JP2002203369A - Optical disk, reproducing method and apparatus and recorder for the optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk for preventing the illegal copy of a digital work recorded thereon, and to provide a reproduction method, apparatus and recorder of the optical disk. SOLUTION: An optical disk 10 has a control region 12 on which control information is recorded, a data region 14 on which main digital information is recorded, and an identification region 13 on which sub-digital information being peculiar to the main digital information is recorded. In the identification region 13, pit sequences are recorded as sub-digital information with clock timing which is locally phase-modulated. In the case the identification information of the disk if recorded as sub-digital information, key information stored into the recorder and identification information (sub-digital information) detected from the fluctuation of the jitter value in the identification region 13 are compared at the time of playback of the optical disk 10. When a correlation is found between them, it is judged that the disk is authorized and reproduction is permitted, thereby preventing illegal copying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium (optical recording medium) for reproducing information by irradiating a converged light beam onto a recording medium and detecting reflected light from the recording medium. is there.

[0002]

2. Description of the Related Art DVD (Digital Versat)
2. Description of the Related Art Optical disks represented by ile / video discs are widely used as media for recording large-capacity digital data such as AV (Audio Video) data and computer data. For example, a high-quality moving image of two hours or more is recorded on a DVD-ROM and sold.

In order to ensure sound distribution of such digital works, there is a need for a technique for preventing a digital work on a recording medium from being illegally copied to another recording medium.

[0004] As a conventional technique for preventing unauthorized copying,
There is a method called content encryption (see Nikkei Electronics Nov. 18, 1996, p. 13-14). FIG. 33 shows a general recording area of a DVD. As shown in FIG.
Has an information area 20a accessible to the user in which the content is stored, and a control information area 20b inaccessible to the user. In the conventional method, compressed digital content such as a movie is encrypted using a three-layer secret key (title key, disk key, master key), and then the encrypted content is stored in an information area accessible to the user. 20a. Of the encryption keys, the most important master key is notified only to the authorized DVD device manufacturer, and the disc key and title key required for each DVD and each title are After encryption based on the master key, it is stored in a control information area (lead-in area) 20b that cannot be accessed by the user.

[0005] This makes it impossible for an unauthorized DVD playback device without a license to decrypt the encrypted content. Therefore, a large number of DVDs on which a digital work in an unencrypted state is recorded are manufactured and sold. Misconduct such as doing so is prevented.

[0006]

However, such a conventional technique cannot prevent the occurrence of a so-called pirated copy. In other words, when the contents of the entire storage area of the DVD including the control information area are directly copied to another DVD, the encrypted content is read by a licensed DVD device in the same manner as a regular DVD. Issued and decrypted.

FIG. 13 shows an example of the dead copy method.
This will be described with reference to FIG. In FIG. 13, the rotations of the spindle motors of the copy source optical disk 20 and the copy destination optical disk 20 ′ are completely synchronized, and the data on the optical disk 20 is reproduced via the reproduction head 2003. The reproduction signal is amplified by a reproduction amplifier 2004, binarized by a binarization circuit 2005, and output to a PLL (Phase Locked Loop) circuit 20.
06. The PLL circuit 2006 generates a clock signal 2010 based on the input signal. The output signal of the binarization circuit 2005 is synchronized and output by the flip-flop 2007 at the timing of the clock signal 2010, and is input to the optical modulator 2008. The optical modulator 2008 generates an optical modulation signal from the input signal, and
9 on an optical disk 20 '.

In this way, if the entire area of the optical disc, including the area 20b inaccessible to the user, is completely copied onto another optical disc, it cannot be distinguished from a legitimate optical disc, so that the content is decoded. There was a problem of getting it.

[0009] With this, even if it is possible to prevent unauthorized production of a DVD storing the encrypted content, it is possible to prevent illegal operation of illegally copying the DVD storing the encrypted content as it is. Can not. If such a pirated version were to be available on the market at low cost, the copyright of the content would be violated.

Accordingly, the present invention has been made in view of such a problem, and an optical disk capable of preventing an optical disk on which a digital work has been recorded from being illegally copied as it is, a recording / reproducing apparatus for the optical disk, and the like. An object of the present invention is to provide a recording and reproducing method.

[0011]

An optical disk according to the present invention is superimposed on main digital information recorded by an optically readable recording mark by displacing the position or shape of the recording mark by a very small amount. An optical disc having sub-digital information, wherein a plurality of areas for storing the same sub-digital information are provided for one content recorded by the main digital information.

Another optical disk according to the present invention comprises a main digital information recorded by an optically readable recording mark and a sub digital information superimposed and recorded by displacing the position or shape of the recording mark by a very small amount. An optical disc having a plurality of areas for storing different sub-digital information for one content recorded by the main digital information.

In the above optical disc, different sub-digital information may be provided for different contents recorded by the main digital information.

[0014] In the above optical disc, the sub-digital information may be formed in an area different from a data area in which content is recorded by the main digital information.

Still another optical disc according to the present invention is an optical disc on which main digital information is recorded by an optically readable recording mark, by displacing the position or shape of the recording mark by a very small amount. Is superimposed and recorded, and the sub-digital information is formed in an area different from the data area where the content is recorded by the main digital information and the control area where the control information is recorded.

According to the present invention, there is provided a method for reproducing an optical disk, wherein the position or shape of the recording mark in the track direction is displaced by a very small amount on an optical disk on which main digital information is recorded by optically readable recording marks. In a method of reproducing an optical disk on which sub-digital information is superimposed and recorded, a pattern is formed based on the sub-digital information, and the pattern is compared with predetermined key information. Restrict playback of recorded content.

Still another optical disk according to the present invention is an optical disk on which main digital information is recorded by optically readable recording marks, and the edge positions of the recording marks are shifted by a very small amount in the track direction by phase modulation. When the sub-digital information is recorded, the sub-digital information is formed at one of a position where the phase is advanced or delayed by a certain small amount with respect to the edge position of the recording mark when only the main digital information is recorded, and The sub-digital information management information necessary for extracting information is recorded in advance.

Another optical disk reproducing apparatus according to the present invention comprises:
The main digital information is recorded by an optically readable recording mark, and the sub-digital information is recorded by phase modulation in which the edge position of the recording mark is displaced by a very small amount in the track direction, and only the main digital information is recorded. The sub-digital information management information necessary for extracting the sub-digital information is formed in one of the position where the phase is advanced or delayed by a certain small amount with respect to the edge position of the recording mark in the case, and the sub-digital information is recorded in advance. Playback means for playing back main digital information from the optical disc, and sub-digital information extraction means for extracting sub-digital information.

An optical disk recording apparatus according to the present invention is an apparatus for recording main digital information by forming an optically readable recording mark, and displaces the edge position of the recording mark in a track direction by a very small amount. A sub-digital information recording unit for recording sub-digital information by phase modulation is provided. The sub-digital information recording means forms, based on the sub-digital information, an edge position of the recording mark corresponding to the main digital information at one of a position where the phase is advanced by a certain small amount and a position where the phase is delayed, and Means are provided for recording on the optical disc the sub-digital information management information necessary for extracting digital information.

Still another optical disk according to the present invention is an optical disk on which main digital information is recorded by optically readable recording marks, wherein the position or shape of the recording marks is changed by a very small amount to make the sub-digital information. Information is recorded, and the main digital information is encrypted with the sub digital information.

Still another optical disk recording apparatus according to the present invention is an apparatus for recording main digital information by forming an optically readable recording mark, wherein the position or shape of the recording mark is changed by a very small amount. A sub-digital information recording means for recording the sub-digital information by means of the sub-digital information;

Still another optical disk reproducing apparatus according to the present invention is an apparatus for reproducing main digital information by detecting a recording mark formed on an optical disk, wherein the apparatus reproduces main digital information from a channel signal corresponding to a row of detected recording marks. Sub-digital information extracting means for extracting sub-digital information, and main digital information decoding means for decoding encrypted main digital information based on the sub-digital information extracted by the sub-digital information extracting means.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a configuration diagram of an optical disk according to Embodiment 1 of the present invention. As shown in FIG. 1, the optical disc 10 has a control area 12 in which control information and the like are recorded, an identification area 13, and a data area 14 in which contents are recorded.

In the identification area 13, a pit train is recorded at the timing of a clock in which the reference clock is locally phase-modulated. The pit train recorded by such phase modulation is detected as a portion having large jitter at the time of reproduction. In the identification area 13, the discrimination information of the disc and the time of large and small jitters generated by combining such a large jitter portion and a normal jitter portion are superimposed.

Regardless of the presence or absence of phase modulation of the clock, the normal information of the pattern of the pit train is referred to as “main digital information” and the difference between the reproduction performance of the pits subjected to phase modulation and the pits not subjected to phase modulation. The information obtained by using is called “sub-digital information”. In the present embodiment, the sub digital information is disc identification information, but may be other information.

FIG. 2 is an enlarged view of the identification area 13. FIG.
As shown in the figure, regions R2 and R4 recorded at the reference clock timing and regions R1, R3 and R5 recorded at the phase-modulated clock timing exist on the track Tr. During reproduction, large jitter is detected in the regions R1, R3, and R5.

The length of each of the regions R1 to R5 may be made equal to the length of one or more sectors in units of sectors. Further, the length of one or more error correction blocks or tracks may be made equal to the length of one or more error correction blocks or tracks. Alternatively, an arbitrary length may be used as a unit as long as the length is equal to or longer than a predetermined length necessary for the reproducing apparatus to detect the magnitude of the jitter.

By lengthening one area recorded at the phase-modulated clock timing, identification information can be correctly reproduced even if there is a flaw or the like in the area. Similarly, by lengthening one area recorded at the reference clock timing, even if there is a flaw or the like in the area, it is possible to reduce the risk of erroneous detection with the area where the identification information is recorded.

In the regions R1, R3 and R5, all the pits may be recorded at the timing of the phase-modulated clock, or only some of the pits may be recorded at the timing of the phase-modulated clock. good. FIG. 3 shows a case where a 3T signal is recorded as an example of a pit recorded at the timing of a phase-modulated clock.

In FIG. 3, pits 31 to 35 are pits representing 3T signals, and vertical lines represent clock timing. The cycle of the clock is T. The pit 31 is a pit recorded at the reference clock timing. The pit 32 is a pit when both edges of the pit are recorded with clock timing phase-modulated forward with respect to the time axis. The pit 33 is a pit when both edges of the pit are recorded at the clock timing phase-modulated backward with respect to the time axis. Pit 34
Is the case where the starting edge of a pit is recorded at a clock timing that is phase modulated forward with respect to the time axis, and the ending edge of the pit is recorded with a clock timing that is phase modulated backward with respect to the time axis. It is a pit. In the pit 35, the start edge of the pit is recorded at a clock timing that is phase-modulated backward with respect to the time axis, and the end edge of the pit is recorded with a clock timing that is phase-modulated forward with respect to the time axis. The pit in case.

In addition to the above, only one of the edges may be recorded at a phase-modulated clock timing. By recording with a partially phase-modulated clock in this way, the jitter increases in the regions R1, R3, and R5, and disc identification information can be added according to the magnitude of the jitter value in each region. . It is desirable that the phase error actually added is set so as to obtain sufficient detection sensitivity without increasing the error of the reproduction signal. It is considered that about 1/8 to 1/4 of one clock cycle is appropriate as an amount satisfying these two conditions.

As described above, in the identification area 13, there is an area where jitter is locally large, and there is a high risk that recorded information cannot be correctly reproduced as compared with other areas. Therefore, as in the present embodiment, the identification area 13 is a dedicated area for determining whether the disc is a regular disc. That is, by providing the identification area 13 separately from the control area 12 and the data area 14, information necessary for reproducing the disc recorded in the control area 12 and the content recorded in the data area 14 can be correctly reproduced. can do.

Also, by making the identification area 13 a dedicated area, the main digital information of the dedicated area 13 can be arbitrarily designed by the disc manufacturer. For example, disc identification information can be included in the main digital information. it can. By combining the identification information in the main digital information and the identification information in the sub-digital information, it is necessary to copy both information accurately when performing unauthorized copying, making creation of an unauthorized disk more difficult. be able to.

