KR20000014770A - Device and method for sensing an original copy and preventing a copy of an optical record medium - Google Patents

Abstract

PURPOSE: A method for sensing an original copy and preventing a copy of an optical record medium is provided to have a compatibility with a driver of the optical record medium. CONSTITUTION: The method for recording data to an optical record medium comprises the steps of: selecting a pair of standard symbols, wherein tow continuous bits are different in the standard symbols; selecting record data including at least one of the standard symbols of the pair; correcting an error correction purpose parity with regard to the record data; delaying one of the two bits of the standard symbol included in the record data to convert the delayed bit into a non-standard symbol; and recording the record data including the non-standard symbol and the correction parity to an optical record medium.

Description

Authenticity Detection / Replication Prevention Method and Apparatus for Optical Recording Media

The present invention relates to a true detection / replication prevention method and apparatus for an optical recording medium, and more particularly, to a symbol that can be reproduced with two standard symbols (hereinafter, referred to as a "non-standard symbol"). And the authenticity detection program are recorded in a specific area on the optical recording medium, and during playback, the control program can detect whether the optical recording medium is authentic or not according to the reproduction type of the abnormal symbol. The present invention relates to a method for detecting and authenticating an authentic optical recording medium.

Recently, with the advent of the multimedia society, optical discs have been developed and distributed as optical recording media capable of storing music, movies, and software. Optical discs are easy to copy the same information to a large amount of optical discs relatively inexpensively, and even if the stored signals are repeatedly copied to the optical disc several times, the signal quality is the same as the original.

In the past, an expensive recording apparatus was used to duplicate information recorded on an optical disk. However, in recent years, an optical disk can be easily manufactured in accordance with a decrease in the price of the apparatus. Therefore, illegal copying of optical discs on which expensive information such as music, movies, and software is recorded becomes easy, and the related industry suffers huge losses due to illegal copying.

Accordingly, various methods have been proposed to prevent illegal duplication of the optical disc, and one of them is a signal recording method and a recording method of the "copy prevention optical disc" proposed by the present inventor and filed in Korean Patent Application No. 97-32576. The copy protection method of the optical disk using the "

In the above application, in order to prevent copying of an optical disc, an abnormal symbol obtained by shifting (delaying) a specific standard symbol or a bit of a codeword by a predetermined size is recorded in a predetermined area of the disc, When a standard symbol is reproduced (hereinafter referred to as a "playback target symbol"), the corresponding optical disc is detected as authentic.

However, the above application does not specifically propose a method for recording an abnormal symbol, a true detection method of an optical disc, and a control method for copy protection. In addition, the above application does not propose a specific signal processing method for compatibility with the existing system. That is, in the case of a CD-ROM or an audio CD driver, after the EFM (Eight to Fourteen Modulation) demodulation of the signal read out from the optical disc, CIRC (Cross Interleave Reed-Solomon Code) processing of ECC (Error Correction Code) is performed. In the ECC decoder, there is a problem in that when ECC processing an abnormal symbol, two predetermined reproduction target symbols are not outputted or a signal other than the standard symbol is outputted to determine the authenticity.

Accordingly, the present invention has been made to solve the above problems, and an object thereof is to provide a method and apparatus for authenticating / replicating an optical recording medium having compatibility with an optical recording medium driver.

Another object of the present invention is to record the control program for detecting the authenticity of the optical recording medium in a predetermined area of the recording medium without adding hardware and software to the optical recording medium driver, and to detect the authenticity of the recording medium by any driver. An object of the present invention is to provide a method and apparatus for authenticating / copying an optical recording medium capable of copy protection.

Another object of the present invention is to provide a method and apparatus for authenticating / replicating an optical recording medium in which an ECC decoder can operate normally by correcting and recording a parity symbol during abnormal symbol recording.

In addition, another object of the present invention is to read the abnormal symbols recorded on the optical recording medium as two reproduction target symbols and to output the reproduction target symbols even after ECC processing so that the authenticity of the optical recording medium can be accurately determined. It is an object of the present invention to provide a method and apparatus for authenticating / replicating an optical recording medium.

Further, another object of the present invention is to provide a corrected parity upon recording in accordance with the error handling capability of ECC parity, whereby authenticity of an optical recording medium capable of reproducing a symbol necessary for authenticity of the recording medium during reproduction / It is an object of the present invention to provide a copy protection method and apparatus.

1 is a block diagram of a data recording processing apparatus employed in the authenticity detection and copy protection device of an optical recording medium according to the present invention;

2 is a diagram showing recording positions of test data and a control program recorded on an optical recording medium according to the present invention;

3 is a diagram illustrating an embodiment of a data format for test data used by the present invention;

4 is a diagram showing another embodiment of a data format for test data used by the present invention;

5A and 5B are diagrams for explaining an example of a method for generating a modified parity by the modified parity generator shown in FIG. 1;

6 is a diagram showing an example of reproduction target data and recording data recorded on an optical recording medium according to the present invention;

7 is a block diagram of a data reproduction processing apparatus employed in the authenticity detection and copy protection device of an optical recording medium according to the present invention;

8A to 8C are diagrams for explaining the form of test data, its reproduction data and error correction decoded data recorded on an optical recording medium according to the present invention;

9A to 9I are diagrams for explaining data arrangement after error correction encoding when test data according to the present invention is applied to a CIRC (Cross Interleave Reed-Solomon Code) code / decoder.

10 is a view for explaining the probability of generation of the reproduction target data according to the error correction mode of the CIRC decoder applied to the present invention,

11 is a flowchart of a method of recording test data and a control program on an optical recording medium in the authenticity detection / replica prevention method of the optical recording medium according to the present invention;

12 is a flowchart illustrating a method of detecting the authenticity of an optical recording medium and preventing illegal copying of the optical recording medium by test data and a control program recorded on the optical recording medium.

