JPH11232778A - Information protecting system, data making device using it, and data restoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increasing a processing time of error correction even if quantity of information of error correction codes for intrinsic ID is increased in an information protecting system recording ID being intrinsic for a medium and using the intrinsic ID as a key of security. SOLUTION: Two kinds of error correction codes for intrinsic ID of which processing time for error correction are different are recorded in a medium A as a recording form being referable to a file system for a first error correction code having a short processing time and as a recording form being not referable to the file system for a second error correction code having a long processing time. Normally error correction for intrinsic ID is performed by using the first error correction code, only when the first error correction code is not correct, error correction is performed by using the second error correction code.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an information protection system for protecting information recorded on a recording medium.

[0002]

2. Description of the Related Art In order to prevent unauthorized use of information (contents) recorded on a portable recording medium and falsification of the information without permission, there is a security system that uses an ID unique to the medium. . In this security system, an ID unique to a medium is recorded in advance, and the information (content) is acquired and stored with the unique ID using the unique ID as a security key.

When such a unique ID is recorded on a medium, it is necessary to record an error correction code for correcting an error in reading the unique ID on the medium. Unique ID
Is recorded in a recording format that cannot be referenced from the file system.

[0004]

Since the parity code has only one-bit error correction capability, there is a problem that the reliability of reading the unique ID is low. Therefore, a Hamming code having an error correction capability of 2 bits or more is used as an error correction code.
Recording in a recording format that cannot be referenced from the file system is conceivable. In such a case, the error correction capability is certainly improved, but there is a problem that the time required for the error correction processing increases.

[0005] The present invention has been made in view of such circumstances, and by recording two types of error correction codes having different error correction processing times, that is, different error correction processing capacities, the error correction processing capability is improved. It is an object of the present invention to provide an information protection system capable of reducing the time required for error correction processing without lowering the data, and a data creation device and a data restoration device used for the information protection system.

[0006]

According to a first aspect of the present invention, there is provided an information protection system for protecting information on a recording medium, comprising: a unique ID of the recording medium; a first error correction code for the unique ID; Recording means for recording, on the recording medium, a second error correction code for the unique ID having a higher error correction processing capability than the first error correction code; and recording means for the first error correction code and the second error correction code. Means for selectively reading any one of them from the recording medium.

According to a second aspect of the present invention, in the first aspect, a file system is incorporated in the recording medium, and the first error correction code is recorded as a recording format that can be referred to from the file system. The second error correction code is recorded as a recording format inaccessible from the file system.

According to a third aspect of the present invention, in the information protection system according to the first or second aspect, the recording means includes means for judging a capacity of the recording medium, and the unique ID, the first error correction Means for determining a recording position of the code and the second error correction code.

According to a fourth aspect of the present invention, there is provided a data creating apparatus for use in an information protection system for protecting information on a recording medium, comprising: means for encoding a unique ID of the recording medium; Means for generating a first error correction code, a second error correction code for the ID having a longer error correction processing time than the first error correction code, and means for encoding the generated second error correction code. It is characterized by having.

A data restoration apparatus according to a fifth aspect is used in an information protection system for protecting information on a recording medium, and is a data restoration apparatus corresponding to the data creation apparatus according to the fourth aspect, wherein the encoded data is restored. Means for decoding an ID, first error correction means for performing error correction of the ID using the first error correction code, means for determining whether or not the error correction has been correctly performed, and A means for decoding the coded second error correction code if not performed; and a second error correction means for performing error correction of the ID using the decoded second error correction code. It is characterized by.

In the present invention, two types of error correction codes (first and second types) having different processing times for the unique ID of the recording medium and the unique ID are used.
The error correction code and the second error correction code) are recorded on a recording medium. The second error correction code has a higher error correction capability than the first error correction code, but has a longer error correction processing time. At this time, the unique ID and the second error correction code are recorded as a recording format that cannot be referred to from the file system, and the first error correction code is recorded as a recording format that can be referred to from the file system so that unauthorized use cannot be performed. .

Normally, the unique ID and the first processing time are short.
The error correction code is read, and error correction is performed using the first error correction code. Then, only when the error correction cannot be performed by the first error correction code, the second error correction code having a longer processing time is read, and the error correction is performed by the second error correction code. Therefore, the processing time for error correction at the time of reading the unique ID is short by using the first error correction code recorded in a recording format that can be referred to from the file system in a normal state. Further, when the first error correction code is illegally erased / rewritten, the second error correction code having a high error correction capability can be used, so that a sufficient error correction capability can be exhibited.

The recording positions of the unique ID, the first error correction code, and the second error correction code are specified according to the capacity of the medium to be recorded. Unauthorized use can be made more difficult.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a schematic configuration diagram of an information protection system according to the present invention. The information protection system according to the present invention includes a data creation device 1 that creates data to be recorded on a medium A, and a device that restores data recorded on the medium A And a data restoration device 2 for performing the operation. The medium A is a portable recording medium composed of, for example, a magneto-optical disk.

