JP2019165404A - Communication system, communication method and program - Google Patents

Abstract

To reduce a security risk in encryption communication between a server device and a client terminal in a system which performs encryption communication via a plurality of communication routes.SOLUTION: A communication system includes: a storage device, which stores server identification information and secret key information to be used for encryption communication; and a server device communicable with the storage device. The communication system further includes: reception means which receives from a client terminal a connection request for encryption communication; selection means which selects a key exchange method in which the transmission of secret key information is unnecessary, among key exchange methods included in the connection request; and communication means which, based on signature information signed using the secret key information, performs encryption communication with the client terminal.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a communication system, a communication method, and a program.

  2. Description of the Related Art There is known a system capable of performing data sharing and remote operation by communicating between a plurality of information processing apparatuses such as an MFP (Multifunction Peripheral / Printer / Product) and a PC (Personal Computer). The communication between the information processing apparatuses uses encrypted communication such as SSL (Secure Sockets Layer) communication in order to prevent malicious third party spoofing and data tampering.

  In addition, in one information processing apparatus, there is an apparatus equipped with a plurality of controllers. In this case, each of the plurality of controllers performs encrypted communication with the client terminal by holding a server certificate and functioning as a server. In addition, there is a system including a relay device that relays communication between a server and a client.

  For example, Patent Document 1 discloses that a relay device provided between a terminal and a server verifies the reliability of a server certificate for encryption communication between the server and the relay device, which is transmitted from the server. The contents of issuing a proxy certificate for encryption communication between a relay apparatus and a terminal corresponding to the reliability of the certificate and transmitting it to the terminal are disclosed.

  In the method described above, encrypted communication between a client terminal and a server is performed via a plurality of communication paths (for example, a terminal and a relay device, a relay device and a server). Therefore, it is necessary to communicate the server certificate and private key information in each of the plurality of communication paths, which raises a problem that security risk increases.

  A communication system according to the present invention is a communication system including a storage device that stores server identification information and secret key information used for encrypted communication, and a server device that can communicate with the storage device. Receiving means for receiving a connection request for encrypted communication; selecting means for selecting a key exchange method that does not require transmission of the secret key information from information indicating a key exchange method included in the connection request; and the secret key information And a communication means for performing encrypted communication with the client terminal based on the signature information signed using.

  ADVANTAGE OF THE INVENTION According to this invention, the security risk of the encryption communication between a server apparatus and a client terminal can be reduced in the system which performs the encryption communication via several communication paths.

It is a figure which shows an example of the system configuration | structure of the communication system which concerns on 1st Embodiment. It is a figure which shows the outline | summary of the communication system which concerns on 1st Embodiment. It is a figure which shows an example of the hardware constitutions of the information processing apparatus which concerns on 1st Embodiment. It is a figure which shows an example of the software configuration of the information processing apparatus which concerns on 1st Embodiment. It is a figure which shows an example of a function structure of the communication system which concerns on 1st Embodiment. It is a figure which shows an example of the server certificate which concerns on 1st Embodiment. It is a figure which shows an example of the authentication information management table which concerns on 1st Embodiment. It is a sequence diagram which shows an example of an authentication process with the communication terminal in the communication system which concerns on 1st Embodiment. It is a flowchart which shows an example of a process of the operation part which concerns on 1st Embodiment. It is a flowchart which shows an example of the process of the main-body part which concerns on 1st Embodiment. It is a flowchart which shows an example of the production | generation process of the server certificate in the main-body part which concerns on 1st Embodiment. It is a flowchart which shows an example of the process of the operation part which concerns on the modification of 1st Embodiment. It is a figure which shows an example of the system configuration | structure of the communication system which concerns on 2nd Embodiment. It is a figure which shows an example of a function structure of the communication system which concerns on 2nd Embodiment. It is a flowchart which shows an example of the process of the server apparatus which concerns on 2nd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

● First embodiment ●
System Configuration FIG. 1 is a diagram illustrating an example of a system configuration of a communication system according to the first embodiment. The communication system shown in FIG. 1 is a system that can enhance the security of encrypted communication between a server device and a client terminal in a system that performs encrypted communication via a plurality of communication paths.

  The communication system includes the information processing apparatus 10 and the communication terminal 90. The information processing apparatus 10 and the communication terminal 90 are connected via the communication network 5. The communication network 5 is constructed by, for example, a LAN (Local Area Network), a dedicated line, the Internet, and the like. The communication network 5 may include a place where wireless communication such as Wi-Fi (Wireless Fidelity) or Bluetooth (registered trademark) is performed in addition to wired communication.

  The information processing apparatus 10 is an image forming apparatus having an image processing function and a communication function such as an MFP (Multifunction Peripheral / Printer / Product), a facsimile, a scanner, or a printer. The information processing apparatus 10 includes an operation unit 30 and a main unit 50 that are connected to each other via a cable so that data communication is possible.

  The operation unit 30 receives screen input and key input by user operation. The main body 50 performs an operation corresponding to the input received by the operation unit 30. Note that the operation unit 30 and the main unit 50 may be wireless (including infrared) connection instead of wired connection using a cable.

  In the information processing apparatus 10, it is conceivable that the operation unit 30 is independent from the main body unit 50 so that the operation response is not reduced even when the load on the main body unit 50 is high. For example, the operating unit 30 is equipped with an OS (Operating System) independent of the main body 50 and operates independently of the main body 50.

  The operation unit 30 functions as a server device that authenticates a user in communication between the information processing apparatus 10 and the communication terminal 90. The information processing apparatus 10 and the communication terminal 90 perform encrypted communication via the network 5. The encrypted communication is, for example, SSL communication based on an SSL (Secure Sockets Layer) protocol compliant with RFC (Request For Comments) 2246 recommendation. SSL is one of encryption protocols used in communication via the Internet. Hereinafter, an example in which SSL communication is used as encrypted communication will be described, but the encrypted communication may be TLS (Transport Layer Security) communication or the like.

  The main body 50 functions as a storage device that stores the server certificate 100 and the secret key information 130 used for negotiation in order to establish a connection for encrypted communication. That is, the main body 50 has a function as a certificate authority (CA) that issues a server certificate.

  The communication system according to the first embodiment has a configuration in which a certificate authority connected to the communication network 5 is provided separately, and the main body 50 communicates with the certificate authority to acquire the server certificate 100 and the private key information 130. It may be. In addition, the information processing apparatus 10 is not limited to the above-described image forming apparatus as long as the information processing apparatus 10 has an independent function as a server device and a storage device.

  The communication terminal 90 is a client terminal that performs encrypted communication with the server device via the communication network 5. The communication terminal 90 is a communication device such as a notebook PC (Personal Computer). The communication terminal 90 includes an MFP (Multifunction Peripheral) printer having an image processing function, a PJ (Projector), an IWB (Interactive White Board: a white board having an electronic blackboard function capable of mutual communication), digital Output devices such as signage, HUD (Head Up Display) devices, sound output devices such as speakers, industrial machines, imaging devices, sound collectors, medical devices, network home appliances, mobile phones, smartphones, tablet terminals, game consoles, PDAs ( Personal Digital Assistant), digital camera, wearable PC, desktop PC, or the like.

