A portable device uses a microphone to listen to ambient audio, ascertains a corresponding identifier, and uses the identifier to enable one or more further functions. One of these can be internet search. Such functionality can also be based on digital datawithout requiring a microphone-equipped device.

An information processing device includes: a data processing unit that executes a process of reproducing content recorded in a medium; and a memory storing a content revocation list in which an identifier (ID) of revoked content is recorded, wherein the data processing unit compares a minimum allowable version of a content revocation list recorded in a token which is management data corresponding to content recorded in the medium with a version of a content revocation list acquired from the memory, and when the version of the content revocation list acquired from the memory is an old version lower than the minimum allowable version of the content revocation list recorded in the token, the data processing unit halts determination on revocation of content based on the content revocation list acquired from the memory and reproduction of content.

There is provided a method for use by a media player to provide access to a media content. The method comprises receiving a request from a user for playing the media content, prompting a user for an authorization code, receiving the authorization code from the user, transmitting the authorization code to an authentication server over a network, receiving a valid authentication message from the authentication server over the network if the authorization code is confirmed to be valid, transmitting the valid authentication message to a content server over the network, retrieving the media content from the content server over the network, wherein the media content incorporates an identification information associating the media content with the user.

When the terminal device attempts to use a special content, which has an attribute including information distinguishing the special content from regular contents and which is stored in the recording medium device, the recording medium device refers to the revocation information indicating terminal devices restricted from using the special content. When the recording medium device determines the terminal device as a terminal device to be restricted from using the special content based on the terminal identifying information of the terminal device, the usage information output unit of the recording medium device does not transmit the necessary information for using the special content to the terminal device.