In order to provide scientific bases for developing rational benign worm propagation policy in P2P networks

the propagation characteristics of benign worms in countering against malicious worms should be detailed researched.In this paper

a modeling and analysis method for propagation of worm-anti-worm in P2P network is proposed based on stochastic process algebra (SPA).Through analyzing the interactions between benign worms and malicious worms and the network node's state transition process

two SPA models are built by using PEPA syntax to describe the malicious worms' initial propagation phase and the worm-anti-worm phase respectively.To analysis these models

the paper makes use of continuous state-space approximation to transform the models into a set of ODEs.Simulation results show that the benign worms can effectively contain the spread of malicious worms

but it should apply scientific propagation policy according to the current network conditions

so as to ease the pressure of the network leaded by the propagation of benign worm.