Patent ID: 7327843

Claim:
A data reproducing device for reproducing data recorded in a data storing disk, said data reproducing device comprising: a pickup unit for reading a copy protection information which is written in advance as slits and holes in a region over a substrate of said data storing disk other than a data storage region; and a copy protection unit adapted, when an encrypted data over the data storage region of said data storing disk is copied in response to a demand of an external device, to perform an authentication with reference to the copy protection information read by said pickup unit thereby to output the information, as contained in the copy protection information and relating to a secret information containing a secret key, to the external device which is recognized to be correct through the authentication, the secret information is written in advance as slits and holes, in the region over the substrate other than the data storage region, in order to allow emitted light to pass through the slits and holes and be received by a receiving diode and output as electrical signals to the copy protection unit.