An efficient key distribution scheme for heterogeneous sensor networks

Key distribution refers to the problem of establishing shared secrets on sensor nodes such that secret symmetric keys for communication privacy, integrity and authenticity can be generated. In a wireless sensor network, pre-distribution of secret keys is possibly the most practical approach to protect network communications but it is difficult due to the ad hoc nature, intermittent connectivity, and resource limitations of the sensor networks. In this paper, we propose a key distribution scheme based on random key pre-distribution for heterogeneous sensor network (HSN) to achieve better performance and security as compared to homogeneous network which suffer from high communication overhead, computation overhead, and/or high storage requirements. In a key generation process, instead of generating a large pool of random keys, a key pool is represented by a small number of generation keys. For a given generation key and publicly known seed value, a one-way hash function generates a key chain, and these key chains collectively make a key pool. Each sensor node is assigned a small number of randomly selected generation keys. The proposed scheme reduces the storage requirements while maintaining the same security strength.