When it is not necessary to provide the main digital information in the identification area 13 with special information, a pit having a large jitter such as the shortest mark and a pattern not including the pit interval may be recorded. As a result, the jitter in the region where the clock phase modulation is not performed can be reduced, the dynamic range between the region where the clock phase modulation is not performed and the region where the clock phase modulation is performed is expanded, and the Erroneous detection can be reduced even when jitter is entirely deteriorated due to contamination of the reproducing head or the like. The above effect can also be realized by not performing phase modulation of a clock when forming a pit having a large jitter such as the shortest mark in an arbitrary pattern.

Similarly, when it is not necessary to provide the main digital information in the identification area 13 with special information, a pattern including many patterns used for synchronization pull-in may be used. As a result, the margin until the PLL pulls out of synchronization is expanded, the area for clock phase modulation is increased, and sub-information can be detected accurately.

In this embodiment, the discrimination area 13 is a dedicated area for disc discrimination. However, when the same main digital information is repeatedly recorded in the control area 12 or the data area 14 or when error correction or the like is performed. If the main digital information can be correctly reproduced even if the jitter increases, the identification area 13 may be provided so as to overlap the control area 12 or the data area 14, or a part of the identification area 13 may be provided in the control area 12 or the data area. It may overlap with the area 14. Thereby, the capacity of the data area 14 can be increased.

Whether the identification area 13 is in the dedicated area, in the control area 12, or in the data area 14, or whether a part of the identification area 13 overlaps the control area 12 or the data area 14, etc. Whether the optical disk 10 is a legitimate disk may be determined based on the information on the location where the identification area 13 exists.
For example, in the case of a legitimate disc, when a part of the identification area 13 overlaps the control area 12, if the sub information is not detected from the control area 12 when reproducing a certain disc, it can be determined that the disc is not a legitimate disc. .

The location information of the identification area on the regular disc may be recorded at a predetermined location on the optical disc 10, may be stored in a reproducing device, or may be obtained from a network or other external device by a billing system or the like. Alternatively, the information may be obtained by attaching an IC card on which information is recorded to a playback device.

When the information is obtained by a billing system, a method may be used in which the information is obtained in combination with the playback apparatus specific information. By combining the information with the playback device-specific information, when one optical disc is played back by a different playback device, a fee can be charged from each playback device.

When the location information is at a predetermined location on the disc, the location information may be at a plurality of locations. By being at a plurality of locations, location information can be obtained more reliably. Further, the location information itself may be recorded as sub-digital information.

FIG. 4 is a block diagram of a reproducing apparatus that detects identification information recorded as sub-information in the identification area 13 and determines whether the disc is a legitimate disc. As shown in FIG. 4, the reproducing apparatus includes a reproducing head 401, a reproducing amplifier 402, a binarizing circuit 403, a PLL circuit 404, a phase comparator 406, an amplitude detector 408, a low-pass filter (LPF) 409, a voltage-controlled oscillation. Circuit (VCO) 41
0, a flip-flop 411, a pattern comparator 418, and a digital signal processing unit 420. Hereinafter, the determination procedure will be described.

First, the reproducing head 401 reproduces the identification area 13 of the optical disk 10 according to the above-mentioned location information. The reproduction signal is amplified by the reproduction amplifier 402, binarized by the binarization circuit 403, and the signal 405 is
04 is input. The PLL circuit 404 generates a clock signal 414 based on the signal 405. With the timing of the clock signal 414, the signal 405 is synchronized in the flip-flop 411, and the obtained reproduced signal 412 is obtained.
Is input to the digital signal processing unit 420.

In the PLL circuit 404, the phase comparator 406 compares the phase of the reproduced clock signal 414 output from the VCO 410 with the phase of the signal 405, and outputs a signal 407. LPF 409 generates signal 416 by band-limiting signal 407. The VCO 410 generates a reproduced clock signal 414 according to the signal 416.

Here, the fluctuation of the signal 405 is
4, the clock signal 414
Does not follow the fluctuation, and the PLL circuit 404 does not try to deviate from the original clock. Therefore, the phase between the clock and the signal edge is applied to the signal 407 in the partially phase-modulated regions R1, R3, and R5. Jitter, which is an error, occurs.

The amplitude detector 408 outputs a signal 413 by, for example, rectifying, smoothing, and binarizing the signal 407, and can recognize identification information based on the pattern of the signal 413.

FIG. 5 is a timing chart of each signal at the time of reproduction of each of the regions R1 to R5 shown in FIG. FIG. 5 (a)
5 shows the respective regions R1 to R5 shown in FIG. 2, and FIG. 5B shows the signal 407 at the time of reproduction of those regions, and FIG.
5 shows the signal 416, and FIG. 5D shows the signal 413.

Subsequently, the pattern of the signal 413 and the pattern of the key information 417 are compared in the pattern comparator 418, and the signal 419, which is the result of the comparison, is input to the digital signal processing section 420. The key information 417 will be described later. The digital signal processing unit 420 performs error correction, demodulation, and the like of the signal 412. If the pattern of the signal 413 matches the pattern of the key information 417, the digital signal processing unit 420 outputs a normal reproduction signal 421. If the patterns do not match, the signal 419 restricts reproduction. Regarding the restriction on the reproduction, the reproduction may not be performed at all, the transfer rate may be reduced to deteriorate the image quality, or the reproduction may be intermittent.

Further, by generating phase modulation forward in the time axis such as pit 32 in FIG. 3 and phase modulation backward in the time axis such as pit 33 uniformly, the average value of the phase error becomes zero. Thus, it is possible to make it harder to follow the edge due to the phase modulation recording of the PLL.

On the other hand, in the normal reproduction of information, since the reproduction clock does not follow the fluctuation of the reproduction signal due to the phase modulation as described above, the signal 405 output from the binarization circuit 403 is latched by the flip-flop 411. Then, a reproduced signal from which jitter has been removed can be output.
Similarly, in the case of illegally copying a disk using the apparatus shown in FIG. 13, when synchronization is performed by the flip-flop 2007, jitter as a source of identification information is removed, and the identification information is lost. , It can be determined whether the disk is unauthorized.

Next, the key information 417 will be described. As a method of determining whether or not a disc has been illegally copied, for example, when creating an optical disc medium, key information having a unique relationship with the identification information recorded by the above-described clock phase modulation is usually stored in the identification area 13. The discrimination information is recorded on the disc as discrimination information, and the discrimination information detected by the fluctuation of the jitter value during reproduction is compared with the key information. Only when there is a correlation, it is determined that the disc is a regular disc.

Specifically, the key information 417 is "1010
In the case of the pattern “1”, the identification area 13 of the optical disc 10 is reproduced, and the H level is set to 1 and the L level is set to 0 and 1 in the signal 413 output from the amplitude detector 408.
If the pattern starting with "10101" is "10101", the key information and the identification information match, so that the optical disk 10 can be determined to be a legitimate disk.

Note that the key information on the regular disc may be recorded at a predetermined location on the optical disc 10, may be stored in a reproducing apparatus, or may be obtained from an external device such as a network by a charging system or the like. Alternatively, the information may be obtained by mounting an IC card on which information is recorded in a reproducing apparatus.

When the information is obtained by the billing system, the obtaining method may be combined with the reproduction apparatus specific information. By combining the information with the playback device-specific information, when one optical disc is played back by a different playback device, a fee can be charged from each playback device.

When the key information is located at a predetermined location on the disk, the key information may be located at a plurality of locations. By being at a plurality of locations, key information can be obtained more reliably. Further, the key information itself may be recorded as sub-digital information.

In the present embodiment, recording is performed in a specific area at the clock timing phase-modulated so that a jitter difference is generated between the other area recorded at the reference clock timing and the jitter of each area. Although a pattern serving as identification information is configured by having information of large and small temporal arrangements, if the identification information is configured using recording at a phase-modulated clock timing, the pattern length and The configuration method is not limited to this. For example, the identification information may be a simple pattern having only one large jitter portion, or may have a specific pattern at the head of the pattern indicating identification information, and the rest may be dummy patterns.

In the present embodiment, it is determined whether or not the playback disk is a regular disk by using a playback device as shown in FIG. 4. However, an area recorded at a phase-modulated clock timing and A reproducing apparatus for detecting a jitter difference between other areas recorded at a reference clock timing, extracting a pattern, comparing the pattern with key information, and determining whether the disc is a regular disc based on the comparison result. May have different configurations.

For example, if it is possible to recognize that each mark is recorded at a phase-modulated clock timing, the number of such marks appearing in a certain area is counted, and the counted number is set to a certain threshold. If it exceeds, it may be determined to be "1", and if not, it may be determined to be "0". At this time, a specific gate may be provided, and when the gate is at the H level, the number of appearances of marks recorded at the phase-modulated clock timing may be counted.

If it is possible to recognize that the leading and trailing edges of each mark are recorded at the phase-modulated clock timing, the number of such edges appearing in a certain area is counted, and there is a count number. If it exceeds the threshold value, it may be determined to be "1", and if not, it may be determined to be "0". At this time, a specific gate may be provided, and when the gate is at the H level, the number of occurrences of the edge recorded at the phase-modulated clock timing may be counted.

The above judgment will be described in more detail with reference to a table. For example, when data of the Run Length Limited (2, 10) modulation method is recorded by the mark edge recording method, there are marks and spaces from the shortest 3T to the longest 11T. Here, “T” represents a reference cycle.

Table 1 shows a table of phase-modulated edges. For example, “3S3M” indicates a phase modulation to the front end of the 3T mark in a signal in which a 3T space is followed by a 3T mark. Similarly, “4M5S” is 4T
4T in a signal with 5T space after mark
This shows phase modulation to the rear end of the mark. Marks and spaces longer than 6T are classified into four types for marks and spaces as the same table as 6T, but the classification method is not limited to this. Instead of a combination of a mark and a space, a table of only a mark or a space may be created as described above.

[Table 1]

Table 2 is a table showing key information obtained by adding a threshold to the table of Table 1. In a predetermined area of the disk, the number of appearances of each edge recorded at the phase-modulated clock timing is counted, and for example, phase modulation (3S3M) to the front edge of the 3T mark in a signal having a 3T space followed by a 3T mark Is more than 10 counts and the phase modulation (5S6M) to the leading edge of the 6T mark or more is 20 counts or more in the signal where the 5T space is followed by the 6T mark and the 5T space is followed by the 5T space. The phase modulation (4M5S) to the trailing edge of the 4T mark is 30 counts or more, and the count number at the other edges is 1
When the count is less than 0, it is determined that the disc is a regular disc.

[Table 2]

Although the above description is directed to the case where the table is used as key information for determination, the table may be used as a specific gate. This case will be described with reference to Table 3. In a predetermined area of the disc, for example, the number of appearances of the phase modulation edge at the leading edge of the 3T mark in a signal in which a 3T mark follows a 3T space, and the number of 6T or more marks in a signal in which a 6T or more mark follows a 5T space The number of appearances of the phase modulation edge at the leading edge and the number of appearances of the phase modulation edge at the trailing edge of the 4T mark in a signal in which a 5T space follows the 4T mark portion are counted. Is a legitimate disk.

[Table 3]

Further, in a predetermined area, the number of appearances of each edge recorded at the phase-modulated clock timing is counted, and an edge having a count of 10 or more is determined to be “1”. It may be determined to be 0 ", and the scrambled data may be descrambled using the obtained table (for example, Table 3).

It should be noted that the method of using and determining the table for judging a normal disk and descrambling is not limited to the method of the present embodiment.

If the leading and lagging of the phase can be recognized for each edge recorded at the phase-modulated clock timing, for example, the number of leading edges is counted, and the counted number exceeds a certain threshold. If so, it may be determined to be "1", and if not, it may be determined to be "0". At this time, a specific gate is provided. When the gate is at the H level, the number of leading edges is counted, and when the gate is at the L level, the number of leading edges is counted. However, if the sum of the two exceeds a certain threshold, it may be determined to be "1", and if not, it may be determined to be "0".

In the present embodiment shown in FIG.
Although there is only one continuous region such as 5 in the identification region 13, there may be a plurality of continuous regions. By providing a plurality of locations, even if one continuous area cannot be correctly detected due to a scratch or the like, it can be determined that the disc is a legitimate disc by detecting the identification information in another continuous area.

In the present embodiment, the identification area 13 is located at one place on the inner periphery, but the identification area may be located at a plurality of places. By providing a plurality of identification areas, even if one of the identification areas cannot be correctly detected due to a scratch or the like, it can be determined that the disc is a regular disc by detecting the other.

For example, as shown in FIG.
By providing a and 1b3 on the inner and outer circumferences, even if one of the identification areas cannot be correctly detected due to scratches or warpage of the disk, the other can be detected to determine that the disk is a regular disk.

