, as shown in Fig. 3(b), an embedded key 711, an encrypted common key 713, an operation permission table 363, and an entry management table 364 are stored. The embedded key 711 is prepared in advance for the management system 100, and distributed to all devices belonging to the management system 100.

[0050] The embedded key 711 is input via the input / output device 303 connected to the server IF 340 , for example, and stored in the server storage unit 360 .

[0051] The operation permission table 363 is a table for managing users who can access the management server 300. In the operation permission table 363, whether or not an operation is permitted is registered for each user ID. An example of the operation permission table 363 is shown in FIG. 4(a). As shown in this figure, information 363b indicating permission (in this figure, ◯) or non-permission is registered in association with a user ID 363a. In this embodiment, the server authentication unit 350 refers to the operation permission table 363 and determines whether or not information permitting an operation is registered in association with the acquired user ID. If permitted information is registered, authentication is performed and the operation is enabled.

[0052] As described above, the user ID is encrypted with the common key and pre-recorded in the IC card 500 as encrypted confidential information 501. The server-connected card reader 301 reads the encrypted confidential information 501 contained in the held IC card 500. The server authentication unit 350 then acquires the encrypted confidential information 501 via the server IF 340. The server authentication unit 350 decrypts the encrypted confidential information 501 with the common key and acquires the user ID. The common key used for decryption is obtained by decrypting the encrypted common key 713 with the encrypted encryption key 712. The encrypted encryption key 712 is acquired from the card reader 200 via the server communication unit 330.

[0053] Note that the operation permission table 363 may register only the user IDs of users who are allowed to operate the management server 300. In this case, the server authentication unit 350 determines whether or not the user ID in the read encrypted confidential information 501 is registered in the operation permission table 363, and performs user authentication.

[0054] The entry management table 364 manages user IDs permitted to enter each area 620. An example of the entry management table 364 is shown in Fig. 4(b). As shown in this figure, for each area 620 (area ID 364b) managed by the management server 300, information 364c indicating whether each user ID 364a is permitted to enter is registered.

[0055] Every time the entry management table 364 is created / updated, data related to each area 620 is transmitted to the card reader 200 that manages that area 620. That is, information on area A in the entry management table 364 is transmitted to the card reader 200 that manages area A, and information on area B in the entry management table 364 is transmitted to the card reader 200 that manages area B. Note that the entry management table 364 is transmitted to the card reader 200 that manages that area 620 every time the information on that area 620 is updated.

[0056] Similarly to the operation permission table 363, the entry management table 364 may register only the user IDs of users who are permitted to enter the room.

[0057] [Card reader] As in the first embodiment, the card reader 200 reads the encrypted confidential information 501 from the IC card 500 possessed by each user, decrypts it, and extracts the user ID. Then, based on the extracted user ID, the card reader 200 manages entry to the management area 620 of the own device.

[0058] 5, the card reader 200 of this embodiment includes a reading unit 210, a decryption unit 220, an IF 230, and an internal storage unit 240, just like the first embodiment. The card reader 200 of this embodiment further includes a communication unit 250, an authentication unit 260, and an output unit 270.

[0059] The components with the same names as those in the first embodiment basically have the same functions as those in the first embodiment. Therefore, the description will be omitted here. However, in addition to the encrypted encryption key 712, an authentication table 242 is stored in the built-in storage unit 240 of this embodiment.

[0060] The authentication table 242 is information related to the management area 620 of the entry management table 364, transmitted from the management server 300. An example of the authentication table 242 is shown in Fig. 4(c) and Fig. 4(d). As shown in this figure, the authentication table 242 registers information 242b indicating whether or not entry to the management area 620 is permitted (in this figure, ◯) in association with a user ID 242a.

[0061] The communication unit 250 transmits and receives information to and from external devices. In this embodiment, the communication unit 250 receives the encrypted encryption key 712 and the encrypted common key 713 from the management server 300 through encrypted communication. Furthermore, the communication unit 250 receives the authentication table 242. For example, the authentication table 242 is received every time the relevant part of the entry management table 364 is updated. Furthermore, when a request for the encrypted encryption key 712 is received from the management server 300, the communication unit 250 transmits the encrypted encryption key 712 to the requesting management server 300 in response to the request.

