Sensors are tiny devices deployed in an unsupervised environment. These devices monitor the readings, process them, and transmit them to the predefined destination. The internet has also availed the users to query the sensors and get the values directly. Users are to register themselves with the gateway node. After registration, they increase flexibility to query the sensors. The sensors are to authenticate the users for their legitimacy before dispatching the requested information. The proposal increases security by minimizing the replay attacks and enhance reliability in sensor-user communication. The proposed work hikes reliability as well as conserves energy substantially. Also, it minimizes replay attacks that are vulnerable in WSN.
Top1. Introduction
Due to the advances in mobile communication and information technology, Wireless Sensor Network (WSN) systems (Ambika N., 2020) have their fullest potential in varieties of modernday applications ranging from sending messages, making calls, accessing web sites, viewing video contents to mobile advertising, internet trading etc. (Lewis F.L., 2004;Yick et al, 2008; S.K.Noh et al., 2013).
Wireless sensor networks are composed of a finite set of sensor devices geographically distributed in a given environment, may be indoor or outdoor (Ambika & Raju, 2014) (Akyildiz, F., Su, Sankarasubramaniam, and Cayirci, 2002). These devices monitor or track any object of interest. Due to this feature, WSNs become suitable for high end applications such as military monitoring (Lee, Hyuk, Lee, Song, & Lee, 2009), home surveillance (Nasution, Hans& Emmanuel, 2007), habitat monitoring (Szewczyk, et al., 2004), elderly care (Abbate, et al., 2010), etc. The devices can self-configure, make a topology, and communicate with each other. The nodes gather sensed and processed data and then forward them to the predefined destination. (Figure 1). These devices are embedded with credentials to secure the transmitted data in the environment. Different methodologies have been explored and implemented to make the data secure in WSN environments.
Figure 1. Wireless Sensor Networks Connected to Internet
Gateway acts as the bridge between WSN and another network, usually the internet. Through the internet, users or the applications can see, control, transfer data to the WSN and also get data.The users may be connected to the sensor nodes available in various topologies (Figure 2).
In several situations, for collaboration purpose, the locations of sensor nodes need to be considered. For example, if one sensor needs to pass data to some other sensor, the other sensor’s location data is important. At the same time, when this location is exposed, it may become critical due to security threats. Especially gateway node has to permit the user to communicate with the sensors. After gaining permission from the gateway node, the user will be able to request the necessary data. The sensors on authenticating the users can provide the requested data.
In WSN, multi-hop routing is in general followed to transfer data between source and destination nodes through the intermediate nodes. Though this improves the performance of WSN w.r.t. energy criterion, it also leads to security issues in the overall system. WSNs become integral part of cloud based or IoT applications, the vulnerabilities happening in any part may affect the overall system.
Out of several attacks possible in WSN, Replay Attack is a major one where a malicious node diverts the flow. Attacker eavesdrop the traffic, replays or changes the actual message (Figure 3).
The proposed work minimizes the replay attack in the network. It also aims to increase reliability in the network. The user registers with the gateway node when by sending the hashed value of biometric extract and unique identity. After registration, the gateway creates n number of hash keys using the unique identity of itself, gateway, and biometric pull-out. The user uses these hash keys for every communication with the sensors. The users can use the hash key only once. It is supposed to delete the same after use. The user creates the hash value of the credential and biometric extract. It is attached to the request and hashed timestamp. The transmitted message undergoes verification for the freshness and also its identity. The summary received by the nodes and the users undergoes evaluation by the gateway node.