Moreover, according to one mode of the present invention, there is provided a communication device supplying common data to a plurality of devices, comprising: a generation unit that generates a session key a reception unit that receives public keys from the devices a first encryption unit that encrypts the session key using the public keys corresponding to the devices, received by the reception unit a first transmission unit that transmits to the devices the session key encrypted using the first encryption unit a second encryption unit that encrypts the common data using the session key and a second transmission unit that transmits to the devices the common data encrypted using the second encryption unit. It is an object of the present invention to carry out communication parameter exchange between a plurality of devices at high speed.Īccording to one mode of the present invention, in order to accomplish the above-mentioned object, there is provided a communication system including a master device and a plurality of slave devices, wherein the master device comprises: a generation unit that generates a session key a unit that receives public keys from the slave devices, encrypts the session key using the public keys and transmits the encrypted session key to the slave devices and a data transmission unit that encrypts data using the session key and transmits the encrypted data to the slave devices and each slave device comprises: a decryption unit that transmits the public key to the master device, receives the session key encrypted using the public key and decrypts it and a data decryption unit that receives data encrypted using the session key from the master device and decrypts it using the decrypted session key. Therefore, other slave devices must wait until the processing by the master device is complete, and the time it takes for all the slave devices to complete wireless parameter setting is prolonged depending on the number of times the master device decrypts the session keys. ![]() However, when wireless communication parameters are set in a plurality of devices, no other processing can be performed simultaneously when the master device performs such processing, and therefore, master device functionality ends up being occupied by a single slave device. Therefore, processing (heavy-load processing) involving decrypting data encrypted with a public key using a private key corresponding to the public key has been performed by the master device. When the decryption is over, the slave device acquires and sets wireless parameters. By doing so, when the slave device receives the wireless parameters encrypted using the session key, it uses the session key for decryption. When the decryption is over, wireless parameters are encrypted using the session key and transmitted to the slave device. On the other hand, when the master device receives a session key encrypted using the public key, it uses the private key for decryption. Here, when the slave devices receive the public key, they encrypt session keys using the public key and transmit them to the master device. The setting of wireless parameters is initiated when the master device transmits a public key to the slave devices. In conventional automatic parameter setting methods, a master device such as an access point, which operates as a master, has a set made up of a public key and a private key, and slave devices, which function as slaves, generate session keys. The demand for communication between a plurality of terminals on such ad hoc networks is on the increase and methods for automatic setting of parameters on a plurality of terminals are required (see Patent document 1: U.S. Moreover, in recent years, communication is also more frequently conducted over so-called ad hoc networks, in which terminals communicate with one another directly over a wireless LAN without passing through an access point. has been implemented as an actual product. ![]() ![]() For instance, a method for automatic transfer of wireless parameter settings between an access point (relay station) and a station (terminal) from the access point to the station by means of a simple operation, etc. Because of the complexity of these setting operations, methods have been proposed for automatically performing them between terminals. When using wireless LANs conforming to the IEEE 802.11, users have to set wireless communication parameters, such as network identifiers (ESSID), encryption methods, cryptographic keys (encryption keys), authentication methods, authentication keys, etc. The present invention relates to a communication system including a master device and a plurality of slave devices, to a communication device, and to a processing method therefor.
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