JP2008159221A - Optical disk recording device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk drive and optical disk recording method rewriting the key information on the optical disk by the defect management information without lowering the security level. <P>SOLUTION: This optical disk drive has a recording section to record information on an optical disk which has the key information already recorded, a measuring means 20 to measure the recording quality of a first recording area 51 having the optical disk key information by using the reproduced signals, and a controller to control the recording section to delete the key information in the first recording area 51 and to record the key information on a second recording area 52 if the measured recording quality of the first recording area 51 is lower than predetermined level when updating the key information. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus and an optical disc recording method for rewriting key information on an optical disc into another recording area based on defect management information.

  In recent years, various types of optical discs have been developed, manufactured and spread. In such an optical disk, a defect management information technique for performing reliable information recording processing by detecting a defective storage area in advance, preparing a replacement area, and recording information in the replacement area is known. It has been.

In Patent Document 1, the defect management information in the defect management area is recorded in the next spare area while it is still considered to be sufficiently rewritable on the information recording medium, and the transition of the defect management information to the last spare area is completed. A technique is disclosed that uses a plurality of loop-shaped or ring-shaped defect management areas in such a manner as to return to the initial defect management area at a later time.
JP 2006-185509 A.

  However, in the prior art of Patent Document 1, there is no special description of how to perform rewrite processing using the defect management information described above for key information for protecting content and the like. Therefore, if the rewriting process using the normal defect management information is performed, the key information remains in the previous area when the recording of the key information is shifted to the alternative area. There is a problem that information increases and security decreases.

  An object of the present invention is to provide an optical disc apparatus and an optical disc recording method in which key information on an optical disc is rewritten with defect management information without lowering security.

One embodiment for solving the problems of the present invention is as follows.
A recording unit (11) for recording information on an optical disc on which key information is recorded;
A measuring unit (20) for measuring the recording quality of the first storage area (51) in which the key information of the optical disc is recorded, based on a reproduction signal;
When updating the key information, if the recording quality of the first storage area (51) measured by the measurement unit is less than or equal to a predetermined value, the key information in the first storage area (51) is deleted. And an optical disc apparatus comprising: a control unit (11, 14) for controlling the recording unit to record the key information in a second storage area (52).

  When the recording quality of the area in which the key information is recorded decreases, the key information in the next storage area is recorded after the key information in the previous storage area is completely deleted, so the key information is rewritten by the defect management information. Since information does not increase, security is not reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Outline of one embodiment according to the present invention>
First, an outline of an embodiment according to the present invention will be described. RW media has a limited number of rewrites, and it is necessary for the host to manage defects. However, it is effective to manage defects in advance by grasping the situation of the recording location and recording in the alternative location as soon as the number of defects increases. Is. A TKF (Title Key File) used in AACS which is one of copy protection methods must be updated without leaving the previous information. When the TKF file is updated by the conventional RW method, the update is successful if there is a defect in the previously recorded location, but the TKF data remains in the previously recorded location. End up. In order to solve this problem, when updating the TKF file, before the recording is performed in the alternative location, a process for forcibly writing the location where the original TKF data was recorded with a predetermined value is performed.

<Optical Disc Device According to an Embodiment of the Present Invention>
(Constitution)
Next, an example of an optical disc apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an example of the configuration of an optical disc apparatus according to an embodiment of the present invention. As shown in FIG. 1, the optical disc apparatus 10 according to an embodiment of the present invention is a recording / reproducing apparatus for HD DVD-RW as an example, but is not limited thereto. As shown in FIG. 1, the optical disc apparatus 10 includes a CPU 11 that controls the entire control, a video data input unit 12 that is connected to the CPU 11 via a cable and inputs video data to the apparatus, and outputs video data from the apparatus to the outside. Video data input unit 12-2 to be performed, file system unit 13 for writing / reading video data and management data as files, and defect management for performing defect management of recording media on the host side under the control of file system unit 13 Unit 14, encryption unit 15 that encrypts content, decryption unit 15-2 that decrypts encrypted content, and TKF management unit 16 that generates and manages TKF (Title Key File) that is key information. Have.

  Further, the optical disc apparatus 10 has a drive unit 17 as shown in FIG. 1, and the drive unit 17 has a writing function for recording data on the optical disc D and a reading function for reading data from the recording medium. In addition, as a method for measuring the recording unit quality of the header 19 controlled by this and the optical disc D, PI errors are measured and stored in a table as necessary, and the number of PI errors at a specified location is inquired. A PI error measurement unit 20 that returns the value is provided.

