The Research and Amelioration of Pattern-matching Algorithm in Intrusion Detection System

This paper makes a summary of pattern matching algorithm in Intrusion Detection System: KMP algorithm, BM algorithm, BMH algorithm, BMHS algorithm, AC algorithm and AC-BM algorithm. The performances of various algorithms are analyzed, and then through the experiment data is verified. Last an improved algorithm based on AC-BM algorithm is proposed. The improved algorithm constructs pattern tree based on binary tree, and it can reduce the time. In addition, the algorithm increases the moving distance of pattern tree, reduces the comparing times by using the bad-character rule of improved BMHS algorithm. Experiments show that the improved algorithm can accelerate the matching speed and has a good time performance.