JP2004213748A - Optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk drive which can prevent furtive look of data by a malicious third party by making protection of data reliable even if the the user of a disk loses the disk or has the disk stolen, etc. <P>SOLUTION: In this optical disk drive, the data area of the disk is divided into block units, and addresses are imparted to the respective block units. The disk write is performed to the divided blocks on the basis of a write request from an external device. The drive is provided with: a memory means for holding a discrimination ID intrinsic to an optical disk drive; and a data shift write means which acquires the discrimination ID from the memory means when write request is transmitted from the external device, shifts the address of a block of a disk to be accessed on the basis of the discrimination ID, and writes data starting from the shifted position. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk device, and more particularly, to an optical disk device that can protect data in a disk and prevent a malicious third party from reading the data.
[0002]
[Prior art]
In recent years, CD-type optical discs such as CD-ROMs (Compact Disc-Read Only Memory), CD-Rs (Recordable), and CD-RWs (ReWritable) have become widespread, and furthermore, DVDs (Digital Versatile Discs or Digital Video Discs). Disc media such as DVD-ROM, DVD + RW, DVD-R, and DVD-RAM have also been developed as discs of the type).
[0003]
As described above, various discs exist, but information in a CD is roughly divided into music and data. For example, the recording format of a music CD is defined by a standard called Red Book, and a physical block of a music CD is composed of 2532 bytes, and when reproduced, 75 blocks are read per second. (1 frame = 2352 bytes = 1/75 second) (see FIG. 7A). On the other hand, since errors are not allowed in data and computer programs unlike music CDs, in the Yellow Book, one block is 2352 bytes as it is, and synchronization data (A), header (B), subheader (C) errors A redundant part of a detection code (EDC: Error Detection Code) and an ECC (Error Correction Code) are secured, and the data part is defined as 2048 bytes (see FIG. 7B).
[0004]
As described above, in the physical format of the CD, the format is different for music and data. The logical format of the CD (= the file structure of ISO9660) has a file structure such as “root directory → directory → file”, and is referred to as “volume descriptor” (VD = Volume Descriptor). Structure that contains descriptive information. " The VD includes PVD (Primary Volume Descriptor = primary volume descriptor), SVD (Supplementary Volume Descriptor = secondary volume descriptor), VPD (Volume Partition Descriptor = volume partition descriptor), and the like. Number) is determined. Among them, the PVD describes the attributes of the volume, the position of the root directory, the position of the path table, and the like. The position on the disk is set in the 17th frame (logical sector number 16) of the first track. It is stipulated that it must be done.
[0005]
FIG. 8 is an explanatory diagram of the relationship between the sectors of the optical disc and the logical block length and the path table based on ISO9660. As shown in the figure, logical sectors 0 to 15 are used as a system area, and a path table is recorded after logical sector 16 of the optical disk. This path table records the recording position of the file recorded on the optical disc, the size of the file, the logical block length, and the like. After logical sector k, data of 2048 bytes (also referred to as one sector) of one logical block continues in sector m, sector m + 1, and so on. In an ordinary optical disk drive, the path table is read into its own semiconductor memory so that a target position can be reached by one access operation. That is, the path table is indispensable for reading the file from the disk at high speed.
[0006]
[Problems to be solved by the invention]
Recently, the number of personal computers equipped with a disk drive device using an optical disk such as a CD as described above has been increasing as a standard, so that technological advances have made it easier for beginners to use the device, and the recording media has become cheaper. As a result, opportunities for general users to handle media such as CDs and DVDs are increasing. On the other hand, in the unlikely event that an optical disk is lost or stolen, the demand for protecting data to prevent leakage of important information has increased dramatically.
[0007]
Generally, in order to protect the reading of data written on a CD from a malicious third party, a method of protecting data on an application or the OS side (for example, setting a password in a spreadsheet application, etc.) is used. However, such a protection method cannot protect a simple text file or an HTML file. For this reason, if a malicious third party finds the disk, it becomes possible to easily read the data, and there is a security problem that the data recorded on the disk is not protected. Was.
[0008]
The present invention has been made in view of the above-described problems, and has as its object to ensure the protection of data even in the unlikely event that a user loses or stolen a disk, An object of the present invention is to provide an optical disk device that can prevent data from being stolen by a malicious third party.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention divides a data area of a disk into blocks and writes data to a disk to which an address is assigned to the divided block. In an optical disk drive that performs based on a write request from a device, a memory unit that holds an identification ID unique to the own optical disk device, and when there is a write request from the external device, acquires the identification ID from the memory unit. Data moving writing means for shifting an address for a block of a disk to be accessed based on the identification ID and writing data from the shifted position.
