Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
2002-03-13
2004-09-07
Peikari, B. James (Department: 2186)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
C711S163000, C711S152000, C713S182000, C713S183000, C713S185000, C713S152000
Reexamination Certificate
active
06789177
ABSTRACT:
BACKGROUND OF THE INVENTION
1) Field of the Invention
Techniques for protecting data from illegal accessing when data of music, videos or the like is transferred between a data recording apparatus for recording data to store it and an access apparatus which accesses the data recording apparatus. The data recording apparatus is, for example, a digital recording and playback apparatus for recording data of music, videos or the like, and the access apparatus is, for example, a personal computer, or a host unit (CPU) in a data recording apparatus.
In recent years, thanks to the improvement in performance of personal computers and the advent of the MPEG2-ISI, it has become easy to handle data of videos and music. Further, it has become possible to acquire a disk of a large capacity of several tens GB (gigabytes)at a moderate price, and also new digital recording and playback apparatus based on a hard disk drive (HDD) or an optical disk drive have appeared.
The key, when it is tried to widely popularize such less expensive data recording apparatus of high performances as described above, is the protection of the copyright of various data (contents) recorded by the data recording apparatus That is, necessary to prevent illegal copying, with high certainty, to guard the rights of the provider of the contents.
Embodiments herein provide techniques by which, when data is transferred between a host unit (access apparatus) and a drive (data recording apparatus), the data can be protected from illegal accessing, thereby protecting the copyright with high certainty and without imposing a burden of processing on the drive recording side.
2) Description of the Related Art
An HDD recorder, a storage-type set top box (STB), or the like, is presently available as a digital recording and playback apparatus presently. For the object of copyright protection, an HDD built in the apparatus is in most cases fixed mechanically so that it may not be removed from the apparatus. In contrast, from a standpoint of a user, there is strong to replace the HDD with a new HDD for a PC (Personal Computer), because HDD capacity has been and is increasing progressively in recent years. The apparatus (the other part than the HDD) may beleft as it is.
This gives rise to a subject of the protection of the copyright upon transfer of data between the host unit and the disk drive (in other words, protection of data from illegal accessing). As a copyright protection method (data protection method) which makes use of the standard interface e.g. ATA/ATAPI (Advances Technologies Attachment/ATA Packet Interface) for a PC, the CPPM (Content Protection for Prerecorded Media) and the CPRM (Content Protection for Recordable Media) are conventionally known.
In the CPRM, an ID (identification information; for example, a media ID of a medium) unique to a drive is set in the drive, and a writing process of writing content data from the host unit onto the disk is performed in accordance with the following procedure [steps (a1) to (a8)].
(a1) A request for transfer of session keys (a plurality of media key blocks, a plurality of secret keys) and a first drive ID (static ID) stored in a ROM area in the drive is issued from the host unit to the drive.
(a2) The session keys and the first drive ID are transferred from the drive to the host unit in accordance with the request in step (a1).
(a3) The session keys and the first drive ID from the drive are stored into a RAM area of the host unit.
(a4) A random number generated on the host unit side is transmitted to the drive, and a request for transfer of a raw second drive ID (dynamic ID) and an encrypted second drive ID is issued from the host unit to the drive.
(a5) The second drive ID is encrypted using the random number from the host unit and a drive key (secret key) written in advance in a hidden area, in accordance with the request in step (a4), and the raw second drive ID and the encrypted second drive ID are transferred from the drive to the host unit.
(a6) A drive key (equivalent) is generated from the session keys and first drive ID which have been stored in step (a3) by the host unit, and the raw second drive ID from the drive is encrypted using the drive key and the random number generated in step (a4). Thereafter, the second drive ID encrypted on the host unit side and the encrypted second drive ID from the drive are compared with each other to discriminate whether or not they are coincident.
(a7) If it is discriminated in step (a6) that the second drive ID encrypted on the host unit side and the encrypted second drive ID from the drive are coincident, then it is discriminated that the drive authentication results in success, and contents data to be written into the drive is encrypted using the contents key and the contents key is encrypted using the session keys and the drive key (equivalent) generated from the first drive ID. Thereafter, the encrypted contents data and the encrypted contents key are transferred from the host unit to the drive and written onto the disk.
(a8) If it is discriminated in step (a6) that the second drive ID encrypted on the host unit side and the encrypted second drive ID from the drive are not coincident, then it is discriminated that the drive authentication results in failure, and the processing is interrupted without transferring the contents data to the drive.
On the other hand, in the case of CPRM, when the contents data written on the disk as described above is read out from the disk to the host unit, after authentication of the drive is performed in accordance with a procedure [steps (a1) to (a6)] similar to the procedure described above, the contents data is read out in accordance with such a procedure [steps (b1) and (b2)] as described below.
(b1) If it is discriminated in step (a6) that the second drive ID encrypted on the host unit side and the encrypted second drive ID from the drive are coincident with each other, then it is discriminated that the drive authentication results in success, and the host unit reads out the encrypted contents key and the encrypted contents data from the drive (disk). Thereafter, the encrypted contents key is decrypted using the drive key (equivalent) generated from the session keys and the first drive ID, and then, the encrypted contents data is decrypted using the decrypted contents key.
(b2) If it is discriminated in step (a6) that the second drive ID encrypted on the host unit side and the encrypted second drive ID from the drive are not coincident, then it is discriminated that the drive authentication results in failure, and the processing is interrupted without reading out the contents data from the disk.
It is to be noted that the CPPM is a copyright protection system only for readout, and in the CPPM, the steps (a1) to (a6), (b1) and (b2) described above are executed.
The drive authentication procedure [steps (a1) to (a6)] described above is called a challenge/response method, and in the CPRM or the CPPM, authentication is executed only on the host unit side. In other words, unidirectional drive authentication is executed, and as a result, a burden of processing on the drive side is reduced.
Further, a contents key and contents data are recorded on a disk based on an ID unique to the drive. Consequently, even if data recorded on the disk of the drive is illegally copied (volume copy) onto another medium, since the ID is not coincident upon data readout, readout of the illegally copied data is impossible. Accordingly, the CPRM and the CPPM are effective for prevention of illegal copying.
As a representative copyright protection method other than the CPRM and the CPPM, the DTCP (Digital Transmission Content Protection) which utilizes the IEEE1394-IF is available. The DTCP assumes data transfer between different apparatuses and is based on mutual authentication. With the DTCP, two methods are available: a full authentication method; and a restrict authentication method. In the full authentication method, an electronic signature algorithm of a public-key/secret-key
Fujitsu Limited
Peikari B. James
Staas & Halsey , LLP
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