[0062] The authentication unit 260 performs authentication using the confidential information decrypted by the decryption unit 220. As described above, the authentication unit 260 extracts a user ID from the decrypted confidential information and performs authentication by referring to the authentication table 242. In this embodiment, when, for example, the authentication table 242 has information 242b indicating permission registered in association with the extracted user ID 242a, the authentication unit 260 notifies the output unit 270 of authentication success as the authentication result.

[0063] The output unit 270 outputs a signal according to the authentication result. In this embodiment, if the authentication unit 260 is successful in the authentication, it outputs an unlock signal to the connected electric lock 400.

[0064] When the electric lock 400 receives the unlock signal, it unlocks and allows the user holding the IC card 500 to enter the management area 620 .

[0065] [Key management process] The flow of key management processing in the management system 100 of this embodiment will be described. In this embodiment, an encryption key is generated by the management server 300. The management server 300 also acquires a common key from the common key storage medium 302. These are then encrypted to generate an encrypted encryption key 712 and an encrypted common key 713, which are then distributed to each card reader 200. Here, the processing for one card reader 200 will be described as an example. When there are multiple card readers 200, the management server 300 executes this processing for each card reader 200.

[0066] 6 is a process flow of key management processing by the management system 100 of this embodiment. This processing is started, for example, in response to an instruction from a user who manages the management system 100.

[0067] First, the encryption key generating unit 310 of the management server 300 generates an encryption key (step S1101).

[0068] Next, the key encryption unit 320 encrypts the generated encryption key with the embedded key 711 to generate the encrypted encryption key 712 (step S1102), and then transmits the encrypted encryption key 712 to the card reader 200 via the server communication unit 330 (step S1103).

[0069] On the card reader 200 side, when the communication unit 250 receives the encrypted encryption key 712 from the management server 300, the communication unit 250 stores the encrypted encryption key 712 in the internal storage unit 240 (step S1201). After that, the management server 300 deletes the encrypted encryption key 712 (step S1104).

[0070] First, the encrypted encryption key 712 is generated by the above process and stored in the built-in storage unit 240 of the card reader 200 .

[0071] After that, at a predetermined timing, the management server 300 reads the common key from the common key storage medium 302 via the server IF 340, thereby acquiring the common key (step S1105).

[0072] Then, the management server 300 requests the encrypted encryption key 712 from the card reader 200 that transmitted the encrypted encryption key 712 via the server communication unit 330 (step S1106).

[0073] When the card reader 200 receives the request, the communication unit 250 transmits the encrypted encryption key 712 stored in the internal storage unit 240 to the management server 300 (step S1202).

[0074] Upon receiving the encrypted encryption key 712, the management server 300 uses it to encrypt the acquired common key, generating the encrypted common key 713 (step S1107).

[0075] The management server 300 then transmits the generated encrypted common key 713 to the card reader 200 that transmitted the encrypted encryption key 712 (step S1108). The management server 300 also stores the encrypted common key 713 in the server storage unit 360, which is a storage unit of the management server 300, and deletes the encrypted encryption key 712 (step S1109).

[0076] Upon receiving the encrypted common key 713, the card reader 200 stores the encrypted common key 713 in the external storage unit 231 via the IF 230 (step S1203).

[0077] As a result, as shown in FIG. 2, the encrypted common key 713 is stored in the server memory unit 360 of the management server 300, the encrypted encryption key 712 is stored in the internal memory unit 240 of the card reader 200, and the encrypted common key 713 is stored in the external memory unit 231.

[0078] [Operation authentication process] Next, the operation authentication process in the management server 300 will be described. This process is a process for restricting users who can operate the management server 300. Fig. 7 shows a process flow of the operation authentication process of this embodiment. This process is started when the server connection card reader 301, which is connected via the server IF 340, reads the encrypted confidential information 501 from the IC card 500. Also, the initial state of the management server 300 is an operation-disallowed state in which no operation from the user is accepted.

[0079] The server authentication unit 350 acquires the encrypted confidential information 501 from the server-connected card reader 301 (step S1301). The encrypted confidential information 501 is acquired via the server IF340.

[0080] The server authentication unit 350 requests the card reader 200 to send the encrypted encryption key 712 (step S1302). The request is transmitted to the card reader 200 via the server communication unit 330.

[0081] In response to the request, the server authentication unit 350 acquires the encrypted encryption key 712 (step S1303), and decrypts the encrypted common key 713 with the encrypted encryption key 712 (step S1304). As described above, the encrypted common key 713 is stored in the server storage unit 360. After decryption, the server authentication unit 350 deletes the encrypted encryption key 712.

