Patent ID: 8411865

Claim:
A key management method for broadcast encryption in a tree topology network, which includes a plurality of nodes, the plurality of nodes comprising actual nodes and virtual nodes: constructing, by a processor, a logical key hierarchy with includes multiple layers in the tree topology network; the bottom layer consists of actual nodes; forming a first virtual node layer above the actual nodes, the first virtual node layer comprising a plurality of virtual node groups, each virtual node group consists of a group of at least one actual node; forming, a second virtual node layer above the first layer of virtual nodes which includes a group of at least one virtual node groups; forming, a third virtual node layer above the second virtual node layer that consist of at least one virtual node groups; after constructing the logical key hierarchy assigning keys to the nodes using key tables that assigns keys respectively to virtual and actual nodes using subsets that have the ability to exclude logical or actual nodes from receiving a key; the keys in the key tables are independent of each other.