Abstract: A transmission device, which continues consistent secure communication, even if a frame counter is reset due to a power cut off, includes a transmission frame counter that counts a value monotonically incremented for each packet transmission and holds the value as a frame counter value. The transmission device includes a transmission unit that adds the frame counter value held in the transmission frame counter to a packet, and transmits the packet to the reception device, and a storage circuit that stores the frame counter value. The transmission frame counter (i) stores the counted and held frame counter value into the storage circuit for each stored-frame-counter updating increment that is a natural number greater than an increment by which the frame counter value is monotonically incremented, and holds, as a new frame counter value, the stored frame counter value added with the stored-frame-counter updating increment, when the transmission device is reset.

Abstract: To easily ensure that appropriate recognition information is used. A remote control system (1) includes a DVR (13) and a remote control (11) that controls the DVR (13) via a wireless communication path. The remote control (11) which is one apparatus out of the DVR (13) and the remote control (11) obtains, by a wireless reception unit (114), recognition information used by the apparatus to uniquely recognize the other apparatus, via another communication path (a communication path through a TV (12)) different from the wireless communication path connecting the apparatus and the other apparatus. When a connected apparatus recognized via the wireless communication path is identified by the obtained recognition information, the remote control (11) sets, by a control circuit (115), the connected apparatus as the DVR (13) which is the other apparatus to enable communication with the connected apparatus.

Abstract: In a wireless communication system including at least a plurality of wireless communication terminal apparatuses each including first and second wireless communication apparatuses, the first wireless communication apparatus includes first and second wireless communication parts. The first wireless communication part transceives digital data in a half-duplex communication mode via a first wireless communication path, and the second wireless communication part transceives digital data in a full-duplex communication mode via a second wireless communication path. A first control part controls transmission of digital data for the first and second wireless communication parts. The second wireless communication apparatus includes third and fourth wireless communication parts.

Abstract: There is provided a secret data transmission method where a first device generates plural pieces of distributed data including data of a master key and transmits these by wireless communication to a second device and where the second device receives the plural pieces of distributed data and reconstructs the master key, wherein the first device arranges data obtained by performing an EXOR operation in sequence on plural pieces of random number data and the master key to generate secret data, generates a last piece of distributed data by performing an EXOR operation in sequence on the plural pieces of distributed data and the secret data, and transmits the plural pieces of distributed data to the second device, and the second device performs an EXOR operation in sequence on the plural pieces of distributed data to reconstruct the secret data, divides the reconstructed secret data, and performs an EXOR operation on the divided pieces of data to reconstruct the master key.

Abstract: A transmission device can continue secure communication having a consistency between a frame counter of a transmission device and a frame counter of a reception device without bothering a user, even if the frame counter is reset due to battery exchange, power cut off, or the like. The transmission device includes: a transmission frame counter (20) that counts a value monotonically incremented for each packet transmission and holds the value as a frame counter value; a transmission unit that adds the frame counter value held in the transmission frame counter (20) to a packet, and transmits the packet to the reception device (200); and a transmission frame counter storage circuit (23) that stores the frame counter value.

Abstract: To easily ensure that appropriate recognition information is used. A remote control system (1) includes a DVR (13) and a remote control (11) that controls the DVR (13) via a wireless communication path. The remote control (11) which is one apparatus out of the DVR (13) and the remote control (11) obtains, by a wireless reception unit (114), recognition information used by the apparatus to uniquely recognize the other apparatus, via another communication path (a communication path through a TV (12)) different from the wireless communication path connecting the apparatus and the other apparatus. When a connected apparatus recognized via the wireless communication path is identified by the obtained recognition information, the remote control (11) sets, by a control circuit (115), the connected apparatus as the DVR (13) which is the other apparatus to enable communication with the connected apparatus.