[0082] The server authentication unit 350 decrypts the encrypted confidential information 501 with the common key obtained by the decryption (step S1305), and acquires the user ID included in the decrypted confidential information (step S1306).

[0083] The server authentication unit 350 refers to the operation permission table 363 and performs authentication processing for the acquired user ID (step S1307). If the acquired user ID is registered as operation permission in the operation permission table 363, the authentication is deemed successful. In other cases, the authentication is deemed unsuccessful.

[0084] If the authentication is successful (S1307; Yes), the server authentication unit 350 sets the management server 300 to an operation permitted state (step S1308). Here, for example, the state is set to one in which input from an input device can be accepted. Also, various data stored in the server storage unit 360 can be updated with the input data.

[0085] Server authentication unit 350 maintains the above state until an end instruction is received (step S1309). On the other hand, if an end instruction is received, server authentication unit 350 returns to the operation disallowed state (step S1310) and ends the process.

[0086] On the other hand, if the authentication is unsuccessful in step S1307 (S1307; No), server authentication section 350 ends the process.

[0087] [Entrance management process] Next, the flow of the entrance management process in the card reader 200 of this embodiment will be described. In this embodiment, the card reader 200 reads the encrypted confidential information 501 from the IC card 500 held by the user, and controls the operation of the electric lock 400 attached to the door of the management area 620. Fig. 8 shows the process flow of the entrance management process of this embodiment. Note that here, it is assumed that the latest authentication table 242 has been transmitted in advance from the management server 300. This process starts when the user holds up the IC card 500.

[0088] First, the reading unit 210 acquires the encrypted confidential information 501 from the IC card 500 (step S1401).

[0089] Then, the decryption unit 220 decrypts the encrypted common key 713 with the encrypted encryption key 712 (step S1402) to obtain the common key. Note that the encrypted encryption key 712 is obtained from the internal storage unit 240, and the encrypted common key 713 is obtained from the external storage unit 231.

[0090] The decryption unit 220 decrypts the encrypted confidential information 501 with the common key (step S1403), and obtains the user ID included in the confidential information (step S1404).

[0091] The authentication unit 260 refers to the authentication table 242 and authenticates the user ID (step S1405). That is, if information indicating permission to enter the room is registered in association with the user ID in the authentication table 242, the authentication is deemed successful, and otherwise the authentication is deemed unsuccessful.

[0092] If the authentication is successful (S1405; Yes), the authentication unit 260 notifies the output unit 270 of that fact. The output unit 270 outputs an unlock signal to the electric lock 400 (step S1406), and ends the process. When the electric lock 400 receives the unlock signal, it unlocks and the door opens.

[0093] On the other hand, if the authentication is unsuccessful (S1405; No), the process ends.

[0094] As described above, according to this embodiment, the card reader 200 has the same configuration as in the first embodiment, and therefore provides the same effects as in the first embodiment.

[0095] Furthermore, according to this embodiment, the management server 300 does not hold the encrypted encryption key 712. Therefore, even if the management server 300 is illegally accessed, the common key cannot be decrypted and cannot be obtained.

[0096] Thus, according to this embodiment, the information necessary to decrypt the common key is stored in a distributed manner in both the card reader 200 and the management server 300 that constitute the management system 100, thereby increasing the difficulty of decrypting the common key.

[0097] Therefore, according to this embodiment, the security of the common key used for encrypting confidential information can be improved in the management system 100. In particular, this is useful when encrypting information such as a user ID recorded on an IC card with a common key and using the encrypted information for authentication in an organization that requires high confidentiality.

[0098] <<Third embodiment>> Next, a third embodiment will be described. The card reader 200 of this embodiment further includes a function for deleting the encrypted encryption key 712 stored in the built-in storage unit 240 in the event of unauthorized interference, etc. This further improves security.

[0099] The overall configuration of the management system 100 of this embodiment is similar to any of the above-mentioned embodiments. The configuration of the management server 300 is also similar to any of the above-mentioned embodiments. Therefore, the description thereof will be omitted.

[0100] In order to realize the above functions, the card reader 200 of this embodiment further includes a tamper detection unit 280 and a deletion unit 290 in addition to the configuration of any of the above embodiments, as shown in Fig. 9. Note that here, an example is shown in which the configuration of the card reader 200 of the second embodiment includes these functions.

