Since sensor nodes join or leave the wireless sensor networks frequently

it is necessary to build a secure and efficient group key management system.An efficient and secure group key management scheme was proposed.Private-key cryptosystems are used to encrypt multicast messages and rekey the group when new nodes join the group

while the tech-nology of identity-based broadcast encryption is used to distribute the group key and rekey the group when nodes leave the group.The proposed scheme satisfies the desired security properties

such as forward secrecy

backward secrecy and collusion resistant.Compared with existing group key management schemes in wireless sensor networks

the scheme can efficiently reduce key storage and communication overhead of rekeying messages.As storage overhead and rekeying cost of nodes are not dependent of the scale of networks

the proposed scheme is applicable to wireless sensor networks.