Patent ID: 8370647

Claim:
A content recording playback processing apparatus comprising: a memory configured to store an apparatus-unique key, the apparatus-unique key being a key that is unique to the content recording playback processing apparatus; an input section configured to input user operation information; a communication section configured to perform data reception processing; a data processor configured to execute validity determination processing for the apparatus-unique key; and an output section configured to input a result of the validity determination processing executed by the data processor, wherein the data processor is further configured to: receive, via the communication section, key-validity determination data for determining whether the apparatus-unique key is valid or invalid, execute the apparatus-unique-key validity determination processing by using the key-validity determination data in response to a user instruction input via the input section, and output a result of the validity determination processing to the output section, wherein: the apparatus-unique key comprises a device key configured to obtain a media key from a media key block in which the media key is stored, the media key configured for cryptography processing during playback of content from a medium or during recording of content to the medium: the key-validity determination data comprises the media key block, wherein the media key block is configured to have a structure that permits a valid media key to be obtained only when a valid device key is used; and the data processor is configured to execute processing on the media key block by using the device key stored in the memory in the content recording playback processing apparatus and to perform validity determination on the device key at least in part based on processing for checking whether or not a valid media key is obtained.