JP2001110136A - Data protection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system capable of adding and extracting information such as copyright protection without increasing the information on an ECC block in recording and reproducing media. SOLUTION: This system decides a specified position indicating the position of specified information by referring to management information 110 provided at a prescribed place that is previously decided in the ECC block 105.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data protection system for protecting copyright.

[0002]

2. Description of the Related Art At present, several methods called digital watermarks for adding specific information to content data and the like have been announced. As one of the methods, Japanese Patent Application Laid-Open No. H11-8
Japanese Patent No. 6436 discloses a technique for inhibiting illegal copying by adding digital watermark information to a data array of an ECC block.

In detail, this method adds digital watermark information to an ECC block, adds management information to a lead-in area of a medium, and uses hardware to reproduce the management information and digital watermark at the time of reproduction. By extracting and comparing information, if the contents match, the output of the content data, for example, audio data, etc., is permitted. Therefore, simply copying the reproduced error-corrected content data to another medium is not sufficient. Digital watermark information and management information cannot be obtained, and in this way, an attempt is made to achieve the purpose of copyright protection by disabling reproduction of the content from the copied media.

[0004]

The conventional data protection system is configured as described above, and it is not possible to reproduce the copied content simply by copying the reproduced content. , It was possible to protect the copyright of the content, but in this conventional system, it is necessary to separately add reference information,
The amount of other information that can be written in the lead-in area is reduced. That is, for example, when copyright protection is performed for each title, more information is required, and the capacity of the data area is reduced. There was a problem. In addition, when an error occurs in the management information, the reproduction becomes impossible, which causes a problem in reliability.

[0005] The present invention has been made to solve the above problems, and even if management information for copyright protection is added, the capacity of the lead-in area does not decrease. An object of the present invention is to provide a data protection system in which an error hardly occurs in management information and a highly reliable system can be constructed.

[0006]

According to a first aspect of the present invention, there is provided a data protection system comprising: a recording / reproducing medium for storing an information block composed of a predetermined amount of information consisting of a data array to which an error correction code is added; Error correction code (ECC) block in the format
In a data protection system in which a plurality of the same specific information is added to a specific position of the data array of the ECC block to which the error correction code is added, the specific position is referred to by a reference provided in the ECC block unit. It is determined based on information.

[0007] The data protection system according to claim 2 is
2. The data protection system according to claim 1, wherein the plurality of specific information for which the position is determined based on the reference information is extracted, and a comparison determination is made as to whether each of the plurality of specific information is the same. When the specific information is the same, the information of the ECC block can be output.

[0008] The data protection system according to claim 3 is:
2. The data protection system according to claim 1, wherein said plurality of identical specific information is added to each of a plurality of ECC blocks.

The data protection system according to claim 4 is
2. The data protection system according to claim 1, wherein the EC
Parity information for error detection is added to specific information for each location added to the C block.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. Description 1: [Format] FIG. 1 is a conceptual diagram showing the format of one ECC (Error Correction Code) block in the DVD (Digital Video Disc) standard using the data protection system according to the first embodiment. In the figure, 105 is E
This is a CC block and is composed of 182 × 208 bytes of data, and 1/16 of this size corresponds to one sector.

Reference numeral 100 denotes a data area, and 101 denotes a PI in which an error correction code for performing inner code correction is stored.
Area, 102 is a PO area in which an error correction code for performing outer code correction is recorded, 110 is management information for specifying the position of the specific information 111a, 111b stored at a specific position in the data area 100 (refer to FIG. Information), which is stored at the beginning of the data area. Also,
112a and 112b are the specific information 111a and 111b.
This is specific information having contents different from the above. The storage location in the data area 100 can be specified by referring to the management information 110 as in the case of the specific information 111a and 111b.

In the first embodiment, the data area 10
0, the same specific information (11a, 111b,
112a, 112b), respectively.
In addition, the reproducing apparatus is configured to compare them and permit reproduction only when the comparison results match.

The ECC (Error Correction Cod)
e) The format in the block will be described in detail.
FIG. 2 shows a detailed format of the ECC (Error Correction Code) block 105.
00 is a 192 × 172 byte data area, 101 is 1
PI called PI (Inne: 92 × 10 bytes)
An r (Parity Code) area 102 is a PO (Outer Parity Code) area called an outer code of 16 × 182 bytes, 103 is a row direction, and 104 is an arrow indicating a column direction.