※ Explanation of code for main part of drawing

10: CIRC encoder 20: EFM modulator

30: shifter 40: multiplexer

50: mastering device 60: optical recording medium

100: optical recording medium driver 110: optical pickup

120: R / F unit 130: analog / digital (A / D) converter

140: EFM demodulator 150: CIRC decoder

200: host 210: control unit

220: memory 230: display unit

The data recording method employed in the authenticity detection / replication prevention method of the optical recording medium according to the present invention for achieving the above object, by generating an abnormal signal that can be reproduced with two standard signals during repeated reproduction of the optical recording medium 10. A method of recording on a computer, the method comprising: generating an error correction parity that meets a preset condition on at least one or more pieces of recorded data; And converting the recording data corresponding to the generated parity into an abnormal signal and recording the recording data on the recording medium.

In addition, the illegal copy prevention data recording apparatus employed in the true detection / replication prevention apparatus of the optical recording medium according to the present invention generates an abnormal signal that can be reproduced by two standard signals during repeated reproduction and records the optical recording medium on the optical recording medium. An apparatus, comprising: parity generating means for generating error correction parity meeting a preset condition on at least one or more pieces of recorded data; And recording means for converting the recording data corresponding to the generated parity into an abnormal signal and recording the recording data on the recording medium.

In addition, the authenticity detection / copy prevention method of the optical recording medium according to the present invention, the recording data including an abnormal signal that can be reproduced as two standard signals, and a control program for performing an operation according to the presence of the abnormal signal A reproduction method of the recorded optical recording medium, comprising: a first step of reading and operating the control program; And a second step of the control program repeatedly reproducing the recording data including the abnormal signal and confirming whether the optical recording medium is authentic according to whether or not the error-corrected data is changed.

In addition, the true detection method of the optical recording medium according to the present invention, in the reproduction method of the optical recording medium in which the abnormal signal that can be reproduced as two standard signals, at least one abnormal signal is included for each error correction unit Reading the recorded recording signal; An error correction step of causing the abnormal signal to be output as two standard signals according to the corrected parity upon repeated reproduction; And an authenticity checking step of discriminating the authenticity according to the detection of the two standard signals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, a true detection / replica prevention method of an optical recording medium according to the present invention and preferred embodiments of the apparatus will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a data recording processing apparatus employed in the authenticity detection and copy protection device of an optical recording medium according to the present invention. An apparatus for recording data of an optical recording medium according to the present invention includes a CIRC encoder (10) for error correction encoding input data; An EFM modulator 20 for modulating the encoded 8-bit data into 14-bit data; A shifter (30) for shifting (delaying) the modulated data by a predetermined length; And a multiplexer 40 which selects the modulated data and the error data by the control signal and outputs the selected data to the mastering device 50. The shifter 30 is for erroring one bit of the modulated data to, for example, approximately 0.5T or less.

The mastering device 50 is not a general system used in the related art, but has a laser cutting precision of about 0.5.T or less, and a pit that is about 0.5T in error, such as the ninth bit of the a 'symbol shown in FIG. It is also possible to record on an optical recording medium. However, when the 'a' symbol shown in Fig. 6 is recorded on the optical recording medium by using a conventional general mastering device, the a symbol or b symbol shown in Fig. 6 is not used because it has no accuracy of 0.5.T or less. Will be recorded.

In the CIRC encoder 10, two units of Reed Solomon encoders are used. They are referred to as C1 encoders and C2 encoders. C2 encoders encode 4 bytes of parity for 24 bytes of signal data. The 28-byte coded data encoded by the C2 encoder is encoded using another 4 bytes of parity. The C2 encoder C2 outputs a total of 28 bytes of code by placing the correction parity (for example, 4 bytes) generated by the correction parity generation unit in the center of the 24 bytes of test data inputted, and outputs a total of 28 bytes of code. C1) outputs a total of 32 bytes of code by placing the correction parity (for example, 4 bytes) of the correction parity generation unit last with respect to the 28 bytes of code encoded and input by the C2 encoder C2. Hereinafter, a signal of 1 byte is referred to as a symbol, and the modified parity will be described in detail below.

In the apparatus of FIG. 1, at the time of recording, the CIRC encoder 10 encodes at least one symbol of test data by adding a correction parity, and the EFM modulator 20 modulates and outputs the encoded data 8-14. do. Subsequently, the shift symbol 30 generates an error symbol by a predetermined length error for the inserted symbol, and the generated abnormal symbol is combined with the standard symbol in the multiplexer 40 to the mastering device 50. As input, the test data is recorded on the optical recording medium 60. At this time, at least one or more abnormal symbols are generated in the ECC block unit. The test data may be recorded in a large amount of about 1 track, for example, or a plurality of different data may be recorded in groups for the same data for authenticity detection.

In addition, a control program for authenticity detection and copy protection is also added to the parity through the CIRC encoder 10 and encoded, and then recorded on the disc in a state of 8-14 modulation by the EFM modulator 20.

The test data and the control program are recorded in a specific area of the optical recording medium, and are preferably recorded together with the header before recording the main data of the program area as shown in FIG. Here, the recording order of the test data and the control program may be changed, and the size of the header, the test data and the control program is preferably about 1 to 2 tracks. The header has respective test data, position information of the control program, and information for installing the control program on the host computer. The installation information may be located at the head of the control program recording area.

The format of the test data varies depending on the type of the optical recording medium. In this embodiment, audio CD and CD-ROM are described as examples of the optical recording medium.

