Information network system and information apparatus

An information network system, comprising a first information apparatus and a second information apparatus, wherein

• the first information apparatus and the second information apparatus comprise respectively:
• an internal recording medium for storing contents data;
• an interface which transfers to record data relative to the contents data recorded in the internal recording medium to an external recording medium which is connected in a freely attachable or removable state to each of the information apparatus;
• and
• a transmission/reception unit for connecting the information apparatus to a network, wherein
• the internal recording medium comprises an area for storing the contents data and a concealment area for storing various kinds of data with limited accessibility, and the first information apparatus:
• upon receiving a request to move the contents data from the second information apparatus through the network, encrypts the contents data as movement-request target;
• generates contents management information that contains key information relative to encryption key used for encryption;
• transfers the encrypted contents data along with the contents management information to the second information apparatus through the network;
• deletes the key information relative to the encryption key from the contents management information after transfer;
• and stores not only the management contents information from which the key information is deleted but also the encrypted contents data to the concealment area, and
• the second information apparatus:
• after requesting movement of the contents data to the first information apparatus through the network and receiving the encrypted contents data along with the contents management information from the first information apparatus to obtain the encryption key within the key information contained in received the contents management information, and then decrypts the encrypted contents data by using the encryption key.

An information apparatus, comprising:

• an internal recording medium for storing contents data;
• a recording/reproducing unit for recording/reproducing the contents data to the internal recording medium;
• an interface which transfers to record data relative to the contents data recorded in the internal recording medium to an external recording medium which is connected in a freely attachable or removable state;
• a transmission/reception unit for transmitting and receiving data between a network;
• and
• a control unit,
• wherein the internal recording medium comprises an area for storing the contents data and a concealment area for storing various kinds of data with limited accessibility, and
• the control unit comprises:
• a compressor which reads out the contents data from the internal recording medium by controlling the recording/reproducing unit to perform conversion under compression of the contents data when a request is inputted to move the contents data to the external recording medium while the external recording medium is being connected;
• a first transfer device to transfer to record the contents data converted under compression to the external recording medium trough the interface;
• an encryption device for encrypting the contents data;
• a storage device for storing the encrypted contents data to the concealment area of the internal recording medium;
• a second transfer device which transfers to record the contents management information containing key information relative to encryption key that is used for encrypting the contents data to the external recording medium through the interface;
• a deleting device for deleting the key information after the contents management information is transferred to record to the external recording medium;
• a searching device which obtains the contents management information from the external recording medium that holds the contents data converted under compression, and searches another information apparatus that is connected to the network through the transmission/reception unit by using obtained the contents management information;
• an acquisition device which, when the another information apparatus is found through the search of the network, that holds the encrypted contents data corresponding to the contents management information, obtains the encrypted contents data from the another information apparatus through the network;
• and
• a decryption device for decrypting the encrypted contents data obtained in the acquisition device by using the encryption key contained in the contents management information.