Efficient Pattern Matching Algorithm for Memory Architecture

1. Efficient Pattern Matching Algorithmfor Memory Architecture Author : Cheng-Hung Lin , Shih-Chieh Chang Publisher ：Very Large Scale Integration (VLSI) Systems, IEEE Transactions on

2. In order to accommodate the increasing number of attack patterns and meet the throughput requirement of networks, a successful network intrusion detection system must have a memory-efficient pattern-matching algorithm and hardware design.

3. This paperpresented a memory-efficient pattern matching algorithm which can significantly reduce the number of statesand transitions by merging pseudo-equivalent states while maintaining correctness of string matching. In addition, the new algorithm is complementary to other memory reduction approachesand provides further reductions in memory needs.

5. 更改 match vector 成 pathVec 與 ifFinal , • define similar states as pseudo-equivalent states • (have identical input transitions, failuretransitions, and ifFinal bit, but different next states.) • Addaregister, called preReg

8. Example • two patterns, “abcdefghijklm” and “abcwsghidefxyklm.” • label the substrings “abc”, “def”, “ghi”, and “klm” as “α” ”β” ”γ” ”δ” • Pattern become”αβγjδ” and “αwsγβxyδ” • Longest common subsecquence between two patterns are “ αβδ” or ” αγδ” • Calculatelargest sharing gain