(Alternative processing and encryption / decryption processing using defect management information)
Next, a key information rewriting process using defect management information which is an embodiment of the optical disc apparatus 10 according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 is an explanatory diagram showing an example of defect management information handled by the optical disc apparatus according to the embodiment of the present invention. FIG. 3 is an explanatory diagram showing an example of an alternative process using defect management information in the optical disc apparatus according to the embodiment of the present invention.

Replacement process using defect management information First, a replacement process using general defect management information will be described with reference to FIGS.

  In FIG. 2, in the volume area 101 of the management area of the optical disk D, four locations are prepared as defect management area candidates 102 as one piece of volume information. In FIG. 2, the initial state of the defect management information K is recorded in the second candidate location. The defect management information K includes an alternative location B and a defect management table T that associates recording locations with alternative locations. In this example, the defect management table T and the alternative location B are written adjacent to each other, but it is also preferable that the defect management table candidate and the alternative location B candidate do not exist in consecutive locations.

  Here, in the optical disc apparatus 10 according to an embodiment of the present invention, as shown in FIG. 3, in the management of the file system unit 13, when information is recorded in the area A, the defect management unit 14 performs defect management information defect. It is confirmed whether or not the area A is registered in the management table T. If not registered, recording is performed directly on the area A.

  However, if the area A is registered in the defect management table of the defect management information, recording is attempted to the replacement destination, here the replacement destination C2. However, if the replacement destination C2 has many defects, the result is NG, and then the replacement destination C3 is selected. If the replacement destination C3 also has many defects, it becomes NG again and is recorded in the replacement destination C4.

Content Encryption / Decryption Processing Using Title Key Next, an example of content information encryption / decryption processing using the TKF management unit 16, the encryption unit 15, and the decryption unit 15-2 will be described. When the content information is recorded on the optical disc D or the like, the optical disc apparatus 10 encrypts the content information using a TKF (Title Key File) that stores a title key that is key information corresponding to the title of the content. Is recorded.

  The encryption / decryption method using the title key of the content information can increase the security by further encrypting and decrypting by using a device key unique to the optical disc apparatus, a media key unique to the optical disc, and the like in as much a procedure as possible. Techniques are described in many documents.

  However, here, an example of content encryption / decryption processing using a title key is given as the most basic method, but more complicated encryption / decryption methods are also shown in the embodiments of the present invention described later. As long as processing operations are used, it is within the scope of the present disclosure.

  That is, the TKF management unit 16 records content information, which is a video / audio signal supplied from the video data input unit 12 or the like, on an optical disc D such as an HD DVD (High Definition Digital Versatile Disc) under the control of the CPU 11. In this case, a title key that is key information corresponding to the title of the content information is generated.

  Next, the encryption unit 15 encrypts content information, which is a video / audio signal supplied from the video data input unit 12 or the like, using this title key, and under the control of the CPU 11, the file system unit 13 and the header driver. The title key which is the encrypted content information and the key information is recorded in the storage area of the optical disc D by the 18 and the header portion 19.

  Further, under the control of the CPU 11, the file system unit 13, the header driver 18, and the header unit 19 transfer the recorded encrypted content information and the title key, which is key information, to the optical disc D under the control of the CPU 11. Read from storage area. Then, the decryption unit 15-2 decrypts the read encrypted content information based on the title key, and outputs the content information. The video / audio data and the like are reproduced by the video data output unit 12-2 and supplied to a PC (Personal Computer) not shown.

(Alternative processing using defect management information of key information)
Next, an alternative process using the defect management information of key information according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 4 is an explanatory diagram showing an example of a key information rewriting process using defect management information that does not have the characteristics of the embodiment of the present invention.

  First, an example of a key information rewriting process using defect management information that does not have the characteristics of one embodiment of the present invention will be described with reference to FIG. In other words, in the drive unit 17 in FIG. 4, the title key file (TKF) supplied from the TKF management unit 16 in FIG. 1 is data necessary for reproducing the title of the recorded video data. VN) is recorded on the disc together with the data (steps S21 and S23).