Overview FIG. 2 is a diagram illustrating an overview of a communication system according to the first embodiment. FIG. 2 is a simplified description of the outline of the communication system according to the first embodiment, and details of functions and the like realized by the communication system will be described with reference to drawings and the like to be described later.

  First, an example of a conventional communication system will be described with reference to FIG. FIG. 2A shows a method of performing SSL communication between a communication terminal and an information processing apparatus each having two controllers connected to a network in a conventional communication system. The information processing apparatus includes an SSL server and a GW controller.

  The GW controller stores a server certificate and a private key. The SSL server acquires a server certificate and a private key from the GW controller. When the SSL server receives a connection request from the SSL client, the SSL server transmits a server certificate and a private key acquired from the GW controller to the SSL client, and establishes a connection for encrypted communication with the SSL client. Negotiate. The SSL client and the SSL server establish a connection for performing encrypted communication by performing negotiation using the server certificate and the private key transmitted from the SSL server.

  However, in the conventional method as described above, since the secret key is transmitted from the GW controller to the SSL server, there is a risk of eavesdropping on secret key information with high secrecy.

  Here, an information processing apparatus having a plurality of controllers can perform SSL communication for each controller. In this case, the root CA certificate issued by the certificate authority and the certificate signed with the CA certificate have to be prepared for each controller. Therefore, for example, the cost to be paid to the certificate vendor is required for the number of controllers, and it takes time to introduce the system, which is not preferable in operation.

  In addition, when the public information key pair is set in the GW controller, the information processing apparatus stores the set public key key pair and the server certificate in the SSL server, and then transmits the same server certificate without transmission / reception. The method of using is also conceivable. However, this method has the same public key pair. Since the security of public key cryptography depends on the fact that the same key pair does not exist in the world, this method cannot be adopted.

  As described above, the conventional system for performing encrypted communication via a plurality of communication paths is a security risk of information exchanged by each communication path (SSL client and SSL server, SSL server and GW controller) or system introduction. There are many operational problems, such as the burden of time.

  Next, an example of a communication system according to the first embodiment will be described with reference to FIG. FIG. 2B shows a method of performing SSL communication between an information processing apparatus having two controllers each connected to a network and a communication terminal in the communication system according to the first embodiment. The information processing apparatus 10 includes an operation unit 30 that functions as an SSL server, and a main body unit 50 that functions as a storage device that stores the server certificate 100 and the secret key information 130.

  In the communication system according to the first embodiment, first, the communication terminal 90 serving as an SSL client transmits a connection request to the operation unit 30. When the operation unit 30 receives a connection request from the communication terminal 90, the operation unit 30 acquires the server certificate 100 stored in the main body unit 50. Then, the operation unit 30 selects a key exchange method that does not require transmission of the secret key information 130 as a key exchange method (key exchange algorithm) in the encryption algorithm (cipher suite).

  Here, as a key exchange method for SSL communication, there are a method that requires transmission of the secret key information 130 and a method that does not require transmission of the secret key information 130. A method that requires transmission of the secret key information 130 is, for example, an RSA (Rivest-Shamir-Adleman cryptosystem) method. A method that does not require a secret key is, for example, a DH (Diffie-Hellman) method.

  In the RSA system, it is necessary to transmit a premaster secret that is a material of a secret key at the time of SSL negotiation. Since this information is highly confidential information, the communication path between the communication terminal 90 (SSL client) and the operation unit 30 (SSL server) or the communication between the operation unit 30 (SSL server) and the main unit 50 (storage device). If communication is performed on the route, there is a risk of eavesdropping, which is not preferable in terms of security.

  On the other hand, in the DH method, the communication terminal 90 (SSL client) and the operation unit 30 (SSL server) can be negotiated by transmitting and receiving only publicly available parameters in each communication path. Therefore, the communication system according to the first embodiment includes the communication terminal 90 (SSL client) and the operation unit 30 even when the server certificate 100 is shared in a system that performs encrypted communication via a plurality of communication paths. The security risk of (SSL server) encrypted communication can be reduced.

  Then, the operation unit 30 transmits the signature information signed by the main body unit 50 using the private key information 130 and the server certificate 100 to the communication terminal 90. Since the signature information and the server certificate 100 are plain text and are publicly available parameters, there is no security problem even if they are intercepted. The operation unit 30 and the communication terminal 90 can establish a connection for performing encrypted communication by performing negotiation using the signature information transmitted from the operation unit 30 and the server certificate 100.

  As described above, the communication system according to the first embodiment transmits only the server certificate 100 stored in the storage device (main unit 50) from the storage device (main unit 50) to the SSL server (operation unit 30). By doing so, the key exchange of SSL communication can be performed. Furthermore, the communication system according to the first embodiment can negotiate encrypted communication with the SSL client (communication terminal 90) without transmitting the highly confidential secret key information 130 to the communication path. In a system that performs encrypted communication via a plurality of communication paths, the security of encrypted communication between the server device and the client terminal can be increased.

Hardware Configuration FIG. 3 is a diagram illustrating an example of a hardware configuration of the information processing apparatus according to the first embodiment. The hardware configuration shown in FIG. 3 may have the same configuration in each embodiment, and components may be added or deleted as necessary. The information processing apparatus 10 includes a main body 50 capable of realizing various functions such as a printer function, a copy function, a scanner function, and a fax function, and an operation unit 30 that receives an input corresponding to a user operation. That is, the operation unit 30 is the operation unit 30 (operation panel) of the main body unit 50 including a control unit of the main body unit 50 and a control unit independent of the main body unit 50. That is, in the first embodiment, the information processing apparatus 10 includes the operation unit 30 including a Cheetah (Android (registered trademark)) or a Cheetah application.

Note that accepting a user operation is a concept including accepting information (including a signal indicating a coordinate value of a screen) input according to the user operation. The main body unit 50 and the operation unit 30 are connected to each other via a dedicated communication path 200 so that they can communicate with each other. The communication path 200 is
For example, the USB (Universal Serial Bus) standard can be used, but any standard regardless of wired or wireless may be used.

  The main body 50 performs an operation according to the input received by the operation unit 30. The main body 50 can communicate with an arbitrary external device, and can also perform an operation according to an instruction received from the external device.

  First, the hardware configuration of the main body 50 will be described. As shown in FIG. 3, the main unit 50 includes a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, a RAM (Random Access Memory) 503, and an HDD (Hard Disk Drive) connected to a system bus 510. 504, a scanner engine 505, a plotter engine 506, a FAX control unit 507, a connection interface ((I / F (Interface)), and a communication interface (I / F) 509.

  The CPU 501 comprehensively controls the operation of the main body unit 50. The CPU 501 controls the overall operation of the main unit 50 by executing a program stored in the ROM 502 or the HDD 504 using the RAM 503 as a work area (working area). The CPU 501 realizes various functions such as the printer function, the copy function, the scanner function, and the fax function described above by the scanner engine 505, the plotter engine 506, or the FAX control unit 507.

  A connection interface (I / F) 508 is an interface for communicating with the operation unit 30 via the communication path 200. A communication interface (I / F) 509 is an interface for communicating with an external device or the like via the communication network 5.