Further, the identification information may be changed in a plurality of identification areas, and when all the identification information or the identification information exceeding a certain standard cannot be detected, the reproduction may be restricted. By providing a plurality of pieces of identification information, it is possible to make the configuration of a manufacturing apparatus for manufacturing an unauthorized disk more difficult, and to strengthen copyright protection.

A plurality of different pieces of identification information may be recorded in one identification area, and when all pieces of identification information or identification information exceeding a predetermined reference cannot be detected, reproduction may be restricted.
By providing a plurality of pieces of identification information, it is possible to make the configuration of a manufacturing apparatus for manufacturing an unauthorized disk more difficult, and to strengthen copyright protection.

In this embodiment, the correlation between the identification information of the identification area and the key information is checked to determine whether the disk being reproduced is a regular disk, and if not, the reproduction is restricted. However, for example, the correlation between the identification information of the identification area and the key information may be checked at regular time intervals, and the reproduction may be prohibited when the correlation is no longer recognized. In order to check the correlation between the identification information of the identification area and the key information at regular intervals, for example, the identification area closest to the reproduction location among the plurality of identification areas may be reproduced. At this time, the identification area that has been reproduced before may not be reproduced.

Further, it is not always necessary to check the correlation between the identification information of the identification area and the key information immediately before or immediately after the reproduction. The correlation between the identification information of the identification area and the key information is checked only after a certain time has elapsed since the start of the content. You may do it.

In this way, even if the disc is illegally copied, part of the content can be reproduced. In such a case, however, the reproduction is restricted from a certain point in time. It can be protected and a certain amount of time can be used for advertising. In the case where the key information is obtained by a billing system, it is possible to determine whether to view a part of the content and then view the remaining part even if the disc is a regular disc.

When a plurality of contents are recorded on a disc, an identification area for each content may be recorded on the disc. Further, in this case, there may be contents for which the correlation between the identification information of the identification area and the key information is not checked.

FIGS. 7 and 8 show examples of the arrangement of the identification areas on the disc. In FIG. 7, the data area 14a contains the first content, and its identification information is in the identification area 13a. The data area 14b has the second
And the identification information is in the identification area 1
3b. The identification areas 13a and 13b may be dedicated areas, or may be partially or entirely shared with the control area 12 and the data areas 14a and 14b. By arranging the identification areas 13a and 13b collectively on the inner peripheral side as shown in FIG. 7, the identification area can be reproduced following the reproduction of the control area at the time of activation.
It is possible to quickly obtain information for restricting reproduction of all contents.

In FIG. 8, the data area 14a has the first
And the identification information is in the identification area 1
It is in 3a. The data area 14b contains the second content, and its identification information is stored in the identification area 13b.
Is in. The identification areas 13a and 13b may be dedicated areas, or may be the control area 12 or the data area 14.
A part or all may be shared with a and 14b.
By making the identification areas 13a and 13b close to or including the corresponding content as shown in FIG. 8, the corresponding identification information can be detected immediately before the desired content is reproduced. This eliminates the need for memory and memory, and is effective in reducing the time required for startup and saving memory.

In this way, although some contents can be reproduced on an illegally copied disc, the copyright of specific contents can be protected.

When the key information corresponding to the identification information is obtained by the charging system, whether or not to view the contents without charging even if it is an original disc, and then to view the remaining contents individually. Can be determined. In this case, the charge for the former may be set lower than the latter for the case where a plurality of contents are obtained collectively and for the case where the contents are obtained for each individual content.

In addition to the predetermined time, an identification area is provided at, for example, a predetermined radius position or a predetermined address unit. For example, every time the identification area is passed, the correlation between the identification information of the identification area and the key information is checked. Reproduction may be restricted when the property is no longer recognized. As a result, copyright protection can be enhanced even when a plurality of contents exist for a short period of time, or in the case of an optical disc made in consideration of random access such as a game.

The protection of the copyright by such an identification area is not limited to a single-layer disc. Even in a disc having two or more reproduction layers, copyright can be protected by providing an identification area for each layer. Since a multi-layer disc has a large capacity and can accommodate many contents, it is more effective to provide identification information for each content as described above. Similarly, the protection of the copyright by such an identification area is not limited to a read-only disc. Even in a recordable disc, the copyright can be protected by providing a disc or content identification area.

FIG. 9 shows identification information for a content,
FIG. 7 is a diagram illustrating an example of a relationship with an identification area where the information is recorded. As shown in FIG. 9A, when two identification areas, one identification area A and another identification area B, are provided on the disc, the identification information for the content A is, for example, as shown in FIG. 9B. It is recorded in the identification area as shown. For example,
When one piece of identification information A1 is provided for the content A, the identification information A1 may be recorded in one of the identification area A and the identification area B as shown in FIG. Alternatively, it may be recorded in both the identification area A and the identification area B. Further, the identification information A1 may be recorded in a plurality of areas (two areas in FIG. 9B) in the identification area A.

When a plurality of pieces of identification information A1 and A2 are provided for the content A, they may be recorded in only one identification area (A or B), or each may be recorded in only one identification area (A or B). It may be recorded in another area (one in area A and the other in area B). The same identification information may be recorded in the identification area A and the identification area B. As described above, various combinations of recording methods of the identification information in the identification area can be considered.

In the present embodiment, the target recording medium is an optical disk. However, the present invention is not limited to such a type of recording medium, but is generally referred to as a CD-RO.
M, DVD-ROM, CD-R, CD-RW, DVD-
It is also applicable to RAM, DVD-RW, MO, and the like. That is, the present invention can be applied to recording not only on uneven pits but also on phase change films, magnetic films, and the like. If the pit (recording mark) position can be written by jitter modulation, it can be applied not only to the drilling method but also to other types of recording media that use a recording method such as phase transition (phase change) or magnetization. Because you can. The configuration and operation shown in FIG. 15 can be applied to the recording apparatus.

In this embodiment, the pits recorded at the phase-modulated clock timing are used as the identification information of the identification area. However, the method of creating the identification information is not limited to this, and other methods may be used. good. For example, as shown in FIG. 10, the identification information may be created by modulation such that the pits are slightly shifted in the radial direction. Further, when a plurality of superimposing methods are used in combination when recording identification information, an unauthorized disk can be more effectively prevented.

In this embodiment, no consideration is given to rotating the disk at different linear velocities. However, if the S / N ratio deteriorates due to, for example, an increase in the linear velocity, the main information cannot be correctly reproduced in the area where the sub-digital information is superimposed, or even the sub-digital information may be lost due to loss of PLL synchronization. May not be detected. Therefore, it is desirable that the identification area is prepared according to the linear velocity to be reproduced. One example is shown in FIG.

In FIG. 11, an identification area 13a is an identification area when the data area 14 is reproduced at the first linear velocity. The identification area 13b is an identification area when the data area 14 is reproduced at the second linear velocity. Here, when the second linear velocity is higher than the first linear velocity, the phase error amount of the identification area 13b is made smaller than the phase error amount of the identification area 13a, so that the discrimination is performed at either linear velocity. Information can be correctly detected.

As described above, by providing a plurality of identification areas according to the linear velocity, even when the content is reproduced at different linear velocities, the identification area can be detected without returning to a specific linear velocity. The time required can be reduced. By arranging the identification area having the higher linear velocity on the outer peripheral side, the fluctuation of the motor rotation speed can be reduced.

Further, as for the identification information recorded in the identification area, there may be only one identification information for different linear velocities, or the identification information may be changed for each different linear velocity. By changing the identification information in accordance with the linear velocity at which the information is reproduced, illegal high-speed reproduction can be prevented. When the key information corresponding to each identification information is obtained by the charging system, the charging system is changed according to the linear speed, such as setting the charging for the higher linear speed higher than the charging for the lower linear speed. May be.

Similarly, considering the difference in the performance of the reproducing head, it is desirable that a plurality of identification areas are prepared.
One example is shown in FIG. In FIG. 12, identification area 1
Both 3a and 13b have the same identification information and differ in the amount of phase error when phase modulating the clock timing. By providing a plurality of identification areas having different phase error amounts in this manner, identification information can be correctly detected in any one of the identification areas even if the performance of the reproducing head is different.

In this embodiment, the information created by using the pits recorded at the phase-modulated clock timing is used as disc or content identification information.
The effect is the same even if the information is not limited to this and is arbitrary information regarding the disc or the content.

According to the present embodiment, by forming the identification area in an area different from the area in which the content is recorded, the content can be correctly reproduced without increasing the jitter at the time of reproducing the content. Further, the disc manufacturer can arbitrarily design the main digital information in the identification area. For example, by including the disc identification information in the main digital information, the copyright protection can be further enhanced.

By providing a plurality of identification areas having the same identification information for one content,
Even when one identification area cannot be detected correctly due to a scratch or the like, the identification information can be detected more reliably by detecting the other identification area.

By providing a plurality of identification areas having different identification information for one content,
The manufacture of unauthorized disks can be made more difficult.

By providing different identification areas for different contents, it is possible to individually protect copyright.

Embodiment 2 <Optical Disk Recording Apparatus> FIG. 14 shows the configuration of an optical disk (optical recording medium) according to Embodiment 2 of the present invention. FIG.
As shown in (a), the optical disc 10 has a user data area 10a and a lead-in area 10b. FIG.
FIG. 4B is a diagram showing a method of modulating the sub-digital information arranged in the data area. FIG. 14C shows the contents of the management information of the lead-in information. Management information 20
7 includes disc management information 208 and sub-digital information management information 209. The sub-digital management information 209 includes threshold information 210, sub-digital information arrangement position information 212, and sub-digital information displacement pattern information 213.

The operation will be described with reference to FIG. The track 32 is formed as a series of pits (31) according to a predetermined modulation rule by cutting (exposure) using a laser in a master stamper manufacturing process for manufacturing a disk. During the cutting of the pit 31, the laser light during the cutting of the pit at the predetermined position or the pit of the predetermined length is displaced by a certain length in the scanning direction of the light spot, thereby cutting the pit 31. The position of the edge is advanced or delayed.

The displacement of the edge is within a range that does not significantly affect the reproduction signal of the information represented by the pit.
Further, the modulation is performed to such an extent that it can be detected by integrating the displacement of the pit. The signal embedded in the disk as jitter by displacing the edge position of the pit by a small amount in this manner is identification information (sub-digital information). On the other hand, normal recording data (main digital information)
In the example, edge position information of a recording mark is recorded at regular intervals. The optical disk with a fraud prevention function of the present invention has sub-digital information management information necessary for reading sub-digital information, which is recorded in advance on the optical disk,
It has a function of detecting the sub-digital information (secret key) and performing an operation for protecting copyright based on the result.

A method for manufacturing an optical disk will be described. FIG. 15 is a block diagram showing a configuration of a main part of an optical disk recording apparatus 100a according to the present invention.

The recording apparatus 100a not only records digital information mainly by the shape of an optically readable recording mark, but also modulates the edge of the recording mark at that time by phase-modulating the hidden information such as a watermark. Here, it is a recording device for an optical disk such as a DVD-ROM having a function of simultaneously recording a secret key) as sub-digital information while embedding it in the main digital information.
The apparatus 100a includes a formatter 102, a sub-digital information generator 121, a phase modulator 107, a recording channel 108,
It includes a recording head 109, an optical disk 10, a spindle servo 123, and a spindle 125.

The formatter 102 is a circuit that modulates main digital information (recording data), specifies sub-digital information, and performs control for recording sub-digital information.

FIG. 16 is a block diagram showing a detailed configuration of the formatter 102. The formatter 102 converts the recording data input to the recording device 100a into the optical disk 10
Modulating section 10 for modulating a signal (channel signal B) suitable for
2a, an initial value storage unit 102e for secretly storing an initial value of a pseudo-random number sequence necessary for generating the sub-digital information generated by the sub-digital information generator 121, and a secret key storage unit for storing a secret key in advance 102f, management information such as recording position information of the sub digital information on the disc (for example, sub digital information arrangement position information, threshold information, integrated value information,
And a sub-digital information management information storage unit 102d in which sub-digital information displacement pattern information and the like are stored in advance.

As shown in the timing chart of FIG. 20, the modulation section 102a converts the input recording data into a corresponding 16-bit channel code A for each 8-bit code (byte) (8-16). Conversion), then N
A channel signal B is generated by RZI conversion, and output to phase modulator 107.

