Recording/reproducing system, recording medium device, and recording/reproducing device

Abstract

A memory card and a recording/playback device are provided that are capable of deterring a memory card manufacturer from illicitly storing a same media ID on a plurality of memory cards. A memory card () includes a media ID storage module unit () and a memory unit (). The media ID storage module unit () includes a media ID storage unit () that stores therein a media ID that is specific to the memory card, and a certification unit () that generates certification information that certifies the validity of the memory card based on the media ID. The memory unit () includes an encrypted content storage unit () for storing encrypted digital content. The recording/playback device () includes a memory card verification unit () that acquires the certification information from the memory card (), verifies the validity of the memory card () based on the acquired certification information, and when the verification has failed, prohibits decrypting an encrypted content or encrypting a content, and a content encryption unit () that, when the verification has succeeded, encrypts the digital content or decrypts the encrypted digital content.