As shown in FIG. 3, the test data format of the audio CD includes at least one or more abnormal symbols in units of ECC blocks, whereby parity is modified to be output in two signal forms after ECC processing during reproduction. In the figure, 24 symbols are test data of a coding unit encoded and input to the CIRC encoder 1, the first four parity symbols are modified parity of the C2 series, and the second four parity symbols are modified of the C1 series Parity. In addition, although the same figure shows the case where one symbol (13th symbol) of 24 symbols is an abnormal symbol, two or more symbols may be an abnormal symbol.

In addition, the test data format of the CD-ROM is the audio shown in FIG. 3 except that a correction parity is inserted into an EDC recorded after the 98 th 24 symbols as shown in FIG. Same as test data format for CD.

Next, a method of selecting test data and generating record data will be described in detail with reference to FIGS. 1, 5A, 6B and 6.

First, when one abnormal symbol is to be recorded in the test data, two reproduction target codes (A code and B code) consisting of 24 symbols are selected as shown in FIG. 5A, and the error correction parity for each is selected. These reproduction target codes are only 2 bits different when the EFM is modulated, and the remaining bits are the same (i.e., "0" is an 8-bit binary number and "01001000100000" when the EFM is modulated. Only 2 bits are different).

The reproduction target codes A code and B code are selected in consideration of the nature of the error correction minimum distance. Since the parity is 4 symbols, the minimum distance must be 5 or more, so the 4 symbol parity of the two codes is used. Each must have a different value. As examples of the a and b symbols, as shown in FIG. 6, the a symbol is a decimal "105" and the b symbol is a decimal "112", and when they are EFM modulated, "10000001000000" and "10000000100000", respectively. Becomes And parity (c, d, e, f) and parity (g, h, i, j) are 8-bit arbitrary values, respectively.

When the data of the A code as the test data is applied to the CIRC encoder 10, the correction parity generator causes the normal parity (c, d, e, f; g, h, i, j) to be corrected for the target reproduction code. In this case, in the case of two symbol error correction in the CIRC decoder 10, corrected parity (c, d, i, j) is generated, and error correction encoding is performed by the parity, and encoded data " 00-0a00-- --- 0cdij "is EFM modulated. Thereafter, only one specific bit (e.g., the eighth bit in the a code of FIG. 6) of the symbol a of the modulated data is changed by the shifter 30 to a symbol by a predetermined length (for example, 0.5T). In the multiplexer 40, the modulation data and the a 'symbol are combined and output as the recording data (00-0a'00 ----- 0cdij).

Next, when two or more abnormal symbols are to be recorded in the test data, as shown in FIG. 5B, two reproduction target codes (A code and B code) consisting of 24 symbols in consideration of the nature of the minimum error correction distance are shown. Select. Since the parity is 4 symbols and the minimum distance must be 5 or more, when two abnormal symbols exist in the test data, at least 3 symbols among the parity of the two codes must be different values, and the abnormal symbols in the test data are different. If three are present, at least two symbols among the parities of the two codes must be different values. In the embodiment of the figure, four abnormal symbols are recorded in the test data, and an example is given when two symbols of parity are the same (one symbol error correction).

When data of the A code (0a-0aa0-a --- 0) is applied to the CIRC encoder 10 as test data, the normal parity (c, d, e, f; g) for the target reproduction code is corrected by the correction parity generator. , h, e, f), in which case a corrected parity (c, h, e, f) is generated in case of one symbol error correction in the CIRC decoder, and error correction encoding is performed by the parity Data (0a-0aa0-a --- 0chef) is EFM modulated. Thereafter, only one specific bit (for example, the eighth bit in the a code of FIG. 6) of the symbol a of the modulated data is changed by the shifter 30 to a symbol by a predetermined length, and the multiplexer 40 changes the symbol to a '. The modulation data and the a 'symbol are combined and output as the recording data (0a'-0a'a'0-a' --- 0chef).

7 is a block diagram of a data reproduction processing apparatus employed in the authenticity detection and copy protection device of the optical recording medium according to the present invention. The data reproduction processing apparatus of the present invention includes: an optical pickup 110 for reading data from an optical disc 60 as an optical recording medium; An R / F unit 120 for filtering the signal detected by the pickup unit 110; An A / D converter 130 for converting the output analog signal of the R / F unit 100 into a digital signal; An EFM demodulator (140) for demodulating the digitally converted 14-bit signal into an 8-bit signal; A CIRC decoder (150) for error correction decoding the demodulated data; And a host 200 which checks whether the reproduction optical recording medium is authentic by using the reproduction test data and the control program, and controls the reproduction program to terminate the reproduction of the optical recording medium by the control program.

The host 200 includes a control unit 210 which controls the installation of a control program and determination of illegal copying; A memory 220 for storing the control program and the test data; And a display unit 230 which indicates to the user that the optical recording medium currently being reproduced is illegally copied when the illegality is determined by the controller 210.

Here, the CIRC decoder 150 employed in the CD-based optical disk driver performs error correction by decoding using the C1 and C2 decoders, and the C1 and C2 decoders use parity of 4 symbols, respectively. Meanwhile, in the error correction, the number of correctable symbols and the number of detection of error symbols can be variously set by four parities. The error processing capability is shown in Table 1 when the parity is 4 symbols, depending on the driver manufacturer. C1 and C2 can be selected using the nature of the minimum distance of error correction [minimum distance = (number of parity + 1)> (2 × (number of error correction possible) + (number of error detection))).

Error symbol correction count Error symbol detection count Mode 1 2 0 Mode 2 One 2 Mode 3 0 4

In the apparatus of FIG. 7, the header, test data, and control program read out from the optical disc 60 as the optical recording medium by the optical pickup 110 are connected to the R / F unit 120 and the A / D converter 130. After waveform shaping and digital conversion, the EFM demodulator 140 converts the data from 14 bits to 8 bits.

