Research On Key Pre-distribution Scheme For Sensor Network

Sensor network is a kind of distributed wireless network which consists of a large number of sensor nodes. To achieve the communication security in sensor network, it's vital to establish pairwise key between sensor nodes. Due to the resource constraints of sensor nodes, many traditional key distribution schemes, such as Diffie-Helman protocol, KDC, RSA etc., are not practical for sensor network. Normally, we use key pre-distribution schemes for sensor network. However, the resilience against physical node capture of these schemes is not satisfying, which reveals pre-distributed keys quickly as captured nodes increases.In this thesis, we analyze the mathematical model of symmetric bivariate polynomial over GF(q), including proposing a method to construct symmetric bivariate polynomial, evaluating the computing overhead of polynomial and analyzing some important parameters of polynomial.Based on above analysis, we proposed a key pre-distribution scheme using 2-hop neighbor key agreement, a key pre-distribution scheme using group-based deployment and a cube-based key pre-distribution scheme. In our schemes, instead of pre-distributing pairwise keys directly, we pre-distribute symmetric bivariate polynomial over GF(q) to sensor nodes, which can help nodes compute the pairwise keys. The polynomials ensure our schemes have security threshold. When the number of captured nodes is no more than security threshold, the network is safe.By using 2-hop neighbor key agreement or group-based deployment, the security threshold can be increased substantially. Moreover, our schemes ensure the security performance of sensor network drops slowly even if the number of captured nodes is larger than the security threshold. Using the cube space to pre-distribute polynomials, the cube-based scheme achieves high probability of security link and high security threshold as well. The result of simulation shows that our schemes have much better security performance compared with some current key pre-distribution schemes. Our schemes substantially improve the security performance and resilience against physical node capture for sensor network.