Artificial Immune Systems (AIS) have long been used in the field of computer security and especially in Intrusion Detection systems. Intrusion detection based on AISs falls into two main categories. The first generation of AIS is inspired from adaptive immune reactions but, the second one which is called danger theory focuses on both adaptive and innate reactions to build a more biologically-realistic model of Human Immune System. Two algorithms named TLR and DCA are proposed in danger theory field that both of them are trying to identify the antigens based on a simple identifier. Both of them suffer from low accuracy and detection rate due to the fact that they are not taking the structure of antigens into account. In this paper, we propose an algorithm called STLR (structural TLR), which is an extended form of TLR algorithm. STLR tries to model the interaction of adaptive and innate biological immune systems and at the same time considers the structure of the antigens. The experimental results show that using the structural aspects of an antigen, STLR can lead to a great increase in the detection rate and accuracy.
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