Abstract: Mobile ad-hoc networks (MANETs) assume that mobile nodes voluntary cooperate in order to work properly. This cooperation is a cost-intensive activity and some nodes can refuse to cooperate, leading to a selfish node behavior. Thus, the overall network performance could be seriously affected. Many message authentication schemes have been developed, based on either symmetric-key cryptosystems or public-key cryptosystems. In our proposed frame work, use hybrid techniques are clustering scheme and RKP for improve network life time and security In this paper, we propose and evaluate an energy efficient clustering scheme for periodical data gathering applications in WSNs. In the cluster head election phase, a constant number of candidate nodes are elected and compete for cluster heads according to the node residual energy. The competition process is localized and without iteration, thus it has much lower message overhead. The method also produces a near uniform distribution of cluster heads. And this cooperation is a cost-intensive activity and some nodes can refuse to cooperate, leading to a selfish node behavior. Many message authentication schemes have been developed, based on either symmetric-key cryptosystems or public-key cryptosystems. In our proposed using RKP (Random Key Pre-distribution) .RKP schemes have several variants. Their system works by distributing a key ring to each participating node in the sensor network before deployment. We propose a key management scheme that relies on probabilistic key sharing among nodes within the sensor network. Therefore, the nodes build up the network using their secret keys after deployment, that is, when they reach their target position.

Keywords: Mobile ad hoc networks, Clustering, Public-key cryptosystems, Key Pre-distribution, Mobile nodes, Secure Authentication.