N. Meghanathan et al. (Eds.): CCSIT 2011, Part II, CCIS 132, pp. 383–390, 2011. © Springer-Verlag Berlin Heidelberg 2011 A Light-Weight Protocol for Data Integrity and Authentication in Wireless Sensor Networks Jibi Abraham 1 , Nagasimha M P 2 , Mohnish Bhatt 2 , and Chaitanya Naik 2 1 Dept. of Computer Engg. College of Engineering Pune - 5, India jibia.comp@coep.ac.in 2 Dept. of Computer Science & Engg. M.S. Ramaiah Institute of Technology, Bangalore – 560054, India {nagasimha.mp,mohnishmb,chaitanyanaikcs021}@gmail.com Abstract. In a wireless sensor network, pre-distribution of secret keys is possibly the most practical approach to protect network communications. To meet the stringent resource constraints of the sensor nodes, such as limited storage capability, low computation capability, and limited battery life, key pre- distribution schemes should be highly efficient, namely requiring as little storage space as possible, and at the same time, maintain a strong security strength, i.e., high resilience against node capture. In this paper, a new approach for random key pre-distribution is proposed to achieve both efficiency and security goals. The novelty of this approach lies in that, instead of using a key pool consisting of random keys, a random key generation technique is carefully designed such that a large number of random keys can be represented by a small number of key generation keys. Then, instead of storing a big number of random keys, each sensor node stores a small number of key-generation keys while computes the shared secret key during the bootstrapping phase on-the-fly using efficient hash operations. 1 Introduction A wireless sensor network (WSN) consists of a large number of tiny sensor nodes with limited computation capacity, storage space and power resource. Typically, WSNs are deployed at high density in regions requiring surveillance and monitoring. In military applications, sensor nodes may be deployed in unattended or hostile environments such as battlefields. WSNs are, therefore, vulnerable to various kinds of malicious attacks like eavesdropping, masquerading, traffic analysis, etc. Hence, it is important to protect communications among sensor nodes to maintain message confidentiality, authenticity and integrity. Symmetric secret key pre-distribution is possibly the only practical approach for establishing secure channels among sensor nodes since the low-power sensor nodes have very limited computational capacity which excludes the applicability of computation-intensive public key cryptographic algorithms.