[0101] Tamper detection unit 280 detects unauthorized interference with card reader 200. Note that tampering means unauthorized interference, analysis, or modification. At the hardware level, it includes actions such as physically disassembling the device and circumventing the encryption circuit. At the software level, it includes actions such as decompiling a program and rewriting data.

[0102] The deleting unit 290 deletes predetermined data when the tamper detection unit 280 detects tampering. In this embodiment, the encrypted encryption key 712 stored in the internal storage unit 240 is deleted.

[0103] The tamper detection unit 280 and the deletion unit 290 may be realized, for example, by an existing tamper-resistant device. The tamper-resistant device is a device that automatically erases the internal secret data if an attempt is made to disassemble or analyze the device in an unauthorized manner. Specifically, it detects unnatural changes in temperature / humidity / voltage / location, damage to the casing, missing screws, etc. as attacks, and activates a data erasure program.

[0104] The other functions of the card reader 200 are similar to those of any of the above embodiments, and therefore will not be described here.

[0105] As described above, the present embodiment has the same configuration as the above-described embodiments, and therefore provides the same effects as those embodiments.

[0106] Furthermore, according to this embodiment, if the card reader 200 is forced open, the encrypted encryption key 712 stored in the internal storage unit 240 is deleted. This makes it impossible to decrypt the common key, further increasing security.

[0107] Therefore, according to this embodiment, it is possible to improve the security of the common key used for encrypting confidential information.

[0108] <Variation 1> In the above embodiment, the embedded key 711 is distributed in advance to all devices in the management system 100. However, this is not limited to this. For example, the embedded key 711 may be held only by the management server 300.

[0109] <Variation 2> In the above embodiment, in the card reader 200, the encrypted encryption key 712 is stored in the built-in storage unit 240, and the encrypted common key 713 is stored in the external storage unit 231. However, this may be reversed. In this case, if the card reader 200 has a tamper function, the deletion unit 290 is set to delete the encrypted encryption key 712 stored in the external storage unit 231 when tampering is detected.

[0110] The encrypted encryption key 712 and the encrypted common key 713 may be stored in different storage areas in a distributed manner. That is, both may be stored in physically different storage areas accessible by the CPU of the card reader 200, whether built-in or external.

[0111] <Variation 3> In the above embodiment, the generation of the encryption key and the acquisition of the common key are not temporally related in the management server 300. For example, the encryption key may be generated at the timing when the common key is read from the common key storage medium 302.

[0112] In this case, the management server 300 first encrypts the encryption key with the embedded key 711 to generate the encrypted encryption key 712. Then, the generated encrypted encryption key 712 is transmitted to the card reader 200. Furthermore, before deleting the generated encrypted encryption key 712, the management server 300 encrypts the common key with the encrypted encryption key 712 to generate the encrypted common key 713. Then, the generated encrypted common key 713 is transmitted to the card reader 200. After that, the encrypted encryption key 712 is deleted.

[0113] This eliminates the need to obtain the encrypted encryption key 712 from the card reader 200 when encrypting the common key, and makes it possible to reduce the number of times encrypted communications with the card reader 200 are performed.

[0114] <Modification 4> In each of the above embodiments, even when the management system 100 has a plurality of card readers 200, one encryption key is used. However, this is not limited to this. For example, a different encryption key may be generated for each set of one or a plurality of card readers 200.

[0115] Here, as an example, this modified example will be described taking a case where a different encryption key is generated for each of two card readers 200 (a first card reader and a second card reader).

[0116] The management system 100 generates an encryption key for the first card reader (first encryption key) for the first card reader 200. Then, the management system 100 encrypts the generated first encryption key with the embedded key 711 to generate an encrypted first encryption key as the encrypted encryption key 712 of the first encryption key. The management system 100 transmits the encrypted first encryption key to the first card reader 200. The management system 100 also encrypts the common key with the encrypted first encryption key to generate a first encrypted common key as the encrypted common key 713 encrypted with the encrypted first encryption key. The management system 100 transmits the generated first encrypted common key to the first card reader 200, and stores it in the server storage unit 360 in association with information (card reader ID) that identifies the first card reader 200.

[0117] Similarly, a second card reader encryption key (second encryption key) is generated for the second card reader 200. The generated second encryption key is then encrypted with the embedded key 711 to generate an encrypted second encryption key as the encrypted encryption key 712 of the second encryption key. The encrypted second encryption key is transmitted to the second card reader 200. The common key is also encrypted with the encrypted second encryption key to generate a second encrypted common key as the encrypted common key 713. The generated second encrypted common key is transmitted to the second card reader 200, and is stored in the server storage unit 360 in association with the card reader ID of the second card reader 200.

