JP6679867B2 - Communication system, communication device, and computer program - Google Patents

Description

  The present invention relates to a communication technique of a communication device and a service providing device that provides a specific service to the communication device.

  Patent Document 1 discloses a network printing system including a client device and a print server. The client device can communicate with a print server connected via the Internet to use the print service provided by the print server. Communication encrypted using a common key is used for communication between the client device and the print server.

JP, 2006-339847, A

  However, in the above technique, when the print server refuses to use the encryption method that can be used by the client device, there is a possibility that the client device and the print server cannot execute encrypted communication. In particular, if the print server changes the encryption method that the client device is permitted to use, the client device will change from the state in which encrypted communication with the print server is possible to the encryption process with the print server. Communication becomes impossible, which is inconvenient for the user of the client device.

  This specification describes that encrypted communication is performed between a communication device and a service providing device even when the use of an encryption method that can be used by the communication device is rejected by a service providing device that provides a specific service. Disclosed is a technique capable of maintaining a possible state.

  The technology disclosed in this specification can be implemented as the following application examples.

Application Example 1 In a communication system including a communication device and a relay device, each of the communication device and the relay device communicating with a service providing device that provides a specific service to the communication device. Therefore, the communication device transmits the first method information indicating one or more encryption methods that can be used by the communication device to the service providing device without passing through the relay device. And a first method notification indicating a first encryption method to be used among one or more encryption methods indicated in the first method information, as a response to the transmission of the first method information, A first receiving unit that receives from the service providing apparatus any one of a refusal notification indicating refusal to use one or more encryption methods included in one method information, and the first method notification is received. If the Using a first establishing unit that establishes encrypted communication according to the first encryption method and an encrypted communication according to the established first encryption method with a network providing device without using the relay device. A first communication unit that communicates target data relating to the specific service with the service providing device; and a first communication unit that establishes encrypted communication with the relay device when the refusal notification is received. A second communication unit that communicates the target data with the service providing device via the relay device by using encrypted communication established between the second establishing unit and the relay device; The relay device includes a third establishing unit that establishes encrypted communication with the communication device, and the encrypted communication between the communication device and the relay device, after establishing encrypted communication with the communication device. A number indicating the multiple encryption methods that the device can use A second transmitting unit for transmitting method information, wherein the one or more encryption methods included in the second method information include an encryption method different from the first encryption method. And, as a response to the transmission of the second scheme information, a second scheme notification indicating a second encryption scheme to be used among one or more encryption schemes included in the second scheme information, the service providing. A second receiving unit which is received from a device, and a fourth establishing unit which establishes encrypted communication according to the second encryption system between the service providing device when the second system notification is received; Relays the communication of the target data between the communication device and the service providing device by using the encrypted communication established with the communication device and the encrypted communication established with the service providing device. A relay unit that
A communication system comprising:

According to the above configuration, even when the service providing apparatus refuses to use the encryption method that can be used by the communication apparatus, the communication apparatus communicates with the service providing apparatus by encrypted communication via the relay apparatus. Thus, it is possible to communicate target data regarding a specific service. As a result, even when the service providing apparatus refuses to use the encryption method that can be used by the communication apparatus, it is possible to maintain a state in which the communication apparatus and the service providing apparatus can perform encrypted communication. it can.
[Application Example 2]
The communication system according to Application Example 1,
The relay device further includes
A first storage unit that stores the second encryption method indicated in the second method notification when the second method notification is received;
A third receiving unit that receives the first system information from the communication device after storing the second encryption system;
A selection unit for selecting a third encryption method to be used from one or more encryption methods included in the first method information using the stored second encryption method;
A third transmission unit that transmits a third method notification indicating the third encryption method to the communication device as a response to the reception of the first method information;
Equipped with
The communication device further comprises
A fourth transmission unit that transmits the first method information to the relay device after the second encryption method is stored,
A fourth receiving unit that receives the third system notification from the relay device as a response to the transmission of the first system information;
Equipped with
The communication system, wherein the second establishing unit of the communication device establishes encrypted communication according to the third encryption system with the relay device when the third system notification is received.
[Application Example 3]
The communication system according to Application Example 2,
The second encryption system and the third encryption system exchange an authentication algorithm for device authentication, an encryption algorithm for encrypting communication data, and an encryption key used in the encryption algorithm. A key exchange algorithm for, and a hash algorithm used in at least one of the authentication algorithm, the encryption algorithm and the key exchange algorithm, a plurality of items of algorithms,
The selection unit of the relay device,
For at least one specific item of the plurality of items of algorithm, specify an algorithm adopted in the second encryption method,
An encryption method that employs an algorithm that is the same as or similar to the algorithm used in the second encryption method for at least one of the specific items among one or more encryption methods included in the first method information. Is selected as the third encryption method.
[Application example 4]
The communication system according to Application Example 3,
The relay device further stores, for at least one of the specific items, priority information indicating a priority when selecting one algorithm from a plurality of algorithms based on at least one of a security level and a processing speed. A second storage unit,
The selecting unit of the relay device uses the priority information to adopt an encryption method in which at least one of security level and processing speed is the same as or close to that of the algorithm used in the second encryption method. Is selected as the third encryption method.
[Application example 5]
The communication system according to any one of Application Examples 2 to 4,
The first storage unit of the relay device stores the second encryption method in association with an identifier indicating the service providing device,
The third receiving unit of the relay device receives the first method information and the identifier indicating the service providing device from the communication device,
The communication system, wherein the selection unit of the relay device selects the third encryption method using the second encryption method stored in association with the identifier indicating the service providing apparatus.
[Application Example 6]
The communication system according to any one of Application Examples 1 to 5,
The communication device includes a generation unit that generates image data by optically reading a document,
The communication of the target data includes transmission of the image data from the communication device to the service providing device,
The relay device further includes
After the fourth establishing unit establishes the encrypted communication according to the second encryption method, the fifth transmitting unit transmits an establishment notification indicating establishment of encrypted communication according to the second encryption method to the communication device. Prepare,
The communication device further comprises
A fifth receiver that receives the establishment notification;
A generation control unit that generates the image data using the generation unit after the establishment notification is received and the encrypted communication with the relay device is disconnected;
Equipped with
The second establishing unit of the communication device establishes encrypted communication again with the relay device after the generation of the image data,
The second communication unit of the communication device transmits the image data to the communication device by using encrypted communication established with the relay device,
The third establishing unit of the relay device establishes encrypted communication again with the communication device after the image data is generated,
The second transmission unit of the relay device transmits the second scheme information again to the service providing device,
The second receiving unit of the relay device receives the second method notification from the service providing device again,
The fourth establishing unit of the relay device, when the second system notification is received again, re-establishes encrypted communication according to the second encryption system with the service providing device. ,
The relay unit of the relay device receives the image data from the communication device by using the encrypted communication established with the communication device, and the encrypted communication established with the service providing device. A communication system for transmitting the image data to the service providing apparatus by using.
[Application Example 7]
The communication system according to any one of Application Examples 1 to 6,
The communication device further transmits, to the relay device, a communication request with the service providing device to communicate by using the encrypted communication established with the relay device by the second establishing unit. A sixth transmitter,
The relay device further uses a cryptographic communication established with the service providing device by the third establishing unit to receive a communication request with the service providing device from the communication device. Equipped with
The communication system, wherein the second transmission unit of the relay device transmits the second method information to the service providing device based on the communication request.
[Application Example 8]
The communication system according to any one of Application Examples 1 to 7,
The communication of the target data is communication between applications belonging to the application layer,
A communication system in which the transmission and reception of the first method information and the second method information is communication in a layer lower than the application.
[Application Example 9]
A communication system according to Application Example 8,
A computer program, wherein a protocol for transmitting and receiving the first method information and the second method information is SSL (Secure Sockets Layer) / TLS (Transport Layer Security).

