An improved algorithm to accelerate regular expression evaluation
Michela Becchi, Patrick Crowley · 2007
Modern network intrusion detection systems need to perform regular expression matching at line rate in order to detect the occurrence of critical patterns in packet payloads. While deterministic finite automata (DFAs) allow this operation to be performed in linear time, they may exhibit prohibitive memory requirements. In [9], Kumar et al. propose Delayed Input DFAs (D2FAs), which provide a trade-off between the memory requirements of the compressed DFA and the number of states visited for each character processed, which corresponds directly to the memory bandwidth required to evaluate regular expressions.