[0010]
According to a second aspect of the present invention, in the optical disk device, the identification ID is represented by n bits, and the data moving / writing unit regards a first n block in a data area as n bits of the identification ID, Data writing means for writing data by shifting a block corresponding to a position where the bit value is High in the n bits to the block after the n-th block, and a predetermined bit for the shifted block And dummy bit inserting means for inserting a value.
[0011]
Further, according to a third aspect of the present invention, there is provided an optical disk apparatus which divides a data area of a disk into blocks and writes the divided blocks to a disk to which an address is assigned based on a write request from an external device. And a memory means for holding an identification ID unique to the optical disk device, and when a write request is issued from the external device, the identification ID is obtained from the memory means, and a corresponding block or the like is obtained based on the identification ID. And a swap writing means for writing data by swapping to a corresponding position in the area.
[0012]
According to a fourth aspect of the present invention, in the optical disk device, the identification ID is represented by n bits, and the swap writing unit determines a position where a bit value is High among the n bits of the identification ID. And a next area swap writing means for writing data by swapping a block corresponding to the next area to a corresponding position in the next area.
[0013]
According to a fifth aspect of the present invention, in the optical disk device, the identification ID is a unique number given to the optical disk device or an arbitrary number specified in advance.
[0014]
According to a sixth aspect of the present invention, in the optical disk device, the identification ID is transferred from a host computer serving as the external device.
[0015]
According to the configuration of the present invention, when writing data to the disk, the data is written by shifting the address of the data area based on the unique number given to the optical disk device, so that the file can be recognized on the OS. Is gone and the disc is protected. Since data can only be unlocked by the drive that wrote the data, it is almost impossible to read the data even if a malicious third party picks up the protected disk as described above. . Therefore, a highly confidential disk can be provided to the user.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a configuration diagram of an optical disk device according to an embodiment of the present invention. In FIG. 1, an optical disk device (hereinafter abbreviated as a drive) is a rewritable optical disk device such as a CD-R or a CD-RW, and an optical disk (hereinafter abbreviated as a disk) 1, an optical pickup 2, and a spindle motor 3. , Spindle motor (SPM) driver 4, laser driver 5, encoder 6, buffer 7, interface circuit (I / F) 8, APC (Auto Power Control) 9, servo processor 10, system controller (= CPU) 11, memory 12 Consists of A host computer 21 is connected to the interface circuit 8 of the drive according to the present invention as an external connection destination. The drive records data on the disk 1 on which information can be written according to a command from the host computer 21. / Play. FIG. 1 shows only a part related to data write processing in the drive according to the present invention.
[0018]
In FIG. 1, a disk 1 is mounted on a turntable, and is rotated at a constant linear velocity (CLV) or a constant angular velocity (CAV) by a spindle motor 3 during a recording / reproducing operation. Then, pit data on the disk 1 is read by the optical pickup 2. The servo processor 10 generates various servo drive signals for focus, tracking, sled, and spindle from a focus error signal FE, a tracking error signal TE, and the like from an RF amplifier (not shown), and executes a servo operation. The servo processor 10 further supplies the spindle motor driver 4 with a spindle drive signal generated according to the spindle error signal. The spindle motor driver 4 causes the spindle motor to execute CLV rotation or CAV rotation according to the spindle drive signal. The APC 9 is a circuit unit that controls the laser output so as to be constant regardless of the temperature or the like. The buffer 7 has a predetermined data capacity and temporarily stores data supplied from the host computer 21. The buffer 7 is, for example, a FIFO method. In this case, the data is read by the encoder 6 in the order in which the data is supplied from the I / F 8 and stored. The encoder 6 EFM-modulates the data supplied from the buffer 7 together with a subcode or the like according to a predetermined standard, and supplies an EFM signal to the laser driver 5. The CPU 11 is connected to the I / F 8 by a signal line including a data bus and a control line, and is connected to a buffer by a data bus. For the I / F 8, for example, a SCSI specification is used. As the host computer 21, for example, a general personal computer can be used.
