As a teenager, Johansen famously cracked the encryption on DVDs.

DoubleTwist, a US company that wants to licence the code, told Reuters yesterday that Johansen, who now lives in San Francisco, had cracked Apple's FairPlay copy protection technology, which controls how many times iPod users can record copy-protected tracks - and also prevents users downloading songs from rival music sites to iPods.

FairPlay allows iPod users to play music on up to five computers, burn an unlimited number of songs to disc, and burn playlists up to seven times.

Johansen apparently wants to license the code to media distribution companies, allowing their songs and videos to by-pass the iTunes online store, but still be played on an iPod. However, to be legal, they would still need a copy protection system approved by the record companies.

"What (Johansen) did was basically reverse-engineer FairPlay," DoubleTwist managing director Monique Farantzos told Reuters: "This allows other companies to offer content for the iPod."

However analysts seriously doubt whether companies like Yahoo!, Rhapsody and Napster would seriously contemplate such a move which would invite legal retaliation from Apple - and possibly the record industry.

Ovum technology analyst John Arber also forecast Apple might simply release a software update for iTunes that stops the program.