[0118] In this case, the card reader 200 requesting the encrypted encryption key 712 when the server-connected card reader 301 decrypts the encrypted confidential information 501 read therein may be any card reader 200. However, the encrypted encryption key 712 is received together with the card reader ID. Then, the encrypted common key 713 registered in association with the card reader ID is decrypted with the received encrypted encryption key 712 to obtain the common key.

[0119] By generating an encryption key for each card reader 200, even if the encrypted encryption key 712 is leaked from one card reader 200, the encrypted encryption key 712 cannot be used in other card readers 200. Therefore, it is necessary to delete only the encrypted encryption key 712 of the leaked card reader 200. This further improves the security of the common key in the entire management system 100.

[0120] <Variation 5> Additionally, the encryption key may be configured to be regenerated at predetermined time intervals or upon the occurrence of a predetermined event.

[0121] For example, every time the management server 300 generates a new encryption key, it encrypts the encryption key with the embedded key 711 to generate an encrypted encryption key 712. Then, it transmits the generated encrypted encryption key 712 to each card reader 200. Every time the card reader 200 receives a new encrypted encryption key 712, it updates the encrypted encryption key 712 in the built-in storage unit 240.

[0122] Furthermore, the management server 300 reads the common key and encrypts it to generate an encrypted common key 713 every time it generates an encrypted encryption key 712. Then, it transmits the generated encrypted common key 713 to each card reader 200. On the card reader 200 side, the encrypted common key 713 in the external storage unit 231 is updated every time a new encrypted common key 713 is received.

[0123] As a result, the encryption key 712 is updated at a predetermined timing, and the security of the common key in the management system 100 is improved.

[0124] <Variation 6> In the second embodiment, the card reader 200 manages / limits entry to the managed area 620, but the objects of management / limitation are not limited to this. For example, the use of a device to which the card reader 200 is connected may be managed / limited.

[0125] [Hardware configuration] The management server 300 and the card reader 200 of each of the above embodiments may be realized, for example, by a general-purpose information processing device. The general-purpose information processing device includes, for example, a CPU (Central Processing Unit) 191, a main storage device (memory) 192, an auxiliary storage device 193, a communication I / F 194, and an expansion I / F 195, which are interconnected by an internal bus, as shown in Fig. 10.

[0126] The CPU 191 realizes the above-mentioned functions and centrally controls the entire device by, for example, loading a program stored in the auxiliary storage device 193 into the main storage device 192 and executing the program. Note that, instead of the CPU 191, one or more processors such as an MPU (Micro Processing Unit) may be used.

[0127] The main storage device 192 is a memory such as a RAM (Random Access Memory), etc. The main storage device 192 is a work area when the CPU 191 processes programs and the like executed by the installed devices.

[0128] The auxiliary storage device 193 is, for example, a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), etc. The auxiliary storage device 193 stores various programs executed by the installed device. In each of the above embodiments and / or modifications, the server storage unit 360 and the built-in storage unit 240 are each constructed in the auxiliary storage device 193.

[0129] The auxiliary storage device 193 may include a storage medium such as a flexible disk, a hard disk, an optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, a DVD, etc. These media may be used as the external storage unit 231 in the card reader 200 instead of the SD card.

[0130] The programs stored in the auxiliary storage device 193 can be provided as program products recorded on a non-transitory computer-readable recording medium. The auxiliary storage device 193 can be used to store various programs recorded on a non-transitory computer-readable recording medium for the medium to long term.

[0131] The communication I / F 194 is an interface for inputting and outputting signals and data by wire or wirelessly. For example, in each of the above-mentioned embodiments and / or modifications, the communication I / F 194 is connected to a LAN, for example, and data is transmitted and received between the management server 300 and the card reader 200. The communication I / F 194 may also include an antenna, a modem, and the like.

[0132] The expansion I / F 195 is, for example, a USB interface or a memory slot, and is connected to an external storage unit, an input device, an output device, etc. The expansion I / F 195 may be provided with a plurality of different types of interfaces.

[0133] For example, the external storage unit 231 of the card reader 200 is connected via the expansion I / F 195. The electric lock 400 may also be connected via the expansion I / F 195.