  Next, the hardware configuration of the operation unit 30 will be described. As shown in FIG. 3, the operation unit 30 includes a CPU 301, a ROM 302, a RAM 303, a flash memory 304, an operation panel 305, a connection interface (I / F) 306, and a communication interface (connected to a system bus 308. I / F) 307.

  The CPU 301 comprehensively controls the operation of the operation unit 30. The CPU 301 controls the operation of the entire operation unit 30 by executing a program stored in the ROM 302 or the flash memory 304 using the RAM 303 as a work area (work area). The information processing apparatus 10 realizes the communication method according to the present invention, for example, by the CPU 301 executing the program according to the present invention. In addition, the CPU 301 realizes various functions such as displaying information (image) corresponding to an input accepted by a user operation.

  The operation panel 305 accepts various inputs according to user operations and displays various information. For example, the various types of information include information corresponding to the accepted input, information indicating the operation status of the information processing apparatus 10, information indicating a setting state, and the like. In the first embodiment, the operation panel 305 is configured by a liquid crystal display (LCD) equipped with a touch panel function, but is not limited thereto. For example, the operation panel 305 may be configured by an organic EL (Electro Luminescence) display device equipped with a touch panel function. Furthermore, in addition to or instead of this, an operation unit such as a hardware key and a display unit such as a lamp can be provided.

  A connection interface (I / F) 306 is an interface for communicating with the main unit 50 via the communication path 200. A communication interface (I / F) 307 is an interface for communicating with an external device or the like via the communication network 5.

Software Configuration Next, the outline of the software configuration of the information processing apparatus 10 will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of a software configuration of the information processing apparatus according to the first embodiment.

  As shown in FIG. 4, the main unit 50 includes an application layer 551, a service layer 552, and an OS (Operating System) layer 553. The application layer 551, the service layer 552, and the OS layer 553 are various types of software stored in the ROM 502, the HDD 504, or the like. The main body 50 provides various functions by executing these software by the CPU 501.

The software of the application layer 551 is application software (hereinafter referred to as “application”) for operating a hardware resource and providing a predetermined function. For example, the application is a copy application for providing a copy function, a scanner application for providing a scanner function, a fax application for providing a fax function, a printer application for providing a printer function, or the like.

  The software of the service layer 552 is interposed between the application layer 551 and the OS layer 553. The software of the service layer 552 is software for providing an application with an interface for using hardware resources included in the main body unit 50. Specifically, the software of the service layer 552 is software for providing a function of accepting operation requests for hardware resources and arbitrating operation requests. The operation request accepted by the service layer 552 is a request such as reading by the scanner engine 505 or printing by the plotter engine 506, for example.

  The interface function by the service layer 552 is provided not only to the application layer 551 of the main body unit 50 but also to the application layer 351 of the operation unit 30. That is, the application layer 351 of the operation unit 30 has a function using the hardware resources (for example, the scanner engine 505, the plotter engine 506, the FAX control unit 507, etc.) of the main body unit 50 through the interface function of the service layer 552. Can be realized.

  The software of the OS layer 553 is basic software (operating system) for providing a basic function for controlling hardware included in the main body unit 50. The software of the service layer 552 converts the use request of hardware resources from various applications into a command interpretable by the OS layer 553 and passes it to the OS layer 553. Then, when the command is executed by the software of the OS layer 553, the hardware resource performs an operation according to the request of the application.

  The main body 50 communicates with an external device via the communication network 5.

The operation unit 30 includes an application layer 351, a service layer 352, and an OS layer 353. The hierarchical structure of the application layer 351, service layer 352, and OS layer 353 provided in the operation unit 30 is the same as that of the main body unit 50 side. However, the functions provided by the applications in the application layer 351 and the types of operation requests that can be accepted by the service layer 352 are different from those on the main unit 50 side. The application in the application layer 351 is software for operating a hardware resource included in the operation unit 30 and providing a predetermined function. The application of the application layer 351 includes software for providing a UI (User Interface) function for performing operation and display related to functions (printer function, copy function, scanner function, fax function) provided in the main body unit 50. included.

  The operation unit 30 is connected to the communication network 5, for example, wirelessly connected between a wireless LAN AP (wireless LAN Access Point) and a communication interface (I / F) 307, and communicates with an external device via the communication network 5. To do.

  In the information processing apparatus 10 shown in FIG. 4, the software of the OS layer 553 on the main body unit 50 side and the software of the OS layer 353 on the operation unit 30 side are different from each other in order to maintain the independence of functions. That is, the main body 50 and the operation unit 30 operate independently of each other with different operating systems. For example, the software of the OS layer 553 on the main body unit 50 side may adopt LINUX (registered trademark), and the software of the OS layer 353 on the operation unit 30 side may employ Android (registered trademark).

  As described above, in the information processing apparatus 10 shown in FIG. 4, the main unit 50 and the operation unit 30 operate with different operating systems, and therefore communication between the main unit 50 and the operation unit 30 is performed in a common device. This is not communication between processes, but communication between different devices. For example, an operation (command communication) for transmitting an input (instruction content by a user operation) received by the operation unit 30 to the main unit 50, an operation for the main unit 50 notifying the operation unit 30 of an event, etc. It is performed as communication. Accordingly, the operation unit 30 can use the function of the main body 50 by performing command communication with the main body 50. The event notified from the main unit 50 to the operation unit 30 includes the execution status of the operation in the main unit 50, the contents set on the main unit 50 side, and the like.

  In the information processing apparatus 10 shown in FIG. 4, power is supplied to the operation unit 30 from the main body unit 50 via the communication path 200. For this reason, the power control of the operation unit 30 can be performed separately (independently) from the power control of the main body unit 50.

Functional Configuration Next, the functional configuration of the information processing system according to the first embodiment will be described. FIG. 5 is a diagram illustrating an example of a functional configuration of the communication system according to the first embodiment.

  The information processing apparatus 10 includes the operation unit 30 and the main body unit 50 as described above. Functions realized by the operation unit 30 include a transmission / reception unit 31, a determination unit 32, a storage / reading unit 33, a storage unit 34, a reception unit 35, a display control unit 36, a control unit 37, and an input / output unit 38.

  The transmission / reception unit 31 has a function of transmitting / receiving various data to / from an external device via the communication network 5. The transmission / reception unit 31 receives a connection request from the communication terminal 90. In addition, the transmission / reception unit 31 negotiates with the communication terminal 90 that is the transmission source of the connection request to establish a connection for encrypted communication. Then, the transmission / reception unit 31 performs encrypted communication with the communication terminal 90 with which the connection has been established.

  Encrypted communication is, for example, SSL communication compliant with RFC2246 recommendation. SSL is one of encryption protocols used in communication via the Internet. The encrypted communication is not limited to SSL communication, and may be TLS communication, for example. The transmission / reception unit 31 is realized by, for example, the program executed by the communication interface (I / F) 307 and the CPU 301 shown in FIG. The transmission / reception unit 31 is an example of a reception unit and an example of a communication unit.

