As a teenager, Johansens didn't try to commercialize his work, but now, aged 22, with a small office in California, his company DoubleTwist Ventures is offering to license its reverse-engineering of Apple's FairPlay digital rights management (DRM) system.

Johanssen still has an open systems hacker mentality, though. "Today's reality is that there's this iTunes-iPod ecosystem that excludes everyone else from the market," he says. "I don't like closed systems."

Apple engineered Fairplay so that its iPod and other makers' machines are mutually incompatible. Johansen's new program allows other companies to sell copy-protected songs that play on the iPod, and allows other devices to play iTunes songs.

Apple's attempt to restrict its musical content to its own devices has run into legal trouble in a number of countries. In August, French legislators approved amendments to the country's copyright law which are likely to force Apple to provide its music download rivals with interoperability information. The new law, in addition to requiring companies to provide information about their music download services and devices to their rivals, provides for the creation of a new regulatory authority to ensure that such an information exchange takes place.

Commenting on the new legislation, US technology industry group Americans for Technology Leadership, argued that: "The final vote today by French lawmakers on legislation that would force Apple to open its iTunes product to competitors’ devices is an attack on intellectual property rights not just of Apple but all companies"

“While the final version is slightly less severe than the earlier draft, it still illustrates France’s complete disregard for intellectual property,” stated Jim Prendergast, Executive Director of Americans for Technology Leadership.

Authorities in Norway, Sweden and Denmark are also said to be investigating Apple over DRM and interoperability issues.

Johansen may not want to find himself on the same side as the French authorities; but in America he may find that the defenders of intellectual property have more teeth than in Old Europe. The legality of Apple's protections are very unclear under existing US law. The legal status of Johansen's software is even more unclear. He says that his program adds copy protection to content played on iPods, whereas the Digital Millennium Copyright Act prohibits removing it. Opening iTunes content to other players is less clearly within the law, but Johansen quotes DMCA language that supports interoperability. "The law protects copyrights," he says, "but it doesn't keep you locked into the iPod."

Bring on the lawyers!