A Review on Wireless Sensor Networks: Different Security Issues and Analysis, and Integration with the Internet

A Review on Wireless Sensor Networks: Different Security Issues and Analysis, and Integration with the Internet

Mr. Ayush Sogani

Assistant Professor

International School of Informatics and Management, Jaipur, Rajasthan

Dr. Aman Jain

Professor & HOD (C.S)

Deepshikha College of Technical Education, Jaipur, Rajasthan

ABSTRACT

In todays scenario, when technologies are growing very fast and frequently, people are adopting these new concepts like Wireless Sensor Networks (WSN), Cloud Computing, Pervasive Computing, etc., in their daily life. Wireless Sensor Networks (WSN) are becoming popular day by day, but there are some issues in wireless sensor networks such as energy consumption, processing time, memory usage, resource limitation and security. In this paper, the authors reviewed on different security issues and analysis in WSN and also focused on the implementation of Wireless Sensor Networks with different type of networks.

UNIT I: INTRODUCTION

Wireless Sensor Networks are currently receiving significant attention due to infinite possibilities available with them. Researchers have focused on different research challenges that have limited capabilities i.e., security, deployment over Internet, power, and localization.

Most research is currently being conducted in the following areas:

• Developing techniques that will enforce secure, private and reliable networks.

• Deployment and Integration of WSN with Internet & recent technologies and impact of different security issues.

• Improving reliability of data transfer (connecting WSN with TCP/IP networks).

• Increasing network lifetime (Energy Consumption).

  Cheap, smart devices with multiple onboard sensors, networked through wireless links and the Internet & deployed in large numbers, provide extraordinary opportunities for instrumenting and controlling homes, cities, and the environment, this is a technology of future, the Networked microsensors technology [1].

  These sensors are becoming smaller. It is possible to fit them into a smaller volume with more power and with less-production costs. This becomes possible with the help of Microelectromechanical Systems (MEMS) technology [2].

  Wireless sensor networks (WSN) are abbreviated wireless networks of small, low- cost sensor nodes, which collect and distribute environmental data. WSNs helps in monitoring and controlling of physical environments from remote locations with better accuracy than other known monitoring systems such as remote sensing. These tiny sensor nodes leverage the idea of sensor networks based on collective effort of a large number of nodes. Sensor networks represent a significant improvement over traditional sensors. As they have the capabilities to route data back by a multi- hop infrastructureless architecture to the base station or sink, which is the entity where information is required. The sensor nodes unite together to collect desired information from the environment by performing in-network data processing and aggregation (data diffusion).

  A sensor device consists of the following components:

• Sensing Unit: It helps to sense and measure physical data from the target area.

• Processing Unit: The processing unit plays a major role in managing collaboration with other Sensors to

  achieve the predefined tasks. The processing unit needs storage for tasking and to minimize the size of transmitted messages by local processing and data aggregation [3].

• Transceiver: Three communication schemes for deployment in sensors are optical communication (laser), infrared and radio-frequency (RF). Laser consumes less energy than radio and provides high security, but requires line-of-sight and is sensitive to atmospheric conditions. Infrared needs no antenna but is limited in its broadcasting capacity. RF is the most easy to use and requires antennas.

• Power Unit: Batteries used in sensors can be categorized into two groups; rechargeable and non- rechargeable. In unapproachable conditions, it is impossible to recharge or change a battery. Therefore, power management is a critical research issue in Wireless Sensor Networks [4]. Two major power saving approaches has been defined. First, unused devices can be shut down and activated when required. This is called Dynamic Power Management (DPM) and second approach is Dynamic Voltage Scheduling (DVS), power can be varied to allow for a non- deterministic workload [5].

  The figure of sensor device components is shown in Fig 1.

  Many wireless sensor network applications cannot run in complete isolation, the sensor network must be connected to monitoring and controlling entities through known wireless/wired networks like IP- based networks. Such interconnection achieves many advantages and increases sensor networks benefits such as:

• Controlling and monitoring sensor networks remotely.

• Providing security at the gateway node

• Integrating data collected from sensor networks into data mines.

• Ability to combine multiple remote sensor networks into one virtual sensor network.

  This paper is isolated into dissimilar units: Unit II- Implementation of WSN with Transport Layer Protocol, Unit III- Integration of Massive WSNs with the Internet, Unit IV- Covers different Security issues in Wireless Sensor Networks, Unit V- Integrating Wireless Sensor Networks and the Internet: A Security Analysis, Unit VI- Encryption and Key Management Approach with In- Network Processing in Wireless Sensor Network and Security Analysis, Unit VII- Talked about Evaluation Based Study of Different Cryptographic and Encryption Techniques Using Message Authentication Code (MAC) in Wireless Sensor Networks (WSN), and Conclusion.