  First, VN data is set in the drive unit 17 prior to recording. Thereafter, TKF is recorded in the recording area 51. However, the original location is generally overwritten unless it is newly recorded. The PI error measurement unit 20 is a table that manages the number of PI errors in each storage area in order to measure the recording quality of the storage area. The PI error measurement unit 20 records PI error information of a place where the read access has been performed before or a place where the read cache buffer has been stored without direct reading.

  This method is used in DRT-DM (Distributed Real Time Defect Management) or the like, and the number of PI errors in the storage area to which TKF is written back is checked (step S24). If the number of errors is not large (steps S27 and S28), the title key and file data are overwritten as they are in the first storage area 51 and updated and recorded.

  However, the number of PI errors in the storage area to which the TKF is written back is checked (step S24). If there are many PI errors (step S25), the result is NG (step S26), and this error information is acquired by the defect management unit 14. The content is not recorded. If an error occurs, the file system unit 13 tries to record in the alternative storage area 52 (step S30). In this case as well, the number of PI errors is similarly checked, and recording processing or resubstitution is performed. If a recording error occurs and replacement occurs even once, TKF data will be recorded in two or more locations (here, the first storage area 51 and the second storage area 52), and security has been reduced accordingly. It is a problem.

TKF Rewriting Process with TKF Deletion Process In order to solve such a problem, a TKF rewriting process with a TKF deletion process according to an embodiment of the present invention will be described with reference to the flowchart of FIG. FIG. 5 is a flowchart showing an example of the TKF update process of the optical disc apparatus according to the embodiment of the present invention. FIG. 6 is an explanatory diagram showing an example of a key information rewriting process using defect management information.

  Note that each step of the flowchart of FIG. 5 below can be replaced with a circuit block, and therefore all the steps of the flowchart of FIG. 5 can be redefined as a block.

  In the optical disk apparatus according to the embodiment of the present invention, as shown in the flowchart at the time of TKF update in FIG. 5, first, the TKF data before update is recorded by the PI error measurement unit 20 with the title key as key information. The PI error in the stored storage area 51 is measured (step S11).

  Then, when the measured number of PI errors is compared with a predetermined threshold value and is smaller than the threshold value, that is, when the recording quality is high quality (step S12), the pre-update data is recorded as the updated title key information. The stored storage area 51 is overwritten (step S16).

However, if the defect management unit 14 determines that the measured number of PI errors is greater than a predetermined threshold based on information from the PI error measurement unit 20, the defect management unit 14 stores the CPU 11 and the file system unit 13. Based on the defect management information K to be performed, the title key information, which is the key information stored in the first storage area 51, is padded with ALL0 and written (step S13). Then, the CPU 11 and the file system unit 13 record the title key, which is updated key information, in the storage area 52 serving as an alternative location based on the defect management information K stored in the defect management unit 14 (step S14). Thereafter, the defect management unit 14 updates the defect management table T and associates the TKF with a new recording location (step S15).
By taking such a procedure, even when the title key or the like as the key information is rewritten to a new area based on the defect management information, the title key or the like as the key information of the original storage area is completely deleted. Therefore, the key information does not increase and the security does not decrease.

  Furthermore, a TKF rewriting process accompanied by a TKF deletion process of the optical disc apparatus 10 according to an embodiment of the present invention will be described with reference to FIG.

  In FIG. 6, the optical disk apparatus 10 according to an embodiment of the present invention first sets VN data on the drive unit 17 side before TKF recording (step S41). Thereafter, the TKF is recorded, but is generally overwritten in the original place except when it is newly recorded.

  The PI error measurement unit 20 is a table that manages the PI error status of a specified location, but records PI error information of a location that has been previously read-accessed or a location that is stored in the read cache buffer without direct reading. Has been.

  The number of PI errors at the location where the TKF is written back is checked. If the number of errors is not large (step S50), the first storage area 51 is overwritten and the file is updated.

  However, if there are many PI errors (step S46), an error occurs and recording is not performed. Up to this point, the processing is the same as in the case of FIG. Next, the file system unit 13 receives a TKF file recording error, temporarily stops the PI error management unit (DRT-MD), and sets the original TKF data recording location 51 to a specific value (for example, all 0). Padding is performed with data (step S48). Thereafter, after PI error management is activated again, the file system tries to record in the alternative storage area 52 (step S53). In this case as well, the number of PI errors is checked in the same manner, and recording or resubstitution is performed. Even if there are many PI errors due to resubstitution, TKF data is not recorded in two or more locations.

