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:
Dec. 03, 2013
Filed:
Aug. 17, 2007
Masafumi Kusakawa, Tokyo, JP;
Tomoyuki Asano, Kanagawa, JP;
Masafumi Kusakawa, Tokyo, JP;
Tomoyuki Asano, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A key generation device according to the present invention hierarchically constructs a Y-ary tree structure where n reception devices are assigned to leaves, and forms subgroups where individual intermediate nodes existing between the leaves and a root of the Y-ary tree structure are defined as parent nodes. By providing new parameters to the individual intermediate parameters, the subgroups can be formed flexibly. In a case where no excluded customer exists or the number of excluded customers is small, the size of a header to be delivered and the calculation amount of an operation that a customer needs to perform can be reduced.