The sub-digital information management information is also input to the input of the modulation section 102a, in addition to the recording data, to generate a channel signal B and output it to the phase modulator 107.

FIG. 18 is a block diagram showing details of the sub digital information generator. When receiving a notification from a controller or the like (not shown) that the recording of a secret key (hereinafter, such an operation is referred to as a “secret key recording mode”) is started, the modulation unit 102a transmits 1-byte recording data. Is output to the timing generator 121a each time a is input.

When the secret key recording mode is started, the initial value storage section 102e outputs the 15-bit data (initial value) held in secret to the pseudo random number generator 121b in advance.

When the secret key recording mode is started, the secret key storage unit 102f stores the secret key having a length of 56 bits, which is held in secret, in the NRZ format in order of 1 bit from the LSB in an XOR (exclusive OR gate). ) 121c. At this time, the secret key storage unit 102f outputs the next higher-order bit every time the modulator 102a modulates 256 bytes of recording data. That is, the secret key storage unit 10
2f outputs a single 56-bit secret key to the XOR 121c as a secret key bit sequence in a bit serial manner in correspondence with a total of 256 × 56 bytes of recording data.

FIG. 21 is a diagram showing a correspondence relationship between a secret key, a pseudo-random number sequence, and recorded data. In order to record the 56-bit secret key as hidden information on the optical disk, a 256-bit pseudo-random number sequence is used for each bit of the secret key, and each bit in the pseudo-random number sequence is 1-byte recording data (16 channel code). It is shown to be embedded in Note that each bit of the 56-bit secret key is
As will be described later, it is used as a flag as to whether or not to logically invert the corresponding 256-bit pseudo-random number sequence.

The timing generator 121a outputs (i) a clock signal (byte clock) synchronized with each byte of the recording data to the pseudo random number generator 121b based on the timing signal from the modulator, and (ii) Based on the timing signal and a clock signal from a clock oscillator (not shown), a timing signal indicating the center of the channel signal B output from the formatter 102 (when the phase becomes 180 degrees) is generated by the pseudo random number generator 121b.
Output to

The pseudo-random number generator 121d uses the initial value from the initial value storage unit 102e as a preset value, uses the byte clock input from the timing generator 121a as a shift clock, and converts 2 15 bit sequences into one cycle. Is generated.

In this embodiment, the pseudo random number generator 121b has a total of 256 in the secret key recording mode.
It is used to generate a pseudo-random number sequence embedded in recording data of × 56 bytes, that is, a pseudo-random number sequence of 256 × 56 bits.

The exclusive OR gate 121c stores the pseudo-random number sequence from the pseudo-random number generator 121b and the secret key storage unit 10.
The exclusive OR with the bit sequence from 2f is calculated, and the resulting pseudo-random number sequence D is output to the PE modulator 121d. In other words, the exclusive OR gate 121c has 5
It is selectively performed whether the pseudo-random number sequence for each bit of the 6-bit secret key is directly input to the PE modulator 121d or is input to the PE modulator 121d after logical inversion.

The PE modulator 121d converts the pseudo-random number sequence D sent from the exclusive OR gate 121c into P based on the timing signal from the timing generator 121a.
E-converted, and the obtained PE modulation signal E is
Output to As a result, the PE modulation signal E falls at the center of the channel signal B when the pseudorandom number sequence D output from the exclusive OR gate 121c is 0, as shown in the timing chart of FIG. When the random number series D is 1, the waveform rises, and when the same random number value continues, the waveform is inverted again at the boundary of the channel signal.

The phase modulator 107 has a PE modulator 121d.
Performs a phase modulation of delaying or advancing the edge of the channel signal B from the formatter by a predetermined minute time on the basis of the PE modulation signal E, and outputs the obtained modulated channel signal F to the recording channel 108. . It should be noted that the above-mentioned minute time is equivalent to the jitter observed when a normal optical disk on which only the main digital information is recorded by bypassing this phase modulator (without recording the sub-digital information) is reproduced by a normal reproducing apparatus. It is set in advance to half the standard deviation σ (σ / 2) in the frequency distribution.

FIG. 17 is a block diagram showing a detailed configuration of phase modulator 107. The phase modulator 107 includes a delay unit 107a for delaying a signal by the very short time and a two-input one-output selector 107b. The selector 107b determines that the gate signal input as the control signal is 1
In this case, the channel signal B directly input from the formatter 102 is passed, and when the gate signal is 0, the channel signal input via the delay unit 107a is passed.

As a result, the rising and falling edges of the channel signal B input to the phase modulator 107 result (in relative time relations) when the gate signal indicates 1 (0 to 180 degrees). In ()), the phase is advanced by the minute time, and when the gate signal indicates 0 (180 to 360 degrees), the phase is delayed by the minute time. That is, the channel signal B input to the phase modulator 107 undergoes jitter modulation based on the output of the sub digital information generator, and is converted into a modulated channel signal F.

The recording channel generates a control signal for turning on / off a laser beam to be exposed on the optical disk in synchronization with 1/0 of the modulated channel signal F from the phase modulator 107 and sends the control signal to the recording head 109. Recording head 109
Is performed by irradiating the surface of the rotating optical disk 10 with a light beam in a spiral while turning on / off the laser beam based on a control signal from a recording channel. In this manner, a modulated recording mark composed of optically readable uneven pits is formed on the optical disc.

FIG. 14B is a diagram showing the surface of the recording surface of the optical disk on which pits have been formed by the recording head. The position of each of the two edges in the scanning direction of the light spot of the pit on which the sub-digital information has been recorded is set at the predetermined minute time with respect to the edge position of the pit formed when the sub-digital information is not recorded. The phase is shifted to a position where the phase is advanced (or delayed) by a corresponding displacement amount.

FIG. 19 is a graph showing the distribution of the frequency (frequency) of the pits formed during the recording of such sub-digital information, that is, the jitter observed with respect to the modulated recording mark recorded with the jitter modulation. .

The curve A shows the jitter distribution only for the edge of the modulated recording mark generated when the gate signal is 0, and the position X (L) shifted in the direction in which the phase is delayed by the displacement amount is defined as the maximum frequency. It becomes a curve close to a Gaussian curve. Curve B shows the jitter distribution only for the edge of the modulated recording mark generated when the gate signal is 1, and the position X shifted in the direction in which the phase has advanced by the displacement amount.
It becomes a curve close to a Gaussian curve with (H) being the maximum frequency.
Curve C shows the total jitter distribution obtained by adding both curves A and B.

According to the present invention, if synchronous detection is performed using the same pseudo-random number sequence as the pseudo-random number sequence used when recording the secret key, the jitter distribution of curve C can be separated into the distributions of curve A and curve B. I use.

<Sub-Digital Information Management Information> Next, the sub-digital information management information for managing the above-mentioned sub-digital information will be described.

The sub digital information management information is information necessary for reading (extracting) the sub digital information. For example,
(1) position information on the disk in which the sub-digital information is embedded (sub-digital information arrangement position information); (2) threshold information necessary for reading the sub-digital information; (3) initial value of the pseudo random number generator; (4) Sub-digital information readout gate information (sub-digital information displacement pattern information) is the content of the sub-digital information management information. The sub-digital information management information is arranged at a specific position on the disc. As places where the sub-digital information management information is arranged, (A) a lead-in area or a lead-out area, (B) a BCA (Burst Cutting Area), (C) a user data area, and the like can be considered.

Referring to FIG. 14, the case where the sub digital information management information is arranged in the lead-in area (case (A) above) will be described. In the data area 10a on the optical disk 10, sub-digital information is recorded after being jitter-modulated. The lead-in area 10b provided on the inner periphery of the optical disc includes physical format information, logical format information, scramble information,
Various information such as area code information is recorded in advance. The lead-in area 10b is used together with a management data area (for example, a TOC area of a CD) so that it can always be checked when the disc is started.

The sub-digital information management information 209 is recorded in advance in the management information of the lead-in area 10b separately from the disc management information 208, so that the information necessary for decoding the sub-digital information can be immediately read out when the disc is started. It is possible.

The sub digital information management information 209 includes threshold information 210, sub digital information arrangement position information 212, sub digital information displacement pattern information 213, pseudo random number generator initial value information 214, and the like.

The sub-digital information arrangement position information 21
Numeral 2 records radial position information, sector information, zone information, and the like on the disk on which the sub digital information is recorded. The threshold value information 210 and the pseudo-random number generator initial value information 214 are information necessary for reproducing (extracting) the sub-digital information by the optical disk device.

The sub-digital information displacement pattern information 213 will be described in detail with reference to FIG. The channel code A is modulated by the PE modulation signal E and is a modulated recording mark G
It is recorded as follows. However, the gate signal J is generated by the sub-digital information displacement pattern information, and the gate signal J
Is in the "High" state, the modulated mark is modulated and recorded, but when the gate signal J is in the "Low" state, the modulated signal is recorded without being modulated. That is, ON / OFF of the jitter modulation is performed by the gate signal.

The ON / OFF of the jitter modulation is determined by the sub-digital information displacement pattern information. For example, when recording a 3T mark by (8-16) modulation, the jitter modulation is turned off.
Then, when recording another run mark, the jitter modulation is turned on.

In the 8-16 modulation, the 3T mark is the shortest run, and is the signal having the worst S / N ratio of the recording / reproducing signal. Therefore, when recording a 3T mark, the jitter modulation is
By setting it to F, the signal quality of the 3T mark of the main digital data does not deteriorate. Further, since the sub-digital information is not embedded, it is possible to reduce detection errors when detecting the sub-digital information.

As described above, if a short mark or space such as 3T, which is most affected by thermal interference or intersymbol interference, is registered in the sub-digital information displacement pattern information so as to exclude jitter modulation in advance, the sub-digital When reading the information, the sub-digital information can be reproduced (extracted) with high reliability.

The contents of the sub digital information management information are as follows:
If the optical disc is divided into multiple areas for each content,
The sub-digital information and the sub-digital information management information may be stored by being divided into respective areas. Further, in the present embodiment, the sub-digital information management information is recorded in the lead-in area, but may be recorded in the lead-out area.

In this embodiment, the sub-digital information management information is recorded in the lead-in area.
It may be recorded as CA.

The sub-digital information management information is stored in BCA (Burst
The case of recording as (Cutting Area) (case (B) above) will be described with reference to FIG.

FIG. 23A shows a BCA (Burst Cutting)
FIG. 3 is a schematic diagram of an optical disc on which sub digital information management information is recorded in an (Area). The BCA exists in a certain area on the inner circumference of the optical disc 10.

The code is additionally written to the BCA 10c by using a high power laser such as a YAG laser after the completion of the disc making process. As shown in FIG. 23A, the disk is formed in a stripe pattern from the inner circumference to the outer circumference, and the reflectance of the formed portion is reduced.

The sub-digital information management information is recorded in the BCA in a form added to the conventional disc management information.

Since the BCA is read out at the time of starting the disk similarly to the lead-in area, it is possible to immediately read out information necessary for decoding the sub-digital information.

In this embodiment, the sub-digital information management information is recorded in the lead-in area or the BCA. However, a dedicated area may be provided in the user area for recording.

Next, the case where the sub-digital information management information is recorded in the user data area (C) will be described.

FIG. 24 is a schematic diagram of an optical disc having sub-digital information management information recorded in a user data area.
The user data area 10a of the optical disk 10 stores user data and management information. Management information 247 in which sub-digital information management information is recorded exists in a certain area between user data. The management information 247 includes disk management information 248 and sub-digital information management information 249 (disk management information 248).
May be omitted). The sub digital information management information 249 includes threshold information 250, sub digital information arrangement position information 252, sub digital information displacement pattern information 253, pseudo random number generator initial value information 254, and the like. The sub-digital information arrangement position information 252 records radial position information, sector information, zone information, and the like on the disk on which the sub-digital information is recorded. Threshold information 2
50 and the initial value information 254 of the pseudo-random number generator are information necessary for reproducing (extracting) the above-mentioned or later-described sub-digital information by the optical disk device.

In order to identify that the sub-digital information management information 249 is located at a specific position in the user data area, the lead-in or lead-out area or B
Information indicating the arrangement position of the sub digital information management information on the disc, such as the recording radius position of the sub digital information management information and the recording zone, is written in advance in the CA. Alternatively, the sub-digital information management information 249 may be fixedly arranged at a fixed radius position or a fixed zone. In this case, the optical disk reproducing device holds information describing the position of the sub-digital management information on the disk in a nonvolatile memory.

