Common use of General Method Clause in Contracts

General Method. In our proposed protocol, the rst round is a clustering method that divides the entire set of nodes into subgroups based on the geometric locations of nodes. Each of these subgroups selects a leader (also called dominator). This selection process is done by generating a connected dominating set (CDS) [16], [17], [18], [19] from the set of wireless nodes. Once the CDS has been constructed, the set of dominators of the CDS form the subgroup leaders; each dominator and the set of its dominatees form an individual subgroup. We use the term subgroup leader and dominator interchangeably hereafter. We could apply the GDH.2 protocol (Algorithm 1) or some other key agreement protocols to the set of dominators and the key is generated as a contribution from all the dominators (and connectors). On suc- cess of the key agreement protocol over the dominators, each dominator and the set of its group members follow the key dis- tribution protocol if the same key for each subgroup is required. The afore mentioned steps make sure that all the nodes share the same key, and an overall key agreement is reached. We rst outline our hybrid key agreement protocol that is suitable for wireless ad hoc networks. 1. Wireless nodes construct a CDS distributively. 2. The contributory key agreement protocol is applied among the set of computed dominators and connectors. 3. Each dominator distributes the computed key to all its dom- inatees if the same key is required. Otherwise, each subgroup performs its own key agreement protocol. Here we prefer the subgroup key be di erent from the key for backbone. This di erence adds more freedom of managing the group members such as joining and leaving. The motiva- tion of using CDS is the presence of group leaders for eÆcient management of the group membership activities. In addition, using CDS will potentially save the communication cost as we will analyze later. It is critical to reduce communication costs in wireless ad hoc networks as the wireless nodes are often powered by batteries only. Although we will not elaborate in detail, we require that two nodes need authenticate each other when they want to com- municate with each other for key agreement. This will prevent some nodes outside of the group from impersonating the node in the group.

General Method. In our proposed protocol, the rst first round is a clustering method that divides the entire set of nodes into subgroups based on the geometric locations of nodes. Each of these subgroups selects a leader (also called dominator). This selection process is done by generating a connected dominating set (CDS) [16], [17], [18], [19] from the set of wireless nodes. Once the CDS has been constructed, the set of dominators of the CDS form the subgroup leaders; each dominator and the set of its dominatees form an individual subgroup. We use the term subgroup leader and dominator interchangeably hereafter. We could apply the GDH.2 protocol (Algorithm 1) or some other key agreement protocols to the set of dominators and the key is generated as a contribution from all the dominators (and connectors). On suc- cess of the key agreement protocol over the dominators, each dominator and the set of its group members follow the key dis- tribution protocol if the same key for each subgroup is required. The afore mentioned steps make sure that all the nodes share the same key, and an overall key agreement is reached. We rst first outline our hybrid key agreement protocol that is suitable for wireless ad hoc networks. 1. Wireless nodes construct a CDS distributively. 2. The contributory key agreement protocol is applied among the set of computed dominators and connectors. 3. Each dominator distributes the computed key to all its dom- inatees if the same key is required. Otherwise, each subgroup performs its own key agreement protocol. Here we prefer the subgroup key be di erent different from the key for backbone. This di erence difference adds more freedom of managing the group members such as joining and leaving. The motiva- tion of using CDS is the presence of group leaders for eÆcient efficient management of the group membership activities. In addition, using CDS will potentially save the communication cost as we will analyze later. It is critical to reduce communication costs in wireless ad hoc networks as the wireless nodes are often powered by batteries only. Although we will not elaborate in detail, we require that two nodes need authenticate each other when they want to com- municate with each other for key agreement. This will prevent some nodes outside of the group from impersonating the node in the group.