Abstract: In wireless sensor networks, single static identity-based node authentication can't meet the dynamic security needs. In order to provide better security we must combine dynamic behaviour-based node trust with static identity-based node authentication. In node behavior trust evaluation, behavior evidence is the fundamental basis of behavior evaluation. Because the node's behavior is random,uncertain,which causes behavior evidence was not complete and bchavior value is not ectual in each interaction, but as far as we know, this very important phenomenon in behavior trust evaluation is rarely considerd. "hhis paper analyzed incomplete behavior evidence obtained in node interaction brings about a significant impact on trust evaluation and discussed the relationship between incomplete behavior evidence and behavior value,gave a kind of behavior trust evaluation strategy for different values interaction such as Less-Filling and Weight Extension. Finally, we used two theorems and two properties to prove strategy's effect and property in behavior trust evaluation. Paper lays the quantity foundation in enhancing valuctrust reliability of node behavior trust.

Key words: Wireless sensor network, Node behavior evidence, Node behavior value, Node behavior trust