High speed pattern matching algorithm based on deterministic finite automata with faulty transition table

Regular expression matching is the time-critical operation of many modern intrusion detection systems (IDS). This paper proposes pattern matching algorithm to match regular expression against multigigabit data stream. As usually used regular expressions are only subjectively tested and often generates many false positives/ negatives, proposed algorithm support the possibility to reduce memory requirements by introducing small amount of faults into the pattern matching. Algorithm is based on the perfect hashing and is suitable for hardware implementation.