Fast filtering for intrusion detection systems with the shift-or algorithm

Intrusion Detection Systems (IDS) play an important role in network security. The main challenge is how to find occurrences of patterns defined in the rule set which describe the signature of malicious activities. In this paper, we propose an efficient exact pattern matching algorithm based on the bit-parallel approach. Experimental results show that our algorithm outperforms the traditional Aho-Corasick automaton at the cost of a small number of false positives.