Provided is a drive device capable of preventing the reproduction of contents from a copied content to promote the copyright protection even if identification information unique to a recording medium used to generate a title key for decoding an encrypted content is exposed and the contents are privately encrypted and copied by using the identification information. The identification information unique to the medium used to generate the title key and a signature for identification information issued by an authentication station terminal device (101) are recorded on a recording medium (103). A drive in a reproduction device (104) performs verification of the signature prior to the decoding and reproduction of the encrypted contents. The drive outputs no identification information in the case of a failure in the verification. Thus, a reproducing program in the reproduction device (104) is unable to generate a decoding key, resulting in a failure in the decoding and reproduction of the encrypted contents. Additionally, the signature is not outputted to the outside of the drive. As a result, an unauthorized person is prevented from making the unauthorized copy of the recording medium (103).