Software "DoubleTwist" hacks iTunes
Jon Lech Johansen became the "enfant terrible" of the DRM industry when he released software which cracked the encryption codes on DVDs, aged just 15.
His firm, DoubleTwist, has now released software allowing users to share digital media files across devices.
It would allow songs bought on Apple's iTunes to be shared on other devices.
At the moment, the only portable music player which can store content downloaded from the iTunes store is Apple's iPod.
Users can copy downloaded songs to a CD and then copy the disc back on to the computer so that the songs can then be moved to other portable devices - but the quality of the music is affected.
In 2003 Mr Johansen distributed a program which bypassed Apple's Fairplay system, the software that enforces this relationship between iTunes and the iPod. Since then he has had several other well-publicised run-ins with the firm.