CiiT International Journal of Wireless Communication, Vol 5, No 6, June 2013 235 0974-9756/CIIT-IJ-4479 /03/$20/$100 © 2013CiiT Published by the Coimbatore Institute of Information Technology Abstract—Wireless Wireless Sensor Networks (WSNs) have become an important component in our daily lives. In near future, it will dominate the technology industry around the world. WSNs gain its importance due to the variety of vital applications it can participate in such as military, health care, agriculture, surveillance and monitoring natural phenomena applications.WSNs consist of small devices with limited energy and storage capabilities, called sensor nodes. The sensor nodes collect data from physical or environmental phenomena. They cooperatively pass the sensed data through the network to a certain location or sink node where the data can be collected and analyzed.Due to the unprotected nature of wireless communication channels and untrusted transmission medium of WSNs, it becomes vulnerable to many types of security attacks. The attackers ultimately seek to eavesdrop, steal confidential data, injecting false data or even jamming the whole network, so securing these networks becomes a must.In this paper, a proposed security schema for WSNs will be introduced. The proposed security schema will be appropriate for real time multimedia streaming. It will construct its security features within the application and transport layer as the information that the attackers seek ultimately exist within these layers.The proposed security schema consists of two security levels; the first level is encrypting the packet data using Advanced Encryption Standard (AES) while the second level is generating Message Authentication Code (MAC) using Cipher-based Message Authentication Code (CMAC). Both levels achieved the principles of WSNs security and they are (authentication, confidentiality, data integrity and availability).Performance comparisons between the proposed security schema and other security frameworks are presented. Finally, all the presented work in this research was developed and implemented using Network Simulator-2 (NS-2). According to our literature reviews, this research is one of the first researches that use NS-2 as a security simulator. As NS-2 does not support any security features before. 1 Keywords—Wireless sensor networks, AES, CMAC, Security simulator, NS-2. I. INTRODUCTION A. Wireless Sensor Networks (WSNs). A WSN is composed of low cost, low power, multifunctional sensor nodes that are small in size and communicate Manuscript received on May 27, 2013. Nour El Deen M. Khalifa is with the Information Technology Department, Faculty of computers and information, Cairo University, Cairo, Egypt. E- Mail: nourmahmoud@fci-cu.edu.eg Mohamed Hamed N. Taha is with the Information Technology Department, Faculty of computers and information, Cairo University, Cairo, Egypt. E-Mail: mnasrtaha@fci-cu.edu.eg Hesham N. Elmahdy is with the Information Technology Department, Faculty of computers and information, Cairo University, Cairo, Egypt. E- Mail: ehesham@fci.cu.edu.eg Imane A. Saroit is with the Information Technology Department, Faculty of computers and information, Cairo University, Cairo, Egypt. E-Mail: isaroit@fci-cu.edu.eg Digital Object Identifier No: WC062013001. wirelessly over short distances. WSN can also be introduced as a self configured wireless networks to collect data from physical or environmental phenomena, such as temperature, sound, pressure, motion or pollutants [1]. It cooperatively passes their data through the network to a main location or sink where the data can be monitored and analyzed. A sink node or base station performs like a gate between users and the network.In general, a wireless sensor network may contain hundreds or thousands of sensor nodes. The sensor nodes can communicate among themselves using radio signals. After the deployment of sensor nodes in the monitored area, they are accountable for self organizing an acceptable network infrastructure often with multi-hop communication with each others. Then they start gathering information of interest. B. Research objectives The area of WSNs attracts research interest mainly because of their greatly exciting potential. In order to achieve that potential, the research community has to overcome the security obstacle which faces great challenges [2]. Privacy and security is an essential element of many applications in the world. By enabling security in the WSNs, a potential is created to use them for demanding requirements. A well designed security schema is essential for the further development and the success of wireless sensor networks. The objective of this paper is to provide a secure schema for multimedia streaming in WSNs within the application and transport layer and made the schema as energy efficient as possible. The process of achieving our objectives will be discussed through the paper. The key challenge in securing sensor networks is how to maximize the lifetime of sensor nodes due to the fact, as it is not feasible to replace the batteries of thousands of sensor nodes. Therefore, computational operations of nodes and communication protocols must be made as efficient as possible in the energy consumption [2]. Among internet protocols, data transmission protocols in application layer have much more importance in terms of energy, since the energy required for data transmission takes 70 % of the total energy consumption of a wireless sensor network [3]. So the process of data transmission should be optimized. This is the second objective of the research, to find a solution to minimize the number of data transmission to make the network energy optimized while adapting the security features we proposed. II. SECURITY GOALS A sensor network is a special type of ad hoc network. So, it participate some common property as a computer network. A Secure Energy Efficient Schema for Wireless Multimedia Sensor Networks Nour El Deen M. Khalifa,Mohamed Hamed N. Taha, Hesham N. Elmahdy and Imane A. Saroit