  The determination unit 32 has a function of determining a key exchange method performed with the communication terminal 90 that is a connection request transmission source. For example, the determination unit 32 selects a key exchange method that does not require transmission of the secret key information 130 from information indicating the key exchange method included in the connection request. SSL communication, which is an example of encrypted communication, includes a plurality of key exchange methods that can encrypt communication between a server and a client. The key exchange method includes, for example, an encryption method that requires transmission of secret key information 130 and an encryption method that does not require transmission of secret key information 130 between a server and a client. An encryption method that requires transmission of the secret key information 130 is, for example, an RSA (Rivest-Shamir-Adleman cryptosystem) method. An encryption method that does not require communication of the secret key information 130 is, for example, a DH (Diffie-Hellman) method.

  The connection request transmitted from the communication terminal 90 includes data such as an encryption algorithm including information indicating an available SSL version number, a current time, and an available key exchange method. The determination unit 32 selects a key exchange method that does not require transmission of the secret key information 130 from information indicating the key exchange method included in the connection request. The determination unit 32 is realized by, for example, a program executed by the CPU 301 illustrated in FIG. The determination unit 32 is an example of a selection unit.

  The storage / reading unit 33 has a function of storing various data in the storage unit 34 and reading out various data from the storage unit 34. The storage / reading unit 33 and the storage unit 34 are realized by, for example, programs executed by the ROM 302, the flash memory 304, and the CPU 301 shown in FIG.

  The accepting unit 35 is a function for accepting a user input operation to the operation panel 305 shown in FIG. The accepting unit 35 is realized by, for example, a program executed by the operation panel 305 and the CPU 301 shown in FIG.

  The display control unit 36 is a function for displaying an operation screen or the like for accepting an input operation by the user on the operation panel 305 shown in FIG. For example, the display control unit 36 causes the operation panel 305 to display a Web page created by HTML (HyperText Markup Language) or the like using a WEB browser. The display control unit 36 is realized by, for example, the operation panel 305 shown in FIG.

  The control unit 37 is a function that controls the processing operation of the operation unit 30. The control unit 37 is realized by, for example, a program executed by the CPU 301 shown in FIG.

  The input / output unit 38 is a function for exchanging various data with the main body unit 50. The input / output unit 38 is communicably connected to the main body 50 via a wired or wireless connection. For example, the input / output unit 38 transmits an acquisition request for the server certificate 100 stored in the main unit 50 to the main unit 50. The input / output unit 38 receives the server certificate 100 transmitted from the main body unit 50.

  In addition, the input / output unit 38 transmits, for example, a signature information acquisition request based on a key exchange method (for example, DH method) that does not require transmission of the secret key information 130 selected by the determination unit 32 to the main body unit 50. . The input / output unit 38 receives the signature information signed by the main body unit 50 using the secret key information 130. The input / output unit 38 is realized by, for example, a program executed by the connection interface (I / F) 306 and the CPU 301 shown in FIG. The input / output unit 38 is an example of a first transmission unit and an example of a second transmission unit.

  The main body 50 includes a transmission / reception unit 51, an authentication processing unit 52, a storage / reading unit 53, a storage unit 54, a generation unit 55, a control unit 56, and an input / output unit 57.

  The transmission / reception unit 51 has a function of transmitting / receiving various data to / from an external device via the communication network 5. The transmission / reception unit 51 is realized by, for example, a program executed by the communication interface (I / F) 509 and the CPU 501 shown in FIG.

  The authentication processing unit 52 is a function that performs an authentication process for encrypted communication between the operation unit 30 that is a server and the communication terminal 90 that is a client. The authentication processing unit 52 performs signature processing using the secret key information 130 stored in the storage unit 54 in response to a request from the operation unit 30. The authentication processing unit 52 is realized by, for example, a program executed by the CPU 501 shown in FIG. The authentication processing unit 52 is an example of a signature unit.

  The storage / reading unit 53 has a function of storing various data in the storage unit 54 and reading out various data from the storage unit 54. The storage / reading unit 53 and the storage unit 54 are realized by, for example, programs executed by the ROM 502, the HDD 504, and the CPU 501 shown in FIG. The storage unit 54 also stores a server certificate 100, private key information 130, and an authentication information management table 150.

  The generation unit 55 is a function that generates the server certificate 100 and the private key information 130. For example, when the server certificate 100 and the private key information 130 are not stored in the storage unit 54, the generation unit 55 generates the server certificate 100 and the private key information 130. The generation unit 55 is realized by, for example, a program executed by the CPU 501 illustrated in FIG. The generation unit 55 is an example of a generation unit.

  The control unit 56 is a function that controls the processing operation of the main body unit 50. The control unit 56 is realized by, for example, a program executed by the CPU 501 shown in FIG.

  The input / output unit 57 is a function for exchanging various data with the operation unit 30. The input / output unit 57 is communicably connected to the operation unit 30 via a wired or wireless connection. For example, the input / output unit 57 receives an acquisition request for the server certificate 100 transmitted from the operation unit 30. Then, the input / output unit 57 transmits the server certificate 100 stored in the storage unit 54 to the operation unit 30.

  Further, the input / output unit 57 receives, for example, a signature information acquisition request transmitted from the operation unit 30. Then, the input / output unit 57 transmits the signature information signed by the authentication processing unit 52 to the operation unit 30. The input / output unit 57 is realized by, for example, a program executed by the connection interface (I / F) 508 and the CPU 501 shown in FIG.

Server Certificate Next, details of data stored in the storage unit 54 will be described. FIG. 6 is a diagram illustrating an example of a server certificate according to the first embodiment. A server certificate 100 shown in FIG. 6 is an electronic certificate used for negotiation in order to perform encrypted communication between a server device (operation unit 30) and a client terminal (communication terminal 90). The server certificate 100 is generated by the main body unit 50 together with the secret key information 130. The main body 50 may be configured to acquire the server certificate 100 and the private key information 130 from a certificate authority connected to the communication network 5.

  The server certificate 100 shown in FIG. 6 includes information on an issuer, a server name, an expiration date, and a public key. The issuer indicates identification information for identifying the certificate authority that issued the server certificate 100. The issuer includes, for example, identification information for identifying the main body 50 that generated the server certificate 100. The server name indicates identification information for identifying the server device authenticated by the certificate authority. The server name includes, for example, the domain name of the operation unit 30 that is a server device. The server name is an example of server identification information.

  The expiration date indicates the expiration date of the server certificate 100. The public key is a public key used by the operation unit 30 serving as a server device for performing encrypted communication. The public key may be set in the server certificate 100 when the server device (operation unit 30) transmits the server certificate 100 to the client terminal (communication terminal 90). The main unit 50 also stores secret key information 130 corresponding to the public key.

Authentication Information Management Table FIG. 7 is a diagram illustrating an example of the authentication information management table according to the first embodiment. The authentication information management table 150 shown in FIG. 7 manages authentication information for performing encrypted communication between the server device (operation unit 30) and the client terminal (communication terminal 90). In the authentication information management table 150, a user ID, a password, a server certificate, and secret key information are stored in association (associated with each other).

  The user ID and password are identification information for identifying a user who uses the communication terminal 90. The user ID may be a user name or the like. Further, the user ID may be a terminal ID or a terminal name for identifying the communication terminal 90.

  The server certificate is, for example, a character code for identifying the server certificate 100 shown in FIG. The private key information is a character code for identifying the private key information 130 corresponding to the server certificate 100.

