Key Management Schemes for Stateless Receivers Based on Time Varying Heterogeneous Logical Key Hierarchy

This paper proposes a family of key management schemes for broadcast encryption based on a novel underlying structure Time Varying Heterogeneous Logical Key Hierarchy (TVH-LKH). Note that the main characteristics of the previously reported key management schemes include the following: employment of a static underlying structure for key management, and addressing the subset covering problem over the entire underlying structure. Oppositely, the main underlying ideas for developing of the novel key management schemes based on TVH-LKH include the following: (i) employment of a reconfigurable underlying structure; and (ii) employment of a divide-and-conquer approach related to the underlying structure and an appropriate communications-storageprocessing trade-off (for example, a small increase of the communication overload and large reduction of the storage and processing overload) for addressing the subset covering problem and optimization of the overloads. The design is based on a set of ”static” keys at a receiver (stateless receiver) which are used in all possible reconfiguration of the underlying structure for key management, and accordingly, in a general case, a key plays different roles depending on the employed underlying structure. A particular family of the components for developing TVH-LKH, is also proposed and discussed. The proposed technique is compared with the recently reported schemes, and the advantages of the novel one are pointed out.