The patent, awarded to AT&T on Nov. 4, describes a "system and method for counteracting message filtering."
The patent details a way to trick filters that compare digital messages to known pieces of spam, altering each message so that no two are exactly the same.
"In this way, spam countermeasures based upon duplicate detection schemes are foiled," according to the patent.
AT&T's patent wins approval as spam and software patents separately preoccupy the Internet. Opponents, pointing to patent-infringement judgments like thatat Microsoft's expense, say software patents have created a siege mentality in the industry. And the spam problem has resulted in a host of proposed solutions in the software, standards and legislative arenas.
AT&T's award left patent and spam foes scratching their heads, questioning the company's interest in an anti-antispam tool.
"Why is ATT inventing and patenting a method for e-mail spammers to fight spam-filtering systems?" Greg Aharonian, publisher of the Internet Patent News Service, wrote in his Patnews e-mail newsletter. "Some legitimate e-mail is being blocked by spam filters, but the solution is not new techniques to make spam more spammable, but rather coordination among ISPs (Internet service providers) and backbones to quickly shut down spammers."
AT&T Labs, the Florham Park, N.J., unit where the patented technology originated, said the patent was purely defensive.
"This is an arms race, and (Bell Labs researcher Robert Hall) tried to stay one step ahead of the spammers," said Michael Dickman, a spokesman for AT&T Labs. "He anticipated that spammers would try to change the message to circumvent the filters."
AT&T said it is re-evaluating the patent now that it has been granted and has not yet decided how to use it.
Spam foes havein the past, pointing to at least one instance in which a sales agent signed a so-called to provide a known spammer with Internet service.
But one Internet activist said the pink contract didn't cause her to doubt AT&T's intentions with respect to the patent.
"Did AT&T screw up by signing that contract? Yes, absolutely," said Laura Atkins, president of the SpamCon Foundation. "Is its existence proof of some great conspiracy by AT&T to spam the world and allow their users to spam the world? I don't believe so."