Kumaraguru College of Technology, Coimbatore, India. Abstract

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1 Volume 116 No , ISSN: (printed version); ISSN: (on-line version) url: doi: /ijpam.v116i11.12 IMPLEMENTATION OF DATA GATHERING SYSTEM USING MOBILE RELAY NODE IN WIRELESS SENSOR NETWORK ijpam.eu M.Mathankumar 1, T.Viswanathan 2 and T.Dineshkumar 3 1,2,3 Assistant Professor, Department of EEE, Kumaraguru College of Technology, Coimbatore, India 1 mathankumarbit@gmail.com, 2 viswanathan@live.com, 3 dinesh161190@gmail.com Abstract Wireless Sensor Networks (WSN) are infrastructure-less network to monitor and share the physical conditions in the environment. There is a growing need for securing the data sharing in WSN. Because it is vulnerable to access unauthorized. In this paper, data sharing is secured by context based cryptographic algorithm which is not only depends on secret key but also depends on context which is set by the sender. To collect secured data from the sensor nodes, Mobile Relay Node (MRN) is used. It is a mobile device which roams around the network for data gathering using Wireless Personal Area Network (WPAN). The sensor nodes and data center are developed using ARM LPC2148 Processor and Mobile Relay Node (MRN) is developed using PIC16F877A microcontroller. To evade the illicit access of the data, context based cryptographic algorithm is developed and loaded into the ARM based sensor nodes and data center. Index Terms Wireless Sensor Network, Mobile Relay Node, Wireless Personal Area Network, ARM LPC2148, PIC16F877A, Cryptography. 1. Introduction Wireless Sensor Network is a group of Sensor Nodes (SN) which can sense, process and transmit information to other SN through relay nodes. The self organizing sensor nodes uses radio signal for communication [1]. In the existing systems, the communication among SN and the Data Center (DC) is established using router. There is variety of routing methods used between SN and the DC. If the router fails, there will be a loss of 111

2 data. Instead of router, relay nodes are used among the SN and the DC. For this several placement algorithms are needed to place the relay node to cover all the sensor nodes in the network. If the relay nodes are not placed correctly they can connect only partial sensor network [2]. To overcome these relay node issues, mobile relay nodes are used. MRN is a mobile device which moves throughout the WSN and collects the information from various sensor nodes placed in different locations by sending the request. It involves point to point communication, improves the packet delivery ratio and life time of the nodes [3] [4] [5]. In wireless communication, there is no assurance that the message is transmitted securely. There is a chance of hacking during the communication. The increasing demand for security in communication between the nodes results in the requirement of several cryptographic algorithms and secret keys [6]. The goal of this paper is to provide enhanced security in WSN. For that context based cryptographic algorithm is used in the sensor node. SN encrypts the data using context based encryption which is not only based on secret keys but it also based on contexts which is set by the sender corresponding to receiver s context [7] [8]. Here, the receiver must satisfy those contexts then only they are able to decrypt. Other encryption algorithms have the drawback of brute force attack. 2. Proposed System A. Process Description Figure 1 shows the secured data communication from sensor node to data center through mobile relay node. Initially, SN encrypts the sensed data using context based encryption 112

3 algorithm and it searches the nearby MRN using WPAN. When MRN receives the search signal, it transmits transmission command. Thereby SN transmits encrypted data to MRN. After receiving the data MRN will send acknowledgement to SN and transmits encrypted data to data center. Finally, data center decrypts using context based decryption algorithm, and then it stores in the memory and monitors the received data [11]. B. Context Based Encryption Algorithm Initially, secret key (K1) and contexts (constraints or rules) are selected and two files are created. In file 1, Rules and facts are concatenated and stored. Where, the rule specifies the contexts and fact specifies the key generation algorithm. In file 2, original information (sensed data) is stored. XOR operation is performed between both files to create cipher text(c*). File 1 is encrypted with secret key (K1) to create cipher text C1 then it is encrypted with secret key (K2) using DES encryption to create cipher text C2. Final cipher text C is formed by concatenating C1 and C2. Cipher text C is transmitted to MRN and it is forwarded to data center. This algorithm overcomes the problem of brute force attack by providing some threshold for the number of failed decryptions [11]. SN Sensor Node, MRN Mobile Relay Node Fig. 1. Proposed Wireless Sensor Network C. Context Based Decryption Algorithm 113