The configuration of the ECC block 105 is such that an error correction code 1 in the PI area 101, which is an inner code,
The configuration is such that 0 bytes are added, and an error correction code of 16 bytes of the PO area 104, which is an outer code, is added to 192 bytes of the data string in the column direction 104 of the data area 100 and the PI area 101.

Here, in the DVD standard, χ ⁸ + χ ⁴ + χ ³ + χ
^{With 2} + 1 as a primitive polynomial, an error correction code is added based on the Reed-Solomon code, and 182
By performing error correction using an inner code in a byte data sequence, it is possible to correct five (5 bytes) error locations, and perform error correction using an outer code in a 208-byte data sequence in the column direction 104. As a result, it is possible to correct eight error locations (eight bytes). If the position of the error is known, the erasure correction is performed, and the error correction using the inner code is performed on the 182-byte data string in the row direction 103, so that the error of 10 places (10 bytes) is performed. A portion can be corrected, and by performing an error correction using an outer code in a 208-byte data sequence in the column direction 104, 16 (16-byte) error portions can be corrected.

Thereafter, in the error correction and erasure correction of the inner code and the outer code, if the number of errors is equal to or less than the error correction capability, it is determined that "error correction has succeeded". Correction failure ".

FIG. 3 is a diagram mainly showing a configuration of a recording / reproducing apparatus employing the data protection system according to the first embodiment. In FIG. 3, reference numeral 300 denotes an inner code and an outer code error correction code. Encoder unit, 301 is an error correction unit that performs error correction and erasure correction of inner code and outer code, 302 is a semiconductor memory, and 303 is row direction 103
305 is a CPU for controlling the operation of various devices, 306 is a bidirectional bus connecting various devices, 307 is a modulation / demodulation unit, 308 Is the laser driver,
Reference numeral 309 denotes an optical head unit, and reference numeral 310 denotes a disk.
With the above configuration, ECC block creation and error correction processing are performed. In addition, 500 designates specific information as E
An additional data unit 501 for adding to the CC block; an additional data detection unit 501 for detecting and determining specific information;
Reference numeral 502 denotes an encryption unit for encrypting or decrypting data, and reference numeral 503 denotes a random number unit that generates a random number. With the above configuration, specific information is added to the ECC block,
And a detection process are executed.

Explanation 2: [ECC Block Creation and Recording Operation] Next, an operation of creating ECC block data on the disk 310 by the recording / reproducing apparatus according to the first embodiment having the above configuration will be described with reference to FIG. This will be described with reference to a flowchart. Here, the input data is 1E
The description will be made on the assumption that the initial value of the row counter 303 and the initial value of the column counter 304 are “0” for each CC block.

First, step start (step S10)
Thereafter, in step S11, the data input from the data input / output side is stored in the semiconductor memory 302 in the 172 (row direction 10).
3) x 192 (104 in the column direction) bytes are recorded. In step S12, the encoder unit 300 reads 17 bytes from the semiconductor memory 302 in the row direction 103.
A data string in units of 2 bytes is read out, and an error correction code of an inner code data string of 10 bytes is added to the data string.
By forming a data string in byte units, the semiconductor memory 302
To memorize.

Then, in step S13, the count value is incremented by "1" in the column counting section 304, and in step S14, the above steps S12 and S13 are repeated 192 times until the column count reaches 192. 172 + 10) (row direction 103) × 192
(Column direction 104) Byte data area 100 and P
An I region 101 is created. In step S15, the encoder unit 300 reads a 192-byte data string from the semiconductor memory 302 in the column direction 104, and
A data string in units of 208 bytes to which an outer code of bytes is added is stored in the semiconductor memory 302.

In step S16, the count value is incremented by "1" in the row counting section 303, and in step S17, the above steps S15 and S16 are repeated 182 times until the row count reaches 182, whereby 182 ( Row direction 103) x 208 (Column direction 104)
The byte ECC block shown in FIG. 2 is created on the semiconductor memory 302. Then, the data modulated by the modulation / demodulation unit 307 is converted from an electric signal into an optical signal by the laser driving unit 308, and is optically recorded on the disk 310 from the optical head unit 309.