  UNIT II: IMPLEMENTATION WITH TRANSPORT LAYER PROTOCOL

  Wireless sensor networks require several attributes such as fault tolerance and scalability. The relatively short lifetime of a sensor is an additional factor when deploying sensors in a target area. Message loss may be a serious problem. Developing a reliable transport protocol for wireless sensor networks to support more applications deployment is an important issue so that the loss of data can be prevent. TCP to wireless sensor networks is expensive because of its three- way handshake mechanisms and packet header size. UDP is considered to be more suitable for sensors although it was designed to provide unreliable data transport [2]. Few new mechanisms are intended to enable the use of TCP/IP for wireless sensor networks: spatial IP address assignment, header compression, application overlay routing and distributed TCP caching (DTC) [7].

  UNIT III: INTEGRATION OF MASSIVE WSNS WITH THE INTERNET

  For practical deployment, a sensor network does not work in isolation. For many important applications, however, it is required to integrate these sensor networks to the existing Internet Protocol (IP) networks.

  The task of connecting WSN to the existing Internet brings with it several challenges [9]. Any network wishing to be connected to the Internet needs to address the question of how it will interface with the standard protocols like the IP. The characteristics of WSN make them different from traditional IP-based networks as summarized in Table 1.

  The foremost among these characteristics are that, WSN are large-scale unattended systems consisting of resource-constrained nodes that are best-suited to application- specific, data-centric routing.

  Giving IP address to everysensor node is not the right approach to integrating sensor networks with the Internet. For this purpose a gateway level protocol approach is developed for both homogeneous networks (where all nodes have the same capability in terms of processing, energy and communication resources) and heterogeneous networks (where some nodes are more capable compare to other nodes). Application level gateway solution is used in integration of Homogeneous networks and the Internet and an overlay IP network (router) is constructed in case of Heterogeneous networks that sits on top of the basic wireless sensor network.

  UNIT IV: SECURITY ISSUES IN WIRELESS SENSOR NETWORKS

  Sensor networks position unique security challenges because of their inherent limitations in communication and computing. The deployment nature of sensor networks makes them more vulnerable to various attacks. Sensor networks are deployed in applications where they have physical interactions with the environment, people and other objects making them more vulnerable to security threats.

  Security goals in sensor networks depend on the requirements of the user to know what users want to protect. Four goals are determined in sensor networks. They are Confidentiality, Integrity, Authentication and Availability [10].

• Confidentiality is the ability to hide message from a passive attacker, where the message communicated on sensor networks remain confidential.

• Integrity refers to the ability to confirm the message has not been altered, or changed while it was on the network.

• Authentication Need to know if the messages are from the node it claims to be from, determining the consistency of messages origin.

• Availability is to determine if a node has the ability to use the resources and the network is available for the messages to move on.

  Few attacks [10] are also identified in wireless sensor networks, they are:

• Passive Information Gathering

• Node Malfunctioning

• Message Corruption

• Traffic Analysis

• Wormholes

• Hello flood Attacks

• Denial of service Attacks.

UNIT V: INTEGRATING WIRELESS SENSOR NETWORKS AND THE INTERNET: A SECURITY ANALYSIS

Access to the information produced by sensor networks has not been considered intensely. Once the data is retrieved from the sensors, the user of the network will be able to read it directly through the base station. This access to the data must be challenged and a security mechanism must be defined for the user authentication. This can be achieved by integrating the sensor networks into the Internet. Sensor networks must be secure by themselves, and the interactions between the sensor networks and the Internet must also fulfill with certain security properties [8]. The integration strategies as shown in Fig 2

In front-end proxy solution, the base station serves as an interface between the data acquisition network (sensor network) and the data dissemination network (the Internet). The base station collects and stores all the information coming from the sensor network, and also sends any control information to the sensor nodes. There is no direct connection between the Internet and a sensor node: all incoming and outgoing information will be parsed by the base station [8].

In the gateway solution, the base station acts as an application layer gateway, in care of translating the lower layer protocols from both networks (e.g. TCP/IP and proprietary). As a result, the sensor nodes and the Internet hosts can exchange information directly.

In the TCP/IP overlay solution, sensor nodes do communicate with other nodes using TCP/IP. Therefore, the main function of the base station is to perform as a router, forwarding the packets from

and to the sensor nodes. These nodes must implement the protocols and standards used on the Internet, such as the TCP/IP stacks and web services interfaces [8].

Sensor networks are not integrally secure. Its nodes must be deployed near the source of the events, and they use wireless communication channels for exchanging data. Therefore, any nasty challenger can manipulate the sensor nodes, the environment, or the communication channel on its own benefit. Besides, if that malicious outsider gains access to one or more sensor nodes, it may be possible to deploy the information flow that navigates the nodes. Therefore, a sensor network must be designed from hardware of its nodes to their application layer to protect or reduce the effect of such attacks.