Application Example 10 A communication apparatus, which transmits method information indicating one or more encryption methods that can be used by the communication apparatus to a service providing apparatus that provides a specific service without using a relay apparatus. A transmitting unit for transmitting, a method notification indicating a specific encryption method to be used among the one or more encryption methods indicated in the method information, as a response to the transmission of the method information, and included in the method information. A rejection notification indicating refusal to use one or more encryption methods from the service providing apparatus, and a service providing apparatus when the method notification is received. Between the service providing device and the first establishing unit that establishes encrypted communication according to the specific encryption method, and the encrypted communication according to the established specific encryption method. The service Between the first communication unit that communicates the target data regarding the network and the relay device when the refusal notification is received, and the second establishment unit that establishes the encrypted communication with the relay device. A second communication unit that communicates the target data with the service providing device via the relay device using established cryptographic communication.

  According to the above configuration, even when the service providing apparatus refuses to use the encryption method that can be used by the communication apparatus, the communication apparatus communicates with the service providing apparatus by encrypted communication via the relay apparatus. Thus, it is possible to communicate target data regarding a specific service. As a result, even when the service providing apparatus refuses to use the encryption method that can be used by the communication apparatus, it is possible to maintain a state in which encrypted communication can be performed between the communication apparatus and the service providing apparatus. it can.

Application Example 11 A computer program for a relay device, comprising a first establishing function for establishing encrypted communication with a communication device, and a specific service after establishing encrypted communication with the communication device. Is a transmission function for transmitting method information indicating a plurality of encryption methods that can be used by the relay device to a service providing apparatus that provides, and one or more encryption methods included in the method information are A transmission function including an encryption method different from one or more encryption methods usable by the communication device, and one or more encryption methods included in the method information as a response to the transmission of the method information. Between the receiving function of receiving a method notification indicating the specific encryption method to be used from the service providing apparatus from the service providing apparatus and the service providing apparatus when the method notification is received, Using a second establishing function for establishing an encrypted communication according to a fixed encryption method, an encrypted communication established with the communication device, and an encrypted communication established with the service providing device, A computer program that causes a computer to realize a relay function of relaying communication of the target data between the communication device and the service providing device.

  According to the above configuration, the relay device establishes the encrypted communication with the communication device and also establishes the encrypted communication with the service providing server 300. Therefore, even when the service providing apparatus refuses to use the encryption method that can be used by the communication apparatus, the target data related to the specific service is exchanged with the service providing apparatus by the encrypted communication via the relay apparatus. Can communicate. As a result, even when the service providing apparatus refuses to use the encryption method that can be used by the communication apparatus, it is possible to maintain a state in which encrypted communication can be performed between the communication apparatus and the service providing apparatus. it can.

  The present invention can be implemented in various forms, for example, a relay device that relays communication between a communication device and a service providing device that provides a specific service to the communication device, and a communication device. Method of communication between a device and a service providing device that provides a specific service to the communication device, a computer program for the communication device, and a recording medium recording the computer program (for example, a non-transitory recording medium) , Etc. can be realized.

It is a block diagram showing a configuration of a system 1000 as a present embodiment. 3 is a conceptual diagram of information held by devices in the system 1000. FIG. 9 is a sequence diagram showing an example of communication of the system 1000. FIG. 9 is a sequence diagram showing an example of communication of the system 1000. FIG. 9 is a sequence diagram showing an example of communication of the system 1000. FIG. It is a flowchart of selection of a used encryption method.

A. Example:
A-1: Configuration of System 1000 Next, an embodiment will be described based on an example. FIG. 1 is a block diagram showing the configuration of a system 1000 according to this embodiment. FIG. 2 is a conceptual diagram of information held by devices in the system 1000.

  The system 1000 includes a device 100 as a communication device, a relay server 200, and a service providing server 300. The device 100 is connected to a LAN (Local Area Network) 70. The LAN 70 is connected to the Internet 80. The relay server 200 and the service providing server 300 are connected to the Internet 80. As a result, the device 100 and the relay server 200, and the relay server 200 and the service providing server 300 can communicate with each other via the LAN 70 or the Internet 80.

  The device 100 is a so-called multi-function peripheral that executes image processing such as image printing and image scanning. The device 100 is not limited to the multifunction peripheral, and may be another image processing device such as a scanner, a printer, a digital camera, or a general-purpose device such as a mobile terminal device or a personal computer. The device 100 includes a CPU 110, a nonvolatile storage device 120 such as a hard disk drive or an EEPROM, a volatile storage device 130 such as RAM, and a printer unit that prints an image by a predetermined method (for example, a laser method or an inkjet method). 140, a scanner unit 150 that generates scan data by optically reading an object (for example, a paper document), an operation unit 160 such as a touch panel and buttons, and a display unit such as a liquid crystal panel that is superimposed on the touch panel. 170 and a network interface (IF) 180. The network IF 180 is, for example, an interface compliant with the Ethernet (registered trademark) standard, and is used to connect to the LAN 70.

  The non-volatile storage device 120 stores a computer program PG1, server information SI, and an encryption method list CL1. The volatile storage device 130 is provided with a buffer area 131 for temporarily storing various intermediate data generated when the CPU 110 performs processing.

  The computer program PG1 is provided in a form of being stored in the nonvolatile storage device 120 in advance when the device 100 is shipped. The computer program PG1 may be provided in the form of being downloaded from a server connected to the device 100 via the Internet 80, or may be provided in the form of being stored in a CD-ROM, a DVD-ROM or the like.

  The CPU 110 functions as a controller of the device 100 by executing the computer program PG1. For example, the CPU 110 controls the printer unit 140 and the scanner unit 150 to execute printing and scanning. Further, the CPU 110 can realize a server communication function of communicating with the service providing server 300 without the relay server 200 or via the relay server 200. Although details will be described later, the server communication function of the present embodiment is executed to transmit the scan data generated in the device 100 to the service providing server 300.

  The server information SI is information on the server to be communicated in the server communication function. The server information SI is information for the device 100 to indicate the relay server 200 and the service providing server 300 with which to communicate, specifically, a URL (abbreviation of Uniform Resource Locator) and authentication for logging in to the service providing server 300. Contains information (username and password).

  The encryption method list CL1 is a list showing one or more encryption methods that the device 100 can use. The encryption method is an encryption communication method between the device 100 and an external device (for example, the relay server 200 or the service providing server 300) connected to the device 100 via a network. The encryption method is defined by an encryption suite that shows the algorithms of a plurality of items used for encrypted communication side by side.

  FIG. 2A shows an example of the encryption method list CL1. The encryption method list CL1 includes a plurality of encryption suites each indicating an encryption method. Algorithms of a plurality of items included in one encryption method include a key exchange algorithm, an authentication algorithm, an encryption algorithm, and a hash algorithm.

  The key exchange algorithm is an algorithm for exchanging an encryption key (shared key) used for encryption of communication data between two devices that perform communication. For the key exchange algorithm, for example, “RSA”, “DHE (abbreviation of Diffie-Hellman key Exchange)”, and “ECDHE (abbreviation of Elliptic Curve Diffie-Hellman key Exchange)” are used.