Abstract: A communication apparatus with a memory (418) holding CA information A(301a) including (i) a CA certificate A(106a) indicating that an AP server certificate A(402a) (that indicates the validity of an application server (401)) is valid and (ii) a URL B(302b) indicating the URL of a download server B(406b) where CA information B(301b) including the next valid CA certificate B(106b) is stored. The communication apparatus also having a server authentication unit (416) verifying the AP server certificate A(402a) using the CA certificate A(106a), and having a CA information update unit (417) obtaining the CA information B(301b) from the download server B(406b) indicated by the URL B(302b), wherein, when the CA certificate A(106a) becomes revoked, the server authentication unit (416) authenticates the application server (401) using the CA certificate B(106b) included in the CA information B(301b) obtained by the CA information update unit (417).

Abstract: A communication system includes a device and a server connected to the Internet, which transfers communications between the device and a terminal connectable to the Internet via the server. The device periodically transmits a notice packet to the server. The server transmits a connection request packet to the device in reply to the notice packet when a transfer to the device is requested from the terminal. The device transmits a TCP connection request to the server when receiving the connection request packet from the server. The server accepts the TCP connection request transmitted from the device to the server in reply to the connection request packet, to establish the TCP connection. Thus, the server transfers communications between the terminal and the device on the TCP connection after the TCP connection is established.

Abstract: A terminal (40a) comprises: a revocation number verification unit (435) that obtains a revocation number from a repository (20) storing such revocation number that is information serving as a criterion for judging the validity of a server certificate (75); a revocation number storage unit (436) that stores the obtained revocation number; a certificate serial number extraction unit (437) that reads out, from the server certificate (75), an identification number for identifying such server certificate (75); a revocation judgment unit (438) that judges the validity of the server certificate (75) by comparing the read-out identification number with the revocation number stored by the revocation number storage unit (436); and a communication unit (420) that establishes a communication with an application server (30a) when the server certificate (75) is judged valid, and does not establish a communication with the application server (30a) when the server certificate (75) is judged invalid.

Abstract: A system includes electronic equipment, an information processing device and a server device. The electronic equipment sends first address change confirmation information containing first address information to the information processing device. The information processing device sends second address change confirmation information obtained by writing second address information in the received first address change confirmation information. The server device determines that the first address information and the second address information, which are contained in the received second address change confirmation information, agree with each other, and updates the address information to new one when the first address information and the second address information do not agree with each other. With such a system, electronic equipment can hold up-to-date address information of the information processing device with extremely light processing at the side of the server device and with small load of communication.

Abstract: A communication apparatus includes: a memory (418) that holds CA information A (301a) including (ú@) a CA certificate A (106a) indicating that an AP server certificate A (402a) that indicates the validity of an application server (401) is valid and (úA) a URL B (302b) indicating the URL of a download server B (406b) where CA information B (301b) including the next valid CA certificate B (106b) is stored; a server authentication unit (416) that verifies the AP server certificate A (402a) using the CA certificate A (106a); and a CA information update unit (417) that obtains the CA information B (301b) from the download server B (406b) indicated by the URL B (302b), wherein when the CA certificate A (106a) becomes revoked, the server authentication unit (416) thereafter authenticates the application server (401) using the CA certificate B (106b) included in the CA information B (301b) obtained by the CA information update unit (417).

Abstract: A communication system includes a device and a server connected to the Internet, which transfers communications between the device and a terminal connectable to the Internet via the server. The device periodically transmits a notice packet to the server. The server transmits a connection request packet to the device in reply to the notice packet when a transfer to the device is requested from the terminal. The device transmits a TCP connection request to the server when receiving the connection request packet from the server. The server accepts the TCP connection request transmitted from the device to the server in reply to the connection request packet, to establish the TCP connection. Thus, the server transfers communications between the terminal and the device on the TCP connection after the TCP connection is established.

Abstract: A transmission apparatus for stably transmitting or receiving data of high priority is provided. In the transmission apparatus of the present invention, processing of the priority packet to be transmitted and processed by priority and processing of the non-priority packet are conducted separately. At transmission side, the above-mentioned priority packet is transmitted by priority by making its average transmission interval shorter than its average generation interval, and said non-priority packet is transmitted during the transmit margin period caused by the above-mentioned processing. At receive side, in the layer of processing the receive frame as a layer lower than the layer of processing the priority packet and non-priority packet, the priority packet and the non-priority packet is sorted based on the communication protocol header of the receive packet stored in the receive frame, and processing of the priority packet and that of the non-priority packet are conducted separately.

