Abstract: P2P anti-worms is one of the effective countermeasure to malignant worms in structured P2P networks,but the existing models are too complex in describing the propagation processes of worms under attack-defense environment．To address this problem,a simple structured P2P worm-anti-worm model was presented．This model performs the form description to the antagonistic propagation of P2P anti-worms and malignant worms in structured P2P networks by the support of logic matrix,and a number of key parameters that affect the propagation speed of malignant worm under attack-defense environment can be deduced rapidly by the model,besides,considering the significant influence of P2P churn feature on worm propagation,the change rate of nodes is added to the model to improve its accuracy．The experimental results show that formalized logic matrix can reduce the complexity of worm propagation model under attack-defense environment,rapidly identify the key factors that restrict the spread of worms,and supply the reference for the following research work on defending worms.

Key words: Structured P2P network,Logic matrix,Worm-anti-worm,P2P churn