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.

A digital information recording apparatus includes a recording circuit for recording information of a retention period included in the digital information and indicating a period for permitting the digital information to be held in the recording medium, starting with a time at which the digital information is recorded on the recording medium; and information of a playback permission period included in the digital information and indicating a period for permitting the digital information to be played back starting with a time at which the information is reproduced initially following recording of the digital information on the recording medium, permitting temporary recording or copying for the information permitted for copy never or copy one generation.

A method of detecting whether data in a tape drive used in a file system is tampered is described according to one embodiment. The method includes the steps of: (a) preparing a first tape cartridge including a tape on which multiple files and archival records of index information are stored in a WORM partition, and index information is stored in the R/W partition; (b) reading and comparing the index information of the R/W partition and the last index information of the WORM partition; and (c) when these two pieces of index information do not match, determining that the index information of the R/W partition is tampered in case these two pieces of index information do not match.