Patent ID: 7464411

Claim:
A method of copy protecting an optical disk comprising: providing data patterns such that the data patterns cannot be accurately copied onto another disc by a writer for recordable discs which has a limited ability to look ahead during encoding, wherein the data patterns have a DSV (digital sum value) which has a rapid rate of change over time; the data patterns making up an authenticating signature; subjecting the data patterns to a first exclusive Or (XOR) scrambling algorithm; applying the scrambled data patterns of the authenticating signature and other data to the optical disc in a mastering process, the mastering process including: using a laser beam recorder controlled by an encoder which has a larger ability to look ahead than the writer; encoding the scrambled data patterns using EFM (eight to fourteen modulation) with a second XOR scrambling algorithm having the same pattern of scrambling data as the first XOR scrambling algorithm; and applying the twice scrambled data patterns and the other data to the optical disk; wherein transitions in the EFM signal from the applied data patterns are shifted from their ideal values, or the ability of disc drives to maintain optimal beam positioning is compromised, by the twice scrambled data patterns.