Abstract: A communication apparatus stores encrypted pieces having plural pieces as a part of a content encrypted, and number of transmission times. At least one first piece is encrypted by plural different encryption keys. The communication apparatus selects as priority pieces plural encrypted pieces corresponding to at least one first piece among the first pieces, based on number of untransmitted encrypted pieces of which number of transmission times is zero among plural encrypted pieces of which first piece is encrypted, and stores priority piece information specifying the priority piece. When a piece request is received from other communication apparatus, the communication apparatus determines an encrypted piece to be transmitted, based on priority piece information, and transmits the encrypted piece to the other communication apparatus.

Abstract: An information storage medium of this invention comprises a first representation object, and a first time map wherein playback management information which controls simultaneous reproduction of the first representation object and a second representation object in at least a specific period includes first reference information to refer to the first time map, the first time map includes second reference information to refer to second management information including first management information about the first representation object, the first management information includes third reference information to refer to the first representation object, the playback management information includes fourth reference information to refer to a second time map, and the second time map has a data structure including fifth reference information to refer to the second representation object.

Abstract: An information storage medium of this invention comprises a first representation object, and a first time map wherein playback management information which controls simultaneous reproduction of the first representation object and a second representation object in at least a specific period includes first reference information to refer to the first time map, the first time map includes second reference information to refer to second management information including first management information about the first representation object, the first management information includes third reference information to refer to the first representation object, the playback management information includes fourth reference information to refer to a second time map, and the second time map has a data structure including fifth reference information to refer to the second representation object.

Abstract: According to one embodiment, there is provided an information reproducing method. The method includes, from an information storage medium storing stream data having a plurality of advanced packs each including a resource file and an advanced ID to identify the resource file, acquiring respective advanced IDs, identifying respective resource files based on the respective advanced IDs, and reproducing the identified respective resource files.

Abstract: According to one embodiment, there is provided an information reproducing method. The method includes, from an information storage medium storing stream data having a plurality of advanced packs each including a resource file and an advanced ID to identify the resource file, acquiring respective advanced IDs, identifying respective resource files based on the respective advanced IDs, and reproducing the identified respective resource files.

Abstract: In an image transmission apparatus an image data generator generates image data that represents an image. An updated image data generator generates updated image data that represents an updated image of an updated region of the image. A compressor compresses the updated image data. A transmitter stores the updated image data that is compressed by the compressor. An updated image data storage stores the updated image data. A transmission result storage stores transmission result data that includes quality information and time information, the quality information relating to an image quality, the time information indicating when the updated image data is generated. A transmission data selector selects the updated image data stored in the updated image data storage, and sets the image quality of the updated image data selected, according to the transmission result data stored in the transmission result storage.

Abstract: According to one embodiment, there is provided a data processing method. The method includes reading management information indicative of a playback and display procedure, acquiring a content from a certain storage position at a timing determined based on the management information, and performing playback and display of the content at a timing determined based on the management information.

Abstract: A screen data transmitting device for transmitting screen data to a screen display terminal through a network. A generation device generates a display image data. A storage device stores compression properties information associating a plurality of compression schemes with a plurality of classes of graphical user interface (GUI) components. A selection device selects one of the compression schemes with respect to a GUI component that is present in a region of the display image data. A compression device compresses the region of the display image data according to the selected compression scheme. Then, a transmission device transmits the screen data including the compressed display image data to the screen display terminal.

Abstract: A communication apparatus obtains file information indicating all or a part of first and second encrypted pieces obtained by encrypting a plurality of pieces constituting a part of a content and version management information with which it is possible to judge whether the file information has validity and receives, for each of the pieces, one of the first encrypted piece and the second encrypted piece from another communication apparatus, by using the file information. The communication apparatus transmits, to a key server, a request message for requesting decryption keys each being used for decrypting the one of the first encrypted piece and the second encrypted piece received for a different one of the pieces and the version management information of the file information used to obtain the one of the first encrypted piece and the second encrypted piece in correspondence with each of the pieces and receives the decryption keys.

Abstract: A communication apparatus that encrypts a plurality of pieces that constitute a part of data and transmits the encrypted pieces stores an encrypted piece that is one of the pieces encrypted by another communication apparatus, and first decryption key information used for decrypting the encrypted piece, while keeping the encrypted piece and the first decryption key information in correspondence with each other. Further, the communication apparatus generates temporary information that can be different at each time of generation, further performs an encrypting process on the encrypted piece based on the temporary information, and outputs a new encrypted piece. The communication apparatus transmits the new encrypted piece, the first decryption key information that is stored in correspondence with the encrypted piece, and second decryption key information used for decrypting the encrypting process.

