On The Security Of Wireless Sensor Networks

The word wireless has almost occupied every field in this era, every wired facility is going to become unwired or wireless one, and maybe after a couple of years we will not see any wire in the world.

The availability of cheap, low power, and miniature embedded processors, radios, sensors, and actuators, often integrated on a single chip, is leading to the use of wireless communications and computing for interacting with the physical world in applications such as security and surveillance applications, smart classroom, monitoring of natural habitats and eco-systems, medical monitoring etc. The resulting systems, often called wireless sensor networks, differ considerably from current networked and embedded systems. They combine the large scale and distributed nature of networked systems such as the internet with the extreme energy constraints and physically coupled nature of embedded control systems. Their design requires a proper understanding of the interplay between network protocols, energy-aware design, signal-processing algorithms, and distributed programming.

The technology of Wireless Sensor Networks (WSNs) is in the front part of the investigation of the computer networks and it could be the next technologic market of a huge sum of money. A WSN contains hundreds to thousands of small sensors where these sensors are designed to be self-organized wireless networks. Sensor nodes have limited processing power, storage, bandwidth, and energy. This limitation makes provision of the security in sensor networks not an easy task.

As discussed in, a WSN has no fixed infrastructure; the sensor nodes are scattered in a special domain, which makes the network threatened by attackers in many ways of attacking. For this reason, an efficient approaches have to be proposed in order to make WSNs secure. The applicable distribution techniques use the key management techniques such as cryptographic public key to provide the security requirements.

A sensor network must be confidential and should not reveal sensor readings to the adversary. The standard approach for keeping sensitive data secret is to encrypt the data with a secret key such that only the intended receivers possess, hence achieving confidentiality. The key in WSN is encrypted at the sender then decrypted by the receiver using such symmetric cryptographic algorithms such as RC4, RC5, and DES.

Probabilistic key management approaches depend on the randomness in selecting a set of encryption keys (to be distributed between the sensor nodes in distributed WSN) from a pool of keys that contain a large number of encrypted keys. These approaches will work after the deployment stage of the sensors and have no idea about the area so every thing is probabilistic-wise.

The problem addressed in this work focuses on the probabilistic key management approaches, based on where all approaches appear to be static and can be applied on the WSN, we propose such adaptable approach that depends on WSN constraints (Battery Life, Transmission Range, Bandwidth, Memory, and Density of sensor in the network). The problem is depicted in Fig.1.

Fig.1.  Problem Statement : How To Get A Secure Channel

Also, the work in this document is motivated by many issues. First, the security of WSN which became very important in real life particularly in military fields. WSN are used today in hostile environments, malls, hospitals, house appliances and armies to do different kinds of jobs, which makes its security level to swing from low to high. Second, previous studies have not leaded to use such approach of key management that can be applied in any WSN. This leaded us to start thinking about some dynamic approach to use for WSN security.

A remarkable issue that faces wireless sensor networks (WSNs) nowadays is security. WSNs should provide a way to transfer data securely particularly when employed for military purposes. Hence, several protocols have been proposed to enhance WSNs by providing minimum level of security requirements. Key management protocols have gained a remarkable interest by researchers. In this paper, we retrieve four probabilistic key management approaches that have been widely used in WSNs. These approaches are: Random key predistribution, Q-composite key scheme, MultiPath Reinforcement Scheme, and Random PairWise Keys Scheme. We also provide here a probabilistic analytical evaluation model to asses these protocols individually. The model comprises several factors that should be considered carefully before deploying the WSN. These factors are: scalability, confidentiality, memory complexity, communication complexity, and power consumption. The results showed that the pairwise key scheme best fits in several diverse environment satisfying most of our study factors.

The randomness in distributing sensor nodes in a WSN makes such environments difficult to study. From the security perspective, there is no specific probabilistic key management approach that could be marked as the best protocol to be applied over any WSN with some setup parameters. Indeed, the variation of parameters makes the use of a certain protocol varied too. In this paper, we have evaluated the performance of four probabilistic key management approaches using two metrics: communication complexity and power consumption.

Simulation results have shown that the simplest protocol to apply over a small sensor network is the random key pre-distribution with a large key pool size. On the other hand, Q-composite scheme improves over basic scheme for small scale network attack.

The Random multipath scheme gives a great level of security if it is used with average size of networks but it consumes much power in transmission and as it is known the power consumed in communication reward doubles of that consumed in computations. It can be said that the pairwise key (provides node-to-node authentication) which does the most of its job before distribution and gives the best results in several metrics to be the best applicable approach especially with large networks where the security is considered the most important factor.


References:


Qasem Abu Al-Haija  “Toward Secure Non-Deterministic Distributed Wireless Sensor Network Using Probabilistic Key Management        Approaches,” Accepted for publication at Journal of Information Assurance and Security (JIAS), By Dynamic Publishers Inc., USA, July 2010.


Yang Xiao, et al. "A Survey Of Key Management Schemes In Wireless Sensor Networks," Computer Communications, Vol. 30, PP. 2314-2341, April 24, 2007.


Omar Banimelhem, Qasem Abu Al-Haija and Ahmad Al-Badawi " Performance Evaluation of Probabilistic Key Management Approaches for Wireless Sensor Networks" ,Proceedings of the first International Conference in Information and Communication Systems - ICICS2009, Paper495, Dec 2009.


Wenliang Du, et al. "Key Management In Wireless Sensor Networks Extended Abstract," In Proceedings Of The 5Th Annual ACM/IEEE International Conference On Mobile Computing And Networking (Mobicom), 1999, Pp. 483-492. Man, September 2004