The field of wireless sensor networks (WSNs) combines sensing, computation, and communication into a single tiny device called a sensor. Sensors are equipped with RF radio, processor, memory and hardware. They are also battery powered and therefore have severe energy, bandwidths and memory constraints, and low computational capability. Communication over WSNs is still known to be attack-prone because the constraints of sensors hinder the development of secure modern cryptographic solutions. The Elliptic Curve Cryptography (ECC) technique and the Rivest Shamir Adleman (RSA) algorithm are the two most popular public key cryptographic schemes deployed over wireless networks. The effectiveness of the ECC technique over RSA has been demonstrated in this research. While ECC with very large key sizes is thought to be computationally expensive, it is possible to use smaller primes, or smaller finite fields, with elliptic curves and achieve a level of security comparable to that for much larger integer mod n. Measurements have been made to prove that ECC algorithms can be executed within the memory limits of sensor nodes. An enhanced ECC scheme with collision resistant hash functions is proposed in this research.
Sensor nodes close to the sinks will deplete their limited energy more rapidly than other sensors, since they will have more data to forward during multihop transmission. This will cause network partition, isolated nodes and much shortened network lifetime. Thus, how to balance energy consumption for sensor nodes is an important research issue. In recent years, exploiting sink mobility technology in WSNs has attracted much research attention because it can not only improve energy efficiency, but prolong network lifetime. In this paper, a modified Election based Protocol, which employs the decision of selecting cluster heads by the sink is based on the associated additional energy and residual energy at each node. Besides, the cluster head selects the shortest path to reach the sink between the direct approach and the indirect approach with the use of the congested link. Simulation results demonstrate that our algorithm has better performance than traditional routing algorithms, such as LEACH.