By arranging the sub-digital information management information 249 in the user data area, the secrecy of the sub-digital information can be improved. It is also possible to arrange the sub-digital information management information 249 over a plurality of areas in the user data area.

For example, by separately setting the sub digital information management information for each zone or for each content, the copyright protection for each content can be easily performed. The user data area is a lead-in area, a lead-out area, or a BC area.
Since there is a space for storing a relatively large amount of information as compared with the A area, there is an effect that a large number of sub-digital information management information can be arranged.

<Optical Disk Reproducing Apparatus> A reproducing apparatus for reproducing an optical disk on which a secret key is recorded as described above will be described.

FIG. 25 is a block diagram showing a configuration of a main part of an optical disk reproducing apparatus 1201 according to the present invention. The waveforms of the main signals H and I shown in the figure are the same as those shown in the timing chart of FIG.

The reproducing apparatus 1201 is an optical disk reproducing apparatus corresponding to the optical disk recording apparatus 100a. The device 1201 not only reproduces the main digital information based on the position of the recording mark on the optical disk, but also detects the sub digital information (secret key) buried in the jitter of the recording mark observed at that time. Has a function of performing an operation for protecting a copyright based on the. Device 12
01 is a reproduction head 1211, a reproduction channel 1212,
A reproduction signal processing circuit 1213, a clock extractor 1214,
It includes a synchronous detector 1215, a verification unit 1216, and a pseudo-random number generator 1217.

The reproducing head 1211 is an optical pickup, which converges and irradiates a recording mark on a rotating optical disk with a light beam, and generates a modulated recording mark G from the reflected light.
, And outputs it to the reproduction channel 1212. Playback channel 121
2 converts the signal into an analog read signal from the reproduction head 1211 and outputs the signal to the reproduction signal processing circuit 1213 and the clock extractor 1214.

The clock extractor 1214 generates four types of clock signals based on the read signal from the reproduction channel 1212, namely, (i) a channel bit clock synchronized with each bit constituting a channel code, and (ii) a (Iii) Similarly, the phase error signal H indicating only the leading component of the read signal with reference to the bit clock, (iii) the phase error signal I indicating only the lag component, and (iv) each recording in the read signal. Extract and generate the byte clock synchronized with the data (byte unit), and (i)
A reproduction signal processing circuit 1213; (ii) a synchronous detector 1215;
(iii) synchronous detector 1215, (iv) reproduced signal processing circuit 12
13. Synchronous detector 1215 and pseudorandom number generator 1217
Output to

FIG. 26 is a block diagram showing a detailed configuration of clock extractor 1214. Clock extractor 121
4 is a PLL circuit, a 4-bit counter 1214d,
The synchronization signal detector 1214e and the phase error signal separator 12
14f. The PLL circuit includes a phase comparator 1
214a, a loop filter 1214b, and a VCO (Vo
ltage Controlled Oscillator) 1214c.

The phase comparator 1214a comprises a counter, an exclusive OR gate, a flip-flop and the like. Based on the channel bit clock fed back from the VCO 1214c and the read signal from the reproduction channel 1212, the phase comparator 1214a calculates the rising and falling edges of the read signal and the rising edge of the channel bit clock closest to the edge. Is calculated and output to the loop filter 1214b and the phase error signal separator 1214f as a phase error signal.

The loop filter 1214b is a low-pass filter that smoothes the phase error signal from the phase comparator 1214a and converts it into a DC voltage signal. VCO121
Reference numeral 4c denotes a voltage controlled oscillator that generates a channel bit clock having a frequency corresponding to the voltage signal from the loop filter 1214b.

The synchronization signal detector 1214e detects a synchronization pattern included in the read signal, and outputs it as a reset signal to the 4-bit counter 1214d. The 4-bit counter 1214d is a counter that divides the channel bit clock from the VCO 1214c by 1/16, and is reset by a reset signal from the synchronization signal detector 1214e. That is, the 4-bit counter 1214d
Is each record data (byte unit) in the read signal
Outputs a byte clock synchronized with.

The phase error signal separator 1214f is a circuit that separates the phase error signal from the phase comparator 1214a into a phase error signal H and a phase error signal I, and outputs the separated signal to the synchronous detector 1215.

FIG. 27A shows a phase error signal separator 121.
It is the schematic of the circuit which shows the detailed structure of 4f. The phase error signal separator 1214f includes two inverters 1330
a and b and two AND gates 1330c and 1330d. FIG. 27B is a timing chart of each signal for explaining the operation of the phase error signal separator 1214f shown in FIG. As shown in FIG. 27B, the phase error signal output from the phase comparator 1214a includes a phase error component and a lag error component, and these phase error signals H and I are channel bits. Since the signals are separated in synchronization with the clock, the signal output from the AND gate 1330c (the leading error signal H) indicates only the leading error signal component, and the signal output from the AND gate 1330d (the late error signal H) I) has a waveform indicating only the delay error signal component.

The reproduction signal processing circuit 1213 is a circuit for demodulating a read signal from the reproduction channel 1212, performing control for detecting sub-digital information, and performing copyright protection based on the detection result. .

FIG. 28 is a block diagram showing a detailed configuration of the reproduction signal processing circuit 1213. Playback signal processing circuit 12
13 is a demodulation unit 1213a, an output gate unit 1213b,
It comprises an initial value storage unit 1213c and a displacement pattern gate generator 1213d.

The demodulation unit 1213a is a demodulation circuit corresponding to the modulation unit 102a of the optical disc recording device 100a.
The demodulation unit 1213 a synchronizes with the channel bit clock from the clock extractor 1214 and
After demodulating to a channel code A by sampling the readout signal from the
Converted into 8-bit recording data corresponding to each channel code in synchronization with the byte clock from 4 (16 to 8 conversion)
Then, the recording data sequence is sent to the output gate unit 1213b.

The output gate unit 1213b is a buffer gate for copyright protection. The output gate unit 1213b transmits the recording data sequence from the demodulation unit 1213a only while the enable signal (notification that the proper secret key has been recorded on the optical disc can be confirmed) from the verification unit 1216 is input. The signal is passed and output to the outside as a reproduction signal.

[0160] The initial value storage unit 1213c
01 is a register that stores in advance the value (15-bit initial value) of the pseudo random number generator initial value information 214 of the sub-digital information management information 209 in the sub-digital information management unit 209. When a notification that the “secret key read mode” has been started is received from a controller (not shown), the initial value is output to the pseudo random number generator 1217.

The displacement pattern gate generator 1213d is
Based on the result of reading the sub-digital information displacement pattern information 213 of the sub-digital information management information 209 in the optical disc 10, a specific mark or space length of the channel code A data sequence demodulated from the demodulation unit 1213a is obtained. A gate signal is generated according to the length.

FIG. 32 shows a timing chart of the displacement pattern gate. For example, 3T in (8-16) modulation
An example will be described in which a run is distinguished from another run (4T or more). In FIG. 32, the gate signal J is Low when the run length of the channel code A is 3T, and otherwise (4
High) is output in the case of (T or more). Here, the runs of 3T and 4T or more are distinguished, but 4T or less and 5T or more and 5T or less and 6T or more are also possible. These pieces of information are described in the sub digital information displacement pattern information.

The pseudo-random number generator 1217 has the same function as the pseudo-random number generator 121b of the optical disc recording apparatus 100a.
Initial value storage unit 102 which stores the value read from No. 4
e as the preset value and the clock extractor 1
Using the byte clock input from 214 as a shift clock, a pseudo-random number sequence (M sequence) having 2 15 bit sequences as one cycle is generated. Playback device 1201
The pseudo random number generator 1217 is used to generate a 256 × 256 bit pseudo random number sequence.

The synchronous detector 1215 is a clock extractor 1
This circuit detects the correlation between the leading phase error signal H and the lagging error signal I output from the pseudo-random number generator 214 and the pseudo-random number sequence from the pseudo-random number generator 1217. The result (with positive correlation, with negative correlation, and without correlation) is transmitted to the verification unit 1216.

FIG. 29 is a circuit diagram showing a detailed configuration of the synchronous detector 1215. The synchronous detector 1215 includes a PE modulator 1215a, a selector 1215b, and an integrator 1215.
c, threshold value determination unit 1215d and 8-bit counter 121
5e.

The PE modulator 1215a is a modulator having both functions corresponding to the timing generator 121a and the PE modulator 121d of the optical disk recording apparatus 100a. The PE modulator 1215a includes a clock extractor 1214
Pseudo-random number generator 121 based on the byte clock from
7 is subjected to PE conversion and output to the selector 1215b as a switching control signal. That is, the PE modulator 1215a performs PE conversion on the pseudo-random number sequence from the pseudo-random number generator 1217, and outputs it to the selector 1215b as a switching control signal. Specifically, the PE modulator 12
15a indicates that the pseudorandom number from the pseudorandom number generator 1217 is 0
In the case of (1), it falls at the center timing of each recording data (byte) in the reproduced read signal, rises when the pseudo random number is 1, and again at the boundary of the recording data to be written when the same random number value continues. A signal having an inverted waveform is output to the selector 1215b.

The selector 1215b is composed of two 2-input / 1-output switching circuits. The selector 1215b allows the early phase error signal H and the late phase error signal I from the clock extractor 1214 to pass through the positive input terminal and the negative input terminal of the integrator 1215c when the control signal from the PE modulator 1215a is 1. , 0, cross the integrator 1
215c is passed through the negative input terminal and the positive input terminal.

The 8-bit counter 1215e is a counter that divides the byte clock from the clock extractor 1214 into 1/256, and uses the result as a reset signal as an integrator 1215c, a threshold determination unit 1215d, and a verification unit 1
216. Therefore, this reset signal has a waveform that outputs one reset pulse every time the pseudorandom number generator 1217 outputs a 256-bit random number sequence.

The integrator 1215c is an analog integrator having an operation input bipolar output. The integrator 1215c subtracts and accumulates the area of the pulse input to the negative input terminal in parallel with adding and accumulating the area of the pulse input to the positive input terminal. The corresponding analog signal is output to threshold determination section 1215d. At this time,
When the reset signal is input from the 8-bit counter, the data is accumulated from zero again.

As a result, the output waveform of the integrator 1215c is accumulated by adding the area of the pulse appearing in the advance error signal H during the period when the PE modulation signal output from the PE modulator 1215a is 1. And the delay error signal I
Shows the accumulation area when the pulse area appearing in FIG. On the other hand, during a period in which the PE modulation signal is 0, the output waveform is obtained by subtracting and accumulating the area of the pulse appearing in the phase error signal H and adding the area of the pulse appearing in the phase error signal I. This shows the accumulation area when accumulation.

Therefore, a positive correlation in which a pulse appears only in the phase error signal H during the period when the PE modulation signal is 1 and a pulse appears only in the phase error signal I during the period when the PE modulation signal is 0 is obtained. Is continued, the integrator 121
The output waveform of 5c is a ramp waveform that increases in the positive direction.
Conversely, a negative correlation appears in which a pulse appears only in the phase error signal I during the period when the PE modulation signal is 1 and a pulse appears only in the phase error signal H during the period when the PE modulation signal is 0. When continuing, the output waveform of the integrator 1215c becomes a ramp waveform decreasing in the negative direction. Further, when there is no correlation, that is, when pulses appear randomly in the leading phase error signal H and the lagging error signal I without depending on the value of the PE modulation signal, both pulses appearing in those error signals are displayed. Since the frequency of appearance of the pulses becomes substantially equal, the output waveform of the integrator 1215c maintains a value close to zero level.

The threshold value judging unit 1215d includes an integrator 1215
The analog signal from c belongs to any of three voltage sections separated by a preset positive threshold voltage or a negative threshold voltage, which is a value obtained by reading the threshold information described in the sub-digital information management information of the optical disc. And a comparator for judging whether or not.

FIG. 30 is a diagram for explaining the operation of threshold decision section 1215d, and shows an example of an analog signal waveform input from integrator 1215c to threshold decision section 1215d. The threshold value determination unit 1215d includes an 8-bit counter 121
At the time (immediately before) the reset signal is input from 5e, (i) NRZ format which is set to 1 when the signal voltage from the integrator 1215c is larger than the positive threshold and set to 0 when smaller than the negative threshold. Verification unit 12
And (ii) when the signal voltage from the integrator 1215c falls between the two threshold values, the verification unit 1216 is notified of a violence signal indicating that fact.

