Key management method in network system

摘要

A method of key management in a network system. In a network system which includes at least one node group having a plurality of nodes, the method of key management includes setting commonly-shared keys for subsets of all, or a part of the plurality of nodes; storing a part of the set keys for each node; and generating the rest of the set keys by substituting the part of the set keys for each node in a predetermined function. As a result, the number of keys for storage by each node can be greatly reduced in the transmission of encrypted contents and updated encrypted keys.