Explanation 3: [Error Correction Operation in ECC Block] Next, the error correction operation of the ECC block reproduced from the disk will be described. FIG.
5 shows an ECC block error correction control flowchart according to the first embodiment. Here, the description will be made on the assumption that the reproduced data is one ECC block, the error correction is error correction in the order of the outer code and the inner code, and the initial values of the column count unit 303 and the row count unit 304 are “0”.

First, the disk 310 is moved to the optical head section 309.
After the data read by optical access by means of the laser converter 308 is converted into an electric signal by the laser driver 308, the data is demodulated by the modem 307 and the semiconductor memory 302
, 182 (row direction 103) × 208 (column direction 104)
Store in bytes.

In step S21, the error correction unit 301
At 20 in the column direction 104 from the semiconductor memory 302.
After reading the data string in units of 8 bytes and performing error correction of the outer code, the semiconductor memory 30 is read in units of 192 bytes.
In step S22, the count value is incremented by "1" in the row counting unit 303, and in step S23, the above steps S21 and S22 are repeated 182 times to obtain 182 (row direction 103) × 192 (column). Direction 104) Confirm that the data string is a byte data string.

Then, in step S24, the error correction unit 301 reads the data from the semiconductor memory 302 in the row direction 103.
After reading the data sequence in units of 182 bytes and performing error correction of the inner code, the result is stored in the semiconductor memory 302 in units of 172 bytes. In step S25, the count value is set to "1" in the column count unit 304. "Is counted up, and in step S26, the above-described step S2
By repeating Steps S4 and S25 192 times, 172 (row 103 in the row direction) × 192 (104 in the column direction) bytes of data before recording are created. As described above, error-corrected data of 172 × 192 bytes is obtained.

Explanation 4: [Erasure Correction Operation in ECC Block] Next, the erasure correction operation of the ECC block reproduced from the disk will be described. Table 1 shows a management format for holding a position for erasure correction in an outer code or an inner code of an ECC block, and FIG.
5 shows an ECC block erasure correction control flowchart at 05.

[0027]

[Table 1] Here, the reproduced data is one ECC block, the correction operation is performed in the order of performing outer code error correction and then performing erasure correction with the inner code, and the initial values of the row count unit 303 and the column count unit 304 are “ This will be described with reference to FIGS. 1, 6 and Table 1. First, after starting the step (Step S30), data read by optically accessing the disk 310 by the optical head unit 309 is converted into an electric signal by the laser driving unit 308, and then the modulation / demodulation unit 30
7, the data is demodulated and stored in the semiconductor memory 302.
It is stored as 182 (row direction 103) × 208 (column direction 104) byte data.

In step S31, the error correction unit 301
At 2 in the column direction 104 from the semiconductor memory 302.
After reading out the data string in units of 08 bytes and performing error correction of the outer code with respect to this, the data is stored in the semiconductor memory 302 in units of 192 bytes. In step S32, the row count unit 303 sets the count value to “ 1 "
Count up.

Subsequently, if it is determined in step S33 that the error correction of the inner code has failed, the flow advances to step S34 to store the count value in the row count unit 303 in the semiconductor memory 302 as shown in Table 1. , As erasure correction position information. In step S35, the above steps S31 to S34 are repeated 182 times to obtain 182 (row direction 103) × 192 (column direction 10).
4) Create a byte data string.

Next, in step S36, the error correction unit 301 reads the data in the row direction 1 from the semiconductor memory 302.
03, a data string in units of 182 bytes and an erasure correction position are read out, erasure correction is performed, and the result is stored in the semiconductor memory 302 in units of 172 bytes.
In step S7, the count value is incremented by one in the column counting unit 304, and in step S38, the above-described step S3 is performed.
6, and S37 are repeated 192 times to obtain 172
(Row direction 103) × 192 (column direction 104) bytes,
Create data before recording. As described above, when the error position is known at the time of error correction, more data correction can be performed by performing erasure correction.

Description 5: [Determining Specific Position] Next, a method for determining the position of the management information 110 for indicating the recording position of the specific information 111a, 111b and 112a, 112b shown in FIG. 1 will be described. Hereafter, the specific position is expressed as follows, and indicates a position in the ECC block 105. Specific position name (row direction position, column direction position)

5-1: Data Reference First, the recording position of the management information 110 is set using the specific data arrangement in the ECC block 105. For example, the first two bytes of the first data column in the row direction 103 of the ECC block 105 indicate the row direction position and the column direction position, respectively.

