METHOD FOR CONSTRUCTING KEY TREE FOR HIERARCHICAL ACCESS CONTROL IN BROADCASTING AND COMMUNICATION SYSTEM, AND METHOD OF KEY MANAGEMENT USING IT

摘要

A key tree constructing method for controlling a hierarchical access in a broadcasting and communication system and a key management method using the same are provided to reduce a storage overhead and a communication overhead generated in a dynamic management in a capacity of a user. A key tree constructing method for controlling a hierarchical access in a broadcasting and communication system comprises the following several steps. A key tree whose root key is a user group key allocated to a corresponding group for each user group is constructed by using a hierarchical access relationship between the user group and a resource. A connected network is constructed by connecting a corresponding session key for each resource to the user group key allocated to the user group affiliated to a corresponding resource on the basis of the hierarchical access relationship. A hierarchical access control key tree is constructed by connecting the key tree for each user group to the user group key on the connected network.