Abstract: To reach the proportional security of the goal network,an approach on network security enhancement strategies based on optimal attack path was proposed．The approach assesses the risk of attack target,and makes strategies for network security enhancement on the basis of optimal attack path．To obtain optimal attack path,an approach to generating optimal attack path based on ant colony optimization algorithm was proposed,and the pheromone updating way was improved．Simulation results show that the proposed approach can generate strategies effectively,and the improved ant colony optimization algorithm has strong global search ability and rapid convergence.

Key words: Attack graphs,Ant colony optimization,Optimal attack path,Network security