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:
Oct. 27, 2009
Filed:
Mar. 25, 2003
Takahiro Nagai, Osaka, JP;
Kaoru Murase, Nara, JP;
Hideshi Ishihara, Katano, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An MPEG2-PS format digital stream is composed of VOBUs and each VOBU except an RDI-Pack at the top is encrypted using a content key Kc. The content key Kc is an encryption key obtained by adding a title key Kt to CCI, and then converting a time varying coefficient using the sum. Accordingly, the resulting content key Kc differs for each VOBU. Since each content key Kc is all different for such a small unit of VOBU, copyright of the digital stream is firmly protected. CCI contained in RDI-Pack represents conditional Copy Freely status which allows the digital stream to be copied on condition that the digital stream is recorded only in encrypted form.