Security Enhancement for Real-time Routing Protocol in Wireless Sensor Networks A. Ali 1 , N. Fisal 2 Faculty of Electrical Engineering, University Technology Malaysia, 81310 Johor Bahru, Johor Darul Ta’zim, Malaysia Email: 1 adelali3@lycos.com , 2 sheila@suria.fke.utm.my Abstract-Wireless sensor network is a wireless ad hoc network that consists of very large number of tiny sensor nodes communicating with each other with limited power and memory constrain. WSN demands real-time routing which requires messages to be delivered within their end-to-end deadlines (packet lifetime). Since many sensor networks will be deployed in critical applications, security is essential. Recently, many real- time routing protocols have been proposed, but none is designed with security as a goal. This paper proposes a novel secure enhancement for real-time routing protocol that provides secure real time data in WSN. The proposed security countermeasures HELLO flooding and selective forwarding attacks. It ensures high packet throughput and minimized power consumption in the present of adversary nodes. The proposed security has been successfully studied through simulation work. I. INTRODUCTION The recent technological advancement in wireless communications, micro-electro-mechanical systems (MEMS), and digital electronics have led to the development of low- cost, low-power, multifunctional sensor nodes that are small in size and communicate within short distances [1]. As can be shown in Fig. 1, the tiny sensor node consists of sensing, data processing, and communicating components. The sensor nodes can be interconnected to form a network defined as wireless sensor network (WSN). WSN consists of very large number of sensor nodes which are densely deployed either inside an event area or in proximity. WSN enables reliable monitoring and analysis of a physical environment. Real-time communication is necessary in many WSN applications. For example, in a fire fighting application, appropriate actions should be made in the event area immediately as delay may cause huge damages further. The sensor data collected and delivered must still be valid at the time of decision making since late delivery of data may endanger the fire fighter’s life. The general research challenges for multi-hop routing in WSN arise primarily due to the large number of constraints that must be simultaneously satisfied. One of the most important constraints on sensor nodes is the low power consumption requirement. Sensor nodes carry limited, generally irreplaceable power sources. WSN applications must operate for months or years without wired power supplies and battery replaced or recharged. Therefore, the power consumption must be considered while designing multi-hop routing in order to prolong the WSN lifetime [2]. Fig. 1. WSN architecture with MICAZ motes Since many WSNs will be deployed in critical applications, security is essential. Unfortunately, security may be the most difficult problem to solve in WSNs [3, 4]. In particular, it is easy to eavesdrop or cause a network layer attacks which fall into one of the following categories: manipulating routing information, selective forwarding, Sybil, sinkhole, wormhole, and Hello flooding (unidirectional) attacks. Furthermore, most real-time communication and coordination routing protocols do not address security, so it is easy for an adversary to exploit those routing protocols on a given WSNs [5, 6]. Lightweight security schemes are required in real-time routing protocols for WSN. The security for real-time routing protocols must exploit the nature of the sensor network and relate to issues such as most data is only valid for a short time [3, 5]. Real- time routing protocol protocols designed for WSN must therefore balance real-time performance, energy efficiency and data security. This paper presents secure real-time with load distribution SRTLD routing protocol that depends on optimal forwarding (OF) decision that takes into account of the link quality, packet delay time and the remaining power of next hop sensor nodes. It also presents the security enhancement which uses the encryption and decryption with authentication of the packet header to supplement secure packet transfer. 978-1-4244-1980-7/08/$25.00 ©2008 IEEE. Authorized licensed use limited to: Guangdong Univ of Tech. Downloaded on January 11, 2009 at 08:56 from IEEE Xplore. Restrictions apply.