Nippon Hoso' Kyokai

Seiichi Namba

Yusei Nishimoto

Tatsuya Kurioka

Toshihiro Uehara

Haruo Okuda

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 apparatusthat encrypts and transmits contents and a content reception apparatusthat receives the encrypted contents are provided. The content transmission apparatusincludes a content scrambling unitthat encrypts contents using a scrambling key Ks, a content key , a work key Kw, a master key Km, and a multiplexing unitthat transmits multiplexed contents. The content reception apparatusincludes a separating unitthat receives and separates the multiplexed encrypted content, and a content descrambling unitthat obtains the contents by descrambling encrypted information separated by the separating unit

Content transmission apparatus, content reception apparatus, content transmission program, and content reception program

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 encrypted contents, the first encrypted information, and the second encrypted information to the reception side.

Diligent control of preview of stored contents

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.

Growing community of inventors

Tokyo, Japan

Seiichi Namba