12-08-2011, 03:35 PM
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SECURE WIRELESS SENSOR NETWORKS - ROBUST OF WSN ATTACKS AND SECURE LOCALIZATION SCHEME
ABSTRACT
The application of wireless sensor networks (WSN), sensors are deployed un-tethered in hostile environments. For location aware WSN applications, it is essential to ensure that sensors can determine their location, even in the presence of malicious adversaries. Our paper mainly projects the problem of enabling sensors of WSN to determine their location in an un-trusted environment. The localization schemes based on distance estimation are expensive for the resource constrained sensors, proposed a range independent localization algorithm. The thumbrule of this algorithm is mainly of the distributed algorithm and does not require any communication among sensors subsequently, it shows that it is robust against severe WSN attacks, such as the wormhole attack, the sybil attack and it compares a threat analysis, performance of it with state-of-the-art range-independent localization schemes. We study the problem of enabling nodes of a wireless sensor network to determine their location even in the presence of malicious adversaries. It is referred to as SecureLocalization. Note that secure localization is a different problemfrom verifying the location claim of a sensor, known as location verification. Location verification is not addressed in this
paper. We consider secure localization in the context of the following design goals: (a) decentralized implementation, (b) resource efficiency, and © robustness against security threats.
SENSOR NETWORKS
Recent technological improvements have made the deployment of small, inexpensive, low-power, distributed devices, which are capable of local processing and wireless communication, a reality. Such nodes are called as sensor nodes. Each sensor node is capable of only a limited amount of processing. But when coordinated with the information from a large number of other nodes, they have the ability to measure a given physical environment in great detail. Thus, a sensor network can be described as a collection of sensor nodes which co-ordinate to perform some specific action. Unlike traditional networks, sensor networks depend on dense deployment and co-ordination to carry out their tasks.
A wireless sensor network consists of hundreds or thousands of low cost nodes which could either have a fixed location or randomly deployed to monitor the environment. Due to their small size, they have a number of limitations. Sensors usually communicate with each other using a multi hop approach. The flowing of data ends at special nodes called base stations (sometimes they are also referred to as sinks). A base station links the sensor network to another network (like a gateway) to disseminate the data sensed for further processing. Base stations have enhanced capabilities over simple sensor nodes since they must do complex data processing; this justifies the fact that bases stations have workstation/laptop class processors, and of course enough memory, energy, storage and computational power to perform their tasks well. Usually, the communication between base stations is initiated over high bandwidth links.
SENSOR NETWORKS VS AD-HOC NETWORKS.
The number of sensor nodes in a sensor network is larger than that of most ad hoc networks. As a result, scalable distributed algorithms must be developed for sensor networks.
• Sensor nodes may not have global identification. Sensor queries in sensor networks are often data-centric, rather than node-centric. Queries are not directed towards a specific node. Any node that has the requested data is equally valid.
• Sensor nodes have limited power supply, and recharge of power is often impractical (considering only the large amount of nodes). Energy efficiency is crucial in sustaining sensor network functionalities and extending system lifetime. Experiments show that wireless communication (rather than computation) contributes a major part to energy consumption. Therefore, reducing communication is the key to energy conservation.
• Sensor nodes are densely deployed, and data is being extracted from the environment. Thus, the data from neighboring nodes is highly redundant. Based on this observation, in network processing and data aggregation (or compression) are topics of high interest because they serve both purposes of relieving network traffic and conserving energy.
• Sensor nodes are prone to failures. Sensor nodes may fail due to lack of power, physical damage, or radio interference. Therefore, robustness (or fault tolerance) is an important design issue in sensor networks.
SECURITY
Wireless Sensor Network may be deployed in hostile environments with sensors operating unsupervised. Hence, an adversary can interrupt the functionality of location-aware applications by exploiting the vulnerabilities of the localization scheme. Obtaining accurate positions of nodes in wireless and sensor networks is important because the location of sensors is a critical input to many higher-level networking tasks. Location-dependent services are deployed; they will increasingly become tempting targets for malicious attacks. Unlike traditional systems, the localization infrastructure is sensitive to non-cryptographic attacks, and these cannot be addressed using traditional security services.
LOCALIZATION
Localization is the process by which sensor nodes determine their location. In simple terms, localization is a mechanism for discovering spatial relationships between objects. The various approaches taken in literature to solve this localization problem differ in the assumptions they make about their respective network and sensor capabilities. A detailed, but not exhaustive, list of assumptions made include assumptions about device hardware, signal propagation models, timing and energy requirements, and composition of network viz homogeneous vs. heterogeneous, operational environment viz indoor vs. outdoor, beacon density, time synchronization, communication costs, error requirements, and node mobility.
SECURE LOCALIZATION SCHEME
The main problem is enabling nodes of a wireless sensor network to determine their location even in the presence of malicious adversaries. This problem will be referred to as Secure Localization. Secure localization is a different problem from verifying the location claim of a sensor, known as location verification.Secure localization design goals are a) decentralized implementation, (b) resource efficiency, and © robustness against security threats.
Secure Range-independent Localization scheme enables sensors to determine their location based on beacon information transmitted by the locators, and present the security mechanisms that protect the location computation, in the presence of malicious adversaries. It is a range-free, distributed, resource-efficient localization technique in which there is no communication requirement between nodes for location discovery. This algorithm is robust against wormhole attacks, sybil attacks and sensor compromise. This algorithm considers two sets of nodes: N, which is the set of sensor nodes equipped with omni directional antennas, and L, which is the set of locator nodes equipped with directional antennas. The sensors determine their location based on the location information transmitted by these locators. Each locator transmits different beacons at each antenna sector with each beacon containing two pieces of information: the locator coordinates and the angles of the antenna boundary lines with respect to a common global axis.
