A San Francisco start-up that helps Apple iTunes users to circumvent encryption and share their music more easily has won venture capital backing and launched its first products.

DoubleTwist has the controversial “DVD Jon” as a co-founder. Jon Lech Johansen, 24, earned notoriety at the age of 15 for co-authoring software that unscrambled encryption on DVDs, allowing them to be copied. He has also, over the past four years, reverse engineered Apple’s FairPlay digital rights management technology used in iTunes, freeing content to be moved around more easily.