Analyze and Improvement of BM Algorithm

When network is overload, snort spends a lot of time to matching rules. The algorithm determines the performance of intrusion detection system to a large extent. Snort adopts BM algorithm in default, in order to enhance the efficiency of network intrusion detection system which is based on snort, this paper analyzes BM algorithm firstly, and proposes an improved algorithm. Secondly, this thesis compares the two algorithms (BM algorithm and the improved BM algorithm) theoretically, and does a quantitative description of the extent of the improved BM algorithm according to the experimental results. Finally, the improve BM algorithm is applied to the network intrusion detection system, and have achieved good results.