A content playback device for playing back a digital content, the content playback device comprising: an information acquisition unit operable to acquire a content playback program from a recording medium in which the digital content and the content playback program, the content playback program being a computer program to be used for playing back the digital content; characterized in that said information acquisition unit further being operable to acquire a digital signature generated for the content playback program from the recording medium, the digital signature being further recorded on the recording medium, the digital signature having an official release type or a test release type as a signature type, and by a medium type judgment unit operable to judge whether the recording medium is read-only; a signature verification unit operable to perform verification of the digital signature acquired by the information acquisition unit; and a playback permission determination unit operable to: (i) prohibit performing processing relating to playback of the digital content by execution of the content playback program if the verification of the acquired digital signature is unsuccessful; (ii) prohibit performing processing relating to playback of the digital content by execution of the content playback program if the verification of the acquired digital signature is successful, the signature type of the acquired digital signature is the official release type, and the recording medium is judged not to be read-only; and (iii) permit performing the processing relating to playback of the digital content by execution of the content playback program if the verification of the acquired digital signature is successful, the signature type of the acquired digital signature is the test release type, and the recording medium is judged not to be read-only. an information acquisition unit operable to acquire a content playback program from a recording medium in which the digital content and the content playback program, the content playback program being a computer program to be used for playing back the digital content; characterized in that said information acquisition unit further being operable to acquire a digital signature generated for the content playback program from the recording medium, the digital signature being further recorded on the recording medium, the digital signature having an official release type or a test release type as a signature type, and by a medium type judgment unit operable to judge whether the recording medium is read-only; a signature verification unit operable to perform verification of the digital signature acquired by the information acquisition unit; and a playback permission determination unit operable to: (i) prohibit performing processing relating to playback of the digital content by execution of the content playback program if the verification of the acquired digital signature is unsuccessful; (ii) prohibit performing processing relating to playback of the digital content by execution of the content playback program if the verification of the acquired digital signature is successful, the signature type of the acquired digital signature is the official release type, and the recording medium is judged not to be read-only; and (iii) permit performing the processing relating to playback of the digital content by execution of the content playback program if the verification of the acquired digital signature is successful, the signature type of the acquired digital signature is the test release type, and the recording medium is judged not to be read-only.