5-2: Table Conversion Then, a specific position in the ECC block is set by table conversion. For example, using the contents of Table 2 as a table, row direction 1 of the ECC block
Assuming that the first data of the first data string in 03 is 3 as an address, from Table 2, the specific position 3 of the management information is (6
4, 32).

[0034]

[Table 2] As described above, the use of the data in the ECC block 105 eliminates the need for a storage area for newly providing information for determining a specific position to which specific information is added, that is, management information. In addition, since the data changes for each ECC block 105, the specific position is not fixed, but is efficiently spread, and therefore, the data is read out in an unauthorized manner. Even so, it is difficult to estimate the specific position because the specific position is diffused, and the security of the protection of the specific information is increased.

Explanation 6: [Operation of Adding Specific Information During Recording] Next, the operation of adding the specific information will be described.
FIG. 7 is a diagram showing a format of specific information in byte units. In FIG. 7, reference numeral 400 denotes a valid data area;
Reference numeral 401 denotes a parity in which “1” or “0” is set so that the number of “1” in the valid data area 400 is an even number, and thereafter, the parity is set in the specific information to be recorded. Shall be.

6-1: [Addition after ECC Block Creation] A procedure for adding the encryption key created as described above as specific information when encrypting ECC block data and recording it on a disk. This will be described with reference to FIGS. Here, the specific information is such that the same information is added to two places in byte units, and the specific position at which the specific information is added to the ECC block uses the method of [5-1] [Data Reference]. , ECC block 10
5, the first data 2 of the first data string in the row direction 103
Bytes.

First, a random number R is generated in the random number unit 503, and the random number R is set in the encryption unit 502 and the data addition unit 500. The data input from the data input side is
In 02, an ECC block is formed by encrypting the random number R as a key and performing an inner code and outer code error correction code generation operation (steps S10 to S18) on the encrypted data.

As an additional operation of the data adding unit 500 after the creation of the ECC block, the first step is as follows.
In order to make the number of “1” in the data array of the random number R an even number, “1” or “0” is added to the data array with the random number R to be the specific information R. The first 4 bytes of the first data string in the row direction 103 of the block are read out, divided into 2 bytes, and specified positions A and B (here, if 4 bytes are X1 to X4 in byte units, as shown in FIG. 8) At specific position A
(X1, X2) and specific position B (X3, X4)).

Then, as a third step, the data at the positions corresponding to the specific positions A and B are read from the ECC block of the semiconductor memory 302, and the specific information R is exclusively ORed with these as data A and B, respectively. By that
Only the added data A and B are taken out and the semiconductor memory 3
02 in the corresponding position of the specific positions A and B of the ECC block, and the reproduction of the specific information ends.

6-2: [Addition during ECC Block Creation] Hereinafter, when the specific information created as described above is recorded on a disk by encrypting the data of the ECC block,
The procedure for the addition will be described with reference to FIG. That is,
In the case where the data of one ECC block is encrypted and recorded on the disk, after the generation of the inner code of the ECC block is completed, the operation of adding the encryption key created as described above as specific information will be described with reference to FIG. This will be described with reference to FIGS. Here, as the specific information, the same information is added to two places in byte units, and the specific position at which the specific information is added to the ECC block is determined by using the method of [5-1] [Data Reference], ie, ECC It is assumed that the head data of the head data string in the row direction 103 of the block 105 is 2 bytes.

First, the random number unit 503 generates a random number R, and sets the random number R in the encryption unit 502 and the additional data unit 500. The data input from the data input side is encrypted by the encryption unit 502 using the random number R as a key, and an inner code error correction code generation operation (steps S10 to S14) is performed on the encrypted data to obtain E.
An inner code of the CC block is created.

As an additional operation of the data adding unit 500 after the completion of the inner code generation of the ECC block, as a first step, “1” or “1” is set so that the number of “1” in the data array of the random number R is an even number. "0" is added to the data array by using a random number P as specific information P. As a second step, the first 3 bytes of the first data column in the column direction 104 of the ECC block are read from the semiconductor memory 302, and 1 byte is assigned to a common row. The direction position is indicated, and the other two bytes are respectively divided into specific positions C and D (here, three bytes are defined as Y1 to Y3 in byte units, and specific positions C (Y2, Y1) as shown in FIG. 9). , Specific position D (Y3, Y1)).

