Research On Logical Hierarchy Based Group Key Management For Ad Hoc Network

As a new type of wireless network, ad hoc network has the following characteristics:absence of fix infrastructure, node mobility and the flexibility of creating network. It can combine with existing communication networks to cover more areas and it can also form a network through the cooperation of nodes, thus ad hoc network is widely used in many areas from military field to civilian field.Group communication is one of the important communication types for ad hoc network and group key management is critical in securing the communication between nodes. With the increase of group based applications in ad hoc, group key management has been a focus for researchers. Therefore, it is very useful to research on the group key management problem of ad hoc network for both theory analysis and practical usage.Based on the overview of existing group key management protocols, we do the following work as for the problem of how to establish a group key effectively in dynamic groups:Firstly, we propose a logical hierarchy based template method for establish group key in dynamic group. This method divides nodes into logical group such that it forms a bifurcate tree like hierarchy structure. Combining this structure with some kind of key distributions, this method can securely establish a group key for group members.Secondly, we illustrate the above method using two instantiations, namely sub-set keying and dual one-way hashing keying. We elaborate how to establish group key using these two schemes combined with the logical hierarchy. We also implement the two key distribution schemes and make detailed analysis of their cost in establishing group key.Thirdly, for the collusion problem, we put forward several solutions for mitigating the bad effect of node collusion, such as dual distributions, adding random values and mingle up method and so on. We also implement those collusion resistant algorithms and analyze their effectiveness.