Research On Distributing Key In Ad Hoc Network

How to implement secure communication between any two nodes in an ad hoc network has been a research focus recent years as its traits of no pre-exiting infrastructure, self organization, distributed management, dynamic topology and multi-hop communication. To achieve this goal, it is necessary for the two nodes in an ad hoc network to share a secret key. A probabilistic approach of distributing keys for secure communication in ad hoc networks can solve this problem well.Before the deployment of a network, i.e., during a key per-distribution phase, every node is loaded with a certain number of keys out of a large pool of keys by a key server. Keys are allocated to each node using a probabilistic scheme that enables every pair of nodes to share one or more keys with certain probability.By using the extension we make of AODV protocol, source node can retrieve necessary information about other nodes when it wants to distribute a key to destination node.Source node splits the to-be-distributed secret key into multiple subsets. If there are one or more keys shared by source and destination node, one subset is encrypted and sent to destination node.The other subsets are encrypted by intermediate nodes and sent to destination node. The destination node combines all received sutsets into the origin key. The number of secret key subsets can be determined by the concrete algorithm.A program is used to simulate the process of distributing a communication key between two nodes, compute the number of splitted key subsets when a node wants to distribute the key to another node and analyze correlative output data. The result proves this approach's feasibility and security. This approach is scalable since every node only needs to possess a small number of keys, independent of the network size; it is computationally efficient because it only relies on symmetric key cryptography based operations.