Abstract: A controller issues a command to an HDD interface to transfer AV data stored in HDDs to a memory. The HDD interface, in compliance with the command, transfers the AV data stored in the HDDs to a memory mapped on a bus. A memory controller reads the AV data out of the bus, and writes the AV data into the memory. The controller outputs the address of the AV data to be outputted to the memory controller. The memory controller reads out the AV data of the designated address, and outputs them to an AV data output interface. And the AV data output interface outputs the AV data. The controller issues a command to the HDD interface memory to record the AV data stored in the memory into the HDDs. The HDD interface, in compliance with the command, reads the data out of a memory mapped on the bus, and stores them in the HDDs. The memory controller reads the AV data out of the memory, and outputs them to the bus.

Abstract: An apparatus for recording and reproducing digital data according to the present invention, includes: a group converter; a controller; a recording converter; a recording unit; a reproducing unit; a reproducing converter; and a group reverse converter, wherein the group converter includes: a block management data generator for receiving the management data from the controller and generating block management data with respect to the corresponding blocked data, the block management data having a variable-length and containing information concerning each blocked data; a group management data generator for receiving the management data and generating group management data containing information concerning the entire grouped data; and a grouped data generator for receiving the blocked data, the block management data, and the group management data, and generating grouped data by arranging the blocked data, the block management data, and the group management data in a predetermined order.

Abstract: An apparatus for recording and reproducing digital data according to the present invention, includes: a group converter; a controller; a recording converter; a recording unit; a reproducing unit; a reproducing converter; and a group reverse converter, wherein the group converter includes: a block management data generator for receiving the management data from the controller and generating block management data with respect to the corresponding blocked data, the block management data having a variable-length and containing information concerning each blocked data; a group management data generator for receiving the management data and generating group management data containing information concerning the entire grouped data; and a grouped data generator for receiving the blocked data, the block management data, and the group management data, and generating grouped data by arranging the blocked data, the block management data, and the group management data in a predetermined order.

Abstract: An apparatus for recording and reproducing digital data according to the present invention, includes: a group converter; a controller; a recording converter; a recording unit; a reproducing unit; a reproducing converter; and a group reverse converter, wherein the group converter includes: a block management data generator for receiving the management data from the controller and generating block management data with respect to the corresponding blocked data, the block management data having a variable-length and containing information concerning each blocked data; a group management data generator for receiving the management data and generating group management data containing information concerning the entire grouped data; and a grouped data generator for receiving the blocked data, the block management data, and the group management data, and generating grouped data by arranging the blocked data, the block management data, and the group management data in a predetermined order.

Abstract: The present invention relates to a data recorder which chronologically records continuous data such as image data without interruption at high speed, a medium which stores the procedure of recording or reproducing in the data recorder as a program, and a method of accessing the data recorder. In one embodiment, the data recorder is equipped with a group of recording units, and each group unit has a SCSI adaptor and a hard disk. The hard disk is connected to the SCSI bus and the SCSI adaptor is connected to a PCI bus. With this construction, data to be recorded in the data recorder is split into units of a prescribed size and assigned and recorded on the group of recording units so as to utilize a plurality of hard disks as a single logical recording space.

Abstract: An apparatus for recording and reproducing digital data according to the present invention, includes: a group converter; a controller; a recording converter; a recording unit; a reproducing unit; a reproducing converter; and a group reverse converter, wherein the group converter includes: a block management data generator for receiving the management data from the controller and generating block management data with respect to the corresponding blocked data, the block management data having a variable-length and containing information concerning each blocked data; a group management data generator for receiving the management data and generating group management data containing information concerning the entire grouped data; and a grouped data generator for receiving the blocked data, the block management data, and the group management data, and generating grouped data by arranging the blocked data, the block management data, and the group management data in a predetermined order.

Abstract: A packet output device for formatting serial data into packets and for transmitting resulting data packets includes a data packet generator for generating each data packet and for generating time data corresponding to the data packet, the time data defining an output time of the data packet, and a packet transmitting circuit for receiving the data packet and the corresponding time data and transmitting the data packet based on the corresponding time data.