As a third step, data at a position corresponding to specific positions C and D is read from the ECC block of the semiconductor memory 302, and data C obtained by exclusive ORing the data with the specific information P is obtained. , D in the specific positions A and B of the ECC block of the semiconductor memory 302, thereby ending the operation of determining the specific information. Then, by performing an error correction code generation operation of the outer code (steps S15 to S18), an outer code is created and an ECC block is formed.

Here, the setting of the specific position includes an ECC
Although the head data string in the row direction 103 of the block is used, a data string at another position may be used, and the specific position is set using the first three bytes of the head data string. It may be used as a specific position. Also,
Here, the same specific information is added to two places in the ECC block. However, two or more places may be added, and one type of the same specific information is added in the ECC block. Alternatively, a plurality of types of specific information may be added.

Explanation 7: [Specific information determination operation at the time of reproduction] Next, a method of determining the specific information added to the specific position as described above from the information of the ECC block will be described. Table 3 is a management format showing error positions and error values at the time of error detection in error correction or erasure correction of an ECC block.

[0046]

[Table 3] 7-1: [Operation by Error Correction in ECC Block] FIG. 10 shows an additional data detection unit 5 that determines the same specific information added to the ECC block by an error correction operation.
11 is a control flowchart showing the operation of the first embodiment. The addition of the specific information to the ECC block is described in “6-1.
The error correction operation of the ECC block is referred to as “addition after block creation”, and the error correction operation of the ECC block is referred to as “error correction operation in the ECC block” of 6-1 in FIGS.
The operation will be described using 0 and Table 3 above.

First, in step S41, an error correction operation (steps S20 to S20) is performed in the order of outer code and inner code.
27) is executed, and the position and numerical value of the detected error are stored in the semiconductor memory 302 as shown in Table 3, and the process proceeds to step S
At 42, if the first data string in the row direction 103 fails in error correction (NO), the process proceeds to step S48, where the process ends without specifying information, and the process ends at step S42.
If the error correction is successful (YES), step S53
To the ECC block of the semiconductor memory 302,
The first 4 bytes of the first data string in the column direction 103 are read out, and are divided into two bytes and designated as specific positions A and B.

In step S44, the error numerical values at the positions corresponding to the specific positions A and B are read out from the data in Table 2 in the semiconductor memory 302, and are set as temporary information A and B. In step S45, the temporary information A and B are If the comparison result shows that there is no match, step S48 is executed to determine that there is no specific information. On the other hand, if it is determined in step S45 that the comparison results of the provisional information match (YES), then in step S46, if “1” in the binary data array of the provisional information A is an odd number (NO), step S48 is performed.
Is executed, and if it is an even number (YES), in step S47, the temporary information A except for the parity 401 is used as specific information. Then, the encryption unit 502 decrypts the reproduction data in the semiconductor memory 302 using the specific information as a key to return to the original data and output the data from the data input / output side.

Although two types of specific information are used here, three or more identical specific information may be added. In this case, in the temporary information extracted in step S43, Using temporary information with many identical information,
Step S46 and subsequent steps may be performed. With the above operation, specific information can be determined efficiently by performing only error correction of data in the ECC block without increasing the amount of information.

7-2: [Operation by Erasure Correction in ECC Block] Next, when performing the error correction of the same specific information in the ECC block stored as described above, the operation at the time of performing the erasure correction is as follows. This will be described with reference to FIG. Here, EC
The addition of the specific information to the C block is an addition during the creation of the ECC block, and the error correction operation of the ECC block is performed as an erasure correction operation of the ECC block using FIGS. 4, 8, 11, and 3. explain.

First, step start (step S50)
Thereafter, in step S51, an outer code error correction operation (steps S30 to S35) is executed, and step S51 is executed.
At 52, if there is no error correction failure (NO) in the head data sequence in the column direction 104, the process proceeds to step S59, and the process ends as there is no specific information.
If the error correction is successful (YES) at 52, the process proceeds to step S53, where the first three bytes of the first data column in the column direction 104 are read from the ECC block of the semiconductor memory 302, and one byte represents a common row direction position. ,
The other two bytes are further divided into specific positions C and D, and the column direction positions at the specific positions C and D are stored in the semiconductor memory 302 as the erasure correction positions in Table 1, and in step S54, the erasure correction operation of the inner code is performed. Steps S36 to S39) are executed, and the position of the error that has occurred and the numerical value are stored in the semiconductor memory 302 as shown in Table 2.