[0019]
Next, a data write operation in the drive configured as described above will be described. FIG. 2 is a diagram for explaining a write operation in the drive. In this example, it is assumed that the drive's memory 12 (ROM, EPROM, flash memory, or the like) stores a unique number of the drive, for example, information on a serial number as an identification ID. For example, assuming that the drive serial number is defined as 32 bits (approximately 4.2 billion ways), in this embodiment, when the drive writes data to a CD, first, the first 32 blocks of the data area are regarded as 32 bits of the serial number. . For example, when the serial number is “4” in decimal (decimal), the last three digits of the binary number of the serial number represented by 32 bits are “100”. In the case of this example, since the position where the bit stands in the production number information is only one of the 30th bit, the 30th block opposite to the position of the 30th bit of the production number information is the 33rd block which is the head of the rear block. Go to the eyes,
The information of the 30th block is written in the 33rd block as the movement destination. Dummy bits, for example, all “1” or “0” are inserted in the moved 30 blocks.
[0020]
As described above, in the present embodiment, the block corresponding to the position where the bit of the serial number is set is shifted and written to the 33rd block and the subsequent blocks.
For this reason, even if a malicious third party finds the disk written in this way and tries to read the data, the desired data is moved to the directory location indicated on the path table. Therefore, it is almost impossible to read the written data because the OS cannot recognize the file. Further, in the present embodiment, since the position of the data is merely moved, the written data can be strongly protected without violating the CD or DVD standards.
[0021]
Next, details of the write operation in the drive will be described with reference to the flowchart of FIG. In describing this flowchart, the hardware configuration in FIG. 1 will be referred to as appropriate.
[0022]
In FIG. 3, upon receiving a data write command from the host computer 21, the CPU 11 of the drive receives a drive-specific number stored in the memory 12 (in this example, it is assumed that the serial number information is managed in 32 bits). Is obtained (S1). Thereafter, the data sent from the host computer 21 is temporarily stored in the buffer 7 in block units. The CPU 11 recognizes from the previously acquired serial number information which bit is located in the serial number represented by 32 bits, and among the first 32 blocks stored in the buffer 7, The position of the block opposite to the standing position is moved to the rear 33rd block or later (S2). The movement position of the block thus moved is stored in the memory 12 as movement information (new address information) (S3). FIG. 4 is a diagram showing an example of movement information stored in the memory 12. In this example, the bits of the serial number stand at 10, 15, 18, and 22 blocks, and the blocks corresponding to these bits are 33, 34. , 35, 36 blocks.
[0023]
Referring back to FIG. 3, after the movement of the blocks in the buffer 7 is completed as described above, the data output from the buffer 7 is subjected to an encoding process by the encoder 6, and then written to the disk (S4). It has become.
[0024]
The data protected in this way cannot be read unless the protection is released. FIG. 5 is a flowchart showing a processing procedure when reading the protected data.
[0025]
In FIG. 5, when the CPU 11 of the drive receives a data read command from the host computer 21 (S11), it acquires movement information of the block stored in the memory 12 (S12). The CPU 11 recognizes which block has moved to which block from the movement information of this block, and based on the block that has been moved to the subsequent block at the time of data writing, of the blocks accumulated in the buffer 7 at the time of data reading. A process of returning to the position of the preceding block is performed (S13). Then, after rearranging the positions of the blocks in the buffer 7 to the original positions, those data are read and decoded by a decoder (not shown) (S14).
[0026]
As described above, according to the present embodiment, when writing data in the drive, the position of the block associated with the unique number given to the drive is moved backward to write the data. Even if three parties find the disk written in this way and try to read the data, the expected data has been moved to the directory location indicated on the path table, so the file is not The data cannot be read because it cannot be recognized. Further, in the present embodiment, since the position of the data is merely moved, it is possible to protect the written data without violating the standard of CD or DVD. Also, since one unique number is given to one drive, data cannot be read correctly even with drives of the same model. In addition, the unique number may be a drive serial number, or a number separately determined by the user may be transferred from the host computer 21 and stored in the memory 12. It is not done. Furthermore, according to this embodiment, it is almost impossible for a general user to change or modify the firmware of the drive, and since the disk itself is protected, protection is performed by a commonly used application. It is possible to make it more confidential than the method.
[0027]
In the above-described embodiment, the position of data is moved to the subsequent block based on the drive-specific number, but the present invention is not limited to such a method. For example, a number unique to a drive may be divided by a manageable number of bits, and a block corresponding to a position where a bit with that number stands may be replaced with a block in the next area, that is, swap processing may be performed. FIG. 6 is a diagram for explaining such a swap process. In this example, a 32-bit serial number is assumed as a unique number for the drive. Therefore, the data field is divided into 32 blocks, and the first 30 blocks in which the information bits of the serial number are set are swapped with the subsequent 62 blocks. As described above, in the present embodiment, the block at the position where the serial number bit is set is swapped between the first 32 blocks and the last 32 blocks of the 64 blocks, and the data is scrambled. When reading the scrambled data, when or after writing the audio data to the buffer, the blocks are rearranged in a normal address and order according to the unique number of the drive (in this example, the serial number). , Normal sound can be reproduced.
