A hacker known for cracking the copy-protection technology in DVDs claims to have unlocked the playback restrictions of Apple's iPod and iTunes music products and plans to license his code to others, an Associated Press report said.According to the Associated Press report, the move by Jon Lech Johansen, also known as 'DVD Jon,' could pit the 22-year-old against Apple's lawyers, experts say, but if successful could free users from some restrictions Apple and its rivals place on digital music.Songs purchased from Apple's online iTunes Music Store can't be played on portable devices made by other companies. Songs purchased from many other online music stores also won't work on iPods because they similarly use a form of copy-protection that Apple doesn't support, the report said.The report also quoted Johansen as saying that he has developed a way to get around those restrictions by creating code that mimics Apple's copy-protection system. But unlike his previous work, which he usually posts for free, the Norway native plans to capitalize on his efforts through his Redwood Shores-based DoubleTwist Ventures, said the company's only other employee, managing director Monique Farantzos.An unnamed client will soon use the technology so its copy-protected content will be playable on iPods, she said, declining to give any specifics.Apple declined to comment, the report said.