  The RSA key exchange algorithm includes a process in which the first device sends to the second device encrypted data in which the shared key is encrypted using the public key of the second device. The second device obtains the shared key by decrypting the encrypted data with the confidence secret key. Since the third party does not have the private key, the third party cannot decrypt the intercepted encrypted communication. However, if a secret key can be obtained in the future, the third party can decrypt and view the encrypted communication that has been eavesdropped by then. Therefore, the RSA key exchange algorithm cannot achieve so-called PFS (abbreviation of Perfect Forward Secrecy).

  On the other hand, in the DHE key exchange algorithm and the ECDHE key exchange algorithm, the shared key is exchanged using random parameters generated by the first device and the second device for each session. If these parameters are leaked, they have no effect on the security of communication in another session. Therefore, so-called PFS can be achieved by the DHE key exchange algorithm and the ECDHE key exchange algorithm.

  From this point of view, it can be said that the DHE key exchange algorithm and the ECDHE key exchange algorithm have a higher security level than the RSA key exchange algorithm.

  The authentication algorithm is an algorithm for authenticating at least one of the two devices that perform communication. As the authentication algorithm, for example, “RSA” and “DSA (abbreviation of Digital Signature Algorithm)” are used.

  The encryption algorithm is an algorithm for encrypting communication data using the exchanged encryption key (shared key). As the encryption algorithm, for example, "DES (abbreviation of Data Encryption Standard)", "3DES (abbreviation of Triple Data Encryption Standard)", and "AES (abbreviation of Advanced Encryption Standard)" are used. It should be noted that a numeral (for example, 128, 256) indicating the key length of the encryption key is added to the end of each alphabet indicating the encryption algorithm, and expressed as, for example, DES128 and DES256. Among encryption algorithms of the same type, the longer the key length, the higher the security level.

  The hash algorithm is an algorithm for generating a digest of data. The hash algorithm is used in at least one of the other algorithms. The hash algorithm is used, for example, in the authentication algorithm to generate signature data and verify a digital certificate. As the hash algorithm, for example, "SHA (abbreviation of Secure Hash Algorithm) 1", "SHA256", "SHA512" or the like is used. The security level increases in the order of “SHA512”> “SHA256”> “SHA1”.

  Here, in this embodiment, as shown in FIG. 2, four types of encryption methods A to D are used. FIG. 2 shows an encryption suite indicating each of the encryption methods A to D. As can be seen from these cipher suites, the combination of the key exchange-authentication-encryption-hashing algorithms of encryption method A is "RSA"-"RSA"-"AES128"-"SHA256". The combination of the algorithms of the encryption method B is "RSA"-"RSA"-"AES256"-"SHA256". The combination of the algorithms of the encryption method C is "DHE"-"RSA"-"AES128"-"SHA1". The combination of the algorithms is “DHE”-“RSA”-“AES256”-“SHA1”.

  As shown in FIG. 2A, the encryption method list CL1 includes an encryption suite indicating the encryption method A and an encryption suite indicating the encryption method B. That is, the device 100 can use the two encryption methods A and B. As shown in FIG. 2A, the encryption methods A and B adopt "RSA" as a key exchange algorithm, and do not adopt "DHE" or "ECDHE" having a higher security level.

  Relay server 200 (FIG. 1) is a server provided by the vendor of device 100. Although the details will be described later, the relay server 200 relays communication between a plurality of devices including the device 100 and a plurality of service providing servers including the service providing server 300.

  The relay server 200 includes a CPU 210, a non-volatile storage device 220 such as a hard disk drive, a volatile storage device 230 such as RAM, and a network IF 280 for connecting to the Internet 80.

  The non-volatile storage device 220 stores a computer program PG2, an encryption method list CL2, a registration table CT, and reference information RI. The volatile storage device 230 is provided with a buffer area 231 that temporarily stores various intermediate data generated when the CPU 210 performs processing.

  The computer program PG2 may be provided in a form uploaded from a computer of a vendor connected via the Internet 80, or may be provided in a form stored in a CD-ROM, a DVD-ROM or the like. The CPU 210 realizes the function of the relay server 200 as a controller by executing the computer program PG2. Details of these functions will be described later.

  The encryption method list CL2 is a list showing a plurality of encryption methods that can be used by the relay server 200. As shown in FIG. 2B, in the encryption method list CL2, in addition to the encryption suites showing the encryption methods A and B shown in the encryption method list CL1, the encryption shown in the encryption method list CL1 is added. An encryption suite indicating encryption methods C and D different from the encryption method is included. That is, the relay server 200 can use four different encryption methods A to D. The relay server 200 communicates not only with the device 100, but also with a plurality of devices (not shown) such as a multifunction peripheral, a scanner, and a printer sold by a vendor who provides the relay server 200. The relay server 200 also communicates with the service providing server 300 and a plurality of service providing servers (not shown). For this reason, the relay server 200 is preferably able to use a number of encryption methods that can be used by these devices and service providing servers.

  The registration table CT is a table in which the information of the service providing server to which the relay server 200 has established the encrypted communication is registered. As shown in FIG. 2C, one entry E1 registered in the registration table CT is associated with a URL as an identifier indicating a service providing server and a used encryption method. The encryption method used is the encryption method used in the encrypted communication established with the service providing server.

  The reference information RI is information indicating the order of security levels for a specific algorithm among algorithms of a plurality of items included in the encryption method. The reference information RI of FIG. 2D indicates that the encryption algorithm has a higher security level in the order of “AES”> “3DES”> “DES”.

  The service providing server is a server that provides a client (for example, the device 100) with a specific service. For example, the service providing server 300 provides a storage service capable of storing image data. The storage service includes, for example, a storage service that stores the data transmitted from the client and a social network service that stores and publishes the data transmitted from the client. The storage service specifically includes known services such as "Evernote (registered trademark)", "Dropbox (registered trademark)", and "Facebook (registered trademark)".

  The service providing server 300 includes a CPU 310, a nonvolatile storage device 320 such as a hard disk drive, a volatile storage device 330 such as RAM, and a network IF 380 for connecting to the Internet 80.

  The non-volatile storage device 320 stores a computer program PG3 and an encryption method list CL3. The volatile storage device 330 is provided with a buffer area 331 that temporarily stores various intermediate data generated when the CPU 310 performs processing.

  The computer program PG3 may be provided in a form uploaded from a computer of an operator of the service providing server 300 connected via the Internet 80, or provided in a form stored in a CD-ROM, a DVD-ROM or the like. May be. The CPU 310 realizes the function as the controller of the service providing server 300 by executing the computer program PG3. Details of these functions will be described later.

  The encryption method list CL3 is a list showing one or more encryption methods that can be used by the service providing server 300. As shown in FIG. 2 (E), the encryption method list CL3 includes two encryption methods C and D and two encryption suites. That is, the service providing server 300 can use the two encryption methods C and D. As shown in FIG. 2 (E), the encryption methods C and D adopt "DHE" as a key exchange algorithm, and do not adopt "RSA" having a lower security level.