In step S55, the error numerical values at the positions corresponding to the specific positions C and D are read out from the data in Table 2 in the semiconductor memory 302, and these are set as temporary information C and D. Information C,
If D does not match, step S59 is executed,
If they match (YES), in step S57, if 1 in the binary data array of the temporary information C is odd (NO), step S59 is executed, and if even (YES),
In step S58, the parity 401 is obtained from the temporary information C.
Except for, it is determined as specific information.

The encryption section 502 decrypts the reproduction data in the semiconductor memory 302 using the specific information as a key, thereby returning the data to the original data and outputting the data from the data input / output side. Here, when three or more pieces of the same specific information are added, the step S57 and the subsequent steps may be performed by using the temporary information extracted in the step S55 and having the same information more. By the above operation, specific information can be determined efficiently by erasure correction based on data extracted from the ECC block without increasing the information amount.

As described above, according to the first embodiment, the specific position indicating the position of the specific information is determined in units of the ECC block 105 by the management information 110 provided at a predetermined location in the ECC block 105. Since the information is determined by reference, the information for indicating the position of the specific information and the specific information are both stored in the ECC block 10.
5, the recording area can be used more effectively than in the case where management information is provided in the lead-in area as in the related art, and the management information itself has an error correction function. Therefore, an error is less likely to occur in the management information, and a highly reliable data protection system can be provided.

Embodiment 2 Next, Embodiment 2 of the present invention
Will be described. In the first embodiment, a plurality of the same specific information are recorded in the same block. However, the second embodiment is characterized in that the same specific information is stored in a plurality of ECC blocks. Hereinafter, an operation of reading a plurality of identical information recorded in a plurality of ECC blocks will be described with reference to FIG.

7-3: [Operation by Error Correction Between ECC Blocks] FIG. 12 shows an additional data detection unit 501 that detects and determines the same specific information added to two ECC blocks n and m.
FIG. 11 is a control flowchart of the ECC block. The addition of the specific information to the ECC block is performed after the ECC block is created.
8 and FIG.
This will be described with reference to FIG.

First, step start (step S70)
Thereafter, in step S71, the specific information extracting operation in the ECC block n (steps S40 to S40 in FIG. 10)
49, and the extracted data is set as temporary information n. In step S72, the specific information extracting operation in the ECC block m (see steps S40 to S49 in FIG. 10).
Is performed and the extracted data is set as temporary information m.

Then, in step S73, the temporary information n and the temporary information m are compared. If the comparison result is inconsistent (NO), the process proceeds to step S75, and the process ends as there is no specific information (step S76). , Step S7
If it is determined in step 3 that the comparison results match (YES), the process proceeds to step S74, and the specific information is determined by removing the parity 401 from the temporary information n. And the encryption unit 5
02, using the specific information as a key, the semiconductor memory 30
By decoding the reproduced data of No. 2, the original data is restored and output from the data input / output side.

As described above, according to the second embodiment, the same specific information is stored in a plurality of ECC blocks, so that the security of the content can be further improved and the ECC blocks can be physically damaged. Even when the specific information is received, since the specific information is stored in another block, there is a high possibility that the specific information will be repaired, and the reliability of the specific information can be strengthened.

In the second embodiment, two ECCs
Although the information is stored in the block, the same specific information may be added to three or more ECC blocks. In this case, among the extracted temporary information, temporary information having a large number of identical information can be handled as specific information.

Furthermore, in each of the above embodiments, the head data string in the row direction 103 of the ECC block is used to set the specific position, and the head four bytes of the head data string are used as the position of the management information. The management information may be used or recorded in data other than the head data.

