Hierarchical Key Agreement Protocols in Group-User Systems

In recent years, the ubiquity of communication networks speed up the development of wireless network and the Internet applications. In addition to the common service provided by the telecommunication enterprise, how to connect some distinct users to form a network which allow them to deal with their own works is a popular topic that many scholars engage in. When constructing the network, the key management is the most important problem that each system has to solve. There are many key agreement protocols which are non-hierarchical. However, the hierarchy is ubiquitous in our real life. In this paper, we have achieved a verifiable hierarchical key derivation scheme using the elliptic curve cryptography and the bilinear mapping function which can achieve the same security level but use less bit number when comparing to the RSA system.