关键词: 生物免疫, 抗原, 抗体, 多样性, 特征表述, 入侵检测

Abstract: In the biological immune system，immune cells usually succeed in dealing with nearly all antigens under the condition that its counts is far smaller than possible antigen oneself，this benefits from the variety of antibody mainly.This paper analyzes a similarity between attack characteristic and antigen，and then puts forward a new expression of signature with the multi-level & multi-characteristic fuzzy with characteristic element，characteristic factor，characteristic base and intrusion pattern.The paper also provides algorithms of drawing and discerning IDS signature based on this expression.The expression inspired by varieties of antigen or antibody makes the intrusion detectors have variety，and more importantly，establish the foundation that the detection evolves.

Key words: biological immunity, antigen, antibody, variety, expression of signature, intrusion detection