Design and Evaluation of Parallel String Matching Algorithms for Network Intrusion Detection Systems

Abstract. Network security is very important for Internet-connected hosts because of the widespread of worms, viruses, DoS attacks, etc. As a result, a network intrusion detection system (NIDS) is typically needed to detect network attacks by packet inspection. For an NIDS system, string matching is the computation-intensive task and hence the performance bottleneck, since every byte of the payload of packets must be checked against numerous predefined signature strings, which may occur arbitrarily in the payload. In this paper, we present the design and evaluation of parallel string matching algorithms targeting hardware implementation on FPGAs and software implementation on multi-core processors. Experimental results show that, on a multi-processor system, the multi-threaded implementation of the proposed parallel string matching algorithm can reduce string matching time by more than 40%.