Improving Public Key Authentication in ad-hoc networks with Cooperative Trust Groups

An ad hoc network is an “infrastructure-less” network which is much different from Internet networks. The main differences are the lacking of fixed infrastructures, the dynamic topology, and the limited transmission range of mobile hosts. Therefore, it is difficult for us to apply the traditional security solution, such as PKI, from the wired network to the mobile environment. According to the issue, we propose an approach to form cooperative trust groups to solve the authentications among mobile hosts in the ad hoc network. The procedure of forming groups should avoid causing too much overhead, so only a simple star topology with radius at most 2 is taken into consideration to deploy the cooperative trust groups. Each member in the same cooperative group has high trust for its group members and all of them simultaneously own a shared group key used for the authentication of digital signature. In other words, a group member may act as a substitute of one another by issuing the certificate signed with the shared group key. We are convinced that the concept can redeem the inefficient authentication only used with the personal public key.