Network Associates is granted broad antispam patent - Network Associates Inc. (NAI) has been granted a broad U.S. patent for technology covering "various computer program products, systems and methods" for filtering unwanted e-mail messages, it said Tuesday. The antivirus software company said that U.S. patent no. 6,732,157 encompasses use of multiple spam-filtering techniques such as compound filters, paragraph hashing, and Bayes rules. These techniques have been proposed and used by a number of antispam technology proponents and it was not clear from the filing how the patent would affect competitors to NAI's McAfee antispam offerings.