Here, in the optical disc driver 100, an undefined area which is not defined in any way between adjacent recording feet units (for example, 8T and 9T) is set. Therefore, when the abnormal symbols of the test data such as a 'of FIG. 6 are recorded on the optical disc, the abnormal symbols are read from the recording medium by the optical pickup 110 and digitally converted by the A / D converter 130. May be a symbol or b symbol shown in FIG. 6, and the output data of the EFM demodulator 140 may be the same.

The EFM demodulation data is then error corrected by the CIRC decoder 150 and then input to the host 200. The host 200 stores reproduction test data in the internal memory 220 based on the error corrected and input header (see FIG. 2), installs a control program for authenticity detection and copy protection, and controls the control. A program calculates a probability for the type of the stored reproduction test data (i.e., A code, B code; see FIGS. 5A and 5B), and confirms whether or not the reproduction optical recording medium is authentic according to the calculated probability.

Here, in the high-precision mastering device employed in the present invention, the a 'code shown in Fig. 6 can be recorded on the optical recording medium as the test data, but a conventional high-precision mastering device can be used. When the a 'code shown in 6 is recorded (when illegally copied), the a code or b code shown in FIG. 6 is actually recorded on the optical recording medium. Therefore, when the genuine optical recording medium is reproduced repeatedly, the test data (a 'code in FIG. 6) to be reproduced is reproduced in a code or b code, and the probability of occurrence thereof is almost the same. However, when the illegally reproduced optical recording medium is repeatedly reproduced, since the test data of the optical recording medium is recorded in a code or b code, the reproduced test data is reproduced by only one of a code and b code, Accordingly, the probability of occurrence of a code and b code is significantly skewed to either side.

Therefore, the control unit 210 of the host 200 generates the probability of occurrence of any one of reproduction test data (ie, A code, B code; see FIGS. 5A and 5B) by the installed control program. Or P '(b)] is significantly large, it can be determined that the optical recording medium is illegally reproduced, while the probability of occurrence [P' () of the form of the reproduction test data (i.e., A code, B code; see FIG. If a) and P '(b)] are almost similar, it can be judged that the optical recording medium is authentic.

In addition, when the controller 210 of the host 200 determines that the current playback recording medium is illegally copied (that is, when the probability of occurrence is shifted to either A code or B code) by the control program, The optical recording medium driver 100 is controlled to terminate the reproduction of the optical recording medium, and the display unit 230 is controlled to display a video, audio, text, or combination thereof that the optical recording medium currently being reproduced is illegally copied to the user. To display.

Next, a method of reproducing the recorded data will be described in detail with reference to Figs. 7 and 8A to 8C.

First, as shown in FIG. 8A, in the test data (00 --- 0a'00 ----- 0cdij) in which one abnormal symbol is recorded, the error processing capability is mode 1 (error correction of two symbols). Will be described. Here, as the test data, reproduction target codes (A code and B code) having one different value symbol at each arbitrary symbol position are selected, and parity different from all four symbols is selected, and the recording in FIG. It is recorded on the optical recording medium by the apparatus.

The test data recorded as described above is read by the optical pickup 110 and passed through the R / F unit 120, the A / D converter 130, and the EFM demodulator 140. 0a00--0cdij) and (00-0b00--0cdij)], where P (a) is the probability of being reproduced as data (00-0a00--0cdij). ), The probability P (b) to be reproduced is [1-P (a)]. Then, two types of data (00-0a00--0cdij) and (00-0b00--0cdij) are error corrected by the CIRC decoder 150, respectively (00-0a00--0cdef) and (00-0b00). --0ghij), where the probability [P '(a)] to be decoded to (00-0a00--0cdef) is equal to P (a) and the probability to be decoded to data (00-0b00--0cdij) [P '(b)' is also the same as [1-P (a)].

Here, the error symbol of the reproduction data (00-0a00--0cdij) is two symbols (ij), and the error symbol of the reproduction data (00-0b00--0cdij) is two symbols (cd). Since mode 1 (in case of error correction of two symbols), error symbols ij and cd of the reproduction data are error corrected by the CIRC decoder 150 and decoded into (ef) and (gh), respectively.

Subsequently, as shown in FIG. 8B, the error handling capability is set to Mode 2 (one in the test data 0a'-0a'a'0-a '-0chef) in which n or more abnormal symbols are recorded. The case of error correction of a symbol and error detection of two symbols) will be described. Here, as test data, reproduction target codes A code and B code having n (≥ 3) different values of symbols at arbitrary symbol positions are selected, and parity having two identical symbols at arbitrary positions is selected. It is selected and recorded on the optical recording medium by the recording apparatus of FIG.

The test data recorded as described above is read by the optical pickup 110 and passed through the R / F unit 120, the A / D conversion unit 130, and the EFM demodulator 140. 0aa0-a--0chef) and (0b-0bb0-b--0chef)], where the probability Pa to be reproduced as data (0a-0aa0-a--0chef) is (P (a) ) ⁿ are data (0b-0bb0-b - probability (Pb) to be reproduced by 0chef) is ^{(P (b)) n =} (1-P (a)) , and to ^n, the data (for the other For example, the probability Po to be reproduced with 0a-0bb0-b--0chef, 0b-0ab0-b--0chef, etc. becomes [1- (P (a)) ^n- (P (b)) ⁿ ]. . Here, n is the number of abnormal symbols in the recording data. When n = 4, Pa and Pb are 1/16 and Po is 14/16.

