Apple has joined hands with a so-called patent troll to sue rivals for allegedly infringing on its patents and designs. A patent troll is a company that buys up patents and sues for royalties without having any other productive business.

U.S. IT website TechCrunch reported that Apple has sold 12 of its patented technologies to Digitude Innovations. Digitude then filed lawsuits with the U.S. International Trade Commission early this month accusing smartphone makers Samsung Electronics, LG Electronics, HTC and Nokia of infringing four patents, two of them from Apple.

TechCrunch said Digitude could be acting as a "mercenary" for Apple by leaving Digitude to bear the brunt of public opprobrium while trying to shed its own litigious image.

Apple transferred the patents to Digitude through a paper company, apparently to conceal the paper trail.

It also is possible that Apple handed them over because Digitude threatened to sue it, but a staffer with a Korean smartphone maker said it is unlikely Apple succumbed to blackmail. "It seems more likely that it handed over the patents so they can be used to attack its rivals," the staffer added.