The data creating device 1 includes a first encoding unit 11
And an error correction code data generator 12 and a second encoder 13
And a medium capacity determination unit 14. First encoding unit 11
Inputs unique ID data to the medium A and encodes it. The error correction code data generator 12 generates two types of error correction code data (first error correction code data and second error correction code data) for the input ID data. The second error correction code data is less likely to be illegally used and has a higher error correction capability than the first error correction code data, but has a longer error correction processing time. Second encoding unit
13 inputs the second error correction code data from the error correction code data generation unit 12 and codes it. The medium capacity determining unit 14 determines the capacity of the inserted medium A.

The coded ID data output from the first coding unit 11, the first error correction code data output from the error correction code data generation unit 12, and the coded ID data output from the second coding unit 13 The coded second error correction code data is recorded on the medium A by predetermined recording means.

The data restoration device 2 includes a first decoding unit 21
, A switch 22, a second decoding unit 23, and an error correction unit 24.
And The first decoding unit 21 decodes the coded ID data recorded on the medium A into the original ID data. The switch 22 switches the input between the first error correction code data and the coded second error correction code data recorded on the medium A. The second decoding unit 23 decodes the coded second error correction code data into the original second error correction code data. The error correction unit 24 outputs the I
An error correction process is performed on the D data using either the first error correction code data from the switch 22 or the second error correction code data from the second decoding unit 23.

Next, the operation will be described. FIG. 2 is a flowchart showing an operation procedure in the data creation device 1. First, after inserting the medium A (step S1),
The medium capacity determination unit 14 determines whether the capacity of the medium A is 230 MB or 540 MB (step S2).
If the capacity of the medium A is 230 MB, the coding ID
The data write start sector is set to 0, the coded second error correction code data and the first error correction code data write start sectors are set to 10 and 20, respectively, so that sectors 20 and beyond can be referenced from the file system ( Step S
3) If the capacity is 540 MB, the former write start sector is 1 and the latter write start sector is
11 and 21 are set (step S4).

The ID data is read into the first encoding unit 11 and the error correction code data generation unit 12 (step S5).
Then, the error correction code data generation unit 12 generates the first error correction code data and the second error correction code data from the ID data (step S6). These first and second
The error correction code data is a parity code, EC
C (Error Checking and Correction) code, CRC (Cy
clic Redundancy Check) code.

The first coding unit 11 codes the ID data to generate coded ID data (step S7),
The coded ID data is recorded on the medium A (step S8). Details of the coding of the ID data will be described later. Further, the generated first error correction code data is recorded on the medium A (step S9). Further, the generated second error correction code data is coded by the second coding unit 13 to generate coded second error correction code data (step S
10) The coded second error correction code data is recorded on the medium A (step S11).

With the above processing, the coded ID data and the coded second error correction code data cannot be referred to from the file system, and only the first error correction code data can be referred to from the file system.

FIG. 3 is a flowchart showing the operation procedure of the ID data encoding process, that is, the subroutine of step S7 in FIG. In the following example, the ID data is (15) _hex . First, 8-bit data indicating 15 is divided into blocks of 4 bits as shown in FIG. 4A (step S21). Then, each 1-bit data is allocated to one sector of the medium A (step S22),
The total 8-bit data is stored in a predetermined sector (for example, FIG.
(8 sectors from LBN 10 to LBN 17 as shown in (b))
Then, each one bit is recorded in each sector (step S23). At this time, data recorded in each sector is written in a non-rewritable state.

The second error correction code data is coded in the same manner, and the coded data is written to a predetermined sector of the medium A in a non-rewritable state.

Next, the operation of the data restoration device 2 will be described. FIG. 5 is a flowchart showing an operation procedure in the data restoration device 2. After inserting the medium A (step S31), it is determined whether or not the medium A has a unique ID (step S32). If there is no unique ID (S32: NO), the process ends.

If a unique ID exists (S32: Y
ES), the coded ID data recorded on the medium A is read out to the first decoding unit 21 (step S33), and is decoded to obtain the original ID data (step S3).
Four). The details of the decoding process of the coded ID data will be described later. It is determined whether or not the first error correction code data is normal, specifically, whether or not the parity is correct (step S35). If the data is normal (S35: YES), the first error correction code data recorded on the medium A is read (step S36), and an error correction process for the ID data is performed using the read first error correction code data. Is performed by the error correction unit 24 (step S3
7).

If the first error correction code data is not normal (S35: NO), the input of the switch 22 is switched to
The coded second error correction code data recorded on the medium A is read out to the second decoding unit 23 (Step S38),
It is decoded to obtain the original second error correction code data (step S39). Then, the error correction unit 24 performs an error correction process on the ID data using the obtained second error correction code data (step S37).