[0134] Furthermore, the server connection card reader 301, the common key storage medium 302, and the input / output device 303 of the management server 300 are connected via an expansion I / F 195. The input device is, for example, a device that accepts user operations such as a keyboard or a mouse. The output device is a display device such as a display. The liquid crystal monitor may have a touch panel function that accepts instructions by touch operations by the user.

[0135] The above-mentioned functions of each device are realized by the CPU 191 loading a program stored in the auxiliary storage device 193 into the main storage device 192 and executing it.

[0136] The hardware configuration of each device is not limited to the above. Each function (server) of each device may be implemented, for example, by an integrated circuit (IC) dedicated to each process, an application specific integrated circuit (ASIC), a system on chip (SOC), a field programmable gate array (FPGA), or the like.

[0137] In addition, the programs for implementing the above-mentioned functions of each device can be recorded on a computer-readable storage medium. The storage medium can be a non-transitory medium such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present disclosure can also be embodied as a computer program product.

[0138] In the process flow used in the above description, multiple steps (processes) are described in order, but the order of execution of each step is not limited to the order described. For example, the order of the steps shown in the figure can be changed to a range that does not affect the content, such as executing each process in parallel.

[0139] Although the embodiments and modifications of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications that can be understood by those skilled in the art can be made. Each embodiment and modification can be appropriately combined with other embodiments. For example, the network configuration and the configuration of each element shown in each drawing are examples to help understand the present disclosure, and are not limited to the configurations shown in these drawings.

[0140] Finally, preferred embodiments of the present disclosure will be summarized. A part or all of the above-described embodiments can be described as follows, but are not limited to the following. (Appendix 1) The portable device is a built-in storage unit for storing an encrypted encryption key obtained by encrypting an encryption key with an embedded key; a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encryption key; a reading unit that reads confidential information encrypted with the common key; A decryption unit that decrypts the confidential information with the common key. The decryption unit decrypts the encrypted common key with the encrypted encryption key to obtain the common key used when decrypting the confidential information. (Appendix 2) 2. The portable device according to claim 1, a tamper detection unit that detects unauthorized interference with the portable device; It is preferable that the electronic device further comprises a deletion unit which deletes the encryption key stored in the built-in storage unit when the tamper detection unit detects the interference. (Appendix 3) 3. The portable device according to claim 1 or 2, an authentication unit that performs authentication using the decrypted confidential information; It is preferable that the device further comprises an output unit that outputs a signal according to a result of the authentication. (Appendix 4) The management server is an encryption key generation unit that generates an encryption key; a key encryption unit that encrypts a key used for encryption; a server storage unit that stores an embedded key; and a server communication unit that transmits and receives keys to and from an external device. The key encryption unit When the encryption key is generated, the encryption key is encrypted with the embedded key to generate an encrypted encryption key, and the encrypted encryption key is transmitted to the external device via the server communication unit; When the common key is obtained, the encrypted encryption key is obtained from the external device, the common key is encrypted with the encrypted encryption key to generate an encrypted common key, which is stored in the server memory unit and transmitted to the external device via the server communication unit. (Appendix 5) The management system is The system includes a management server and a portable device. The management server includes: an encryption key generation unit that generates an encryption key; a key encryption unit that encrypts a key used for encryption; a server storage unit that stores an embedded key; and a server communication unit for transmitting and receiving a key to and from the portable device. The key encryption unit When the encryption key is generated, the encryption key is encrypted with the embedded key to generate an encrypted encryption key, and the encrypted encryption key is transmitted to the portable device via the server communication unit; Upon obtaining the common key, the encryption encryption key is obtained from the portable device, the common key is encrypted with the encryption encryption key to generate an encrypted common key, which is stored in the server memory unit and transmitted to the portable device via the server communication unit. The portable device comprises: an internal storage unit that stores the encryption key received from the management server; a removable external storage unit that stores the encrypted common key received from the management server; a reading unit that reads confidential information encrypted with the common key; A decryption unit that decrypts the confidential information with the common key. The decryption unit decrypts the encrypted common key with the encrypted encryption key to obtain the common key used when decrypting the confidential information. (Appendix 6) In a portable device including an internal storage unit that stores an encrypted encryption key obtained by encrypting an encryption key with an embedded key, and a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encrypted encryption key, a decryption method for decrypting confidential information encrypted with the common key comprises the steps of: a computer of the portable device, Decrypting the encrypted common key with the encrypted encryption key to obtain the common key; The confidential information is decrypted using the obtained common key. (Appendix 7) A method for decrypting confidential information encrypted with the common key in a management server including a server storage unit that stores an embedded key and an encrypted common key obtained by encrypting a common key with an encrypted encryption key obtained by encrypting a generated encryption key with the embedded key, and a server communication unit that acquires the encrypted encryption key from an external device, comprising: obtaining the encryption key from the external device via the server communication unit; Decrypting the encrypted common key with the encrypted encryption key to obtain the common key; The confidential information is decrypted using the obtained common key. (Appendix 8) A key management method in a management system including a management server including an encryption key generation unit that generates an encryption key, and a portable device including an internal storage unit and a removable external storage unit, comprising: the management server generates an encrypted encryption key by encrypting the generated encryption key with an embedded key, and transmits the encrypted encryption key to the portable device; the portable device stores the encryption key transmitted from the management server in the built-in storage unit; the management server acquires the encrypted encryption key from the portable device, encrypts a common key using the encrypted encryption key to generate an encrypted common key, stores the encrypted common key, and transmits the encrypted common key to the portable device; The portable device stores the encrypted common key transmitted from the management server in the external storage unit. (Appendix 9) A computer includes an internal storage unit that stores an encrypted encryption key obtained by encrypting an encryption key with an embedded key, and a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encrypted encryption key, a step of decrypting the encrypted common key with the encrypted encryption key to obtain the common key; and a program for executing a procedure of using the obtained common key to decrypt confidential information that has been encrypted in advance with the common key. (Appendix 10) A computer includes a server storage unit that stores an embedded key and an encrypted common key obtained by encrypting a common key with an encrypted encryption key obtained by encrypting a generated encryption key with the embedded key, and a server communication unit that acquires the encrypted encryption key from an external device, obtaining the encryption key from the external device via the server communication unit; a step of decrypting the encrypted common key with the encrypted encryption key to obtain the common key; and a program for executing a procedure of using the obtained common key to decrypt confidential information that has been encrypted in advance with the common key. (Appendix 11) 9. The key management method according to claim 8, When unauthorized tampering with the portable device is detected, the encrypted encryption key stored in the built-in storage unit is deleted. In addition, the form of Supplementary Note 5 can be expanded into the form of Supplementary Note 2-3, similarly to Supplementary Note 1.