The threshold voltage certainly exceeds (with a very high probability) when the jitter modulation according to the present invention is performed, but does not exceed (with a very low probability) otherwise. The output voltage value of such an integrator 1215c is set. The specific values are the degree of jitter modulation during recording (the amount of delay of the delay unit of the phase modulator), the number of bytes input to the integrator 1215c (25
6), average number of edges per byte, standard deviation in natural (randomly occurring) jitter distribution, etc.

As described above, the code string output from threshold determination section 1215d indicates a change in the polarity (positive or negative) of the correlation observed for each 256-bit pseudorandom number. Such a change in the polarity is information corresponding to a bit string indicating, for each 256-bit pseudo-random number sequence, whether the pseudo-random number sequence has been recorded by jitter modulation without logical inversion or recorded after logical inversion.

The verifying unit 1216 determines whether or not the currently read optical disk is a medium recorded by the proper optical disk recording device 200 based on the code string and the violence signal sent from the synchronous detector 1215. And outputs an enable signal to that effect to the reproduction signal processing circuit 1213 only when the judgment is affirmative.

FIG. 31 is a block diagram showing a detailed configuration of verification section 1216. The verification unit 1216 includes a secret key storage unit 1216a, a shift register 1216b, a match comparison unit 1216c, and an output latch unit 1216d.

The secret key storage unit 1216a is a register for storing in advance the same 56-bit secret key as the secret key storage unit 102f of the optical disk recording device 100a. The shift register 1216b uses the reset signal from the clock extractor 1214 as a shift clock to
Is a shift register of 56 stages (bits) that stores the code string while shifting it.

Immediately after the 56-bit code string is input to the shift register 1216b, the coincidence comparison section 1216c completely matches the code string with the 56-bit secret key stored in the secret key storage section 1216a. The result is notified to the output latch unit 1216d.

The output latch unit 1216d is connected to the synchronous detector 1
An enable signal is output to the reproduction signal processing circuit 1213 only when the violence signal from the H. 215 is not notified, and when a notification indicating complete match is sent from the match comparison unit 1216c. That is, the pseudorandom number generator 1217
The fact that there is a positive or negative correlation between the 256-bit pseudo-random number sequence input to the synchronous detector 1215 and the phase error signal included in the readout signal continuously from 56
Times (for a 256 × 56 bit pseudo-random number sequence) and only when the change in the polarity of the correlation at that time completely matches the 56-bit secret key stored in the secret key storage unit 1216a. The enable signal is output from the verification unit 1216 to the reproduction signal processing circuit 1213.

As described above, when the secret key reading mode is completed and the enable signal is output from the verifying unit 1216 to the reproduction signal processing circuit 1213 at that time, the optical disk is a normal optical disk recording device 100a. The playback signal processing circuit 1213 determines that the medium is the medium in which the secret key is embedded,
A reproduction signal obtained by demodulating the readout signal from the block 12 is output to the outside. On the other hand, when the enable signal is not output from the verification unit 1216 to the reproduction signal processing circuit 1213, the optical disc is
00, it is determined that the medium is not a medium in which the secret key is embedded, and the reproduction signal processing circuit 1213 does not output the reproduction signal to the outside for copyright protection.

As a result, it is possible to prevent the recording data from being illegally read out from the optical disk for which the embedding of the secret key cannot be confirmed. Therefore, even if a new optical disk is created by dead-copying a regular optical disk including a secret key, unless the secret key embedded by jitter modulation is also copied together,
The reproduction of the optical disk is prohibited by the reproducing apparatus 1201, and the copyright is protected.

As described above, the recording medium and the recording / reproducing apparatus for jitter modulation according to the present invention have been described based on the embodiments. However, it is needless to say that the present invention is not limited to the embodiments.

For example, in this embodiment, a 256 × 56 bit pseudo-random number sequence logically inverted for one 56-bit secret key is embedded in 56-byte continuous recording data. However, the present invention is not limited to such numerical values. ECC block, sector,
It is also possible to embed not only one kind but also a pseudo-random number sequence starting from two or more kinds of initial values in a plurality of areas for the number of bytes related to the physical recording structure such as a frame or the recording data in a specific area. it can.

Also, in this embodiment, in order to confirm that the optical disk is valid, a positive or negative correlation must exist between the phase error signal and the pseudo-random number sequence every 256 bytes. Is repeated 56 times, but may be, for example, 50 times or more out of 56 times.
As shown in FIG. 19, the distribution of jitter has a certain degree of spread. Therefore, depending on the number of pulses used for determining the correlation, the degree of jitter modulation, and the like, the presence or absence of a significant correlation depends on the criterion having a certain degree of spread. It may be more appropriate to judge.

In the present embodiment, the reproduction of the main digital information is restricted when the coincidence between the code string output from the synchronous detector and the secret key is equal to or less than a predetermined number. However, it is not necessary to use a secret key, and if the magnitude of the phase error signal integrated by the synchronous detector is simply compared with a predetermined threshold value and the threshold value is exceeded, the correlation with the pseudo-random number sequence is strong. , And the reproduction may be restricted. This makes it possible to obtain a certain effect with a simpler configuration.

Further, in the present embodiment, in synchronous detection of the phase error signal, the correlation is determined by integrating the pulse areas of the phase error signal H and the phase error signal I in an analog manner. However, in order to simplify the circuit, a digital system in which the numbers are simply counted while adding and subtracting them may be used.

When the jitter modulation according to the present invention is applied to the recording data recorded in the user data area 10a of the optical disc, it can be applied to the lead-in area, the lead-out area, and the BCA. Further, it is also possible to use the content encryption by overlapping with the above-described conventional content encryption. For example, when a disc key or a title key stored in the control information area 9b is recorded, by performing the jitter modulation according to the present invention, the recorded content (digital information) by the conventional content encryption is not changed at all. In addition, it is possible to enhance copyright protection against illegal copying such as piracy.

Further, in the present embodiment, optical disk device 1201 outputs a demodulated reproduced signal only when it is possible to verify the existence of a secret key buried in the optical disk. The present invention is not limited to the use form of the verification result. For example, when the validity of the optical disc cannot be verified, a usage form such as allowing reproduction of only the title recorded in a specific area of the optical disc may be adopted.

In the present embodiment, the secret key used as the sub-digital information is
a and the optical disk device 1201 are stored in advance, but may be rewritten by an instruction from a user or by secret communication with an external device. Alternatively, the information may be recorded on a disk in advance in a form encrypted as sub-digital information management information or the like.

In the present embodiment, the target recording medium is an optical disk. However, the present invention is not limited to such a type of recording medium, and is generally referred to as a CD-RO.
M, DVD-ROM, CD-R, CD-RW, DVD-
It is also applicable to RAM, DVD-RW, MO, and the like. That is, the present invention can be applied to recording not only on uneven pits but also on phase change films, magnetic films, and the like. If the pit (recording mark) position can be written by jitter modulation, it can be applied not only to the drilling method but also to other types of recording media that use a recording method such as phase transition (phase change) or magnetization. Because you can. The configuration and operation shown in FIG. 15 can be applied to the recording apparatus.

Although the jitter modulation according to the present invention has been used for concealing the sub-digital information and embedding it in an optical disk, the present invention is not limited to such a concealment use. For example, audio information (sub-digital information)
May be used in non-encryption applications in which different types of digital information are recorded in a separable and reproducible state, such as writing on a recording medium by superimposing the digital information on image information (main digital information).

As described above, according to the optical disk of the above embodiment, the sub-digital information is embedded in the main digital information in a manner that is difficult to read. Therefore, when the optical disk is copied only based on the presence or absence of the recording mark, Since the sub-digital information is not copied, it is possible to distinguish whether the optical disk is a copy source optical disk or a copied optical disk. As a result, it is possible to prevent copyright infringement caused by illegally copying the digital work on the optical disk as it is. Further, by recording the sub-digital information management information on the optical disk in advance, a different master key can be easily provided for each disk, and even if one key is exposed, other devices may be affected. Nothing. In addition, sub-digital information management information such as threshold information and arrangement position of sub-digital information can be assigned differently for each disc, and information can be obtained by encrypting sub-digital information having common threshold information or sub-digital information arrangement position. Can be further enhanced.

The initial value of the random number sequence of the sub digital information may be recorded in advance on the optical disc as the sub digital information management information. As a result, the initial value of the random number sequence can be changed arbitrarily for each disk, and the confidentiality of information can be improved. Further, even when one secret key is used across a plurality of disks, by changing the pseudo-random number sequence, it is possible to enhance the confidentiality without affecting the copyright protection of other disks.

Further, with respect to the recording mark, the leading portion and the sending portion are integrated for a random number sequence of a fixed length, and sub-digital information is generated based on whether the size of the integrated value is larger or smaller than a predetermined threshold value. In this case, the threshold may be recorded in advance as the sub-digital information management information. As a result, the threshold value can be changed arbitrarily for each disk, and the confidentiality of information can be improved. Further, even when one secret key is used over a plurality of disks, by changing the threshold value, confidentiality can be improved without affecting the copyright protection of other disks.

Further, the arrangement position of the sub digital information may be recorded in advance as sub digital information management information. This makes it possible to arbitrarily change the arrangement position of the sub-digital information on each disc, thereby improving the confidentiality of the information. Further, even when one secret key is used over a plurality of disks, by changing the arrangement of the sub-digital information, it is possible to enhance the confidentiality without affecting the copyright protection of the other disks. Also, depending on the length of the recording mark, ON / OF of phase modulation
The sub-digital information may be recorded while switching F.
As a result, the signal quality of a recording mark having a length with a poor S / N ratio of a reproduced signal is not deteriorated by phase modulation. Further, since the sub-digital information is not embedded in the recording mark having a length having a bad S / N ratio, detection errors of the sub-digital information itself are reduced, and the sub-digital information can be reproduced (extracted) with high reliability. .

[0197] Length information of a recording mark for determining ON / OFF of phase modulation may be recorded in advance as sub-digital information management information. This makes it possible to arbitrarily change the length of the recording mark to be subjected to the phase modulation for each disk, thereby improving the confidentiality of the information. Further, even when one secret key is used over a plurality of disks, by changing the length of the recording mark for determining ON / OFF of the phase modulation, concealment can be performed without affecting the copyright protection of other disks. Can be enhanced. The sub-digital information management information may be recorded in a control data area on the optical disc in advance. This makes it possible to read the sub-digital information management information at the time of starting the disc, and to quickly extract the sub-digital information.

The sub-digital information management information may be recorded in a user data area on an optical disk in advance. This makes it possible to arrange the sub-digital information and the corresponding sub-digital information management information over a plurality of areas in the user data area. For example, by separately setting the sub-digital information and the corresponding sub-digital information management information for each zone or each content, the copyright protection for each content can be easily performed. Further, since the user data area has a space capable of storing information having a relatively large capacity as compared with the lead-in / lead-out area or the BCA area, there is an effect that a large number of sub-digital information management information can be arranged. Further, the sub-digital information management information may be recorded in a BCA on an optical disc in advance. As a result, as in the case of the lead-in area, the sub-digital information management information is read when the disc is started, so that the information necessary for decoding the sub-digital information can be read immediately.

Further, according to the optical disk reproducing apparatus of the above embodiment, since jitter modulation is performed on the edge position of the recording mark based on the random number sequence, it becomes difficult to decode the sub digital information buried in the jitter. , Various information required to extract the sub-digital information (threshold information,
(Disposition position information, etc.) can be changed arbitrarily for each disk, and the confidentiality of the information can be enhanced. Further, even when one secret key is used over a plurality of disks, the content of the sub-digital information management information is made different for each disk, thereby improving the confidentiality without affecting the copyright protection of other disks. Is possible.

The secret key is recorded by jitter modulation in which the position of the edge of the recording mark (each of the two edges in the track direction) is shifted by a very small amount in the track traveling direction (light beam spot scanning direction). Therefore, the secret key cannot be read by an ordinary reproducing device that does not have a function of reading information embedded in the jitter.

Therefore, even if the entire contents of the optical disk on which such a secret key is recorded are read out as-is using an ordinary reproducing apparatus and then recorded on another optical disk, only the original main digital information is copied. Sub-digital information (secret key) recorded and buried in jitter
Will not be copied. This makes it possible to distinguish between the original optical disk and the illegally copied optical disk.
By providing a mechanism that permits only reproduction of an optical disk including a secret key, it is possible to avoid infringement of copyright due to the pirated optical disk being sold.

