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(12) PATENT APPLICATION PUBLICATION (21) Application No.1395/DELNP/2004 A
(19) INDIA
(22) Date of filing of Application :24/05/2004 (43) Publication Date : 16/03/2007
(54) Title of the invention : KEY MANAGEMENT APPARATUS
(51) International classification :G11B 20/00 (71)Name of Applicant :
(31) Priority Document No :2001-329862 1)MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
(32) Priority Date :26/10/2001 Address of Applicant :1006, OAZAKADOMA, KADOMA-SHI, OSAKA
(33) Name of priority country :Japan
571-8501, JAPAN Japan
(86) International Application No
:PCT/JP02/10870 (72)Name of Inventor :
Filing Date
:21/10/2002 1)NAKANO, TOSHIHISA;
(87) International Publication No :WO 03/036859 2)YAMAMICHI, MASATO;
(61) Patent of Addition to Application Number
:NA
3)FUTA, YUICHI;
Filing Date
:NA
4)YOKOTA, KAORU;
(62) Divisional to to Application Number
:NA
5)MATSUZAKI, NATSUME;
Filing Date
:NA
6)TATEBAYASHI, MAKOTO;
No of Pages : 54 No of Claims : 16
(57) Abstract :
A digital work protection system composed of (a) user apparatuses that are recording apparatuses and/or reproduction apparatuses for recording or
reproducing digital contents such as movies, (b) a recording medium, and (c) a key management apparatus that manages the assignment of device keys to the
user apparatuses using a tree structure. The key management apparatus always keeps some leaves with which no user apparatus is not correlated in the tree
structure, generates new leaves that are connected from the leaves and belong to a new layer, and assigns new user apparatuses to the newly generated leaves.
The Patent Office Journal 16/03/2007 5756