An apparatus for preventing an unauthorized use of a copyright medium adapted to identify a purchaser by authentication of the purchaser's fingerprint at the time of purchasing an encrypted copyright medium, so that only the purchaser can reproduce or copy work data recorded in the copyright medium. Data is read from a copyright medium identification database in order to write a copyright medium unique identification database and a cipher key database into a Smart card or other recording mediums using a Smart card or other recording medium data reading/writing device. Moreover, fingerprint data of the purchaser of the copyright medium is read by using a fingerprint authentication device. The purchaser's fingerprint data, the copyright medium unique identification data, and the cipher key are written into the Smart card or other recording medium using the Smart card or other recording medium data reading/writing device.