Jon Lech Johansen used his web site - defiantly named "So Sue Me" - to release a software key that helps to unlock the encryption Apple uses for its AirPort Express, a device that lets users broadcast digital music from Apple's online iTunes Music Store on a stereo.
Some security consultants say that with the key and another program he released, Mr Johansen, also known as DVD Jon, has helped pave the way for other software applications other than Apple iTunes to work with AirPort Express.
Mr Johansen, an open source advocate, has been critical of Apple's proprietary system, which largely restricts Apple's hardware and software products to work only with each other.
On his web site, for instance, he praised a newly developed technology by RealNetworks that will make songs from its online music service compatible with the market-dominating Apple iPod portable music player.
Mr Johansen's latest endeavours mark the third time he has circumvented Apple's music copy-protection technologies this year.
Apple officials did not immediately return calls for comment.
Mr Johansen, now 20, was 15 when he posted on the internet software that unlocked the codes the film industry used on DVD movies to prevent illegal copying. The act made him a folk hero among hackers.
After the film industry complained, Norwegian authorities charged him with data break-in, but Mr Johansen was acquitted at trial and on appeal.
From> Associated Press