Abstract: In order to assess network security situation in real-time and quantification,an assessment method based on immune danger theory was proposed.Through studying the immune operation mechanism,antigen,antibody and immune cell in the problem of network security were defined.On the premise of describing the judgment rules of danger signal,the antigen is recognized accurately.Based on the changes of antibody density in the immune response and immune balance mechanisms,the calculation method of antibody density was given.Finally,by analyzing the relationship between antibody density and danger level,a danger awareness model based on antibody density was built to assess network security situation in real-time and quantification.The simulation results show that antibody density calculated by using the proposed method accurately reflects the danger level that the system faces,which can provide effective decision-making support for network management.

Key words: Danger theory,Artificial immune,Antibody density,Network security,Situation evaluation