  Server certificate 100 and private key information 130 are provided independently for each user. The server device (operation unit 30) and the client terminal (communication terminal 90) establish a connection for encrypted communication using the server certificate 100 and the private key information 130 associated with the user ID of the user who transmitted the connection request. Negotiate to do.

Authentication Method Next, authentication processing of the communication terminal 90 in the information processing apparatus 10 will be described. FIG. 8 is a sequence diagram illustrating an example of authentication processing of the communication terminal in the communication system according to the first embodiment. FIG. 8 shows an example in which SSL communication is performed between the communication terminal 90 that is an SSL client and the information processing apparatus 10 that is an SSL server.

  In step S <b> 101, the communication terminal 90 transmits a connection request to the operation unit 30 of the information processing apparatus 10. The connection request is transmitted in a command corresponding to “Client_Hello” of the SSL protocol. The connection request includes “Client_ramdom” (random number data) generated in the communication terminal 90, information indicating a key exchange method that can be used by the communication terminal 90, and the like. The operation unit 30 receives the connection request transmitted from the communication terminal 90 (an example of a reception step).

  In step S102, when the operation unit 30 of the information processing apparatus 10 receives a connection request, the operation unit 30 selects a key exchange method used for encrypted communication (an example of a selection step). Specifically, when the connection request is received by the transmission / reception unit 31, the determination unit 32 of the operation unit 30 is a key that does not require transmission of the secret key information 130 among information indicating a key exchange method included in the connection request. Select the exchange method. Here, it is assumed that the determination unit 32 selects the DH method as an example of a key exchange method that does not require transmission of the secret key information 130. In addition, the determination unit 32 selects a key exchange method and generates “Sever_ramdom” (random number data).

  In step S103, the transmission / reception unit 31 of the operation unit 30 transmits information indicating the key exchange method selected by the determination unit 32 to the communication terminal 90 that is the transmission source of the connection request. Information indicating the key exchange method is transmitted in a command corresponding to “Sever_Hello” of the SSL protocol.

  In step S <b> 104, the input / output unit 38 of the operation unit 30 transmits an acquisition request for the server certificate 100 to the main body unit 50. The input / output unit 57 of the main body unit 50 receives the acquisition request for the server certificate 100 transmitted from the operation unit 30.

  In step S <b> 105, the main body unit 50 of the information processing apparatus 10 reads the server certificate 100 from the storage unit 34 when receiving an acquisition request from the operation unit 30. Specifically, the transmission / reception unit 51 of the main body unit 50 outputs a request for reading the server certificate 100 to the storage / reading unit 53. The storage / reading unit 53 reads the server certificate 100 stored in the storage unit 54 when detecting the output read request. Then, the storage / reading unit 53 outputs the read server certificate 100 to the transmission / reception unit 51.

  In step S <b> 106, the input / output unit 57 of the main body unit 50 transmits the read server certificate 100 to the operation unit 30. The input / output unit 38 of the operation unit 30 receives the server certificate 100 transmitted from the main body unit 50.

  In step S <b> 107, the transmission / reception unit 31 of the operation unit 30 transmits the server certificate 100 acquired from the main body unit 50 to the communication terminal 90. The server certificate 100 is transmitted in a command corresponding to “Certificate” of the SSL protocol. In addition, the order of the process of step S102-step S103 and the process of step S104-step S107 may be changed, and may be performed in parallel.

  In step S <b> 108, the operation unit 30 transmits a request for signature information to the main body unit 50. Specifically, the transmission / reception unit 31 of the operation unit 30 uses the “Client_ramdom” (random number data) transmitted from the communication terminal 90 and the “Sever_ramdom” (random number data) generated by the determination unit 32 as a signature information acquisition request. As shown in FIG. Here, since the data (“Client_ramdom” and “Sever_ramdom”) transmitted as the signature information acquisition request is plain text, it has contents that do not affect the encrypted communication even if it is tapped.

  In step S <b> 109, the authentication processing unit 52 of the main body unit 50 reads the secret key information 130 from the storage unit 54 when the transmission / reception unit 51 receives a signature request for the DH parameter. Specifically, the authentication processing unit 52 of the main body unit 50 outputs a read request for the secret key information 130 to the storage / reading unit 53. The storage / reading unit 53 reads the secret key information 130 stored in the storage unit 54 when detecting the output read request. Then, the storage / reading unit 53 outputs the read secret key information 130 to the authentication processing unit 52.

  In step S <b> 110, the authentication processing unit 52 of the main body unit 50 performs signature processing of the requested data (“Client_ramdom” and “Sever_ramdom”) using the read secret key information 130.

  In step S <b> 111, the input / output unit 57 of the main body unit 50 transmits the signature information signed by the authentication processing unit 52 to the operation unit 30. The signature information includes three data of “Client_ramdom”, “Sever_ramdom” and signatures for these random number data.

  In step S <b> 112, the transmission / reception unit 31 of the operation unit 30 transmits signature information to the communication terminal 90. The signature information is transmitted in a command corresponding to “Sever_Key_Exchange” of the SSL protocol. Then, the communication terminal 90 receives the signature information transmitted from the operation unit 30. Here, since the signature information is plain text, it has contents that do not affect the encrypted communication even if it is tapped. In addition, the order of the process of step S107 and the process of step S112 may be followed, and may be performed in parallel.

  In step S113, the communication terminal 90 negotiates with the operation unit 30 using the received server certificate 100 and signature information (an example of a communication step). Subsequent negotiation processing follows the SSL protocol. The communication terminal 90 and the operation unit 30 that have been successfully negotiated can establish a connection and perform encrypted communication.

  Note that transmission / reception of the server certificate 100 between the operation unit 30 and the main body unit 50 (the processing in steps S104 to S106) may be performed when the operation unit 30 is activated. In this case, the operation unit 30 can simplify the processing and reduce performance degradation as compared to the case of transmitting the acquisition request for the server certificate 100 each time a connection request is received. .

  FIG. 9 is a flowchart illustrating an example of processing in the operation unit according to the first embodiment. FIG. 9 illustrates an example in which a connection request is transmitted from the communication terminal 90 that is an SSL client to the operation unit 30 that is an SSL server, and a negotiation for establishing a connection is performed between the operation unit 30 and the communication terminal 90. It is. The operation unit 30 acquires the server certificate 100 from the main body unit 50 in advance and stores it in the storage unit 34.

  In step S201, when the transmission / reception unit 31 receives a connection request from the communication terminal 90 that is a client, the transmission / reception unit 31 shifts the processing to step S202 (an example of a reception step). On the other hand, the transmission / reception part 31 repeats the process of step S201, when the connection request is not received.

  In step S202, the determination unit 32 selects a key exchange method that does not require transmission of the secret key information 130 from information indicating the key exchange method included in the connection request (an example of a selection step). The connection request includes, for example, information indicating the RSA method as a key exchange method that requires transmission of the secret key information 130 and the DH method as a key exchange method that does not require transmission of the secret key information 130. For example, the determination unit 32 selects the DH method as a key exchange method that does not require transmission of the secret key information 130.

  In step S203, the transmission / reception unit 31 transmits information indicating the key exchange method selected by the determination unit 32 to the communication terminal 90 that is the transmission source of the connection request. Specifically, the transmission / reception unit 31 transmits information indicating a key exchange method (for example, DH method) that does not require transmission of the secret key information 130 selected by the determination unit 32 to the communication terminal 90.