(Other embodiments)
As another embodiment, the following procedure is also suitable. In other words, the initialization of the optical disc usually only initializes the management information, so that the file content itself remains, although it does not exist as a file. If used as it is, there is a possibility that a new TKF may be recorded in another place while the contents of the previous TKF remain. Therefore, when the disk is initialized, the TKF file is first erased by clearing it to 0 or the like. In addition, by performing initialization of the management information in the conventional initialization, it is possible to prevent a decrease in security in the same manner by preventing the TKF history from remaining.

  As described above in detail, in the above embodiment, when the number of PI errors in the first recording area 51 is large at the time of updating the TKF data, the TKF data before the update remains in the first recording area 51. The updated key information is prevented from being recorded in the next recording area 52 as it is. That is, if TKF data before update remains in the first recording area 51, it may be analyzed and used for unauthorized copying, resulting in a decrease in security.

  In the key information update process using the defect management information according to the embodiment of the present invention, it is possible to prevent a decrease in security by deleting the TKF data before the update of the first recording area 51 by the padding process or the like. For example, an AACS TKF file can be updated even on an RW disk whose defect is managed by the host side.

  With the various embodiments described above, those skilled in the art can realize the present invention. However, it is easy for those skilled in the art to come up with various modifications of these embodiments, and have the inventive ability. It is possible to apply to various embodiments at least. Therefore, the present invention covers a wide range consistent with the disclosed principle and novel features, and is not limited to the above-described embodiments.

1 is a block diagram showing an example of the configuration of an optical disc device according to an embodiment of the present invention. Explanatory drawing which shows an example of the defect management information which the optical disc device concerning one Embodiment of this invention handles. Explanatory drawing which shows an example of the alternative process using the defect management information in the optical disc apparatus which concerns on one Embodiment of this invention. Explanatory drawing which shows an example of the rewriting process of the key information using the defect management information which does not have the characteristic of one Embodiment of this invention. 6 is a flowchart showing an example of TKF update processing of the optical disc apparatus according to the embodiment of the present invention. Explanatory drawing which shows an example of the rewriting process of the key information using the defect management information in the optical disc device which concerns on one Embodiment of this invention.

Explanation of symbols

  D ... Optical disk, 11 ... CPU, 12 ... Video data input unit, 12-2 ... Video data output unit, 13 ... File system unit, 14 ... Defect management unit, 15 ... Encryption unit, 15-2 ... Decryption unit, 16 TKF management unit, 17 drive unit, 18 header driver unit, 19 header unit, 20 PI error measurement unit.

Claims (8)

A recording unit for recording information on an optical disc on which key information is recorded;
A measurement unit for measuring the recording quality of the first storage area in which the key information of the optical disc is recorded, based on a reproduction signal;
When updating the key information, if the recording quality of the first storage area measured by the measurement unit is less than or equal to a predetermined value, the key information in the first storage area is deleted and the second storage area is deleted. A control unit for controlling the recording unit to record the key information;
An optical disc apparatus comprising:   When updating the key information, if the recording quality of the first storage area measured by the measurement unit is less than or equal to a predetermined value, the key information is deleted by padding the first storage area. 2. The optical disk apparatus according to claim 1, wherein An encryption unit for encrypting content information based on the key information;
2. The optical disc apparatus according to claim 1, wherein the control unit records the content information encrypted by the key information in a storage area of the optical disc, and simultaneously updates the key information recorded on the optical disc. .   A defect management unit for managing defect management information in a storage area of the optical disc; and the controller updates the defect management information when the key information is recorded in the second storage area. 2. The optical disk apparatus according to claim 1, wherein Measuring the recording quality of the first storage area of the optical disk in which the key information is recorded in the first storage area, based on the reproduction signal;
When updating the key information, if the recording quality of the first storage area is less than or equal to a predetermined value, the key information in the first storage area is deleted and the key information is recorded in the second storage area An optical disc recording method.   6. When updating the key information, if the recording quality of the first storage area is equal to or less than a predetermined value, the key information is deleted by padding the first storage area. The optical disc recording method described. Content information is encrypted based on the key information;
6. The optical disc recording method according to claim 5, wherein the content information encrypted with the key information is recorded in a storage area of the optical disc, and at the same time, the key information recorded on the optical disc is updated.   6. The defect management information relating to the first storage area is updated when the key information recorded in the first storage area is deleted and recorded in the second storage area. Optical disc recording method.

Images