Efficient Pattern Matching Algorithm for Intrusion Detection Systems

To overcome the defects of low efficiency of pattern matching in intrusion detection systems ( IDS), an efficient pattern matching algorithm is proposed. The proposed algorithm first preprocesses pattern to record pattern information, then it recursive compares the nodes to find the most common part of pattern to improve efficiency. The proposed algorithm also appends auxiliary structure of m nodes in pattern to reduce time and space complexity. Theoretical analysis shows that for the subject with n nodes, the time complexity of the proposed algorithm is (O(nlog2n mlog2m)), and space complexity is (O(n + m)). Detailed experimental results and comparisons with existed algorithms show that the proposed algorithm outperforms current state-of-the-art algorithms in terms of time efficiency, space efficiency and matching ratio.