  In step S <b> 204, the input / output unit 38 transmits a signature information acquisition request to the main body unit 50. The signature information acquisition request includes random number data generated by the communication terminal 90 and random number data generated by the determination unit 32.

  In step S205, when the input / output unit 38 receives the signature information signed by the main body unit 50, the input / output unit 38 shifts the processing to step S207. On the other hand, when the signature information signed by the main body unit 50 has not been received, the input / output unit 38 repeats the process of step S205.

  In step S206, the transmission / reception unit 31 transmits the server certificate 100 and signature information acquired from the main body unit 50 to the communication terminal 90 (an example of a communication step). Thereafter, the communication terminal 90 and the operation unit 30 perform negotiation for establishing a connection for encrypted communication, and can perform encrypted communication when the connection is established.

  FIG. 10 is a flowchart illustrating an example of processing in the main body according to the first embodiment. The storage unit 54 of the main unit 50 stores the server certificate 100 and the secret key information 130 used for negotiation for establishing a connection for encrypted communication between the operation unit 30 and the communication terminal 90. And

  In step S301, when the input / output unit 57 receives an acquisition request for the server certificate 100 from the operation unit 30, the input / output unit 57 shifts the processing to step S302. On the other hand, when the input / output unit 57 has not received the acquisition request for the server certificate 100 from the operation unit 30, the input / output unit 57 repeats the process of step S <b> 301. In step S <b> 302, the input / output unit 57 transmits the server certificate 100 stored in the storage unit 54 to the operation unit 30.

  In step S303, when the input / output unit 57 receives a signature information acquisition request from the operation unit 30, the input / output unit 57 shifts the processing to step S304. On the other hand, if the input / output unit 57 has not received the signature information acquisition request, the input / output unit 57 repeats the process of step S303. In step S <b> 304, the storage / reading unit 53 reads the secret key information 130 stored in the storage unit 54.

  In step S305, the authentication processing unit 52 performs signature processing of the requested data using the read secret key information 130, and creates signature information. Specifically, the authentication processing unit 52 performs signature processing using the private key information 130 on the random number data included in the signature information acquisition request received by the transmission / reception unit 51 to create signature information. The signature information includes received random number data and signature data for the random number data. In step S <b> 306, the input / output unit 57 transmits the signature information created by the authentication processing unit 52 to the operation unit 30.

  Here, a process of generating the server certificate 100 in the main body unit 50 that functions as a certificate authority that issues the server certificate 100 will be described. FIG. 11 is a flowchart illustrating an example of a server certificate generation process in the main body according to the first embodiment. In step S <b> 401, when the input / output unit 57 of the main body unit 50 receives an acquisition request for the server certificate 100 from the operation unit 30, the process proceeds to step S <b> 402. On the other hand, when the input / output unit 57 has not received the acquisition request for the server certificate 100 from the operation unit 30, the input / output unit 57 repeats the process of step S 401.

  In step S402, when the server certificate 100 is stored in the storage unit 54, the storage / readout unit 53 of the main body unit 50 shifts the processing to step S403. In step S <b> 403, the storage / reading unit 53 reads the server certificate 100 from the storage unit 54.

  On the other hand, if the server certificate 100 is not stored in the storage unit 54 in step S402, the storage / reading unit 53 of the main body unit 50 shifts the processing to step S404. In step S <b> 404, the generation unit 55 of the main body unit 50 generates the server certificate 100 and the private key information 130. In step S <b> 405, the storage / reading unit 53 of the main body unit 50 stores the server certificate 100 and the private key information 130 generated by the generation unit 55 in the storage unit 34.

  In step S <b> 406, the input / output unit 57 of the main body unit 50 transmits the server certificate 100 generated by the generation unit 55 or the server certificate 100 read from the storage unit 54 to the operation unit 30.

Advantages of the First Embodiment As described above, the communication system according to the first embodiment includes the main body 50 that stores the server certificate 100 and the private key information 130 used for encrypted communication, and the main body 50. The information processing apparatus 10 includes an operation unit 30 that can communicate with the communication unit 90, and performs encrypted communication between the operation unit 30 of the information processing apparatus 10 and the communication terminal 90.

  In the communication system according to the first embodiment, the operation unit 30 that has received the connection request transmitted from the communication terminal 90 has the secret key information 130 as a key exchange method (key exchange algorithm) in an encryption algorithm (cipher suite). Select a key exchange method that does not require transmission. The main body 50 performs signature processing using the secret key information 130 on the random number data transmitted from the operation unit 30 to create signature information. Then, the operation unit 30 establishes a connection for encrypted communication by negotiating with the communication terminal 90 that has transmitted the connection request, using the signature information and the server certificate 100 transmitted from the main body unit 50. can do.

  Therefore, the communication system according to the first embodiment performs encrypted communication between the operation unit 30 that is a server device and the communication terminal 90 that is a client terminal in a system that performs encrypted communication via a plurality of communication paths. Security risk can be reduced.

● Modification of the first embodiment ●
Next, a communication system according to a modification of the first embodiment will be described. The modification of the first embodiment is a process when the information indicating the key exchange method included in the connection request transmitted from the communication terminal 90 does not include a key exchange method that does not require transmission of the secret key information 130. is there.

  FIG. 12 is a flowchart illustrating an example of processing performed by the operation unit according to the second modification of the first embodiment. In step S501, when the transmission / reception unit 31 of the operation unit 30 receives a connection request from the communication terminal 90, which is a client, the process proceeds to step S502. On the other hand, the transmission / reception part 31 repeats the process of step S501, when the connection request is not received.

  In step S502, the determination unit 32 of the operation unit 30 includes a key exchange method (for example, DH) that does not require transmission of the secret key information 130 among the information indicating the key exchange method included in the connection request received by the transmission / reception unit 31. In other words, if the information indicating the key exchange method that can be used by the communication terminal 90 includes a key exchange method that does not require transmission of the secret key information 130, the process proceeds to step S503. The processing from step S503 to step S507 is the same as the processing from step S202 to step S206 shown in FIG.

  On the other hand, in step S <b> 502, the determination unit 32 of the operation unit 30 transmits the secret key information 130 out of information indicating a key exchange method that can be used by the communication terminal 90 included in the connection request received by the transmission / reception unit 31. If the key exchange method (for example, DH method) that does not need to be selected cannot be selected, that is, if the key exchange method that can be used by the communication terminal 90 does not include the key exchange method that does not require transmission of the secret key information 130, The process proceeds to step S508.

  In step S508, the display control unit 36 of the operation unit 30 displays a message screen indicating that the communication terminal 90 that is the transmission source of the connection request is not adapted to a key exchange method that does not require transmission of the secret key information 130. It is displayed on the operation panel 305. The display control unit 36 may display not only the message screen but also a reception screen for accepting a request for changing the setting of the communication terminal 90 on the operation panel 305. The display control unit 36 is an example of a display control unit.