A-2: Operation of system 1000 A-2-1. Communication Protocol In this embodiment, a protocol for communication between a plurality of devices including the device 100 and the relay server 200 will be described. Communication between each device and the relay server 200 is performed according to the application layer programs of the device and the relay server 200 (hereinafter, simply referred to as an application), with each device serving as a client and the relay server 200 serving as a server. Done. Each device and the application of the relay server 200 perform communication according to HTTP (abbreviation of Hypertext Transfer Protocol) which is a protocol of the application layer. Communication in the lower transport layer of the application is performed according to TCP (abbreviation of Transmission Control Protocol). Then, in a layer lower than HTTP of the application layer and a layer higher than TCP of the transport layer, a secure communication path encrypted by communication according to SSL / TLS (abbreviation of Secure Sockets Layer / Transport Layer Security) (hereinafter, (Also referred to as encrypted communication) is established.

  In the present embodiment, the communication between the relay server 200 and the service providing servers including the service providing server 300 is performed using the relay server 200 as a client and the service providing server as a server. The communication between the relay server 200 and the service providing server is the same as the above-described communication between the device and the relay server 200, that is, HTTP, TCP, and SSL / TLS in a layer between TCP and HTTP. And so on.

  That is, transmission / reception of application data (for example, image data described later) between the device and the relay server 200 and between the relay server 200 and the service providing server uses encrypted communication established according to SSL / TLS. Done by using. As a result, the security of the application data of the user is maintained.

A-2-2: Communication of System 1000 The operation of the system 1000 will be described by taking communication between the device 100, the relay server 200, and the service providing server 300 as a specific example. 3 to 5 are sequence diagrams showing an example of communication of the system 1000. The communication of FIGS. 3 to 5 is performed so that the device 100 optically reads a document to generate image data representing the document and transmits (uploads) the image data to the service providing server 300. For example, the user places a document on the document table of the scanner unit 150 of the device 100 and then inputs a start instruction via the operation unit 160. The communication of FIGS. 3 to 5 is started when the CPU 110 of the device 100 receives a start instruction from the user.

  First, the device 100 accesses the service providing server 300 without going through the relay server 200, and attempts to establish encrypted communication with the service providing server 300. Specifically, in S10, CPU 110 of device 100 transmits a communication start request to service providing server 300. The service providing server 300 of the transmission destination is specified based on the URL included in the server information SI described above. The communication start request includes the encryption method list CL1 shown in FIG.

  When the service providing server 300 receives the encryption method list CL1, in S12, the CPU 310 of the service providing server 300 selects one of the plurality of encryption methods to be used from the encryption methods list CL1. Select an encryption method (hereinafter referred to as the used encryption method). Specifically, it is an encryption method shown in the encryption method list CL1 and can also be used by the service providing server 300 itself (that is, an encryption method list CL3 in FIG. 2E). One of the available encryption methods) is selected as the encryption method to be used.

  In S12, the selection of the used encryption method may be successful or unsuccessful. For example, the encryption method list CL1 of the device 100 includes only the encryption methods A and B as shown in FIG. 2A, and the encryption method list CL3 of the service providing server 300 is shown in FIG. As shown, consider the case where only encryption methods C and D are included. In this case, there is no encryption method shown in the encryption method list CL1 that can also be used by the service providing server 300 itself, so the selection of the used encryption method fails.

  If the encryption method list CL1 of the device 100 is different from that shown in FIG. 2A and includes the encryption method C, the encryption method shown in the encryption method list CL1 is Moreover, since the encryption method C exists as an encryption method that can be used by the service providing server 300 itself, the selection of the used encryption method is successful.

  If the selection of the used encryption method is successful (S14: YES), the CPU 310 sends a notification of the used encryption method (for example, the encryption method C) as a response to the communication start request in S16. Send to 100.

  When the device 100 receives the notification of the encryption method used, the communication establishing process is performed in S18. That is, in S18, communication for establishing the encrypted communication using the used encryption method is executed between the device 100 and the service providing server 300.

  Note that the processing and communication of S10 to S18 up to this point are performed in the SSL / TLS layers of both the device 100 and the service providing server 300 according to SSL / TLS.

  In S20, the CPU 110 executes scan processing. That is, in S20, the CPU 310 controls the scanner unit 150 to optically read the document placed on the document table to generate image data representing the document.

  In S22, the CPU 110 executes a series of communication for transmitting (uploading) the generated image data to the service providing server 300 without using the relay server 200, using the encrypted communication established in S18. To do. Although a detailed description is omitted, the series of communications includes, for example, transmission of authentication information for logging in to the service providing server 300 and subsequent image data transmission.

  When the service providing server 300 receives the image data, the CPU 310 saves the image data in the storage area allocated to the user in the nonvolatile storage device 320 in S24. In S26, the CPU 310 transmits to the device 100 a storage completion notification indicating that the storage of the image data has been completed. The processing and communication in S20 to S26 are performed by the applications of both the device 100 and the service providing server 300.

  The communication is terminated when the device 100 receives the notification of the completion of storage. For example, the CPU 110 notifies the user of the completion of the storage of the image data in the service providing server 300 via the display unit 170, and ends the processing.

  Next, a case will be described where the CPU 310 of the service providing server 300 fails to select the used encryption method in S12. When the selection of the used encryption method fails (S14: NO), the CPU 310 transmits a communication refusal notification to the device 100 in S30 of FIG. The communication refusal notification is a notification indicating refusal to use the encryption method included in the encryption method list CL1 received from the device 100, in other words, the relay server 200 and the device 100 directly communicate with each other. This is a notification indicating that it is not possible. The transmission / reception of the communication refusal notification is performed in the SSL / TLS layer.

  When the device 100 receives the communication refusal notification, the CPU 110 transmits a communication start request to the relay server 200 in S32. Relay server 200 of the transmission destination is specified based on the URL included in server information SI described above. The communication start request includes the encryption method list CL1 shown in FIG. When relay server 200 receives encryption method list CL1, in S34, CPU 210 of relay server 200 selects one used encryption method from the plurality of encryption methods shown in encryption method list CL1. select.

  Specifically, the encryption method shown in the encryption method list CL1 and also usable by the relay server 200 itself (that is, the encryption method shown in the encryption method list CL2 in FIG. 2B). One of the encryption methods) is selected as the encryption method to be used.

  For example, the encryption method list CL1 of the device 100 includes only the encryption methods A and B as shown in FIG. 2 (A), and the encryption method list CL2 of the relay server 200 is shown in FIG. 2 (B). Thus, consider the case where the encryption methods A to D are included. In this case, for example, one of the encryption methods A and B commonly included in both lists is selected as the used encryption method. The relay server 200 is operated by a vendor of the device 100, and the vendor selects an encryption method that the relay server 200 can use so that the relay server 200 can communicate with devices of all vendors to be supported. It is set. Therefore, in S34, it is not assumed that the selection of the used encryption method will fail in Relay Server 200. The details of the selection of the used encryption method in S34 will be described later.

  In S36, the CPU 210 transmits to the device 100, as a response to the communication start request in S32, a notification of the encryption method used, for example, encryption method A in this embodiment.

  When the device 100 receives the notification of the encryption method used, the communication establishing process is performed between the device 100 and the relay server 200 in S38. That is, in S38, communication for establishing encrypted communication using the used encryption method is executed between the device 100 and the service providing server 300.

  Note that the processing and communication in S32 to S38 up to this point are performed in the SSL / TLS layers of both the device 100 and the relay server 200.

  In S40, the CPU 110 transmits a communication request with the service providing server 300 to the relay server 200 using the established encrypted communication. The communication request includes a request for relay server 200 to establish communication with service providing server 300 and the URL of service providing server 300 included in server information SI. Based on these pieces of information, the CPU 210 of the relay server 200 specifies the service providing server (for example, the service providing server 300) that the device 100 desires to connect with when transmitting a communication start request to be described later to the service providing server 300 and performs communication. A start request can be sent. In S42, the CPU 110 periodically (for example, every 5 seconds) transmits to the relay server 200 a polling transmission for receiving a communication establishment notification described later. The transmissions in S40 and S42 are performed as HTTP request transmissions.

