11. A method for detecting presence of a target complex strings in a data stream, the method comprising configuring at least one processor to execute processes of: locating coherent strings of said target complex string in said data stream, said target complex string comprising a number of ambiguous strings interleaved by coherent strings, each character in said coherent strings being uniquely defined in an alphabet, each character in said ambiguous strings belonging to one of predefined classes of characters; and accessing a table of said predefined classes of characters, each class corresponding to a respective subset of characters of an alphabet, to ascertain equality of classes of likewise positioned characters of portions of said data stream which interleave said coherent strings and respective ambiguous strings of said target complex string; and performing corrective actions subject to said locating coherent strings and ascertaining said equality of classes.
11. A method for detecting presence of a target complex strings in a data stream, the method comprising configuring at least one processor to execute processes of: locating coherent strings of said target complex string in said data stream, said target complex string comprising a number of ambiguous strings interleaved by coherent strings, each character in said coherent strings being uniquely defined in an alphabet, each character in said ambiguous strings belonging to one of predefined classes of characters; and accessing a table of said predefined classes of characters, each class corresponding to a respective subset of characters of an alphabet, to ascertain equality of classes of likewise positioned characters of portions of said data stream which interleave said coherent strings and respective ambiguous strings of said target complex string; and performing corrective actions subject to said locating coherent strings and ascertaining said equality of classes. 12. The method of claim 11 wherein the processes of locating and ascertaining are pipelined.