(Embodiment 3) In this embodiment, an encryption key for encrypting main digital information is recorded on a predetermined area as sub-digital information on an optical disk.

<Optical Disk> FIG. 34 shows a DV of this embodiment.
D10 is shown. When the user information is composed of n pieces of content (content 1, content 2,..., Content n), each content is encrypted with an encryption key corresponding to each content. The total number of encryption keys is n equal to the total number of contents, and these encryption keys (encryption key 1, encryption key 2,... Encryption key n)
Are recorded as sub-digital information in a predetermined area in the control information area. The sub-digital information is recorded by phase modulation for displacing the edge position of the recording mark by a minute amount in the track direction. Encryption key 1 is content 1
Is a key for encrypting the other encryption keys 2 and 3
.., N, similarly, the encryption key ID and the content I
D corresponds. The main digital information for recording the sub digital information is dummy data (the data itself has no meaning). One sub-digital information is composed of 56 bits, and one bit of the sub-digital information is 25 bits.
It is recorded so as to be superimposed on 6-byte main digital information.
Therefore, to record one piece of sub-digital information, 143
36 bytes of main digital information are used. The n pieces of sub digital information are continuously recorded.

Therefore, even if the entire contents of a DVD on which such an encryption key is recorded are read out as-is using an ordinary reproducing apparatus and then recorded on another DVD, only the original main digital information is stored. The sub-digital information (encryption key) copied and buried in the jitter is not copied. Therefore DV copied illegally
D cannot decrypt the encrypted main digital information in the playback device. This makes it possible to avoid infringement of copyright due to the distribution of pirated DVDs.

Further, by adopting a form in which the encryption key is recorded in the control information area, for example, when a function of reading the encryption key at the time of starting the disc is provided in a regular DVD reproducing apparatus, this function is used. Unauthorized playback devices that do not have the ability to decrypt the encrypted primary digital information.
Therefore, it is possible to avoid infringement of copyright due to an illegal DVD reproducing device being circulated.

Further, the user information is composed of a plurality of contents, and each of the contents is recorded by being encrypted with an encryption key updated for each content. Even if the content is issued and the content is decrypted, the other content is not decrypted. Therefore, stronger concealment of the user information becomes possible.

[0207] There may be unencrypted contents in the contents constituting the user information. In addition, the encrypted content may include data that is not partially encrypted. For example, this is effective when recording content that is preferable not to be encrypted, such as a trailer of a movie title, a company PR, and an advertisement of a product.

[0208] Further, it is possible to record two or more keys for encrypting one content. Thereby, Pr
The key can be exclusively used by a combination of product ID, electronic money, and the like.

<Optical Disk Recording Apparatus> FIG. 35 is a block diagram showing a configuration of a main part of an optical disk recording apparatus according to the present invention. The waveforms of the signals B, D, E, and F shown in FIG. 35 are as shown in the timing chart of FIG.

The recording apparatus 100 is an apparatus for recording main digital information by forming optically readable recording marks. The recording device 100 has a function of encrypting the main digital information according to the encryption key, and a function of recording the encryption key as the sub-digital information by phase modulation for displacing the edge position of the recording mark by a very small amount in the track direction. It is a recording device for DVD-ROM.
The recording apparatus 100 includes, in addition to a recording channel 108 and a recording head 109, an encryptor 101 for encrypting main digital information, and further includes a formatter 102, a pseudorandom number generator 104, a timing generator 103, an exclusive logic Sum gate 105, PE (Phase Encoding) modulator 10
6. A phase modulator 107 is provided.

When recording the content data, the encryptor 101 outputs encrypted data obtained by encrypting the main digital information based on the encryption key to the formatter 102,
When recording the encryption key, the encryption key and the recording data that does not encrypt the main digital information are stored in the formatter 10.
2 is a circuit for outputting the signal.

FIG. 37 is a block diagram showing a detailed configuration of the encryptor 101. The encryption device 101 stores a plurality of encryption keys and selects an encryption key L corresponding to the content, and encrypts the recording data J input to the recording apparatus according to the encryption key L. An encryption encoder 101b that performs encryption and a data selector 101c that selects the encrypted data K when the encryption enable signal is 1, and selects the unencrypted recording data J when the encryption enable signal is 0.

First, the operation of recording an encryption key in a predetermined area in the control information area will be described. Encryption key selector 1
01a internally holds n encryption keys. The encryption key selector 101a records the encryption key corresponding to the i-th content (content ID = i (i = 1, 2,..., N)) (hereinafter, such an operation is referred to as “encryption key When a notification to start recording mode) and a content ID signal for identifying content ID = i are received from a controller (not shown), encryption key i is selected and output to formatter 102. I do.

At this time, the data selector 101c receives the encryption enable signal 0 from a controller (not shown), selects non-encrypted recording data, and outputs it to the formatter 102. The formatter 102 is a circuit that modulates main digital information (recording data), specifies sub-digital information, and controls recording of sub-digital information.

FIG. 38 is a block diagram showing a detailed configuration of formatter 102. The formatter 102 modulates recording data input to the recording apparatus 100 into a signal (channel signal B) suitable for the DVD 10.
And an initial value storage unit 102b for secretly storing an initial value of a pseudo random number sequence generated by the pseudo random number generator 104 in advance.
And an encryption key storage unit 102c that holds a 56-bit encryption key input from the encryptor.

As shown in the timing chart of FIG. 36, the modulating section 102a converts the input recording data into a corresponding 16-bit channel code A for each 8-bit code (byte) (8- 16 conversions)
A channel signal B is generated by performing NRZI conversion,
Output to the phase modulator 107. Also, the modulation unit 102a
When the encryption key recording mode is started, every time one byte of recording data is input, the timing signal indicating the head of the byte is output to the timing generator 103.

When the encryption key recording mode is started, the initial value storing
The bit length data (initial value) is output to the pseudo random number generator 104.

When the encryption key recording mode is started, the encryption key storage section 102c stores the 56-bit encryption key input from the encryptor in NRZ one bit at a time in order from the LSB.
Output to the exclusive OR gate 105 in the format. At this time, the encryption key storage unit 102c
Each time 2a modulates 256 bytes of recording data, the next upper bit is output. That is, the encryption key storage unit 102
c outputs a single 56-bit encryption key to the XOR 105 as an encryption key bit sequence in a bit-serial manner in correspondence with a total of 256 × 56 bytes of recording data.

FIG. 39 is a diagram showing the correspondence between an encryption key, a pseudo-random number sequence, and recorded data. In order to record the 56-bit encryption key as hidden information on the optical disk, a 256-bit pseudo-random number sequence is used for each bit of the encryption key, and each bit in the pseudo-random number sequence is 1 byte of recording data (16 bits). Channel code). Each bit of the 56-bit encryption key is used as a flag as to whether or not to logically invert the corresponding 256-bit pseudo-random number sequence, as described later.

The timing generator 103 generates (i) a clock signal (byte clock) synchronized with each byte of the recording data based on the timing signal from the modulation section 102a.
To the pseudo-random number generator 104, and (ii) the center of the channel signal B output from the formatter 102 (having a phase of 180 degrees) based on the timing signal and a clock signal from a clock oscillator (not shown). A timing signal indicating the timing is output to the PE modulator 106.

The pseudo random number generator 104 has an initial value storage unit 1
A pseudo-random number sequence (M sequence) having 2 15 bit sequences as one cycle is generated using the initial value from 02b as a preset value and the byte clock input from the timing generator 103 as a shift clock.

FIG. 40 is a circuit diagram showing a detailed configuration of pseudorandom number generator 104. The pseudo-random number generator 104 includes a 15-bit preset register 104a that holds an initial value from the initial value storage unit 102b, and 15 stages (bits).
Shift register 104b and its shift register 10
Exclusive OR gate 104c for calculating exclusive OR of the MSB (14th digit) of 4b and the output value of each of the 10th digit
It is composed of

When the initial value sent from the initial value storage section 102b is set in the preset shift register 104a, the initial value is written into the shift register 104b by the strobe signal sent from the formatter 102 immediately after that. It is. Thereafter, in synchronization with the byte clock from the timing generator 103, the 15-bit value stored in the shift register 104b is shifted to the left by a digit, and the output value from the exclusive OR gate 104c is shifted to the shift register 104b. Is fed back to and stored in the LSB (0th digit). As a result, a new random number of 1 bit is generated for each byte in the MSB of the shift register 104b and sent to the exclusive OR gate 105 as a pseudo-random number sequence.

In the present embodiment, pseudo-random number generator 104 has a total of 25 in encryption key recording mode.
It is used to generate a pseudo-random number sequence embedded in 6 × 56-byte recording data, that is, a 256 × 56-bit pseudo-random number sequence.

The exclusive-OR gate 105 stores the pseudo-random number sequence from the pseudo-random number generator 104 and the encryption key
The exclusive OR with the bit sequence from c is calculated, and the resulting pseudo-random number sequence D is output to the PE modulator 106. That is, the exclusive OR gate 105 inputs the 256-bit pseudo-random number sequence generated from the pseudo-random number generator 104 to the PE modulator 106 as it is in accordance with each bit value of the 56-bit encryption key. Alternatively, whether to input the signal to the PE modulator 106 after logical inversion is selectively performed.

The PE modulator 106 is the timing generator 1
03, the pseudo-random number sequence D sent from the exclusive OR gate 105 is expressed as PE (Ph
aseEncoding), and outputs the obtained PE modulation signal E to the phase modulator 107. As a result, the PE modulation signal E
36, the pseudorandom number D output from the exclusive OR gate 105 is 0, as shown in the timing chart of FIG.
In the case of, falling at the center of the channel signal B,
When the pseudorandom number D is 1, the waveform rises, and when the same random number value continues, the waveform is inverted again at the boundary of the channel signal B.

The phase modulator 107 performs phase modulation on the basis of the PE modulation signal E from the PE modulator 106 to determine whether to delay or advance the edge of the channel signal B from the formatter 102 by a certain minute time. The modulated channel signal F is output to the recording channel 108. In addition,
The minute time is the jitter observed when the normal DVD 10 that records only the main digital information by bypassing the phase modulator 107 (that is, without recording the sub digital information) is reproduced by the normal reproduction device. Is set in advance to a value (0.5σ) that is half the standard deviation σ in the frequency distribution.

FIG. 41 is a block diagram showing a detailed configuration of phase modulator 107. Referring to FIG. The phase modulator 107 includes a delay unit 107a for delaying a signal by the above-mentioned minute time and a selector 107b having two inputs and one output. The selector 107b outputs the PE modulation signal E input as a control signal.
Is 1, the channel signal B directly input from the formatter 1 is passed, and when the PE modulation signal E is 0, the channel signal B input via the delay unit 107a is passed.
Through.

As a result, the rising and falling edges of the channel signal B input to the phase modulator 107 result (in relative time relations) when the PE modulation signal E indicates 1 (0 to 0). (180 degrees), the phase is advanced by the minute time, and when the PE modulation signal E indicates 0 (180 to 360 degrees), the phase is delayed by the minute time. That is, the channel signal B input to the phase modulator 107 undergoes jitter modulation based on the pseudorandom number sequence D, and is converted into a modulated channel signal F as shown in FIG.

The recording channel 108 is connected to the phase modulator 107
Synchronized with 1/0 of the modulated channel signal F from
A control signal for turning on / off the laser beam to be exposed to the light 10 is generated and sent to the recording head 109. The recording head 109 cuts by turning a laser beam ON / OFF based on a control signal from the recording channel 108 and spirally applying a spot to the surface of the rotating DVD 10. In this manner, the modulated recording mark G composed of optically readable concave or convex pits is formed on the DVD 10.

FIG. 42 is an external view showing the surface of the recording film of the DVD 10 in which pits have been formed by the recording head 109. The position of each of the two edges in the track direction of the pits formed in the encryption key recording mode is different from the edge position of the pits formed in the case of not the encryption key recording mode by a displacement corresponding to the above-mentioned fixed minute time It is formed so as to be shifted to a position where the phase is advanced (or delayed) by an amount.

FIG. 43 is a graph showing the frequency (frequency) distribution of the pits formed in such an encryption key recording mode, that is, the jitter observed for the modulated recording mark G recorded after undergoing the jitter modulation. It is.