Abstract: In a data transfer scheme using a caching technique and/or a compression technique which is capable of reducing the network load of a network connecting between data transfer devices, correspondences between data and their names are registered at the data transfer devices and the corresponding names are transferred, instead of transferring the data, for those data for which the correspondences are registered, so that it is possible to reduce the amount of transfer data among the data transfer devices.

Abstract: A communication apparatus receives, from another communication apparatus, a plurality of encrypted pieces obtained by encrypting a plurality of pieces constituting a part of a content and obtains a part or all of decryption keys used for decrypting the encrypted pieces. The communication apparatus also obtains an invalid piece list showing one or more identifiers of one or more encrypted pieces that can respectively be decrypted by using one or more decryption keys that have already been invalidated. In the case where at least one of the encrypted pieces is listed in the invalid piece list, the communication apparatus deletes the at least one of the encrypted pieces, based on an obtainment status of the encrypted pieces or an obtainment status of the decryption keys.

Abstract: A communication apparatus stores encrypted pieces having plural pieces as a part of a content encrypted, and number of transmission times. At least one first piece is encrypted by plural different encryption keys. The communication apparatus selects as priority pieces plural encrypted pieces corresponding to at least one first piece among the first pieces, based on number of untransmitted encrypted pieces of which number of transmission times is zero among plural encrypted pieces of which first piece is encrypted, and stores priority piece information specifying the priority piece. When a piece request is received from other communication apparatus, the communication apparatus determines an encrypted piece to be transmitted, based on priority piece information, and transmits the encrypted piece to the other communication apparatus.

Abstract: A content reproduction apparatus including reproduction unit configured to reproduce content data item stored in recording medium storing first server identifier and content data item including destination identifier, reads first server identifier from recording medium, to store first server identifier in table, certifies first server corresponding to first sever identifier, receives first server policy from first server being certified, first server policy including second server identifier redirecting to second server, to store second server identifier in table, certifies second server, acquires destination identifier while reproduction unit reproduces content data item, determines whether destination identifier being acquired is equal to first identifier stored in table, and accesses to second server, when at least destination identifier is equal to first identifier and second server is certified.

Abstract: A plurality of first encrypted pieces is generated by encrypting the pieces with a first encryption key. The second encrypted piece is generated by encrypting at least one of the pieces with a second encryption key. The first encryption key and the second encryption key for encrypting the same piece are different from each other. A communication apparatus receives a first encrypted piece or a second encrypted piece from other communication apparatus for each piece, transmits a request message for requesting a decryption key for decrypting the encrypted piece to a key server, and receives the decryption key from the key server in response to the request message.

Abstract: In a data transfer scheme using a caching technique and/or a compression technique which is capable of reducing the network load of a network connecting between data transfer devices, correspondences between data and their names are registered at the data transfer devices and the corresponding names are transferred, instead of transferring the data, for those data for which the correspondences are registered, so that it is possible to reduce the amount of transfer data among the data transfer devices. Server side data transfer devices and client side data transfer devices can be provided in multiple-to-one, one-to-multiple, or multiple-to-multiple manners.

Abstract: An information storage medium according to one embodiment of the present invention comprises a management area in which management information to manage content is recorded and a content area in which content managed on the basis of the management information is recorded. The content area includes an object area in which a plurality of objects are recorded, and a time map area in which a time map for reproducing these objects in a specified period on a timeline is recorded. The management area includes a play list area in which a play list for controlling the reproduction of a menu and a title each composed of the objects on the basis of the time map is recorded.

Abstract: In a data transfer device, presence/absence of a prescribed header in the received request message is analyzed, and information indicating the presence/absence of the prescribed header, or information indicating either presence or absence of the prescribed header when the prescribed header is either present or absent as a result of analysis is stored. Then, when a reply message corresponding to the request message is received, the presence/absence of the prescribed header is checked by referring to the stored information, and the reply message is transferred according to a result of checking.

Abstract: In a data transfer scheme using a caching technique and/or a compression technique which is capable of reducing the network load of a network connecting between data transfer devices, correspondences between data and their names are registered at the data transfer devices and the corresponding names are transferred, instead of transferring the data, for those data for which the correspondences are registered, so that it is possible to reduce the amount of transfer data among the data transfer devices. Even when the name corresponding to the data is not registered so that it is impossible to transfer the corresponding name instead of transferring the data, it is possible to reduce the amount of transfer data among the data transfer devices by transferring the compressed data in which this data is expressed in a compressed form by utilizing the name corresponding to the registered reference data.

Abstract: In a data transfer scheme using a caching technique and/or a compression technique which is capable of reducing the network load of a network connecting between data transfer devices, correspondences between data and their names are registered at the data transfer devices and the corresponding names are transferred, instead of transferring the data, for those data for which the correspondences are registered, so that it is possible to reduce the amount of transfer data among the data transfer devices. Server side data transfer devices and client side data transfer devices can be provided in multiple-to-one, one-to-multiple, or multiple-to-multiple manners.