Copy protection of data carrying discs

A method of accessing data on a copy protected data carrying disc, where a data carrying disc has been copy protected by recording selected data thereon such that the recorded selected data has predetermined physical characteristics, the accessing method comprising:

• extracting the selected data from said copy protected disc and determining the physical characteristics thereof;
• and
• enabling access to the data on said disc if the physical characteristics determined from the disc are substantially the same as said predetermined physical characteristics.

A theoretical model of a data carrying disc for use in copy protecting data carrying discs, the model describing the information to be carried on the disc and the intended locations of the information on the disc in a manner enabling the relative locations of any two pieces of the information to be calculated.

A fingerprint for use in a method of determining the provenance of a data carrying disc, the fingerprint identifying selected data recorded on a data carrying disc and identifying physical characteristics of said selected data.

A copy protected data carrying disc, wherein the disc has data recorded thereon, and wherein, to provide copy protection, selected data has been recorded onto the disc to have predetermined physical characteristics.

Apparatus for producing a copy protected data carrying disc, said apparatus comprising:

• a writing apparatus for writing data to a disc,
• a drive for rotating the disc as it is written, and
• control means for controlling the writing apparatus and the drive such that selected data is written to the disc to have predetermined characteristics.