Communication is a very basic need for survival, providing communication while moving from a point-point or portability is very important. This is provided only by wireless networking. Through wireless networking passing a particular message can be done effortlessly. Attacking a wireless network may cause data loss or data manipulation. Providing security would be a major challenge. Routing is known as the selection of a Particular path for the transmission of the data through a full traffic network. A wireless sensor network needs the routing to be secured throughout the transmission of data for its integrity.
The basic function for wireless sensor network is to sense and send the acquired data to and from the base stations for the further processing. Routing is essential for these operations; there are many protocols proposed and some of them are being used todayfor the effective transmission of data. Hence providing security to the wireless sensor network would be a challenging task as it has limited number of sensor nodes. Protocols like MANETS (Mobile and ad hoc Networks) where introduced for secure routing, but it failed because.
It requires many computations for routing and security
It's designed to find and establish routes from multiple pair of nodes which is different from many to on traffic pattern.
The Routing Protocols differ depending upon the application and the network architecture. Wireless Sensor Networks (WSN's) are exposed to various routing threats such as node capture, physical tampering, Denial of Service. As it's an application and network based there is no perfect secure routing protocol.
The Definition from national Research Council of USA is:
"Sensor Networks are massive numbers of small, inexpensive, self-powered device pervasive throughout electrical and mechanical systems and ubiquitous throughout the environment that monitor (i.e. sense) and control (i.e. effort) most aspects of our physical world"
A wireless sensor network has many applications in various fields. They are:
Satellite Communication ex: GPRS
Bio sciences etcâ€¦
Wireless Sensor Networks Model:
The wireless sensor networks have limited resource networks and they are more prone to the failures unlike the previous protocols like MANETS. The network topologies of the wireless sensor network changes constantly, they use the broadcast communication medium. The major components of a Wireless Sensor Networks are
Task Manager Node
Sensor Fields are where the sensor nodes are placed.
Sensor Nodescollect the data and route back the information to the sink
Sinkthey receive process and store data from the other sensor nodes.
Task Manager Nodesare called the base station or the centralized points, the extracted information is sent via the internet to the other sensor nodes. The range of nodes differs by the communication protocol.
The wireless sensor networks face many challenges and are vulnerabilities. They are
The wireless sensor networks are openly accessed by everyone within the limit range hence they are more convenient to break through.
As these networks are accessed publicly the attackers find it easy to attack through a weak hole and attack as it is moderately secured.
The algorithms used are not complicated when compared with the other routing algorithms, hence it is an easy task to write and break into it
It's not an easy task to check the infrastructure continuously.
Battery life is very limited.
It has limited bandwidth.
The attacks on the wireless sensor networks are classified into
Internal and External threats: The external threat deals with the physical tampering of the data, whereas the external deals with the compromised nodes.
Mote-class attacker and Laptop class attacker: The mote class attacker deals with fewer nodes present in the field where as the laptop class attacker deals with more powerful nodes.
Inside attacker and Outside attacker: The outside attacker has no special access to the secure routing whereas on the other hand the inside attacker has all the encryption keys which are currently being used by the wireless sensor network.
Active attacker and Passive attacker: The passive attacker attacks the network and only collects the sensitive data and compromises the privacy, but has no intensions of modifying it or misusing it. There are two types of attacks, they are
Release of message contents
On the other hand the aim of this attacker is to disrupt the network. This kind of attacks can be detected instead of prevention. There are four types of attacks, they are
Modification of message
Denial of Service (DoS)
The attacks possible on the wireless sensor networks are
Spoofed/Altered/replayed Routing Information: They are used for creating routing loops, and for redirecting network traffic towards or from some specified nodes, extending or shortening the number of source routes. They generate false message and increase the latency among the other nodes.(Figure 1)
Selective forwarding: The duped nodes dump all the received packets, they have a high chance of being attacked if its' not detected. The more complex form of this attack can be emulated by the eavesdropping and jamming the transmission of particular packets. A possible counter measure can be used against this type i.e. using multiple paths to transmit the data.
