REVERSE NFA GENERATION AND PROCESSING

In a processor of a security appliance, an input of a sequence of characters is walked through a finite automata graph generated for at least one given pattern. At a marked node of the finite automata graph, if a specific type of the at least one given pattern is matched at the marked node, the input sequence of characters is processed through a reverse non-deterministic finite automata (rNFA) graph generated for the specific type of the at least one given pattern by walking the input sequence of characters backwards through the rNFA beginning from an offset of the input sequence of characters associated with the marked node. Generating the rNFA for a given pattern includes inserting processing nodes for processing an input sequence of patterns to determine a match for the given pattern. In addition, the rNFA is generated from the given type of pattern.