  When relay server 200 receives the URL of service providing server 300, in S43, CPU 210 registers the global IP address of device 100 in a predetermined table (not shown) in association with the URL of service providing server 300. . The global IP address is included in the header of the communication request (HTTP request) received in S40, for example. Accordingly, when the CPU 210 next receives the communication start request in S56, the CPU 210 sets the service providing server (for example, the service providing server 300) used by the device (for example, the device 100) that is the transmission source of the communication start request, Can be recognized. In subsequent S44, CPU 210 transmits a communication start request to service providing server 300. The service providing server 300 of the transmission destination is specified based on the URL received from the device 100. The communication start request includes the encryption method list CL2 of FIG. 2 (B). When the service providing server 300 receives the encryption method list CL2, in S46, the CPU 310 of the service providing server 300 selects one encryption method from among the plurality of encryption methods shown in the encryption method list CL2. Select the activation method. Specifically, it is the encryption method shown in the encryption method list CL2, and is also shown in the encryption method list CL3 of the encryption method (that is, FIG. 2E) that can be used by the service providing server 300 itself. One of the available encryption methods) is selected as the encryption method to be used.

  For example, the encryption method list CL2 of the relay server 200 includes the encryption methods A to D as shown in FIG. 2B, and the encryption method list CL3 of the service providing server 300 is shown in FIG. As shown, consider the case where only encryption methods C and D are included. In this case, for example, one of the encryption methods C and D commonly included in both lists (in this embodiment, the encryption method D) is selected as the used encryption method. The vendor operating the relay server 200 sets the encryption method usable by the relay server 200 so that the device manufactured by the vendor to be supported can communicate with the service providing server that may want to connect as much as possible. . Therefore, in S46, it is not assumed that the selection of the used encryption method will fail in the service providing server 300.

  In S48, the CPU 210 transmits to the relay server 200, as a response to the communication start request, a notification of the encryption method used, in this embodiment, for example, the encryption method D.

  When the device 100 receives the notification of the used encryption method, the communication establishing process is performed between the device 100 and the service providing server 300 in S49. As a result, encrypted communication using the used encryption method is established between the device 100 and the service providing server 300.

  Note that the processing and communication in S44 to S49 up to this point are performed in the SSL / TLS layers of both the relay server 200 and the service providing server 300.

  In S50, the CPU 210 stores the use encryption method used for the encrypted communication established with the service providing server 300, in other words, the use encryption method indicated in the notification received in S48. Specifically, the used encryption method is registered in the registration table CT in association with the URL of the service providing server 300.

  In S51, the CPU 210 transmits to the device 100 a communication establishment notification indicating that encrypted communication has been established with the service providing server 300. The communication establishment notification is transmitted as a response (that is, an HTTP response) to the HTTP request transmitted as the polling in S42.

  When the device 100 receives the communication establishment notification, the CPU 110 disconnects the currently established communication between the device 100 and the relay server 200. For example, the device 100 takes the lead in disconnecting the logical communication path in the TCP layer or the SSL / TLS layer. Note that, as a modification, the relay server 200 may take the lead in disconnecting the logical communication path. In S53, the CPU 210 of the relay server 200 disconnects the currently established communication between the relay server 200 and the service providing server 300. For example, the relay server 200 plays a main role and disconnects the logical communication path in the TCP layer or the SSL / TLS layer.

  Here, it is necessary to disconnect the communication between the device 100 and the relay server 200, and between the relay server 200 and the service providing server 300 once during a scan process described later, which takes a relatively long time. This is because it is not necessary to maintain the established communication. Another reason is that it is not preferable in terms of security to keep these communications established.

  In S54, the CPU 210 executes the scan process as in S20 of FIG. That is, the scanner unit 150 optically reads a document placed on the document table, and thereby image data representing the document is generated.

  After the image data is generated, the communication between the device 100 and the relay server 200 and between the relay server 200 and the service providing server 300 is reestablished. Specifically, the processing of S56 to S73 of FIG. 5 is performed in the same manner as the processing of S32 to S49 of FIG. As a result, for example, encrypted communication using the encryption method A is established between the device 100 and the relay server 200. For example, encrypted communication using the encryption method D is established between the relay server 200 and the service providing server 300. In S74, Relay Server 200 transmits a communication establishment notification to device 100.

  When the device 100 receives the communication establishment notification in S74, in S76, the CPU 110 transmits a series of communications for transmitting (uploading) the generated image data to the service providing server 300, and the reestablished encrypted communication. It is executed for the relay server 200 by using. As described above, the series of communication includes, for example, the transmission of the authentication information and the subsequent transmission of the image data.

  In S78, the CPU 210 of the relay server 200 relays a series of communications between the device 100 and the service providing server 300. For example, the CPU 210 transmits a notification indicating that the reception of the authentication information and the image data has been completed to the device 100 (not shown), and then, in S78, the authentication information and the image data transmitted from the device 100 remain unchanged. , Is transmitted to the service providing server 300 using the encrypted communication that has been reestablished with the service providing server 300.

  When the service providing server 300 receives the image data, the CPU 310 saves the image data in the nonvolatile storage device 320 in S80, as in S24 of FIG. In S82, the CPU 310 transmits to the relay server 200 the same notification of the completion of storage as in S26 of FIG. In S84, the CPU 210 transmits the storage completion notification received from the service providing server 300 to the device 100 as it is. It should be noted that the storage completion notification is transmitted to the device 100, for example, as a response to polling (not shown) performed by the device 100 after receiving the notification indicating the completion of data reception. As a modification, the storage completion notification may be transmitted to the device 100 as a response to the authentication information and the image data transmitted to the relay server 200 in S76. The communication is terminated when the device 100 receives the notification of the completion of storage. Note that the communication and processing of S76 to S84 are performed by the applications of the device 100, the relay server 200, and the service providing server 300.

A-2-3: Selection of Use Encryption Method with Device 100 Next, regarding the use encryption method selection executed by the CPU 210 of the relay server 200 in S34 of FIG. 4 and S58 of FIG. Further details will be described later. In S34 and S58, the used encryption method used in the encrypted communication between the device 100 and the relay server 200 is selected. FIG. 6 is a flowchart for selecting the encryption method to be used.

  In S110, the CPU 210 determines whether or not the used encryption method used between the service providing server scheduled to communicate and the relay server 200 has been registered. The service providing server 300 to be communicated is specified by the URL received from the device 100 in S40 of FIG. Specifically, for example, the CPU 210 acquires the global IP address of the device 100 included in the header of the communication start request received in S56 before S58. The CPU 210 acquires the URL recorded in association with the global IP address in S43 of FIG. 4 described above. As a result, the URL of the service providing server (for example, the service providing server 300) used by the device (for example, the device 100) that is the transmission source of the communication start request is acquired. Then, the CPU 210 determines whether the URL is already registered in the registration table CT, and if the URL is already registered, it is used between the service providing server scheduled to communicate and the relay server 200. It is determined that the used encryption method has been registered.