Thereafter, (0a-0aa0-a--0chef) and (0b-0bb0-b--0chef) of the EFM demodulation data are error corrected by the CIRC decoder 150, respectively (0a-0aa0-a-0cdef). And (0b-0bb0-b--0 ghef), where the probability P'a to be decoded with (0a-0aa0-a--0cdef) is equal to Pa and the data (0b-0bb0-b--0ghef). ), The probability P'b to be decoded is equal to Pb. Here, the reproduction data (0a-0aa0-a--0chef) has one error symbol (h), and the reproduction data (0b-0bb0-b--0chef) also has one error symbol (c), Since the error handling capability is mode 2 (error correction of one symbol and error detection of two symbols), error symbols (h, c) of the reproduction data are error corrected by the CIRC decoder 150, respectively (d). And (g). On the other hand, since the other reproducible data (for example, 0a-0bb0-b--0chef, 0b-0ab0-b--0chef, etc.) have at least two error symbols, the CIRC decoder 150 uses one or more errors. Only two symbols are error corrected, and two symbols are only error detected (i.e., error correction failed), and the probability P'o of such data occurrence is equal to Po.

Next, as shown in FIG. 8C, the error processing capability is mode 3 in the test data (0a'-0a'a'0-a'a '-0cdef) in which n (≥ 5) or more abnormal symbols are recorded. The case of (0 error corrections and 4 error detections) will be described. Here, as the test data, target codes A code and B code having n (≧ 5) different values of symbols at respective symbol positions are selected, and the same parity is selected, and the optical data is recorded by the recording apparatus of FIG. It is recorded on the recording medium.

The test data recorded as described above is read by the optical pickup 110 and passed through the R / F unit 120, the A / D conversion unit 130, and the EFM demodulator 140. 0aa0-aa--0cdef) and (0b-0bb0-bb--0cdef)], where the probability Pa to be reproduced as data (0a-0aa0-aa--0cdef) is (P (a) ) ⁿ are data (0b-0bb0-b - probability (Pb) to be reproduced as a chef 0) is (P (b) is a ^{n) n = (1-P} (a)), other data (for example, For example, the probability Po to be reproduced with 0a-0bb0-bb--0cdef, 0b-0ab0-bb--0cdef, etc.) is set to [1- (P (a)) ^n- (P (b)) ⁿ ]. do. Here, when n = 5, Pa and Pb are 1/32 and Po is 30/32.

Thereafter, (0a-0aa0-aa--0cdef) and (0b-0bb0-bb--0cdef) in the EFM demodulation data are error corrected by the CIRC decoder 150 and (0a-0aa0-aa--0cdef) and Decoded by (0b-0bb0-bb--0ghef), where the probability P'a to be decoded by (0a-0aa0-aa--0cdef) is equal to Pa and the data (0b-0bb0-bb--0cdef) The probability P'b to be decoded to be equal to Pb. On the other hand, since the other reproducible data (for example, 0a-0bb0-bb--0cdef, 0b-0ab0-bb--0cdef, etc.) has at least one or more error symbols, the CIRC decoder 150 uses 4 Only error detection (error correction failure) up to four symbols is possible, and the probability of occurrence of such data (P'o) is the same as Po.

Next, a process of CIRC for test data according to the present invention will be described in detail with reference to FIGS. 9A to 9I.

FIG. 9A is a diagram illustrating a data arrangement by C2 encoding and C1 encoding in a CIRC encoder in order to perform two error corrections by C1 decoding and C2 decoding in a CIRC decoder. In the case of the same figure, a C2 code generates a total of 28 symbols of C2 codes (28, 24) consisting of 24 symbols of test data and 4 symbols of parity. One error symbol a 'is selected at a predetermined position with respect to the code. In addition, C1 encoding generates a total of 32 symbols of C1 codes (32, 28) consisting of 24 symbols of the C2 coded data and four symbols of parity, where C1 codes (32, 28) are used for one code. One error symbol a 'is selected at a predetermined position. In the figure, symbols other than a ', c1, d1, i1, j1, c2, d2, i2, j2 are all "0", and the a' symbol is shown in FIG. 6 in the subsequent processing. It becomes a shifted outlier symbol.

As a result of error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is indicated by symbol a 'as shown by " 1 " The probability to be decoded by (see Fig. 6) is P (a), and the probability [P (b)] by which a 'symbol is decoded by b symbol (see Fig. 6) is 1-P (a).

FIG. 9B shows data of C2 encoding and C1 encoding in a CIRC encoder in order to perform two error corrections by C1 decoding and one error correction and two error detection by C2 decoding in a CIRC decoder. It is a figure which shows an arrangement. In the case of the figure, as the C2 codes 28 and 24 generated by C2 encoding, n error symbols a 'are selected at a predetermined position for one code (assuming n = 3 here). have. Further, the C1 codes 32 and 28 generated by C1 encoding are selected to have one error symbol a 'at a predetermined position for one code based on the a' position of the C2 code.

As a result of error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is indicated by symbol 'a' of FIG. The probability of decoding with (see Fig. 6) is (P (a)) ⁿ and the probability that the symbol a 'is decoded with b symbol (see Fig. 6) is (1-P (a)) ⁿ .

FIG. 9C shows data of C2 encoding and C1 encoding in a CIRC encoder in order to perform two error corrections by C1 decoding in a CIRC decoder and zero error correction and four error detections by C2 decoding. It is a figure which shows an arrangement. In the case of the figure, as the C2 codes 28 and 24 generated by C2 encoding, m error symbols a '(assuming n = 5) are selected at a predetermined position for one code. have. Further, the C1 codes 32 and 28 generated by C1 encoding are selected to have one error symbol at a predetermined position for one code based on the a 'position of the C2 code.

As a result of error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is indicated by symbol 'a' of FIG. The probability to be decoded by (see FIG. 6) is (P (a)) ^m , and the probability that a 'symbol is decoded by b symbol (see FIG. 6) is (1-P (a)) ^m .

