Clustering Strategies in Wireless Sensor Network & Security Concern in Data Aggregation

A sensor network is a network of low-powered, energy-constrained nodes which are equipped with sensors, processors, memory and wireless communication devices. The sensor nodes are operated by lightweight batteries. The capability of an individual sensor node is limited, and that are densely deployed within the sensing field. Clustering is method of grouping sensor nodes. It is a basic approach for designing energy-efficient, robust and highly scalable distributed sensor networks. By using clusters we can reduce the communication overhead, thereby decreasing the energy consumption and interference among the sensor nodes. In clusters we have a cluster head node all other nodes of the cluster communicate through this cluster head so communication overhead is reduce and energy is saved. Most existing proposals for data aggregation are subject to attack. Once a single node is compromised, it is easy for an adversary to inject false data into the network and mislead the aggregator to accept false readings. Because of this, the need for secure data aggregation is raised. A general definition for secure data aggregation is the efficient delivery of the summary of sensor readings that are reported to an onsite user in such a way that ensures these reported readings have not been altered.