LAUSR

Security approaches in Wireless Sensor Networks (WSNs) are normally based on symmetric cryptography. Instead of symmetric encryption, some alternative approaches have been developed by using public-key cryptography. However, the higher computational cost represents a hard limitation to their use. In this paper, a new key management protocol is proposed. A transitory symmetric key is used to authenticate nodes in the network during the key establishment. However, pairwise keys are established using asymmetric cryptography. A theoretical analysis shows that the computational effort required by the public key cryptosystem is greatly reduced, while the security of the network is increased with respect to state-of-the-art schemes based on a transitory master key. Moreover, an experimental analysis demonstrates that this proposed approach can reduce the time spent for key establishment by about 35%.