Processing device and associated methodology for authorized device certificate updating

A configuration for preventing authentication processing due to continuous use of an old authorized device certificate, and illegal use of contents is provided. An arrangement is made wherein with playback or recording processing of contents accompanying data transfer between two different devices such as a drive and a host or the like, when performing mutual authentication between devices for executing data transfer, the number of times of authentication is counted, and in the event of this reaching a predetermined upper limit value of the number of times of authentication, authentication processing is cancelled, and it is necessary to update a certificate to be applied to authentication. The present configuration eliminates contents use due to continuity of authentication processing to which an old certificate is applied, and enables prompting a user to obtain the newest certificate.