Group key exchange with non-linear trust

Group Key Exchange allows a set of parties to communicate over a public network and securely establish a secret session key. Thus, it is a critical protocol for emerging network applications that require collaborated output from various peers. There have been many protocols have been proposed, designed and implemented for group key exchange. However, in all the protocols proposed so far for group key exchange a scenario of linear trust is assumed i.e. either all the nodes in the group are uniformly considered trustworthy or completely trustless. We present, in this paper, a novel problem of how to deal with establishing a session key in a scenario where the trust is non-linearly distributed and a solution there of. A protocol is proposed using which every time a session key refresh happens in a group, it recognizes and eliminates the malicious node in the group thus securing every protocol session. We argue that our protocol is best suited in highly dynamic scenarios like Mobile Adhoc Networks (MANET).