KEY GENERATION DEVICE, ENCRYPTION DEVICE, RECEPTION DEVICE, KEY GENERATION METHOD, ENCRYPTION METHOD, KEY PROCESSING METHOD, AND PROGRAM

摘要

A key generation device builds a hierarchical Y-branched tree structure in which n reception devices are allocated. A new parameter is supplied to each of sub groups respectively using as a parent node, an intermediate node existing between a leaf and a route of the Y-branched tree structure, so that the sub groups can be flexibly configured. When there is no or few contractors to be excluded, it is possible to reduce the header size to be distributed and the calculation amount of an operation to be executed by the contractor. ® KIPO & WIPO 2009