Abstract: The present invention provides an access control method of controlling acceptance or rejection of access to content from metadata. The access control method according to the present invention includes a step of producing metadata 3A for content 6A and embedding a digital signature 4A of a producer who has produced the metadata as producer information in the produced metadata 3A, a step of embedding an identifier 5A indicating which metadata are accessible to the content in license information required to play back the content 6A, and an access propriety control step of comparing the digital signature 4A with the identifier 5A to control propriety of access to the content 6A from the produced metadata 3A.

Abstract: A content transmission method, a content reception method, an apparatus and a computer program using same, that improve the efficiency of descrambling a scrambled content, make the management of cryptography keys for descrambling easy, and protect the copyright of contents, are provided. A content transmission apparatus 3 that encrypts and transmits contents and a content reception apparatus 5 that receives the encrypted contents are provided. The content transmission apparatus 3 includes a content scrambling unit 7 that encrypts contents using a scrambling key Ks, a content key , a work key Kw, a master key Km, and a multiplexing unit 9 that transmits multiplexed contents. The content reception apparatus 5 includes a separating unit 13 that receives and separates the multiplexed encrypted content, and a content descrambling unit 15 that obtains the contents by descrambling encrypted information separated by the separating unit 13.

Abstract: A method of transmitting contents, which are to be received at a reception side where a portion of the contents is previewed while the contents are not accessible for playing other than for a preview purpose, includes the steps of encrypting the contents by a first encryption key, generating information indicative of an elapsed time of the contents that indicates a relationship between positions on a time axis of the contents representing an amount of time that passes as the contents are played and a time count that accrues as a preview time when the contents are previewed, encrypting the first encryption key and the information indicative of an elapsed time of the contents by a second encryption key, thereby generating first encrypted information, encrypting the second encryption key and content-usage control information by a third encryption key, thereby generating second encrypted information, the content-usage control information indicating usage of the contents on the reception side, and transmitting the

Abstract: A method of transmitting a content to a reception side includes the steps of encrypting the content by use of a scramble key that varies with time, encrypting scramble-key-associated information that includes at least the scramble key and usage-control information, the usage-control information indicative of usage of the content on the reception side, and transmitting the encrypted content and the encrypted scramble-key-associated information to the reception side.

Abstract: The present invention provides an access control method of controlling acceptance or rejection of access to content from metadata. The access control method according to the present invention includes a step of producing metadata 3A for content 6A and embedding a digital signature 4A of a producer who has produced the metadata as producer information in the produced metadata 3A, a step of embedding an identifier 5A indicating which metadata are accessible to the content in license information required to play back the content 6A, and an access propriety control step of comparing the digital signature 4A with the identifier 5A to control propriety of access to the content 6A from the produced metadata 3A.

Abstract: A method of transmitting contents, which are to be received at a reception side where a portion of the contents is previewed while the contents are not accessible for playing other than for a preview purpose, includes the steps of encrypting the contents by a first encryption key, generating information indicative of an elapsed time of the contents that indicates a relationship between positions on a time axis of the contents representing an amount of time that passes as the contents are played and a time count that accrues as a preview time when the contents are previewed, encrypting the first encryption key and the information indicative of an elapsed time of the contents by a second encryption key, thereby generating first encrypted information, encrypting the second encryption key and content-usage control information by a third encryption key, thereby generating second encrypted information, the content-usage control information indicating usage of the contents on the reception side, and transmitting the

Abstract: A method of distributing contents in a system including a distribution station for distributing contents, a relay station for relaying the contents, a management apparatus for receiving the contents distributed from the distribution station or the relay station and managing the contents, and a plurality of terminal apparatuses for receiving the contents distributed from the management apparatus, the method comprising the steps of: attaching metadata to the contents distributed from the distribution station; and adding location information of the relay station, the management apparatus or each of the terminal apparatuses to the metadata of the contents when the contents are stored in the relay station, the management apparatus or the terminal apparatus. The contents can be displayed on the user side concentratedly regardless of locations of the contents so that the contents can be acquired or played back without user's consciousness of locations of the large number of contents.

Abstract: A method of transmitting a content to a reception side includes the steps of encrypting the content by use of a scramble key that varies with time, encrypting scramble-key-associated information that includes at least the scramble key and usage-control information, the usage-control information indicative of usage of the content on the reception side, and transmitting the encrypted content and the encrypted scramble-key-associated information to the reception side.

Abstract: A content transmission method, a content reception method, an apparatus and a computer program using same, that improve the efficiency of descrambling a scrambled content, make the management of cryptography keys for descrambling easy, and protect the copyright of contents, are provided. A content transmission apparatus 3 that encrypts and transmits contents and a content reception apparatus 5 that receives the encrypted contents are provided. The content transmission apparatus 3 includes a content scrambling unit 7 that encrypts contents using a scrambling key Ks, a content key Kc, a work key Kw, a master key Km, and a multiplexing unit 9 that transmits multiplexed contents. The content reception apparatus 5 includes a separating unit 13 that receives and separates the multiplexed encrypted content, and a content descrambling unit 15 that obtains the contents by descrambling encrypted information separated by the separating unit 13.