  By this time, if relay server 200 has not established communication with service providing server 300, the encryption method used by service providing server 300 is not registered in registration table CT. In this case, it is determined that the used encryption method has not been registered. On the other hand, if the relay server 200 has established communication with the service providing server 300 up to this point, for example, in S50 of FIG. The encryption method used is stored. In this case, it is determined that the encryption method used is already registered. For example, in the process of S58 performed when the communication start request and the encryption method list CL1 are received from the device 100 after storing the used encryption method of the service providing server 300 in S50, the used encryption method is registered. Is determined. Further, when performing a series of communication starting from S10 of FIG. 3 in which the device 100 should access the service providing server 300 after the second time, the used encryption method is already registered also in S34 of FIG. Is judged.

  When the used encryption method is not registered (S110: NO), the CPU 210 is the encryption method shown in the encryption method list CL1 received from the device 100 in S115, and also the relay server 200. An encryption method that can be used by itself (that is, one of the encryption methods shown in the encryption method list CL2 in FIG. 2B) is selected as the used encryption method. At this time, when there are a plurality of encryption methods that satisfy this condition, the CPU 210 simply uses the encryption method that is higher in the encryption method list CL1 for communication with the device 100. Select as the encryption method. For example, in the example of FIG. 2A, the encryption method A is selected from the two encryption methods A and B in the encryption method list CL1.

  When the used encryption method is already registered (S110: YES), in S120, the CPU 210 identifies the used encryption method of the service providing server to be connected with reference to the registration table CT. Specifically, the CPU 210 identifies the used encryption method associated with the URL of the service providing server that has been received from the registration table CT. As a result, even when there are a plurality of types of service providing servers, it is possible to appropriately select the encryption method to be used with the service providing server 300.

  Then, the CPU 210 identifies the encryption algorithm used in the encryption method used with the specified service providing server 300 (hereinafter, referred to as the encryption algorithm used). For example, when the encryption method used with the service providing server 300 is the encryption method D (FIG. 2 (E)), the encryption algorithm “AES256” of the encryption method D is Is specified as an algorithm.

  In S125, the CPU 210 determines whether or not the encryption method list CL1 of the device 100 has an encryption method that uses the same encryption algorithm as the specified encryption algorithm used.

  If there is an encryption method that uses the same encryption algorithm as the used encryption algorithm (S125: YES), the CPU 210 at S130 uses the encryption method with the device 100. Select as the activation method. For example, when the used encryption algorithm is “AES256”, the encryption method B is selected from the encryption methods A and B included in the encryption method list CL1 of FIG. This is because the encryption algorithm of the encryption method A is “AES128”, which is different from the encryption algorithm used, but the encryption algorithm of the encryption method B is “AES256”, which is the same as the encryption algorithm used.

  When there is no encryption method that uses the same encryption algorithm as the used encryption algorithm (S125: NO), in S135, the CPU 210 uses the encryption algorithm that has the closest security level to the used encryption algorithm. Select the activation method. At this time, when comparing the security levels of the encryption algorithms, reference information RI indicating the order of the security levels of the encryption algorithms is referred to. It is assumed that there are three candidate selectable encryption methods, and their encryption algorithms are “3DES128”, “3DES256”, and “DES256”, respectively. Then, it is assumed that the encryption algorithm used is "AES256". In this case, first, the key length is ignored and the types of algorithms themselves are compared. As shown in the reference information RI, the security level of “3DES” is closer to “AES” than “DES”, so the candidates are narrowed down to “3DES128” and “3DES256”. Next, two candidates having the same algorithm type are compared with each other, and "3DES256" having a key length close to the key length "256" of the encryption algorithm used (the same in this example) is selected. As a result, the encryption method adopting "3DES256" is finally selected. As can be understood from the above description, the reference information RI can be said to be information indicating the priority when selecting one algorithm from a plurality of algorithms based on the security level.

  According to the embodiment described above, when the service providing server 300 refuses to use the encryption method that can be used by the device 100 (that is, one or more encryption methods included in the encryption method list CL1). (S30 in FIG. 4), the device 100 establishes encrypted communication with the relay server 200 (S32 to S38 in FIG. 4, S56 to S62 in FIG. 5). Then, relay server 200 establishes encrypted communication with service providing server 300 (S44 to S49 in FIG. 4, S66 to S73 in FIG. 5). Then, the device 100 transmits data (specifically, image data) regarding the service provided by the service providing server 300 to the service providing server 300 via the relay server 200 (S76 and S78 in FIG. 5). ). Therefore, even if the service providing server 300 refuses to use the encryption method that can be used by the device 100, the device 100 can communicate with the service providing server 300 through the encrypted communication via the relay server 200. , Can communicate data regarding a specific service. As a result, even when the service providing server 300 refuses to use the encryption method that can be used by the device 100, the device 100 and the service providing server 300 maintain a state in which encrypted communication is possible. be able to.

  More specifically, the encryption method usable by the service providing server 300 may be changed by the operator of the service providing server 300. For example, the service providing server 300 uses the key exchange algorithm “RSA” that cannot achieve PFS described above is stopped, and only the key exchange algorithm (eg, “DHE”) that can achieve PFS is allowed. Possible ciphers may change. In such a case, if the encryption method that can be used by the device 100 is only the method that adopts “RSA” as the key exchange algorithm, the device 100 can directly communicate with the service providing server 300. It will be impossible. However, promptly updating computer programs of a plurality of devices including the device 100 so that the key exchange algorithm “DHE” that can achieve PFS can be used is burdensome for both the user and the vendor of the device. May be large. Even in such a case, according to the present embodiment, if the relay server 200 can use the encryption method including the key exchange algorithm “DHE”, the plurality of devices including the device 100 can be, for example, the key exchange algorithm. Even if the encryption method including “DHE” cannot be used, it is possible to communicate with the service providing server 300 via the relay server 200. The relay server 200 is operated by a device vendor, and the number of relay servers 200 is smaller than that of the devices (for example, one). Therefore, it is not possible to add or change the encryption method usable by the relay server 200. It's easy.

  Further, according to the present embodiment, when the relay server 200 receives the notification of the use encryption method from the service providing server 300 (S48 in FIG. 4), the use encryption method indicated in the notification of the method is used. Is stored (S50). Then, when the relay server 200 subsequently receives a communication start request including the encryption method list CL1 from the device 100 (S56 of FIG. 5, S32 of FIG. 4 after the second time), the stored service providing server 300 is stored. The encryption method used between the devices 100 is selected from the encryption methods included in the encryption method list CL1 using the encryption method used during the period (S58 in FIG. 5 and the second and subsequent times in FIG. 4). S34, S120 to S135 of FIG. 6). Then, thereafter, encrypted communication according to the use encryption method selected by using the use encryption method with the service providing server 300 is established between the device 100 and the service providing server 300 (for example, FIG. 5). S60, S62). As a result, the encrypted communication according to the third encryption method selected using the second encryption method shown in the second method notification from the service providing apparatus is established between the relay apparatus and the communication apparatus. Therefore, encrypted communication suitable for communication with the service providing device via the relay device can be established between the communication device and the relay device.

  Specifically, Relay Server 200 adopts a specific item (encryption algorithm in this embodiment) of the algorithms of the plurality of items of the encryption method in the encryption method used with service providing server 300. The encryption method that employs the same or similar algorithm as the above-described algorithm is selected as the encryption method to be used with the device 100. As a result, an encryption method more suitable for communication between the device 100 and the relay server 200 and communication with the service providing server 300 via the relay server 200 can be selected. For example, with regard to the encryption algorithm, encrypted communication with a security level that is the same as or close to the security level required by the service providing server 300 can be established between the device 100 and the relay server 200.