[0141] The disclosures of the above patent documents and the like are incorporated herein by reference. Within the framework of the entire disclosure of the present invention (including the scope of claims), modifications and adjustments of the embodiments and modifications are possible based on the basic technical ideas. Furthermore, within the framework of this disclosure, various combinations and selections of various disclosed elements (including each element of each claim, each element of each embodiment or modification, each element of each drawing, etc.) are possible. In other words, this disclosure naturally includes various modifications and corrections that a person skilled in the art would be able to make in accordance with the entire disclosure including the scope of claims and the technical ideas. In particular, with regard to the numerical ranges described in this specification, any numerical value or subrange included in the range should be interpreted as being specifically described even if not otherwise specified. [Explanation of symbols]

[0142] 100: management system, 191: CPU, 192: main memory device, 193: auxiliary memory device, 194: communication I / F, 195: expansion I / F, 200: card reader, 210: reading unit, 220: decryption unit, 230: IF, 231: external storage unit, 240: internal storage unit, 242: authentication table, 242a: user ID, 242b: permission / non-permission information, 250: communication unit, 260: authentication unit, 270: output unit, 280: tamper detection unit, 290: deletion unit, 300: Management server, 301: Server connection card reader, 302: Common key storage medium, 303: Input / output device, 310: Encryption key generation unit, 320: Key encryption unit, 330: Server communication unit, 340: Server IF, 350: Server authentication unit, 360: Server storage unit, 363: Operation permission table, 363a: User ID, 363b: Permission / denial information, 364: Entry management table, 364a: User ID, 364b: Area ID, 364c: Permission / denial information, 400: Electric lock, 500: IC card, 501: Encrypted confidential information, 610: network, 620: area, 711: embedded key, 712: encryption key, 713: encryption common key

Claims

1. a built-in storage unit for storing an encrypted encryption key obtained by encrypting an encryption key with an embedded key; a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encryption key; a reading unit that reads confidential information encrypted with the common key; a decryption unit that decrypts the confidential information using the common key; an authentication unit that performs authentication using the decrypted confidential information; an output unit that outputs a signal according to a result of the authentication, The decryption unit decrypts the encrypted common key with the encrypted encryption key to obtain the common key used when decrypting the confidential information.

