METHOD OF GENERATING REKEY INDEX AND REKEY INDEX GENERATOR USING THE SAME

摘要

A method for generating a rekey index and a rekey index generator using the same are provided to reduce a transmission overhead by reducing the amount of information. A first field composition unit(910) inserts join information into a first field of a rekey index when new members join a group. A second field composition unit(920) inserts node numbers corresponding to each of the new members into a second field of the rekey index, in order to select necessary keys of encryption keys received from a receiving side. The receiving side recognizes an ancestor node of a node corresponding to a node number included in the second field of the rekey index, as an update target node.