  Further, in the above-described embodiment, the relay server 200 uses the encryption method used with the stored service providing server 300 to select the encryption method used with the device 100, and the reference information RI. Refer to. As a result, it is possible to appropriately select an encryption method that employs an algorithm having the same security level or a similar security level for a specific item.

  Further, in the above embodiment, after the encrypted communication is once established between the relay server 200 and the service providing server 300 (S44 to S49 in FIG. 4), the establishment notification is sent from the relay server 200 to the device 100. It is transmitted (S51 in FIG. 4). Upon receiving the establishment notification, the device 100 generates image data (S54 in FIG. 4) after the encrypted communication between the device 100 and the relay server 200 is disconnected (S52 in FIG. 4). After that, encrypted communication between the device 100 and the relay server 200 and between the relay server 200 and the service providing server 300 is established again (S56 to S73 in FIG. 5). The relay server 200 receives the image data from the device 100 by using the encrypted communication established with the device 100 (S76 in FIG. 5), and establishes the encrypted communication established with the service providing server 300. Then, the image data is transmitted to the service providing server 300 (S78 in FIG. 5). Furthermore, it is possible to prevent the state in which the encrypted communication is unnecessarily established from continuing while the image data is being generated. As a result, communication security can be improved.

  Further, in the above-described embodiment, the device 100 transmits a communication request with the service providing server 300 to the relay server 200 (S40 in FIG. 4). Then, based on the communication request, Relay Server 200 transmits a communication start request including encryption method list CL2 to service providing server 300 (S44 in FIG. 4). As a result, the relay server 200 can relay the communication between the appropriate service providing server 300 and the device 100 based on the communication request from the device 100.

  Further, in the above embodiment, the communication of the image data is the communication between the applications belonging to the application layer, and the transmission / reception of the encryption method lists CL1 and CL2 is the communication in the layer (SSL / TLS layer) lower than the application. is there. The protocol for transmitting / receiving the encryption method lists CL1 and CL2 is SSL / TLS. As a result, the security level of communication between applications can be maintained at a required level by using SSL / TLS without providing a special mechanism for applications.

B. Modification:
(1) In the above embodiment, the relay server 200 sends the encryption method list CL2 including all the encryption methods A to D that can be used by the relay server 200 to the service when the communication start request is transmitted to the service providing server 300. It is transmitted to the providing server 300 (S44 of FIG. 4, etc.). Instead, the relay server 200 has at least one encryption method different from the encryption methods A and C available to the device 100 among the encryption methods A to D available to the relay server 200 ( For example, the encryption method list CL2 including the encryption method D) may be transmitted to the service providing server 300.

(2) The use encryption method used with the device 100 may not be selected using the use encryption method registered for the service providing server 300 to be connected illustrated in FIG. In this case, the relay server 200 may omit registration of the used encryption method with the service providing server 300 (S50 in FIG. 4). In this case, Relay Server 200 may arbitrarily select the encryption method that Relay Server 200 can use from the encryption methods that Device 100 can use.

(3) In the above embodiment, in S125 to S135 of FIG. 6, one item (specifically, encryption algorithm) of the plurality of items of algorithms is used and encrypted with the service providing server 300. An encryption method that employs an algorithm that is the same as or similar to the method is selected from the encryption methods that the device 100 can use. Alternatively, more than one item of the multiple item algorithm (eg, encryption algorithm and hash algorithm) may be considered, or all items of the multiple item algorithm may be considered. Good. Generally speaking, an encryption method that employs an algorithm that is the same as or similar to the encryption method used with the service providing server 300 may be selected for at least one of the multiple-item algorithms. . This makes it possible to select an encryption method more suitable for communication with the service providing server 300 via the relay server 200 for at least one item of the algorithms of the plurality of items.

(4) Instead of the relay server 200 registering the global IP address of the device 100 in association with the URL of the service providing server 300 in S43 of FIG. 4, the relay server 200 is switched from the device 100 to the relay server 200 in S32 or S56. The URL of the service providing server 300 may be included in the communication start request transmitted to the server. Even in this case, the CPU 210 can recognize the service providing server used by the device 100 that is the transmission source of the communication start request when the communication start request is received in S32 or S56. Therefore, similarly to the above embodiment, the selection of the used encryption method of FIG. 6 can be appropriately executed in S34 and S58.

(5) In the above embodiment, once the encrypted communication between the device 100 and the relay server 200 and between the relay server 200 and the service providing server 300 is established, the communication is temporarily disconnected. After that, the image data is generated by the device 100. Instead, the image data is generated from the device 100 via the relay server 200 using the communication in which the image data is generated and maintained without being disconnected. It may be transmitted to the service providing server 300.

(6) The reference information RI (FIG. 2D) in the above embodiment is information indicating the order of security levels for encryption algorithms. Instead of this, the reference information RI may be information indicating the order of processing speeds related to encrypted communication for the encryption algorithm. In other words, the reference information RI may be information that indicates the priority when selecting one algorithm from a plurality of algorithms based on at least one of the security level and the processing speed.

(7) Image data is transmitted from the device 100 to the service providing server 300 via the relay server 200 or not via the relay server 200. Instead of this, the service providing server 300 is a server that provides print data, and the print data may be transmitted (downloaded) from the service providing server 300 to the device 100. The application data transmitted and received between the device 100 and the service providing server 300 is not limited to image data and print data, but other data corresponding to the service provided by the service providing server 300, such as text data and music. It may be data.

(8) The relay server 200 and the service providing server 300 may be so-called cloud servers including a plurality of devices (for example, computers) that can communicate with each other via a network.

(9) In each of the above-described embodiments, a part of the configuration realized by hardware may be replaced with software, and conversely, a part or all of the configuration realized by software may be replaced with hardware. You may do it.

  Although the present invention has been described above based on the examples and modifications, the above-described embodiments of the present invention are intended to facilitate understanding of the present invention and do not limit the present invention. The present invention can be modified and improved without departing from the spirit and scope of the claims, and the present invention includes equivalents thereof.

  80 ... Internet, 100 ... Device, 110 ... CPU, 120 ... Non-volatile storage device, 130 ... Volatile storage device, 131 ... Buffer area, 140 ... Printer section, 150 ... Scanner unit, 160 ... Operating unit, 170 ... Display unit, 180 ... Network IF, 200 ... Relay server, 210 ... CPU, 220 ... Non-volatile storage device, 230 ... Volatile storage device, 231, ... Buffer area, 280 ... Network IF, 300 ... Service providing server, 310 ... CPU, 320 ... Non-volatile storage device, 330 ... Volatile storage device, 331 ... buffer area, 380 ... network IF, 1000 ... system

Claims (10)