  As described above, the communication system according to the modification of the first embodiment includes the secret key among the key exchange methods (key exchange algorithms) in the encryption algorithm (cipher suite) included in the connection request transmitted from the communication terminal 90. When a key exchange method that does not require transmission of information 130 cannot be selected, the operation unit 30 is displayed to the effect that the key exchange method does not require transmission of secret key information 130. Therefore, the communication system according to the modification of the first embodiment prompts the setting change of the communication terminal 90 when the communication terminal 90 is not adapted to a key exchange method that does not require transmission of the secret key information 130. it can.

● Second embodiment ●
Next, a communication system according to the second embodiment will be described. The same configurations and functions as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the communication system according to the second embodiment, the operation unit 30 of the information processing apparatus 10 according to the first embodiment is configured as a single server device separated from the main body unit 50.

  FIG. 13 is a diagram illustrating an example of a system configuration of a communication system according to the second embodiment. The communication system illustrated in FIG. 13 includes the information processing device 20, the server device 40, and the communication terminal 90. The information processing device 20 is a device corresponding to the main body 50 of the information processing device 10 according to the first embodiment. The server device 40 is a device corresponding to the operation unit 30 of the information processing apparatus 10 of the first embodiment.

  The server device 40 can store the server certificate 100 in the storage unit 34, and selects a key exchange method (key exchange algorithm) in an encryption algorithm (cipher suite) depending on whether or not it is connected to the information processing device 20 To do. Specifically, when connected to the information processing apparatus 20, the server device 40 rejects (does not select) a key exchange method that requires transmission of the secret key information 130 as a key exchange method. That is, it is the same state as the configuration shown in the first embodiment. On the other hand, when not connected to the information processing apparatus 20, the server device 40 does not reject (can select) a key exchange method that requires transmission of the secret key information 130 as a key exchange method.

  As a result, the communication system according to the second embodiment allows the server device 40 and the communication terminal even when the information processing device 20 (storage device) that stores the server certificate is removed from the server device 40 (SSL server). Encryption communication (SSL communication) can be performed with 90 (SSL client).

  FIG. 14 is a diagram illustrating an example of a functional configuration in the communication system according to the second embodiment. The functions realized by the information processing apparatus 20 shown in FIG. 14 are the same as the functions realized by the main body 50 of the information processing apparatus 10 shown in FIG. 14 includes a detection unit 39 in addition to the functions realized by the operation unit 30 shown in FIG.

  The detection unit 39 is a function for detecting whether or not there is a connection with the information processing apparatus 20 that functions as a main body unit. The detection unit 39 is realized by, for example, a program executed by the CPU 301 shown in FIG. The detection unit 39 is an example of a detection unit.

  For example, when the connection of the information processing apparatus 20 is not detected by the detection unit 39, the determination unit 32 selects a key exchange method (for example, RSA method) that requires transmission of the secret key information 130. On the other hand, for example, when the detection unit 39 detects the connection of the information processing apparatus 20, the determination unit 32 selects a key exchange method (for example, DH method) that does not require transmission of the secret key information 130.

The storage unit 34 stores a server certificate 100a, secret key information 130a, and an authentication information management table 150a. The server certificate 100, the secret key information 130, and the authentication information management table 150 stored in the storage unit 34 are respectively stored in the storage unit 54 of the main body unit 50.
The server certificate 100, the private key information 130, and the authentication information management table 150 are the same as those stored in FIG.

FIG. 15 is a flowchart illustrating an example of processing of the server apparatus according to the second embodiment.
In step S601, when the transmission / reception unit 31 of the server apparatus 40 receives a connection request from the communication terminal 90, the process proceeds to step S602. On the other hand, the transmission / reception part 31 repeats the process of step S601, when the connection request is not received from the communication terminal 90. FIG.

  In step S602, when the detection unit 39 of the server device 40 detects that the information processing device 20 is connected by the input / output unit 38, the detection unit 39 shifts the processing to step S603. In step S603, the determination unit 32 of the server device 40 selects a key exchange method (for example, DH method) that does not require transmission of the secret key information 130.

  On the other hand, if the detection unit 39 of the server device 40 cannot detect that the information processing device 20 is connected by the input / output unit 38 in step S602, the process proceeds to step S604. In step S604, the determination unit 32 of the server device 40 selects a key exchange method (for example, RSA method) that requires transmission of the secret key information 130.

  In step S <b> 605, the transmission / reception unit 31 transmits information indicating the key exchange method selected by the determination unit 32 to the communication terminal 90.

Effect of the Second Embodiment As described above, the communication system according to the second embodiment is a key that requires transmission of the secret key information 130 when the server device 40 is not connected to the information processing device 20. When an exchange method is selected and the server device 40 is connected to the information processing device 20, a key exchange method that does not require transmission of the secret key information 130 is selected. Therefore, in the communication system according to the second embodiment, when the server device 40 is not connected to the information processing device 20 (storage device) that stores the server certificate 100, that is, the server device 40 is connected to the information processing device 20. Even if it is removed, encrypted communication with improved security can be performed.

● Summary ●
As described above, the communication system according to an embodiment of the present invention is a storage device (main body unit 50, information that stores server certificate 100 (an example of server identification information) and private key information 130 used for encrypted communication. It is a communication system provided with the processing apparatus 20) and the server apparatus (the operation part 30, the server apparatus 40) which can communicate with a memory | storage device. In addition, the communication system according to an embodiment of the present invention receives a connection request for encrypted communication from the communication terminal 90 (an example of a client terminal), and among the information indicating the key exchange method included in the received connection request, A key exchange method that does not require transmission of the secret key information 130 is selected. Based on the signature information signed using the secret key information 130, encrypted communication is performed with the communication terminal 90.

  Therefore, the communication system according to the embodiment of the present invention can perform encrypted communication with the communication terminal 90 without transmitting the highly confidential secret key information 130 to the communication path. In a system that performs encrypted communication via the network, the security of encrypted communication between the server device and the communication terminal 90 can be increased.

  In the communication system according to an embodiment of the present invention, the server device (operating unit 30, server device 40) and the storage device (main unit 50, information processing device 20) are connected to the server certificate 100 (server identification information An example) acquisition request is transmitted. In the communication system according to the embodiment of the present invention, the server device (the operation unit 30 and the server device 40) sends a signature based on the selected key exchange method to the storage device (the main body unit 50 and the information processing device 20). Send an information acquisition request. The communication system according to an embodiment of the present invention performs encrypted communication with the communication terminal 90 (an example of a client terminal) based on the acquired server certificate 100 and signature information.

  Therefore, the communication system according to an embodiment of the present invention needs to communicate the server certificate 100 and the private key information 130 through a communication path when the server certificate 100 is shared between the server device and the storage device. Therefore, more secure encrypted communication can be operated.

  Furthermore, in the communication system according to an embodiment of the present invention, the server device (the operation unit 30 and the server device 40) sends a server certificate to the storage device (the main unit 50 and the information processing device 20) when the server device is activated. An acquisition request for 100 (an example of server identification information) is transmitted. Therefore, in the communication system according to the embodiment of the present invention, every time the server apparatus receives a connection request from the communication terminal 90 (an example of a client terminal), a server certificate 100 acquisition request is transmitted to the storage device. In comparison, the processing can be simplified and the influence on the performance of the server device can be reduced.