FIG. 9D shows data of C2 encoding and C1 encoding in a CIRC encoder in order to perform one error correction and two error detection by C1 decoding and two error corrections by C2 decoding in a CIRC decoder. It is a figure which shows an arrangement. In the case of the same figure, as the C1 codes 32 and 28 generated by C1 encoding, n error symbols a 'are selected at a predetermined position with respect to one code (assuming n = 3 here). have. Further, the C2 codes 28 and 24 generated by the C2 encoding are selected to have one error symbol at a predetermined position for one code based on the a 'position of the C1 code.

As a result of the error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is indicated by the symbol 'a' of FIG. The probability of decoding with (see Fig. 6) is (P (a)) ⁿ and the probability that the symbol a 'is decoded with b symbol (see Fig. 6) is (1-P (a)) ⁿ .

FIG. 9E shows C2 encoding and C2 encoding in a CIRC encoder in order to perform one error correction and two error detection by C1 decoding and one error correction and two error detection by C2 decoding in the CIRC decoder. A diagram showing data arrangement by C1 encoding. In the case of the figure, as the C2 codes 28 and 24 generated by C2 encoding, n error symbols a 'are selected at a predetermined position for one code (assuming n = 3 here). have. In addition, as the C1 codes 32 and 28 generated by C1 encoding, n codes having n error symbols (assuming n = 3 here) at predetermined positions are based on the a 'position of the C2 code. Is selected.

As a result of error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is a symbol as shown by the number 5 in FIG. The probability to be decoded with (see FIG. 6) is (P (a)) ^{n * n} , and the probability that a 'symbol is decoded with b symbol (see FIG. 6) is (1-P (a)) ^{n * n} . do.

FIG. 9F illustrates C2 encoding and C2 encoding in a CIRC encoder in order to perform one error correction and two error detection by C1 decoding and zero error correction and four error detection by C2 decoding. A diagram showing data arrangement by C1 encoding. In the case of the figure, as the C2 codes 28 and 24 generated by C2 encoding, m error symbols a '(assuming m = 5) are selected at a predetermined position for one code. have. In addition, as the C1 codes 32 and 28 generated by C1 encoding, m codes having n error symbols (assuming n = 3 here) at predetermined positions are based on the a 'position of the C2 code. Is selected.

As a result of error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is indicated by symbol a (see FIG. 6). The probability to be decoded with (see FIG. 6) is (P (a)) ^{m * n} , and the probability that a 'symbol is decoded with b symbol (see FIG. 6) is (1-P (a)) ^{m * n} . do.

FIG. 9G shows data of C2 encoding and C1 encoding in a CIRC encoder in order to perform zero error correction and four error detection by C1 decoding and two error correction by C2 decoding in a CIRC decoder. It is a figure which shows an arrangement. In the case of the figure, m error symbols (a ') (assuming m = 5 in this case) are selected as the C1 codes 32 and 28 generated by C1 encoding at predetermined positions for one code. have. As C2 codes 28 and 24 generated by C2 encoding, codes having one error symbol at a predetermined position are selected based on the a 'position of the C1 code.

As a result of the error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is indicated by the symbol 'a' of FIG. The probability to be decoded by (see FIG. 6) is (P (a)) ^m , and the probability that a 'symbol is decoded by b symbol (see FIG. 6) is (1-P (a)) ^m .

FIG. 9h shows C2 encoding and C2 encoding in a CIRC encoder in order to perform zero error correction and four error detection by C1 decoding and one error correction and two error detection by C2 decoding. A diagram showing data arrangement by C1 encoding. In the case of the figure, as the C2 codes 28 and 24 generated by the C2 encoding, n error symbols a 'are selected at a predetermined position for one code (assuming n = 3 here). have. Further, as the C1 codes 32 and 28 generated by C1 encoding, codes having m error symbols (assuming m = 3 here) at predetermined positions are selected based on the a 'position of the C2 code. do.

As a result of the error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is indicated by the symbol 'a' of FIG. The probability to be decoded with (see FIG. 6) is (P (a)) ^{m * n} , and the probability that a 'symbol is decoded with b symbol (see FIG. 6) is (1-P (a)) ^{m * n} . do.

9i shows C2 encoding and C2 encoding in the CIRC encoder in order to perform zero error correction and four error detection by C1 decoding and C2 decoding in order to perform zero error correction and four error detection. A diagram showing data arrangement by C1 encoding. In the case of the figure, as the C2 codes 28 and 24 generated by C2 encoding, m error symbols a '(assuming m = 5) are selected at a predetermined position for one code. have. In addition, as the C1 codes 32 and 28 generated by C1 encoding, m codes having m error symbols (assuming m = 5 here) at predetermined positions are based on the a 'position of the C2 code. Is selected.

As a result of error correction by CIRC decoding of the reproduction data with respect to the data recorded on the optical recording medium by CIRC encoding as described above, the symbol 'a' (see FIG. 6) is indicated by symbol 'a' of FIG. The probability to be decoded with (see FIG. 6) is (P (a)) ^{m * m} , and the probability that a 'symbol is decoded with b symbol (see FIG. 6) is (1-P (a)) ^{m * m} . do.

Next, a method of generating a pattern of data and parity to be applied in the present invention will be described.

First, in the above-described embodiment, the data pairs for making test data recording data have been described using the decimal number 105 (10000001000010) and the decimal number 112 (10000000100010) as examples, but the data pairs shown in Table 2 below are the same. It is applicable.