The communication device includes a communication device including a generation unit that optically generates an image data by reading an original, and a relay device, and each of the communication device and the relay device provides a specific service to the communication device. A communication system for communicating with a service providing device to be provided,
The communication device is
Responsive to receiving a start instruction of the specific service from a user, indicating to the service providing apparatus one or more encryption methods that can be used by the communication apparatus without going through the relay apparatus. Send method information ,
As a response to the transmission of the first scheme information, a first scheme notification indicating a first encryption scheme to be used among one or more encryption schemes shown in the first scheme information, and the first scheme information. And a refusal notification indicating refusal to use one or more encryption methods included in the above .
When the notification of the first method is received, encrypted communication according to the first encryption method is established with the service providing device ,
When cryptographic communication according to the first encryption method is established, the generation unit is caused to generate specific image data relating to the specific service,
Using the encryption communication according to the first encryption method already established, not through the relay device, to the service providing device, sending the particular image data,
When the rejection notification is received, encrypted communication is established with the relay device ,
The relay device,
Establishes encrypted communication with the communication device ,
After establishing the encrypted communication with the communication device, to said service providing apparatus, the second method information is a by the first encryption scheme showing the plurality of encryption schemes available the relay device Transmitting the second method information including one or more encryption methods indicating an encryption method different from
From the service providing device, as a response to the transmission of the second method information, a second method notification indicating a second encryption method to be used among one or more encryption methods included in the second method information. Received ,
When the second method notification is received, the encrypted communication according to the second encryption method is established with the service providing device,
In response to the establishment of the encrypted communication according to the second encryption method, an establishment notification indicating the establishment of encrypted communication according to the second encryption method is transmitted to the communication device,
Disconnecting the encrypted communication according to the established second encryption method,
The communication device,
When the notification of establishment is received, the encrypted communication with the relay device is disconnected,
After disconnecting the encrypted communication with the relay device, causing the generation unit to generate the specific image data,
After the specific image data is generated, the encrypted communication is established again with the relay device without transmitting the first method information again to the service providing device,
Using the encrypted communication established again with the relay device, the specific image data is transmitted to the relay device,
The relay device is
After the generation of the specific image data, the second method information is transmitted again to the service providing device,
As a response to the transmission of the second scheme information transmitted again, the second scheme notification is received again from the service providing apparatus,
When the second method notification is received again, the encrypted communication according to the second encryption method is established again with the service providing apparatus,
The specific image data received from the communication device, wherein between the service providing apparatus, using the encrypted communication is established again, that sends to the service providing apparatus, a communication system. The communication system according to claim 1, wherein
The relay device,
If the second mode notification is received, and stores the second encryption method shown in the second mode notification,
After storage of the second encryption system, to receive the first type information from the communication device,
Using said second encryption scheme already stored, of one or more encryption method included in the first system information, selects the third encryption method to be used,
As a response to the reception of the first method information, a third method notification indicating the third encryption method is transmitted to the communication device,
The communication device,
After the second encryption method is stored in the relay device, the first method information is transmitted to the relay device,
Receiving the third system notification from the relay device as a response to the transmission of the first system information ,
If the previous SL third method notification is received, to establish a cryptographic communication according to the third encryption scheme between the relay device, a communication system. The communication system according to claim 2, wherein
The second encryption system and the third encryption system exchange an authentication algorithm for device authentication, an encryption algorithm for encrypting communication data, and an encryption key used in the encryption algorithm. A key exchange algorithm for, and a hash algorithm used in at least one of the authentication algorithm, the encryption algorithm and the key exchange algorithm, a plurality of items of algorithms,
The relay equipment is,
For at least one specific item of the plurality of items of algorithm, specify an algorithm adopted in the second encryption method,
An encryption method that employs an algorithm that is the same as or similar to the algorithm used in the second encryption method for at least one of the specific items among one or more encryption methods included in the first method information. Is selected as the third encryption method. The communication system according to claim 3, wherein
The relay device further includes
For one of said specific item even without low, based on at least one of the security levels and processing speed, and stores the priority information indicating the priority in selecting one algorithm from a plurality of algorithms,
Using pre SL priority information, an encryption scheme in which at least one of an algorithm employed and the security level and processing speed employs an algorithm that same or similar in the second encryption system, the third encryption scheme Image processing device to be selected as. The communication system according to any one of claims 2 to 4,
The relay equipment is,
The pre-Symbol second encryption method, stored in association with the identifier indicating the service providing device,
Before Symbol communication apparatus receives said identifier indicating the service providing device and the first system information,
Using said second encryption scheme that is stored in association with the identifier indicating the previous SL service providing apparatus selects the third encryption scheme, a communication system. The communication system according to any one of claims 1 to 5
When the communication device receives the refusal notification , the communication device sends a request for communication with the service providing device to be communicated to the relay device, using encrypted communication established with the relay device. transmitted,
The relay device,
Using the encrypted communication is established between the front Symbol communication device, a communication request with the service providing apparatus, received from the communication device,
Based on the previous SL communication request, to the service providing apparatus, transmitting the second system information, communication system. The communication system according to any one of claims 1 to 6
Transmission of the previous SL particular image data is a communication between the applications belonging to the application layer,
The first method information and sending and receiving of the second type information is a communication in the lower layer than the application communication system. The communication system according to claim 7 , wherein
The first method information and protocols for transmitting and receiving the second system information is SSL (Secure Sockets Layer) / TLS (Transport Layer Security), a computer program. A communication device,
A generation unit that generates image data by optically reading a document,
A control unit;
Equipped with
The control unit is
One or more encryption methods that can be used by the communication device for a service providing device that provides the specific service without passing through a relay device in response to receiving an instruction to start a specific service from a user. sends the system information indicating,
As a response to the transmission of the scheme information, a scheme notification indicating a specific encryption scheme to be used among the one or more encryption schemes shown in the scheme information, and one or more ciphers included in the scheme information. rejection notice and indicating to reject the use of the scheme, one of the, received from the service providing device,
When the method notification is received, the encrypted communication according to the specific encryption method is established with the service providing device,
When encrypted communication according to the specific encryption method is established, the generation unit is caused to generate specific image data relating to the specific service,
Using the encrypted communication according to the established specific encryption method, without transmitting the relay device, to the service providing device, the specific image data is transmitted ,
When the rejection notification is received, encrypted communication is established with the relay device,
When the establishment notification transmitted from the relay device in response to the establishment of the encryption communication between the relay device and the service providing device is received, the encryption communication with the relay device is disconnected. ,
After disconnecting the encrypted communication with the relay device, causing the generation unit to generate the specific image data,
After the generation of the specific image data, to the service providing device, without transmitting the method information again, to establish encrypted communication again with the relay device,
Wherein between the relay apparatus, using established encrypted communication again, that sends the specific image data to the relay device, the communication device. A computer program for a relay device,
Establishes encrypted communication with the communication device ,
After establishing encrypted communication with the communication device, a plurality of encryption methods that can be used by the communication device and that can be used by the relay device for a service providing device that provides a specific service 1 Transmitting method information indicating the plurality of encryption methods including an encryption method different from one or more encryption methods,
Wherein in response to the transmission of the system information, the method notification indicating specific cipher to use of the one or more encryption method included in the system information, received from the service providing device,
If the previous SL system notification is received, between the service providing apparatus establishes an encrypted communication according to the particular encryption scheme,
In response to the encrypted communication according to the specific encryption method being established, an establishment notification indicating the establishment of encrypted communication according to the specific encryption method is transmitted to the communication device,
Disconnect the encrypted communication according to the established specific encryption method,
After the specific image data relating to the specific service is generated in the communication device after disconnecting the encrypted communication according to the specific encryption system, the system information is transmitted again to the service providing device,
As a response to the transmission of the scheme information transmitted again, the scheme notification is received again from the service providing device,
When the system notification is received again, the encrypted communication with the service providing device is again established according to the specific encryption system,
By using the encrypted communication already established between the front Symbol communication device, and a cryptographic communication according to the particular encryption scheme that is re-established between the service providing apparatus, the communication device and the service providing apparatus during in, to relay the communication of a specific image data and,
A computer program that a computer realizes.

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