METHOD OF UPDATING GROUP KEY AND GROUP KEY UPDATE DEVICE USING THE SAME

摘要

A method for updating a group key and a group key update device using the same are provided to process rapidly a group key update operation by accumulating leave requests of a constant time or a constant number. A group key update device includes a sub root selection unit(510), a node change unit(520), and a node key update unit(530). The sub root selection unit selects a sub root node of a binary tree. The node change unit generates a changed binary tree by performing a node change for a group according to a type of the sub root node. The node key update unit performs a node key update process for the changed binary tree. The sub root node is one of the highest node of ancestor nodes except for members of all leaf nodes corresponding to children nodes and the highest node of the ancestor nodes except for the members of the leaf nodes except for one leaf node of the leaf nodes corresponding to the children nodes.