UNIT VI: ENCRYPTION AND KEY MANAGEMENT APPROACH WITH IN-NETWORK PROCESSING IN WIRELESS SENSOR NETWORK AND SECURITY ANALYSIS

A sensor network is a combination of three different nodes: normal sensor nodes, aggregators, and a querier. Aggregator collects the information from the normal sensor nodes available in the sub-network with the help of a suitable aggregation function and then transmits the result to the higher aggregator or to the querier (query generator). A communication gets established between these nodes and a meaningful information is derived which reflects the events in the target field. The major problem faced by wireless sensor network is through the transmission of data from one intermediate node to another node. Hence security becomes a very important issue, as the information transmit between the nodes in a hierarchical sensor environment, only the authorized sensors should have the cryptographic keys by which they can decrypt the encrypted information. Thus a requirement of different access control

policies occurred at each level of the hierarchical network. Sensor networks require protection against eavesdropping, injection and modification of information like traditional networks does. Therefore the requirement is of such a network where the message should be transferred in a confidential way. Opponents that overhear communication between the sensors, aggregators, and the sink shall not obtain the exchanged information. This is achieved by encrypting transmitted data. Therefore, Cryptography becomes the standard defense mechanism. If the encryption key is not distributed properly with a proper research then this key will be available for all the node and intruder can easily retrieve it and take the information from the cipher text. Therefore, key management and aggregation are the important problems in wireless sensor networks on which lot of research is still required.

End to end encryption for wireless sensor networks is a challenging problem. The communication inside the network consumes a large amount of the total energy of the WSN. To save the complete energy resources of the network it is approved that sensed data need to be shared and aggregated. If end to end encryption is preferred, then distributing usual encryption algorithms implies that intermediate nodes have no possibility for efficient aggregation allowing shrinking the size of messages to be forwarded. This approach of usual encryption algorithms combined with the necessity of efficient data aggregation provides only the possibility of encrypting the messages hop-by-hop. This means that an aggregator has to decrypt each received message, then aggregate the message according to the matching aggregation function and, finally, encrypt the aggregation result before forwarding it[11].

For point-to-point communication, end to end cryptography attains a high level of

security but requires that keys must be set up among all the end points and be unsuited with passive participation and local broadcast. Link -layer cryptography with a network-wide shared key simplifies key setup and supports passive participation and local broadcast, but in this case the intermediate nodes might eavesdrop or alter messages. Therefore, an evaluation of the network traffic is carried out to calculate the measure of the attackers ability to compromise a message traversing a particular route. An intelligent attacker an easily guess the vulnerability of traffic and initiate attack on the nodes by observing the network topology and gathering information from the hidden data aggregation and homomorphic encryption. There is a resource expenditure associated with the attacking of nodes and extraction of keys from the memory. Hence, the best attack strategy is the one in which a set of nodes are attacked with minimum total resource expenditure. Thus through this proposal it can be seen that aggregated consideration of information from the concealed data aggregation and privacy homomorphism protocols can lead to a major reduction in resource expenditure[12].

UNIT VII: EVALUATION BASED STUDY OF DIFFERENT CRYPTOGRAPHIC AND ENCRYPTION TECHNIQUES USING MESSAGE AUTHENTICATION CODE (MAC) IN WIRELESS SENSOR NETWORKS (WSN)

In todays scenario, when technologies are growing very fast and frequently, people are adopting these new concepts like wireless sensor networks (WSN), cloud computing, pervasive computing, etc., in their daily life. Wireless Sensor Networks (WSN) are becoming popular day by day, but there are some issues in wireless sensor networks such as energy consumption, processing time, memory usage, resource limitation and security.

Keeping in mind about all these issues, different cryptographic techniques such as symmetric key and asymmetric key cryptography are investigated.

Cryptographic algorithm plays an important role in the security protection of wireless sensor networks (WSN). Different encryption techniques like stream cipher (RC4), block cipher (RC2, RC5, RC6, etc.) and hashing techniques (MD2, MD4, MD5, SHA, SHA1, etc.) are compared with each other by selecting different comparison problems.

After performing simulation of these algorithms it was found that public key is not energy efficient and is expensive in terms of both computation and communication as compared to symmetric key. As sensor networks have limited resources, therefore most of the researcher used symmetric keys in WSNs. Thus it was concluded that symmetric key techniques are more feasible for WSNs as compared to public key. More comparisons are applied on different encryption techniques and it was concluded that RC5 is feasible and consumes less energy/resources as compared to other algorithms (AES, MD5, and SHA1). Finally, it was proposed that RC5 is a best algorithm to create Message Authentication Code (MAC) in sensor networks [13].

CONCLUSION

Recent advances in wireless communication and embedded computing technologies have led to the rise of wireless sensor networks technology. These nodes can be deployed in many fields including health, environment and battlefield monitoring and represent a big source of varied data. In order to support huge amount of data, today solutions are based on different Internet Applications. Accordingly, it seems obvious to bring wireless sensor networks to the Internet.

However, this integration process raises many key challenges. Among them security, localization and power management are few problems and may be the most critical is the security of sensor networks, the interaction between these networks and the Internet. An Algorithm must be proposed which will define the best security mechanism and method, which can be implemented in between the integration of wireless sensor networks with Internet. The future research should be consistent with the next generation Network (NGN) to support pervasive computing (Anytime Anywhere).

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