APPARATUS FOR AND METHOD OF MULTIPLE PARALLEL STRING SEARCHING

An apparatus for and method of simultaneously searching an input character stream for the presence of multiple strings. The strings to be searched for are determined a priori, processed and stored in substring tables during a configuration phase. The strings to be searched for are divided into a plurality of two and three character substrings and stored in substring tables. A hash of each substring is calculated and stored in a hash table whose output is an index to a substring table. During searching, the content filter generates the hash of the input character stream and attempts to find a matching substring stored in the hash table. A string is declared found if all the substrings making up the string have been received in correct consecutive order.