With the above processing, in the normal routine, the error correction of the ID data is performed using the correction code (first error correction code data) recorded in a recording format that can be referred to from the file system. The processing time can be reduced. If the error correction cannot be performed using the correction code (first error correction code data), the correction code (second error correction code data) having a higher correction processing capability is used.
Since error correction of D data is performed, reliable correction processing is possible.

FIG. 6 is a flowchart showing the operation procedure of the decoding process of the coded ID data, that is, the subroutine of step S34 in FIG. In the following example, it is assumed that the original ID data (15) _hex is obtained from the coded ID data as described above (see FIGS. 3 and 4).
First, a predetermined start sector of the medium A (for example, as shown in FIG.
LBN 10) to the end sector (for example, LBN 17 in FIG. 4B)
Until that time, coded ID data having one bit per sector is read (step S41). Then, the original ID data is obtained by dividing it into blocks every 4 bits (step S4).
2).

Next, an example of the recording format of the medium A according to the present invention will be described. FIGS. 7A to 7D show examples of the first error correction code and the second error correction code described above.

In the example shown in FIG. 7A, as a first error correction code having a low error correction capability but a short error correction processing time, a first parity code is recorded in an area accessible from a file system, and error correction is performed. As a second error correction code having a long processing time and a high error correction capability, a second parity code is recorded in an area inaccessible from the file system. In this case, the first parity code and the second parity code have the same logic, and the second parity code is read when an abnormality occurs in the first parity code.

In the example shown in FIG. 7B, the first parity code is recorded as the first error correction code in an area accessible from the file system, and the second parity code and the ECC code are stored in the second error correction code. It is recorded as a correction code in an area that cannot be accessed from the file system. In the example shown in FIG. 7C, a first parity code is recorded as the first error correction code in an area accessible from a file system, and a second parity code and a CRC code are used as the second error correction code. Recorded in an area that cannot be accessed from the file system. Further, FIG.
In the example shown in (1), a first parity code is recorded in the area accessible from the file system as the first error correction code, and a second parity code, an ECC code and a CRC code are accessed from the file system as the second error correction code. Recording is made in an area that cannot be used.

[0032]

As described above, according to the present invention, the error correction processing time is different, that is, the specific I.I.
Two types of error correction codes for D are recorded on a recording medium, and an error correction code having a shorter processing time is used in a normal state. Since the error correction code is used, it is possible to shorten the time of the error correction processing in the normal state.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an information protection system of the present invention.

FIG. 2 is a flowchart showing an operation procedure in the data creation device.

FIG. 3 is a flowchart illustrating an operation procedure of an ID data encoding process.

FIG. 4 is an explanatory diagram of a coding process of ID data.

FIG. 5 is a flowchart showing an operation procedure in the data restoration device.

FIG. 6 is a flowchart showing an operation procedure of a decoding process of coded ID data.

FIG. 7 is a schematic diagram illustrating an example of a recording format of an error correction code.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 data creation device 2 data restoration device 11 first encoding unit 12 error correction code data generation unit 13 second encoding unit 14 medium capacity determination unit 21 first decoding unit 22 switch 23 second decoding unit 24 error correction unit A medium

Claims (5)

[Claims] 1. An information protection system for protecting information of a recording medium, comprising: a unique ID of the recording medium;
Recording means for recording, on the recording medium, a first error-correcting code for the unique ID and a second error-correcting code for the unique ID having a higher error-correcting processing capability than the first error-correcting code; And a means for selectively reading any one of the second error correction codes from the recording medium. 2. A file system is incorporated in the recording medium, the first error correction code is recorded as a recording format that can be referred to from the file system, and the second error correction code is recorded from the file system. 2. The information protection system according to claim 1, wherein the information is recorded as a non-referenceable recording format. 3. The recording means includes means for determining the capacity of the recording medium, and the unique ID,
3. The information protection system according to claim 1, further comprising: means for determining recording positions of the first error correction code and the second error correction code. 4. A data creation device used in an information protection system for protecting information on a recording medium, wherein a means for encoding a unique ID of the recording medium, a first error correction code for the ID, and A data generator comprising: means for generating a second error correction code for the ID having a longer error correction processing time than the first error correction code; and means for coding the generated second error correction code. apparatus. 5. A data restoration device used in an information protection system for protecting information on a recording medium and corresponding to the data creation device according to claim 4, wherein the encoded ID is
Means for decoding the ID, first error correction means for performing error correction of the ID using the first error correction code, means for determining whether or not the error correction has been correctly performed, and correct error correction. If not, it comprises means for decoding the coded second error correction code, and second error correction means for performing error correction of the ID using the decoded second error correction code. Characteristic data restoration device.