2. 2. The portable device of claim 1, a tamper detection unit that detects unauthorized interference with the portable device; a deletion unit that deletes the encryption key stored in the built-in storage unit when the tamper detection unit detects the interference.

3. an encryption key generation unit that generates an encryption key; a key encryption unit that encrypts a key used for encryption; a server storage unit that stores an embedded key; A server communication unit that transmits and receives a key to and from an external device, The key encryption unit When the encryption key is generated, the encryption key is encrypted with the embedded key to generate an encrypted encryption key, and the encrypted encryption key is transmitted to the external device via the server communication unit; Upon obtaining the common key, the management server obtains the encrypted encryption key from the external device, encrypts the common key with the encrypted encryption key to generate an encrypted common key, stores the encrypted common key in the server memory unit, and transmits the encrypted common key to the external device via the server communication unit.

4. A management system including a management server and a portable device, The management server includes: an encryption key generation unit that generates an encryption key; a key encryption unit that encrypts a key used for encryption; a server storage unit that stores an embedded key; a server communication unit for transmitting and receiving a key between the portable device and the server communication unit; The key encryption unit When the encryption key is generated, the encryption key is encrypted with the embedded key to generate an encrypted encryption key, and the encrypted encryption key is transmitted to the portable device via the server communication unit; When the common key is acquired, the encryption key is acquired from the portable device, and the common key is encrypted with the encryption key to generate an encrypted common key, which is stored in the server storage unit and transmitted to the portable device via the server communication unit; The portable device comprises: an internal storage unit that stores the encryption key received from the management server; a removable external storage unit that stores the encrypted common key received from the management server; a reading unit that reads confidential information encrypted with the common key; a decryption unit that decrypts the confidential information with the common key, The decryption unit decrypts the encrypted common key with the encrypted encryption key to obtain the common key used when decrypting the confidential information.

5. A method for decrypting confidential information encrypted with a common key in a portable device including an internal storage unit that stores an encrypted encryption key obtained by encrypting an encryption key with an embedded key, and a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encrypted encryption key, the method comprising: a computer of the portable device, Decrypting the encrypted common key with the encrypted encryption key to obtain the common key; Decrypting the confidential information using the obtained common key; performing authentication using the decrypted confidential information; A method of decoding, comprising: outputting a signal depending on the result of said authentication.

6. A method for decrypting confidential information encrypted with the common key in a management server including a server storage unit that stores an embedded key and an encrypted common key obtained by encrypting a common key with an encrypted encryption key obtained by encrypting a generated encryption key with the embedded key, and a server communication unit that acquires the encrypted encryption key from an external device, the method comprising: obtaining the encryption key from the external device via the server communication unit; Decrypting the encrypted common key with the encrypted encryption key to obtain the common key; and decrypting the confidential information using the obtained common key.

7. A key management method in a management system including a management server including an encryption key generation unit that generates an encryption key, and a portable device including an internal storage unit and a removable external storage unit, comprising: the management server generates an encrypted encryption key by encrypting the generated encryption key with an embedded key, and transmits the encrypted encryption key to the portable device; the portable device stores the encryption key transmitted from the management server in the built-in storage unit; the management server acquires the encrypted encryption key from the portable device, encrypts a common key using the encrypted encryption key to generate an encrypted common key, stores the encrypted common key, and transmits the encrypted common key to the portable device; The portable device stores the encrypted common key transmitted from the management server in the external storage unit.

8. A computer includes an internal storage unit that stores an encrypted encryption key obtained by encrypting an encryption key with an embedded key, and a removable external storage unit that stores an encrypted common key obtained by encrypting a common key with the encrypted encryption key, a step of decrypting the encrypted common key with the encrypted encryption key to obtain the common key; using the obtained common key to decrypt confidential information that has been encrypted in advance with the common key; performing authentication using the decrypted confidential information; a program for executing a procedure for outputting a signal depending on the result of the authentication;

9. A computer includes a server storage unit that stores an embedded key and an encrypted common key obtained by encrypting a common key with an encrypted encryption key obtained by encrypting a generated encryption key with the embedded key, and a server communication unit that acquires the encrypted encryption key from an external device, obtaining the encryption key from the external device via the server communication unit; a step of decrypting the encrypted common key with the encrypted encryption key to obtain the common key; and a program for executing a procedure of using the obtained common key to decrypt confidential information that has been encrypted in advance with the common key.

Images