Abstract: A contents use right discrimination card corresponding to encrypted contents is sold to a user, who then transmits data recorded on the contents use right discrimination card to a contents use right management center. The contents use right management center then discriminates the contents and the card, based on data of the received contents use right discrimination card, to encrypt the contents key for decoding the contents with, for example, a session key, to transmit the encrypted contents key to the user. The contents use right discrimination card sold to the user can be set for enabling the resale, and can be transferred between different users so that the contents key can be transmitted plural times from the contents use right management center. This enables the contents to be utilized without executing on-line settlement processing.

Abstract: An information recording device includes a control unit and a memory interface unit. An ICV for each sector data of data to be stored in units of sectors is stored in the redundant part of each sector. An ECC and an ICV are stored in the redundant part of each sector, so that sector-unit ICV storage can be performed without reducing the storage capacity of the data part of the sector. processing that combines data parts by using the file system of a device can be performed similarly to conventional data combination processing that only combines data parts in which ones purely used as data are stored. The control unit does not have any load because only each sector which is regarded as valid (no interpolation) as a result of ICV checking is transmitted to the control unit, and the ICV checking is performed by the memory interface unit.

Abstract: In a content delivery system, delivery of a content and charging for the fee of the content are performed and managed in a highly secure and effective fashion. If a content-purchasing request is transmitted from a user device to a shop server, a charging process is performed. If the charging process is successfully completed, the shop server transmits, to the user device, an encrypted content key in a form which can be decrypted by a key stored in the user device. A user device authentication server, which manages content delivery, converts an encrypted content key KpDAS(Kc) encrypted using a public key of the user device authentication server (DAS) into an encrypted content key KpDEV(Kc) encrypted using a public key KpDEV of the user device. Provided that the charging process has been successfully completed in response to the content-purchasing request, the shop server transmits the key-converted content key to the user device.

Abstract: A data processing device includes a memory interface (I/F) unit and a control unit. When accessing a data storage device such as a memory card having a built-in flash memory, the data processing device sets a block permission table (BPT) as an access permission table in the memory I/F unit, whereby only when the BPT permits a process to be executed does the memory I/F unit access the storage device, and the memory I/F unit does not execute a process when it is out of an allowable range. Regardless of a process type performed by the control unit and a command type, the memory I/F unit always accesses the storage device in accordance with the BPT set in the memory I/F unit. This effectively prevents the rewriting of data in rewrite-prevented recording media.

Abstract: Between a data recording/playback device and a data storage device, CBC-mode encryption processing is executed which encrypts a plurality of encryption keys of content which correspond to sectors. The encrypted data is stored in a header corresponding to the content. The CBC-mode encryption processing is executed by using a storage key unique to media in which the content is stored. For using the content, only by decrypting the key data in media in which mutual authentication is established, the content can be used, so that highly-secure key storage is implemented.