No a data b data Decimal Binary number EFM conversion data Decimal Binary number EFM conversion data One 41 101001 10000001001000 80 1010000 10000000100100 2 49 110001 10000010001000 73 1001001 10000001000100 3 90 1011010 10010000000100 122 1111010 10010000000010 4 58 111010 10010000001000 90 1011010 10010000000100 5 73 1001001 10000001000100 80 1010000 10000000100100 6 81 1010001 10000010000010 105 1101001 10000001000010 7 59 111011 10001000001000 91 1011011 10001000000100 8 91 1011011 10001000000100 123 1111011 10001000000010 9 105 1101001 10000001000010 112 1110000 10000000100010

Subsequently, in the case of one error correction (i.e., having one abnormal symbol in the data), two symbols of parity in the pattern pair are the same. Thus, the probability that two symbols in the parity are the same in the pattern pair is 1 / (256 × 256) × ₄ C ₂ = 1/10922. In addition, at least three symbols among the 24 data symbols in the pattern pair must be different values (a and b values) according to the ECC characteristic, and three of the target data candidates (nine pairs in Table 2) must be selected. The number of searches for the target data pair is ₂₄ C ₃ × 18 ³ = 11803968.

However, the present inventors have the same parity result even if an arbitrary symbol pair is changed in the pattern pair, and the "" + "(GF SUM)" of any symbol pair is the same pair [(90,122) and (91,123); (105, 112) and (73, 80); (58,90) and (59,91)] can be reduced to six (90,105,41,58,49,81) of the 18 target data candidates by the ECC linear characteristic of having the same parity result. In consideration of this, as a result of searching for the target data pair, it was found that the number of searches was significantly reduced to ₂₄ C ₃ × 6 ³ = 437184. This can reduce the time by approximately 27 times as compared to the conventional method, and the simulation was performed in Ultra Spark 1, which took about 10 minutes.

Next, in the case of zero error correction (i.e., having five abnormal symbols in the data), all symbols of parity in the pattern pair are the same. Therefore, the probability that the four symbols of parity in the pattern pair are the same is 1 / (256 × 256 × 256 × 256) = 1/4294967296. In addition, at least five symbols among the 24 data symbols in the pattern pair must be different values (a and b values) according to the ECC characteristic, and five of the target data candidates (nine pairs in Table 2) must be selected. The number of searches for the target data pair is ₂₄ C ₅ × 18 ⁵ = 80314198272.

However, in view of the fact that the 18 target data candidates can be reduced to 6 due to the above-described ECC linear characteristics, the present inventors searched for a target data pair, and the number of searches was ₂₄ C ₅ × 6 ⁵ = 33051104. It was found to decrease significantly. This can reduce the time by about 243 times compared to the general method, and the simulation was performed with Ultra Spark 1, which took about 400 minutes.

Next, a method of recording the test data and the control program on the optical recording medium will be described with reference to the flowchart of FIG.

First, to generate an abnormal symbol, as shown in Table 2, at least one symbol pair having two different bits is selected, and at least one symbol of the selected symbol pair is included and the remaining symbols Twenty-four symbols of "0" are selected as test data (step S11). Here, 24 symbols including at least one symbol of the selected symbol pair and the remaining symbol is "0", and at least one other symbol of the selected symbol pair and the remaining symbols are "0". The 24 symbols "" become reproduction target data output during reproduction.

Thereafter, the selected set of test data; A control program for performing authenticity detection control and copy protection control of the optical recording medium; And header data having position information of each of the test data, the control program, and information for installing the control program on the host computer (step S13).

Subsequently, an error correction parity is generated for the input data, and the generated parity is corrected and generated for the test data as shown in FIGS. 5A and 5B (step S15).

Next, error correction coding (eg, CIRC) is performed on the test data using the modified parity, and error correction coding is performed on the control program and header data using the unmodified parity. Then, EFM conversion is performed on the error correction coded test data, control program and header data (step S17).

Thereafter, in the reproduction target data (symbols other than "0") of the EFM-converted test data, only bits having a value of "1" among bits having different values when selecting the symbol pair have a predetermined length (e.g., For example, by shifting the output by 0.5T), an abnormal symbol such as the a 'symbol of FIG. 6 is generated and synthesized with the remaining data to generate test data having an abnormal symbol (step S19).

Subsequently, the test data having the abnormal symbol, the control program and the header data are applied to the mastering device to record these data on the optical recording medium (step S21).

Next, a method of detecting the authenticity of the optical recording medium by the test data and the control program recorded on the optical recording medium and preventing the illegal copying of the optical recording medium will be described with reference to the flowchart of FIG.

First, in the optical recording medium driver, the header, the test data, and the control program recorded on the optical recording medium are read by the optical pickup 110 (step S31). The read data are waveform-formed and digitally converted through the R / F unit 120 and the A / D converter 130, and then converted into 14-bit to 8-bit data by the EFM demodulator 140, followed by a CIRC decoder ( 150) error correction decoding (step S33). Here, the error correction is performed by the test data as shown in FIGS. 8A to 8C and 9A to 9I.

Thereafter, the error corrected header, test data and control program are input to the host 200, and the host 200 stores the test data in the internal memory based on the header and installs the control program (step S35). .

Subsequently, the host 200 compares the stored test data with the two pieces of reproduction target data by the control program, and calculates a probability that the test data is reproduced with each piece of reproduction target data (step S39).

Next, the host 200 determines whether the optical recording medium currently reproduced is authentic based on the calculated probability (steps S41 and S43). Here, when the optical recording medium is authentic, the test data is reproduced as two reproduction target data, and their occurrence probability is almost the same. However, when the illegally reproduced optical recording medium is reproduced, the test data of the optical recording medium is reproduced to either one of the two reproduction target data, so that the probability of occurrence of the reproduction target data is significantly shifted to either side.

Thereafter, when the optical recording medium is determined to be authentic, the host 200 controls the optical recording medium driver 100 to reproduce subsequent data stored in the optical recording medium (step S45), and then ends playback by the user. If this is done, playback ends (step S47). On the other hand, if the host 200 determines that the optical recording medium is illegally copied, the host 200 records the corresponding optical recording by video, text, sound, or a combination thereof to inform the user that the optical recording medium currently being reproduced is illegally copied. It indicates that the medium has been illegally copied, and the control program controls the optical recording medium driver 100 to forcibly terminate the reproducing operation (step S49).