Sinkhole attack: The main objective of the attacker is to attract all the neighboring nodes through the compromised nodes and use them to broadcast it to the other nodes. The nodes which receive this message make the compromised node as there next hop address which creates ripples and cause a sinkhole which is named as the sinkhole attack. And the traffic is directed towards it by hoping the real base station. (Figure 2)
Warmhole attack: Here the attacker uses the laptop class attack by using the high and powerful nodes to control the traffic and send them into a different channel and send back a beaconing to the base station as out of bound channel. The warm holes are used for creating the sinkholes, and the nodes use the warm holes to understate their distance to the base stations. (Figure 3)
HELLO flood attack: In this type of attack the attacker uses the most common message HELLO to the network which is transmitted throughout a large area of the network. The un-polluted nodes consider the message as the message from the neighboring nodes and transmit it to the base station. However the sent packet is actually received by the compromised node and the data is lost. All the nodes cannot receive this HELLO message because some nodes are attached by the asymmetric link. A simple countermeasure for this attack is to check for bi-directionality for each and every link which is being used a transmission medium.(Figure 4)
Sybil Attack: In this type of attacks the attacker creates multiple false identities as nodes which do not exist and performs all the actions on their behalf which creates confusion in the network. Hence capturing the packets and routing them towards him. When these compromised nodes are selected for the transmission of the information the data is manipulated. A simple countermeasure for this type of attack is that each and every node has a symmetric key which cannot be duped, hence their identities are verified and then the data is transmitted.
Secure Routing in Wireless Sensor Network:
The main aim of this protocol is to provide security to the information and to prevent the critical damage i.e. exchange of information, modification of data. The information acquired by these individual sensors is always unknown and they communicate wirelessly among themselves. Thus having more risk of attacks. The security is the main challenge to be provided in order to protect the data. Most of the routing protocols consider the energy for their efficiency in terms of energy. A protocol with less security measures use very less energy hence they have to perform some extra preventive measures for communication. Each and every basic routing protocol has various security levels, even the wireless sensor network has a security level which is not always under attack and hence it uses a minimum amount of the energy produced to provide the security and saves energy. The Security protocols has Implicit Geographical Forwarding protocol combined MAC layering handshake. In the secure routing which is the extension of Implicit Geographical Forwarding does not choose its next hop. It helps in sequence number of messages to differentiate old messages from new messages.
The present Wireless Security Networks Provides much tolerant to the wireless attacks when compared to the other existing routing protocols. The Wireless sensor Protocols have a secure routing because of the combination of IGF and the MAC application layer. When reading about this article I found some flaws which can rectified by the following points. They are
Infinite Battery Life: The Wireless Sensor Networks provides a moderate security as it uses the minimum energy for the routing protocols, which can be replaced by the solar panel for the maximum use of the energy to provide strong security
Unlimited Bandwidth: The limited bandwidth in Wireless Sensor Network is a major backdrop as the connectivity between the nodes in the network is the base for all the operations
Unlimited support for networking: The support provided by this network is very limited. All the nodes are connected by the asymmetric links which may cause an error in transmission of data from the base station.
Countermeasures: If the prevention of the data transmission from the compromised node is note possible then some simple countermeasures can be used for the detection. They are
For Selective forwarding: using multiple paths to transmit the data.
For HELLO flood attack: checking bi-directionality for each and every link which is being used a transmission medium.
For Sybil attack: using some unique identities for recognizing them and verifying them before the transmission of the data.
Implementation of frequency hopping.
To analyze, implement and evaluate AODV protocol.
In order to evaluate the performance of the system, the output destination needs to be analyzed.
If the source and compromised node are sending the same data to the same destination first examine the output without using frequency hopping and then, compare it with output by using frequency hopping.
Everyone is a victim of an attack on the wireless sensor network; every network has a specified level of security. A Wireless Sensor Network is an application specific in nature. While choosing a secure routing, minimum care should be taken that they meet all the requirements. Physical tampering of the data or the detection of the compromised node should be done using the countermeasures. Link layer encryption and authentication should be provided for the defense against all threats, only cryptography will not be enough. Complex algorithms should be designed to prevent the strong attacks, infrastructure should be checked continuously to maintain the consistency and for better performance of the network.