Wireless　sensor　networks　are　widely　used　in　a　variety　of　commercial　and　military　applications.　As　a　fundamental　requirement　for　providing　security　functionality　in　sensor　networks,　key　management　plays　an　essential　role　in　authentication　and　encryption.　In　this　paper,　we　propose　a　Refined　Key　Link　Tree　(RKLT)　scheme　that　incorporates　dirty　key　path　into　the　key　link　tree-based　group　key　management　scheme.　By　delaying　key　update　operations　in　dirty　key　paths,　the　number　of　duplicate　key　update　messages　for　auxiliary　nodes　can　be　reduced,　which　also　brings　down　the　energy　cost.　We　show　through　experiments　that　our　RKLT　scheme　requires　fewer　rekeying　messages　than　those　in　the　existing　group　key　management　schemes.