A Pattern-Matching Scheme With High Throughput Performance and Low Memory Requirement

Abstract—Pattern-matching techniques have recently been ap-plied to network security applications such as intrusion detection, virus protection, and spam filters. The widely used Aho–Corasick (AC) algorithm can simultaneously match multiple patterns while providing a worst-case performance guarantee. However, as trans-mission technologies improve, the AC algorithm cannot keep up with transmission speeds in high-speed networks.Moreover, it may require a huge amount of space to store a two-dimensional state transition table when the total length of patterns is large. In this paper, we present a pattern-matching architecture consisting of a stateful pre-filter and anAC-based verification engine. The stateful pre-filter is optimal in the sense that it is equivalent to utilizing all previous query results. In addition, the filter can be easily realized with bitmaps and simple bitwise-AND and shift operations. The size of the two-dimensional state transition table in our proposed architecture is proportional to the number of patterns, as opposed to the total length of patterns in previous designs. Our proposed ar-chitecture achieves a significant improvement in both throughput performance and memory usage. Index Terms—Aho–Corasick (AC) algorithm, Bloom filter, deep packet inspection, pattern matching