METHOD FOR KEY GENERATION FOR DIGITAL RIGHTS CONTROL, RECORDING MEDIUM, PLAYER, RECORDER AND SYSTEM FOR COPY RIGHT CONTROL

摘要

When a recording medium is recorded using a method for control of the crosstalk between tracks using control points any change in track pitch will directly result in other optimum values for those control points. If the recording medium is copied by a bit copier the control point values are also copied without modification but because of a shift of the data in adjacent tracks relative to each other the control point values are no longer the optimum values. This can be used to distinguish between an original and a copied recording medium. If the original recording medium is copied but the control point values are recalculated to be appropriate for the copied recording medium it can easily be detected that these recalculated values differ from the expected correct values, thus distinguishing a copied disc from the original disc