Server device that sets security levels in accordance with distances between devices, client device, communication system, integrated circuit for server control, integrated circuit for client control, server program, client program, method for connecting to a client device, method for connecting to a server device, and communication system connection method

A communication system that includes a server device and a client device, and in which a service is provided from the server device to the client device,

• the server device comprising:
• an information management unit that stores and manages a plurality of types of connection information which have different importance levels, respectively, in association with the respective importance levels, the connection information being necessary for connection to a service provided by the server device;
• an optical signal transmission unit that modulates the plurality of types of connection information stored in the information management unit into optical signals, such that a type of connection information stored in association with a higher importance level has a smaller amount of change in light intensity, and repeatedly transmits the optical signals having the plurality of types of connection information, respectively, by use of a first communication function;
• and
• a service provision unit that has an authentication function which performs authentication when the client device has issued a connection request containing a predetermined type of connection information among the plurality of types of connection information by use of a second communication function which is different from the first communication function, in accordance with the importance level of communication information of the connection request, the authentication being for providing the service to the client device,
• the client device comprising:
• a connection information acquisition unit that receives optical signals outputted by the optical signal transmission unit included in the server device by use of the first communication function, demodulates the received optical signals, and attempts to acquire the plurality of types of connection information;
• and
• a service use unit that transmits, when the connection information acquisition unit has acquired the predetermined type of connection information, a connection request containing the predetermined type of connection information to the server device by use of the second communication function, and receives the provision of the service.

An integrated circuit for server control configured to be used by a server device that provides a service to a client device, the integrated circuit integrating circuits functioning as:

• an information management unit that manages a plurality of types of connection information which have different importance levels, respectively, in association with the respective importance levels, the connection information being necessary for connection to a service provided by the server device;
• an optical signal transmission unit that modulates the plurality of types of connection information managed by the information management unit into optical signals, such that a type of connection information stored in association with a higher importance level has a smaller amount of change in light intensity, and repeatedly transmits the optical signals having the plurality of types of connection information, respectively, by use of a first communication function;
• and
• a service provision unit that has an authentication function which performs authentication when the client device has issued a connection request containing a predetermined type of connection information among the plurality of types of connection information by use of a second communication function which is different from the first communication function, in accordance with the importance level of communication information of the connection request, the authentication being for providing the service to the client device.

A server program configured to be executed by a server device that provides a service to a client device, the program causing the server device to perform:

• an information management step of managing a plurality of types of connection information which have different importance levels, respectively, in association with the respective importance levels, the connection information being necessary for connection to a service provided by the server device;
• an optical signal transmission step of modulating the plurality of types of connection information managed in the information management step into optical signals, such that a type of connection information stored in association with a higher importance level has a smaller amount of change in light intensity, and of repeatedly transmitting the optical signals having the plurality of types of connection information, respectively, by use of a first communication function;
• and
• a service provision step having an authentication function which performs authentication when the client device has issued a connection request containing a predetermined type of connection information among the plurality of types of connection information by use of a second communication function which is different from the first communication function, in accordance with the importance level of communication information of the connection request, the authentication being for providing the service to the client device.

A method for connecting to a client device performed by a server device that provides a service to a client device, the method comprising:

• an information management step of managing a plurality of types of connection information which have different importance levels, respectively, in association with the respective importance levels, the connection information being necessary for connection to a service provided by the server device;
• an optical signal transmission step of modulating the plurality of types of connection information managed in the information management step into optical signals, such that a type of connection information stored in association with a higher importance level has a smaller amount of change in light intensity, and of repeatedly transmitting the optical signals having the plurality of types of connection information, respectively, by use of a first communication function;
• and
• a service provision step having an authentication function which performs authentication when the client device has issued a connection request containing a predetermined type of connection information among the plurality of types of connection information by use of a second communication function which is different from the first communication function, in accordance with the importance level of communication information of the connection request, the authentication being for providing the service to the client device.

A connection method in a communication system that includes a server device and a client device, and in which a service is provided from the server device to the client device, the method comprising:

• an information management step, performed in the server device, of managing a plurality of types of connection information which have different importance levels, respectively, in association with the respective importance levels, the connection information being necessary for connection to a service provided by the server device;
• an optical signal transmission step, performed in the server device, of modulating the plurality of types of connection information managed in the information management step into optical signals, such that a type of connection information stored in association with a higher importance level has a smaller amount of change in light intensity, and of repeatedly transmitting the optical signals having the plurality of types of connection information, respectively, by use of a first communication function;
• a service provision step, performed in the server device, having an authentication function which performs authentication when the client device has issued a connection request containing a predetermined type of connection information among the plurality of types of connection information by use of a second communication function which is different from the first communication function, in accordance with the importance level of communication information of the connection request, the authentication being for providing the service to the client device,
• a connection information acquisition step, performed in the client device, of receiving optical signals outputted by an optical signal transmission unit included in the server device by use of the first communication function, of demodulating the received optical signals, and of attempting to acquire the plurality of types of connection information;
• and
• a service use step, performed in the client device, of transmitting, when the connection information acquisition step has acquired a predetermined type of connection information, a connection request containing the predetermined type of connection information to the server device by use of the second communication function, and of receiving the provision of the service.