4 The data center receives the encrypted data from MRN and decrypts the data using context based decryption algorithm. From the received cipher text C, first cipher text C1 is extracted and decrypted with secret key (K1). From this file 1 is obtained and then the rules and facts are extracted. Afterward rules and facts make a decision whether receiver satisfies the context or not. If the receiver satisfies the context, then second key is generated by specified key generation algorithm. Using the second key cipher text C2 is decrypted to provide original information. If the receiver does not satisfy the context, then error message is displayed [11]. 3. Hardware implementation The proposed system consists of three nodes namely sensor node, mobile relay node and data center. Here, sensor node is used to sense the environment and encrypt the data. MRN is used to collect the data from sensor nodes. Data Center is used to decrypt the encrypted data and monitoring. A. Sensor Node Sensor Node consists of ARM LPC2148 processor, zigbee, temperature sensor, amplifier, LCD display, buzzer and RS232. Here the sensor (temperature sensor) is connected to ARM through amplifier and zigbee is connected to UART of ARM through RS232. Initially temperature sensor senses the environment, then amplifies the sensed signal and gives it to processor. The processor converts the received analog signal into the digital signal then encrypts the information using context based encryption algorithm and displays the encrypted information in the LCD display connected to it. The encrypted information is transmitted through zigbee. Buzzer is provided for failed 114

5 decryption notification. The block diagram of sensor node is represented in figure 5. Hardware setup for this node is shown in figure 6. Fig. 2. Block diagram of Sensor Node. Fig. 3. Sensor Node with encrypted information B. Mobile Relay Node MRN consists of PIC16F877A Microcontroller, Moving robot, zigbee, LCD display and RS232. Here zigbee is connected to USART of PIC microcontroller through RS232. The MRN receives the encrypted information from sensor node through zigbee. Moving robot allows the relay node to roam throughout the network. The data received and transmitted notifications are indicated in the LCD Display. The MRN forwards the received information to data center through zigbee. The diagrammatic representation of MRN is shown in figure 7. Hardware setup for this node is shown in figure

6 Fig. 4. Mobile Relay Node Fig. 5. C. Data Center Hardware setup for Mobile Relay Node Data center consists of ARM processor, zigbee, LCD display, keypad and RS232. Here, data are received through zigbee which is connected to ARM processor through RS232. Decryption is performed in the ARM processor using context based decryption algorithm where decryption key is entered through keypad connected to ARM. The decrypted information is stored in the database and displayed in LCD display. The block diagram of data center is shown in figure 9. Hardware setup for this node is shown in figure 10. Fig. 6. Block diagram of Data center 116

7 4. Conclusion Fig. 7. Data Center with decrypted information Thus, the context based cryptographic algorithm and mobile data gathering functions are successfully implemented in both the software and hardware. Using NetBeans IDE simulator, context based cryptographic algorithm was simulated successfully. In this system, ARM LPC2148 is used as sensing node as well as monitoring node for providing enhanced security and PIC16F877A is used as mobile relay node for easy mobility and cost effective purposes. Using this system data sharing is secured and authentication is improved by overcoming brute force attack, man in the middle attack etc. It also reduces the memory requirement and communication delay. References [1] M.Preethi, M.Mathankumar and N.Sugandhi Elucidation of Effectual and Immune Multipath Routing With Multilevel Data Aggregation in Wireless Sensor Networks International Journal of Applied Engineering Research, Vol. 10 No.20, [2] Jorge Mena, Vana Kalogeraki Dynamic Relay Node Placement in Wireless Sensor Networks International Symposium on Applications and the Internet, [3] Weimin Wen et al. Energy Efficient Data Collection Scheme in Mobile Wireless Sensor Networks 31st International 117

8 Conference on Advanced Information Networking and Applications Workshops (WAINA), [4] Songtao Guo1, Cong Wang2, and Yuanyuan Yang2 Joint Mobile Data Gathering and Energy Provisioning in Wireless Rechargeable Sensor Networks IEEE Transactions on Mobile Computing, [5] Hu Yin and Yunfei Lv A Proposal of Sensor Data Collection System Using Mobile Relay Nodes International Conference on Information Security and Intelligence Control (ISIC), [6] C. Mohanraj et al. Design and development of secret session key generation using embedded crypto device ARM- LPC2148, Journal of Artificial Intelligence, vol. 6 (2), [7] Chinmoy Mukherjee, Mehak Soni and Rajarathnam Nallusamy A context based cryptographic content sharing system International Conference on Advances in Computing, Communications and Informatics (ICACCI),

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