The present invention relates to a technique for authenticating data
stored on media in order to prevent piracy. According to the present
invention, a lookup table contains broken or modified modulation rules
comprising one or more authentication keys or components thereof, that
are derived by the table's intentional breaking of standard 8-14 and 8-16
modulation rules. The authentication keys are formed and remain hidden
without being transferred in the audio/video. Additionally, the lookup
table is employed using conventional hardware and/or software in CD or
DVD players. Each output value according to the present invention is a
function of the physical characteristics of a disc that does not travel
with the audio or video or graphics data. Authentication systems of the
present invention optionally encompass singular, multiple or multi-level
authentication systems, each of which successively must be deciphered
before the audio/video is finally available.