[0062]

As described above, according to the data protection system of the first aspect of the present invention, an information block composed of a predetermined amount of information consisting of a data array to which an error correction code is added is In a data protection system, a plurality of identical specific information is added to a specific position of a data array of the ECC block to which the error correction code is added as an error correction code (ECC) block in a format of a recording / reproducing medium. Since the position is determined based on the reference information provided in the ECC block unit, the specific position can be determined efficiently without increasing the amount of information. Since the data changes from block to block, the specific position can be efficiently spread without being fixed. Next, thereby, the estimation of the specific position becomes difficult, it is possible to enhance the security of the identification information, the effect is obtained that.

According to the data protection system of the second aspect, in the data protection system of the first aspect, the plurality of pieces of specific information for which the position is determined based on the reference information are extracted, and each of the plurality of pieces of specific information is extracted. A comparison is made to determine whether or not the specific information is the same. If the specific information is the same, the information of the ECC block can be output. The effect that the contents can be provided with security can be obtained.

According to the data protection system of the third aspect, in the data protection system of the first aspect, the plurality of the same specific information are added to each of a plurality of ECC blocks. The effect that the security of this can be improved more is obtained.

According to the data protection system of the fourth aspect, in the data protection system of the first aspect, parity information for error detection is added to the specific information for each location added to the ECC block. Therefore, the effect of increasing the reliability of the specific information can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conceptual configuration of an ECC block in a data protection system according to the present invention.

FIG. 2 is a diagram showing a more detailed configuration of an ECC block of the data protection system according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of the data protection system according to the first embodiment, centering on a recording / reproducing device.

FIG. 4 is a diagram showing a flowchart for explaining an ECC block creation operation of the data protection system according to the first embodiment.

FIG. 5 is a diagram showing a flowchart for explaining an error correction operation of an ECC block in the data protection system according to the first embodiment.

FIG. 6 is a diagram showing a flowchart for explaining an erasure correction operation of an ECC block in the data protection system according to the first embodiment.

FIG. 7 is a diagram showing a parity format structure of specific information of the data protection system according to the first embodiment.

FIG. 8 is a diagram for explaining specific information adding operation after ECC block creation in the data protection system according to the first embodiment.

FIG. 9 is a diagram for explaining a specific information adding operation during ECC block creation of the data protection system according to the first embodiment.

FIG. 10 is a diagram illustrating a flowchart for explaining an operation of determining specific information by error correction in an ECC block in the data protection system according to the first embodiment.

FIG. 11 is a diagram illustrating a flowchart for explaining an operation of determining specific information by erasure correction in an ECC block in the data protection system according to the first embodiment.

FIG. 12 is a diagram illustrating a flowchart for explaining an operation of determining specific information by error correction between ECC blocks in the data protection system according to the second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 data area 101 PI area 102 PO area 103 row direction 104 column direction 105 ECC block 110 management information (reference information) 111 a, b specific information 112 a, b specific information 300 encoder section 301 error correction section 302 semiconductor memory 303 row count 304 column Count 305 CPU 306 Bidirectional bus 307 Modulation / demodulation unit 308 Laser drive unit 309 Optical pickup 310 Disk 400 Valid data area 401 Parity 500 Additional data unit 501 Additional data detection unit 502 Encryption unit 503 Random number unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G11B 20/12 G11B 20/12 H03M 13/29 H03M 13/29 F-term (Reference) 5B017 AA06 BA07 BA09 BB03 CA09 CA11 CA16 5B018 GA02 HA12 JA26 MA16 RA11 5D044 BC06 CC04 DE02 DE03 DE48 DE52 DE68 GK17 5J065 AB01 AC03 AD01 AE01 AE02 AH01 5J104 AA14 PA14

Claims (4)

[Claims] An information block composed of a predetermined amount of information consisting of a data array to which an error correction code is added is defined as an error correction code (ECC) block in a format of a recording / reproducing medium. In a data protection system in which a plurality of identical specific information is added to a specific position of a data array of the added ECC block, the specific position is determined based on reference information provided in the ECC block unit. A data protection system. 2. The data protection system according to claim 1, wherein the plurality of pieces of specific information for which the position is determined based on the reference information are extracted, and whether each of the plurality of pieces of specific information is the same is determined. The data protection system according to claim 1, wherein when the specific information is the same, the information of the ECC block can be output. 3. The data protection system according to claim 1, wherein said plurality of identical specific information is added to each of a plurality of ECC blocks. 4. The data protection system according to claim 1, wherein the specific information for each location added to the ECC block includes:
A data protection system to which parity information for error detection is added.