[0028]
As described above, according to the present embodiment, scrambling is performed over the entire data area, so that the drive cannot be recognized as normal data unless the drive serial number is known. For this reason, the data protection of the music CD can be further strengthened, and protection against secondary distribution (distribution of data and programs to companies other than Company A without the permission of Company A) and malicious third parties. Can prevent unauthorized use.
[0029]
Further, since the data scrambling method described in the present embodiment is only a swap process between blocks, it is possible to protect data without violating the CD or DVD standard. Instead of swapping blocks to scramble the data, the data itself may be encrypted.
[0030]
In the above-described embodiment described above, the drive-unique number information used to release the protection of data is stored in the memory 12, and the number information is referred to at the time of the processing of the protection release. The number information need not be stored in the memory 12. In this case, the number information is input from the host computer 21 and the OS, application, firmware, driver, or the like interprets the number information, so that only a user who knows the unique number of the drive is allowed to read the data. It is possible to do so. As a result, it is possible to permit only a person with limited conditions to read data.
[0031]
In the above example, the memory function of the memory 12 corresponds to the memory means, and the write control function of the CPU 11 corresponds to the data movement writing means, the data writing means, the dummy bit insertion means, the swap writing means, and the next area swap writing means.
[0032]
【The invention's effect】
As described above, according to the present invention, when writing data to a disk, the data is written by shifting the address of the data area based on the unique number given to the optical disk device. Cannot be recognized and the disc is protected. Since data can only be unlocked by the drive that wrote the data, it is almost impossible to read the data even if a malicious third party picks up the protected disk as described above. . Therefore, a highly confidential disk can be provided to the user.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an optical disc device according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining a data write operation in the optical disk device shown in FIG.
FIG. 3 is a flowchart illustrating a processing procedure of a data writing operation in the optical disc device.
FIG. 4 is a diagram illustrating an example of block movement information stored in a memory;
FIG. 5 is a flowchart illustrating a processing procedure of a data reading operation in the optical disc device.
FIG. 6 is a diagram for explaining a second data write operation in the optical disc device according to the present invention.
FIG. 7 is a diagram showing an example of a recording format of an optical disc.
FIG. 8 is an explanatory diagram of a relationship between a sector of an optical disc and a logical block length and a path table.
[Explanation of symbols]
1 optical disk (disk)
2 Optical pickup 3 Spindle motor 4 Spindle motor driver (SPM driver)
5 Laser Driver 6 Encoder 7 Buffer 8 Interface (I / F) Circuit 9 APC
10 Servo processor 11 System controller (CPU)
12 Memory 21 Host computer

Claims (6)

In an optical disk device, a data area of a disk is divided into blocks, and writing to a disk to which an address is assigned to the divided blocks is performed based on a write request from an external device.
Memory means for holding an identification ID unique to the optical disc device;
When a write request is issued from the external device, the identification ID is obtained from the memory unit, an address for a block of a disk to be accessed is shifted based on the identification ID, and data is written from the shifted position. An optical disk device, comprising: The optical disk device according to claim 1,
The identification ID is represented by n bits,
The data movement writing means regards the first n blocks in the data area as n bits of the identification ID, and sets a block corresponding to a position having a bit value of High in the n bits after the n blocks. Data writing means for writing data shifted to the block,
An optical disk device, comprising: dummy bit insertion means for inserting a predetermined bit value into the shifted block. In an optical disk device, a data area of a disk is divided into blocks, and writing to a disk to which an address is assigned to the divided blocks is performed based on a write request from an external device.
Memory means for holding an identification ID unique to the optical disc device;
Swap writing means for obtaining the identification ID from the memory means when there is a write request from the external device, and for writing data by swapping the data to a corresponding position in another area of a corresponding block based on the identification ID. An optical disc device comprising: The optical disk device according to claim 3,
The identification ID is represented by n bits,
The swap writing means includes a next area swap writing means for writing data by swapping a block corresponding to a position having a high bit value among n bits of the identification ID to a corresponding position in a next area. An optical disk device comprising: The optical disk device according to claim 1, wherein
The optical disc device, wherein the identification ID is a unique number given to the own optical disc device or an arbitrary number designated in advance. The optical disk device according to claim 5,
The optical disc device, wherein the identification ID is transferred from a host computer as the external device.

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