On the other hand, the present invention is not limited to the above specific embodiments, it can be carried out by variously modified and modified within the scope not departing from the gist of the present invention.

For example, in the above-described specific embodiment, a case in which the same test data is recorded in a large amount of about one track or a plurality of different test data are grouped and recorded for the same data has been described. A small amount of the same test data (e.g., one error correction block or one sector) is recorded on the recording medium, and the small amount of test data is repeatedly reproduced by a predetermined number of times according to the control of the control program. The authenticity of the optical recording medium may be determined based on the frequency of occurrence.

In addition, in the above specific embodiment, the audio CD and the CD-ROM which record data by converting 8-14 bits as an optical recording medium have been described. It is applicable to any optical recording medium in which only two consecutive bits of the recording data codes exist.

In addition, in the specific embodiment described with reference to FIGS. 9A to 9I, a case in which symbols other than the error symbol a 'are set to "0" symbols in the test data has been described. Symbols other than (a ') may be set to arbitrary symbols.

As described above, according to the method and apparatus for detecting and copying an optical recording medium according to the present invention, an optical recording medium includes a test data and an authenticity detection control program including an abnormal symbol that can be reproduced by two standard symbols. It is recorded in a specific area on the screen, and when the playback is performed, the control program detects the authenticity of the optical recording medium according to the reproduction type of the test data, and if the copy is illegal, the playback is terminated. It can exert a powerful effect.

According to the present invention, since the error symbol encoding and decoding of the optical recording medium are selected in consideration of the error symbol and error correction parity of the test data, compatibility with any driver can be achieved.

In addition, according to the present invention, illegal copying can be prevented without adding additional hardware or programs to the optical recording medium driver, and thus it can be easily applied to an existing optical recording medium driver.

Claims (15)

In the method of generating an abnormal signal that can be reproduced with two standard signals during repeated playback, and recording on an optical recording medium, A first step of generating error correction parity meeting a preset condition on at least one or more pieces of recording data; And And converting the recording data corresponding to the generated parity into an abnormal signal and recording the recording data onto the recording medium. The method of claim 1, The preset condition of the first step is a data recording method of an optical recording medium, characterized by combining error correction parity with respect to two standard signals represented by the abnormal signal. The method of claim 1, And wherein said second step determines the number of said abnormal signals included in said recording data at a predetermined interval of error correction processing in consideration of the error correction capability at the time of reproduction. A method of recording data on an optical recording medium; A first step of selecting at least one pair of standard symbols in which only two consecutive bits are different from each other; Selecting a recording data including at least one standard symbol from the pair of standard symbols; A third step of correcting an error correction parity for the recorded data; A fourth step of converting one bit of the two bits into an abnormal symbol with respect to a standard symbol included in the recording data; And And a fifth step of recording the recording data including the abnormal symbol and the correction parity on the optical recording medium. The method of claim 4, wherein In the first step, a plurality of pairs of standard symbols different from each other in only two consecutive bits are selected. In the second step, by using a linear characteristic of the error correction code, a search area of an error correction code having a part of parity added is reduced to search for and generate an error correction data pattern pair to select as record data. Data recording method of optical recording medium. The method of claim 5, The reduction of the search area may include selecting one of a plurality of standard symbols respectively present in different pairs and selecting a standard symbol having a value equal to two sums (GF SUM) of the standard symbols in the plurality of selected standard symbols. And reducing the object of the error correction code by removing the data recording method. The method of claim 4, wherein The third step is Generating error correction parity for each of the selected record data and corresponding data including the same number of other standard symbols of the pair of standard symbols at positions corresponding to the selected record data; And And a correction step of combining the generated parity in consideration of error correction capability during reproduction. The method of claim 4, wherein The second step is a data recording method of an optical recording medium, characterized in that for determining the number of the standard symbols included in the recording data in consideration of the error correction capability. An apparatus for generating an abnormal signal that can be reproduced with two standard signals upon repeated reproduction, and recording the same on an optical recording medium. Parity generating means for generating error correction parity meeting a preset condition on at least one or more pieces of recording data; And And recording means for converting the recording data corresponding to the generated parity into an abnormal signal and recording the recording data onto the recording medium. At least one or more abnormal signals that are error corrected by the corrected recorded parity and can be reproduced as two standard signals are recorded. The method of claim 10, And the at least one abnormal signal is recorded in a test area for authenticity verification on the optical recording medium. The method of claim 10, When reproducing the recording data including the abnormal signal, a control program for checking the authenticity of the optical recording medium according to the frequency of reproducing each of the standard signals and performing an operation according to the standard signal is further recorded. Optical recording medium to prevent illegal copying. In the method of reproducing an optical recording medium having recorded data including an abnormal signal capable of being reproduced by two standard signals and a control program for performing an operation according to the existence of the abnormal signal, A first step of reading and operating the control program; And And a second step of the control program repeatedly reproducing the recording data including the abnormal signal and confirming whether the optical recording medium is authentic according to whether or not the error-corrected data is changed. Authenticity detection / replica prevention The method of claim 13, According to the verification result, the present invention further comprises a third step of indicating that the currently mounted optical recording medium is illegally copied or forcibly terminating the subsequent reproduction of the optical recording medium. / How to avoid cloning. In the method of reproducing an optical recording medium on which an abnormal signal that can be reproduced by two standard signals is recorded, Reading a recording signal including at least one abnormal signal for each error correction unit; An error correction step of causing the abnormal signal to be output as two standard signals according to the corrected parity upon repeated reproduction; And Authenticity detecting step of authenticating the authenticity according to the detection of the two standard signals.