  In the communication system according to the embodiment of the present invention, when the storage device (the main body unit 50, the information processing device 20) receives the signature information acquisition request, the secret key information 130 is used for the received data. Perform signature processing. In the communication system according to the embodiment of the present invention, the server device (the operation unit 30 and the server device 40) acquires the signed signature information from the storage device. Therefore, the communication system according to an embodiment of the present invention needs to communicate the server certificate 100 and the private key information 130 through a communication path when the server certificate 100 is shared between the server device and the storage device. Therefore, more secure encrypted communication can be operated.

  Furthermore, in the communication system according to the embodiment of the present invention, when the storage device (main body unit 50, information processing device 20) receives an acquisition request for the server certificate 100 (an example of server identification information), the server certificate 100 and secret key information 130 are generated. Therefore, the communication system according to the embodiment of the present invention generates the server certificate 100 by itself even when the server certificate 100 is not stored in the storage device, and provides the generated server certificate 100 to the server device. can do.

  In the communication system according to the embodiment of the present invention, the server device 40 detects the presence / absence of connection with the storage device (information processing device 20). In the communication system according to the embodiment of the present invention, the server device 40 selects a key exchange method that requires transmission of the secret key information 130 when the connection with the storage device is not detected, and the storage device Is detected, a key exchange method that does not require transmission of the secret key information 130 is selected. Therefore, the communication system according to an embodiment of the present invention performs encrypted communication between the server device 40 and the communication terminal 90 (an example of a client terminal) even when the server device is removed from the storage device. Can do.

  Furthermore, in the communication system according to an embodiment of the present invention, the server device (the operation unit 30, the server device 40) includes information indicating a key exchange method that does not require transmission of the secret key information 130 in the received connection request. If not, a display screen to that effect is displayed. Therefore, the communication system according to the embodiment of the present invention changes the setting of the communication terminal 90 when the communication terminal 90 (an example of a client terminal) is not adapted to a key exchange method that does not require transmission of the secret key information 130. Can be encouraged.

  The communication method according to an embodiment of the present invention also includes a storage device (main unit 50, information processing device 20) that stores a server certificate 100 (an example of server identification information) and secret key information 130 used for encrypted communication. And a communication method executed by a communication system including server devices (operation unit 30 and server device 40) that can communicate with the storage device. The communication method according to an embodiment of the present invention includes a reception step of receiving a connection request for encrypted communication from a communication terminal 90 (an example of a client terminal), and information indicating a key exchange method included in the connection request. A selection step of selecting a key exchange method that does not require transmission of the secret key information 130, and a communication step of performing encrypted communication with the communication terminal 90 based on the signature information signed using the secret key information 130. Execute.

  Therefore, the communication method according to the embodiment of the present invention can perform encrypted communication with the communication terminal 90 without transmitting the highly confidential secret key information 130 to the communication path. In a system that performs encrypted communication via the network, the security of encrypted communication between the server device and the communication terminal 90 can be increased.

● Supplement ●
The functions of the embodiments can be realized by a computer-executable program written in a legacy programming language such as an assembler, C, C ++, C #, Java (registered trademark), an object-oriented programming language, or the like. The program for executing the function can be distributed through a telecommunication line.

  In addition, programs for executing the functions of the embodiments are ROM, EEPROM (Electrically Erasable Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), flash memory, flexible disk, CD (Compact Disc) − Store and distribute in device-readable recording media such as ROM, CD-RW (Re-Writable), DVD-ROM, DVD-RAM, DVD-RW, Blu-ray Disc, SD card, MO (Magneto-Optical disc), etc. You can also.

  Furthermore, part or all of the functions of each embodiment can be mounted on a programmable device (PD) such as an FPGA (Field Programmable Gate Array), or can be mounted as an ASIC. Circuit configuration data (bitstream data) downloaded to the PD in order to realize the above functions on the PD, HDL (Hardware Description Language) for generating the circuit configuration data, VHDL (Very High Speed Integrated Circuits Hardware Description Language), It can be distributed on a recording medium as data described in Verilog-HDL or the like.

  The communication system, communication method, and program according to an embodiment of the present invention have been described so far. However, the present invention is not limited to the above-described embodiment, and other embodiments may be added, changed, or deleted. These modifications can be made within the range that can be conceived by those skilled in the art, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

5 Communication Network 10 Information Processing Device 20 Information Processing Device (Example of Storage Device)
30 operation unit (an example of a server device)
31 Transmission / reception unit (an example of a reception unit, an example of a communication unit)
32 Judgment part (an example of selection means)
36 Display control unit (an example of display control means)
38 Input / output unit (an example of a first transmission unit, an example of a second transmission unit)
39 Detection unit (an example of detection means)
40 Server device 50 Main unit (an example of a storage device)
52 Authentication processing unit (an example of signature means)
55 Generation Unit (Example of Generation Unit)
90 Communication terminal (example of client terminal)

JP2015-115893A

Claims (10)

A communication system comprising a storage device that stores server identification information and secret key information used for encrypted communication, and a server device that can communicate with the storage device,
Receiving means for receiving a connection request for encrypted communication from a client terminal;
A selection means for selecting a key exchange method that does not require transmission of the secret key information from information indicating a key exchange method included in the connection request;
Communication means for performing encrypted communication with the client terminal based on signature information signed using the secret key information;
A communication system comprising: The communication system according to claim 1, further comprising:
The server device
First transmission means for transmitting an acquisition request for the server identification information to the storage device;
Second transmission means for transmitting the signature information acquisition request to the storage device,
The communication means is a communication system that performs the encrypted communication with the client terminal based on the acquired server identification information and the signature information.   The communication system according to claim 2, wherein the first transmission unit transmits an acquisition request for the server identification information to the storage device when the server device is activated. The communication system according to claim 2 or 3, further comprising:
The storage device
A communication system comprising signature means for performing signature processing using the secret key information on the received data when the signature information acquisition request is received. The communication system according to any one of claims 2 to 4, further comprising:
The storage device
A communication system comprising generating means for generating the server identification information and the secret key information when receiving the server identification information acquisition request. The communication system according to any one of claims 1 to 5, further comprising:
The server device
A detection means for detecting the presence or absence of connection with the storage device;
When the connection with the storage device is not detected, the selection means selects a key exchange method that requires transmission of the secret key information,
A communication system in which, when connection with the storage device is detected, the selection means selects a key exchange method that does not require transmission of the secret key information. The communication system according to any one of claims 1 to 6, further comprising:
The server device
When the received connection request does not include information indicating a key exchange method that does not require transmission of the secret key information, a communication system including display control means for displaying a display screen indicating that. The encrypted communication is SSL (Secure Sockets Layer) communication or TLS (Transport Layer Security) communication,
The communication system according to any one of claims 1 to 7, wherein the key exchange method that does not require transmission of the secret key information is a DH (Diffie-Hellman) method. A communication method executed by a communication system comprising a storage device that stores server identification information and secret key information used for encrypted communication, and a server device that can communicate with the storage device,
Receiving a connection request for the encrypted communication from a client terminal;
A selection step of selecting a key exchange method that does not require transmission of the secret key information from information indicating a key exchange method included in the connection request;
A communication step for performing encrypted communication with the client terminal based on signature information signed using the secret key information;
Communication method to execute.   A program for causing a computer to execute the communication method according to claim 9.

Images