The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 15, 2008
Filed:
Mar. 18, 2003
Takatoshi Ono, Ama-gun, JP;
Yoji Kumazaki, Kasugai, JP;
Shigeru Yamada, Mino, JP;
Hiroki Murakami, Suita, JP;
Tetsuya Inoue, Ibaraki, JP;
Motoji Ohmori, Hirakata, JP;
Takatoshi Ono, Ama-gun, JP;
Yoji Kumazaki, Kasugai, JP;
Shigeru Yamada, Mino, JP;
Hiroki Murakami, Suita, JP;
Tetsuya Inoue, Ibaraki, JP;
Motoji Ohmori, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A key management apparatus which can be used to encrypt/decrypt content data in a content playback device includes a storing unit for storing a secret key, a key information decrypting unit for decrypting encrypted key information and an updating unit operable to update the secret key with an algorithm stored therein, when the decrypted key information is key-updating information. Seed information can be received for use with the algorithm to provide a new secret key, and preliminary trigger information can be used to poll a group of appliances to request key information to determine any duplication of appliances.