Optical medium with added descriptor to reduce counterfeiting

An optical medium having authenticity information added thereto to reduce counterfeit duplication of the optical medium, the optical medium comprising:

• a physical descriptor having plural descriptor elements added to the optical medium, the plural descriptor elements corresponding to data-level regions on the optical medium having lengths that produce indeterminate interpretations when read plural times;
• reference descriptor information based on the physical descriptor, the reference descriptor information reflecting characteristics of the plural descriptor elements corresponding to the data-level regions having the lengths that produce the indeterminate interpretations;
• and
• authenticity information, wherein the authenticity information comprises a cryptographic signature applied to the reference descriptor information.

An optical disc having authenticity information added thereto to reduce counterfeit duplication of the optical disc, the optical disc comprising:

• a physical descriptor having plural descriptor elements added to the optical disc, the physical descriptor being produced by providing at least one data-level region having a length that produces indeterminate interpretations when read plural times;
• reference descriptor information formed based on the physical descriptor, the reference descriptor information including element type information which conveys whether the plural descriptor elements are:
• deterministic elements, or
• probabilistic elements;
• and
• authenticity information, wherein the authenticity information comprises a cryptographical signature applied to the reference descriptor information.