Abstract: A content management system including a content management server and a client terminal connected to the content management server via a communication network, wherein the content management server transmits, to the client terminal, a management server ID identifying the content management server and a content deletion request, the client terminal receives the management server ID and the content deletion request from the content management server, determines whether or not the received management server ID matches a management server ID saved on the client terminal side, and if they match, deletes the content saved on the client terminal side, in a removable media, the content corresponding to the deletion request. A content, that is saved in various forms on the client terminal side is disabled for playback at an appropriate timing; accordingly, it is possible to reduce risks such as information leakage to ensure security, and also ensure content integrity.

Abstract: A system includes a content playback apparatus, a removable media reading apparatus 20 that is provided with a nonvolatile memory 22m in which first viewing restriction information is stored, and that is detachably attached to the content playback apparatus, and a removable media in which second viewing restriction information is stored, and the removable media being detachably attached to the removable media reading apparatus, and the content playback apparatus checks the first viewing restriction information against the second viewing restriction information, and if the first viewing restriction information satisfies a condition of the second viewing restriction information, removes a playback restriction on a content stored in the removable media in a state of being restricted for playback. It is possible to restrict viewers of the content to specific target persons, and also to reduce the risk of tampering of the viewing restriction information, and increase security in content management.

Abstract: A system includes a content playback apparatus, a removable media reading apparatus 20 that is provided with a nonvolatile memory 22m in which first viewing restriction information is stored, and that is detachably attached to the content playback apparatus, and a removable media in which second viewing restriction information is stored, and the removable media being detachably attached to the removable media reading apparatus, and the content playback apparatus checks the first viewing restriction information against the second viewing restriction information, and if the first viewing restriction information satisfies a condition of the second viewing restriction information, removes a playback restriction on a content stored in the removable media in a state of being restricted for playback. It is possible to restrict viewers of the content to specific target persons, and also to reduce the risk of tampering of the viewing restriction information, and increase security in content management.

Abstract: A content management system including a content management server and a client terminal connected to the content management server via a communication network, wherein the content management server transmits, to the client terminal, a management server ID identifying the content management server and a content deletion request, the client terminal receives the management server ID and the content deletion request from the content management server, determines whether or not the received management server ID matches a management server ID saved on the client terminal side, and if they match, deletes the content saved on the client terminal side, in a removable media, the content corresponding to the deletion request. A content, that is saved in various forms on the client terminal side is disabled for playback at an appropriate timing; accordingly, it is possible to reduce risks such as information leakage to ensure security, and also ensure content integrity.