In this case, the curve A indicates that the PE modulation signal E is 0
Shows the jitter distribution only for the edge of the modulated recording mark G generated at the time of (1), and becomes a curve close to a Gaussian curve having a maximum frequency at a position X (L) shifted in a direction in which the phase is delayed by the displacement amount. A curve B shows the jitter distribution only for the edge of the modulated recording mark G generated when the PE modulation signal E is 1, and the position X (H) shifted in the direction in which the phase is advanced by the displacement amount is the maximum. It becomes a curve close to the Gaussian curve used as the frequency. Curve C shows the total jitter distribution obtained by adding both curves A and B.

According to the present invention, if synchronous detection is performed using the same pseudo-random number sequence as the pseudo-random number sequence used when recording the encryption key, the jitter distribution of curve C can be separated into the distributions of curve A and curve B. Use that thing.

The encryption key i is recorded according to the above-described sub-digital information recording method. This operation is continuously performed for the encryption keys 1 to n, and n encryption keys are continuously recorded in a predetermined area in the information control area.

Next, the operation of encrypting and recording contents will be described. The encryption selector 101a outputs the i-th content (content ID = i (i = 1, 2,...)
., N)) when encrypting and recording the main digital information, and a notice to start encryption and recording of the main digital information (hereinafter, such an operation is referred to as “main digital information encryption & recording mode”). ID for identifying content ID = i
When receiving a signal from a controller (not shown), an encryption key i is selected and the encryption encoder 101b is selected.
Output to

The encryption encoder 101b adds the value of the encryption key i to the 8-bit data of the input recording data, and outputs the result to the data selector 101c. For example, when the encryption key i is 1, 1 is added to the 8-bit data of the recording data.

At this time, the data selector 101c receives an encryption enable signal 1 from a controller (not shown), selects encrypted data, and outputs the selected data to the formatter 102. Thus, the recording data is encrypted according to the encryption key i.

The modulating section 102a converts the input encrypted data into a corresponding 16-bit channel code A (8-16 conversion) for each 8-bit code (byte), and then performs NRZI conversion. A channel signal B is generated and output to the phase modulator 107. Phase modulator 107
Outputs the channel signal B to the recording channel without phase modulation.

Thus, the recording data is recorded after being encrypted according to the encryption key i. This operation is the content 1
To content n, and the content data is recorded while being encrypted with an encryption key updated for each content.

Therefore, even if the entire contents of a DVD on which such an encryption key is recorded are read out in its entirety using a normal reproducing apparatus and then recorded on another DVD, only the original main digital information remains. The sub-digital information (encryption key) copied and buried in the jitter is not copied. Therefore DV copied illegally
D cannot decrypt the encrypted main digital information in the playback device. This makes it possible to avoid infringement of copyright due to the distribution of pirated DVDs.

<Optical Disk Reproducing Apparatus> A reproducing apparatus corresponding to a DVD on which an encryption key is recorded as described above will be described. FIG. 44 is a block diagram showing a configuration of a characteristic portion of the optical disc reproducing device 300 according to the present invention.

[0243] The reproducing apparatus 300 is a DVD reproducing apparatus corresponding to the optical disk recording apparatus 100 described above. The reproducing apparatus 300 not only reproduces the main digital information based on the position of the recording mark on the DVD, but also detects the sub digital information (encryption key) embedded in the jitter of the recording mark observed at that time, It has a function of decrypting the encrypted main digital information based on the detection result. Playback device 3
Reference numeral 00 includes a reproduction head 302, a reproduction channel 303, a reproduction signal processing circuit 304, a clock extractor 305, a synchronous detector 307, an encryption key reproduction circuit 308, and a pseudo random number generator 306.

The reproducing head 302 is an optical pickup, which focuses and irradiates a recording mark on the rotating DVD 301 with a light beam, and generates an analog read signal indicating the edge position of the recording mark from the reflected light. Output to the reproduction channel 303. The reproduction channel 303 converts the analog read signal from the reproduction head 302 into a digital read signal by equalizing or shaping the waveform, and outputs the digital read signal to the reproduction signal processing circuit 304 and the clock extractor 305.

The clock extractor 305 has the reproduction channel 3
Based on the readout signal from C.03, four types of clock signals, namely (i) a channel bit clock synchronized with each bit constituting a channel code, and (ii) a readout signal based on the channel bit clock A phase error signal H indicating only a leading component, (iii) a delay error signal I indicating only a lag component, and (iv) a byte clock synchronized with each recording data (byte unit) in the read signal. Extract and generate. The clock extractor 305 converts these clock signals into (i) a reproduced signal processing circuit 304, (ii) a synchronous detector 307, (iii) a synchronous detector 307, (iv) a reproduced signal processing circuit 304, and a synchronous detector 307. And a pseudo random number generator 306.

FIG. 45 is a block diagram showing a detailed configuration of clock extractor 305. Clock extractor 305
Comprises a PLL circuit, a 4-bit counter 305d, a synchronization signal detector 305e, and a phase error signal separator 305f. The PLL circuit includes a phase comparator 305a, a loop filter 305b, and a VCO (Voltage Controlled).
Oscillator) 305c.

The phase comparator 305a comprises a counter, an exclusive OR gate, a flip-flop, etc.
From the channel bit clock fed back from 305 c and the read signal from the reproduction channel 303, the phase difference between the rising and falling edges of the read signal and the rising edge of the channel bit clock closest to the edge is determined. The calculated value is output to the loop filter 305b and the phase error signal separator 305f as a phase error signal.

The loop filter 305b is connected to the phase comparator 3
This is a low-pass filter that smoothes the phase error signal from the signal 05a and converts it into a DC voltage signal. VCO305c
Is a voltage controlled oscillator that generates a channel bit clock having a frequency corresponding to the voltage signal from the loop filter 305b.

[0249] The synchronization signal detector 305e detects a synchronization pattern included in the read signal, and outputs the same to the 4-bit counter 305d as a reset signal. The 4-bit counter 305d is a counter that divides the channel bit clock from the VCO 305c by 1/16, and is reset by a reset signal from the synchronization signal detector 305e. That is, the 4-bit counter 305d outputs a byte clock synchronized with each recording data (byte unit) in the read signal.

The phase error signal separator 305f is a circuit that separates the phase error signal from the phase comparator 305a into a phase error signal H and a phase error signal I and outputs the separated signal to the synchronous detector 307.

FIG. 46A shows the phase error signal separator 30.
It is a circuit diagram which shows the detailed structure of 5f. The phase error signal separator 305f includes two inverters 400a and 400b
And two AND gates 400c and 400d. FIG. 46B is a timing chart of each signal for explaining the operation of the phase error signal separator 305f shown in FIG. 46A. As shown in FIG. 46 (b), the phase error signal output from the phase comparator 305a includes a leading error component and a lagging error component. The signal (leading error signal H) output from the AND gate 400c shows only the leading error component, and the signal output from the AND gate 400d (the lagging error signal I) Is a waveform showing only the delay error component.

A reproduction signal processing circuit 304 is a circuit for demodulating a read signal from the reproduction channel 303, performing control for detecting sub-digital information, and performing an operation for protecting copyright based on the detection result. is there. Further, when reproducing the content, the reproduction signal processing circuit 304 decodes the demodulated signal based on the encryption key read at the time of reading the encryption key, and outputs it as a reproduction signal. When reading the encryption key, the demodulated signal is output as a reproduced signal.

FIG. 47 is a block diagram showing a detailed configuration of the reproduction signal processing circuit 304. Reproduction signal processing circuit 30
4 includes a demodulation unit 304a, a decoding decoder 304b, a data selector 304c, and an initial value storage unit 304d.

First, the operation of reading the sub-digital information (encryption key) recorded in a predetermined area in the control information area will be described. When the user information is composed of n pieces of content, n encryption keys are embedded as sub-digital information in a predetermined area in the control information area.

After the disk is inserted into the drive, the encryption key reproducing circuit 308 reads out these encryption keys from a predetermined area in the control information area during the lead-in operation, and returns the n keys to the encryption key reproducing circuit. 308.

The reproduction signal processing circuit 304 is shown a notice to start reading an encryption key from a predetermined area in the control information area (hereinafter, such an operation is referred to as “encryption key read mode”). If it is received from a controller that has not been updated, the initial value held in the initial value storage unit 304d is output to the pseudo-random number generator 306.

The pseudo-random number generator 306 has the same function as the pseudo-random number generator 104 of the optical disc recording apparatus 100. The pseudo-random number generator 306 uses the initial value from the initial value storage section 304d as a preset value and inputs the same from the clock extractor 305. The generated byte clock is used as a shift clock to generate a pseudo-random number sequence (M sequence) having 2 15 bit sequences as one cycle. In the reproducing apparatus 300, the pseudo random number generator 30
Reference numeral 6 is used to generate a 256 × 56 bit pseudo-random number sequence.

The synchronous detector 307 includes the clock extractor 30
5 is a circuit for detecting the correlation between the early phase error signal H and the late phase error signal I output from the pseudo-random number generator 306 and the pseudo-random number sequence from the pseudo-random number generator 306. (Positive correlation, negative correlation, no correlation)
To the encryption key reproducing circuit 308.

FIG. 48 is a circuit diagram showing a detailed configuration of the synchronous detector 307. The synchronous detector 307 includes a PE modulator 307a, a selector 307b, an integrator 307c, a threshold value determination unit 307d, and an 8-bit counter 307e.

The PE modulator 307a comprises the timing generator 103 and the PE modulator 106 of the optical disc recording apparatus 100.
These modulators have functions corresponding to the respective functions, and perform a PE conversion of the pseudo-random number sequence from the pseudo-random number generator 306 based on the byte clock from the clock extractor 305 and output it to the selector 307b as a switching control signal. That is, when the pseudorandom number from the pseudorandom number generator 306 is 0, it falls at the center timing of each recording data (byte) in the reproduced read signal, and when the pseudorandom number is 1, it rises and has the same random number value. Is continued, a signal having a waveform that is inverted once again at the boundary of each recording data is output to the selector 307b.

The selector 307b is composed of two 2-input / 1-output switching circuits, and outputs the leading error signal H and the trailing error signal I from the clock extractor 305 to the PE modulator 3 respectively.
When the control signal from 07a is 1, the signal is passed through the positive input terminal and the negative input terminal of the integrator 307c, and when the control signal is 0, the signal is crossed and passed through the negative input terminal and the positive input terminal of the integrator 307c.

The 8-bit counter 307e is a counter that divides the byte clock from the clock extractor 305 into 1/256, and uses the result as a reset signal as an integrator 307c, a threshold value determination unit 307d, and an encryption key reproduction. Output to the circuit 308. Therefore, this reset signal
Each time the pseudo-random number generator 306 outputs a 256-bit random number sequence, it has a waveform that outputs one reset pulse.

The integrator 307c is a differential input bipolar output analog integrator. The integrator 307c adds and accumulates the area of the pulse input to the positive input terminal, and simultaneously outputs the pulse input to the negative input terminal. Are subtracted and accumulated, and an analog signal corresponding to the accumulated total area is output to the threshold value determination unit 307d. At this time, when a reset signal is input from the 8-bit counter, the data is accumulated from zero again.

As a result, the output waveform of the integrator 307c is accumulated by adding the area of the pulse appearing in the phase error signal H during the period when the PE modulation signal output from the PE modulator 307a is 1. 7 shows the result of subtracting and accumulating the area of the pulse appearing in the delay error signal I. PE
During the period when the modulation signal is 0, the output waveform of the integrator 307c subtracts and accumulates the area of the pulse appearing in the phase error signal H, and adds the area of the pulse appearing in the phase error signal I. This shows the storage area when the data is accumulated.

Therefore, a positive correlation in which a pulse appears only in the phase error signal H during the period in which the PE modulation signal is 1 and a pulse appears only in the delay error signal I in the period in which the PE modulation signal is 0 is obtained. Is followed by the integrator 307
The output waveform of c is a ramp waveform that increases in the positive direction. Conversely, a negative correlation continues in which a pulse appears only in the phase error signal I during the period when the PE modulation signal is 1 and a pulse appears only in the phase error signal H during the period when the PE modulation signal is 0. In this case, the output waveform of the integrator 307c is a ramp waveform that decreases in the negative direction. When neither correlation exists, that is, when pulses appear in the leading phase error signal H and the lagging error signal I at random without depending on the value of the PE modulation signal, both pulses appearing in those error signals are used. Are almost equal, the integrator 307
The output waveform of c maintains a value close to zero level.

The threshold value determining section 307d includes an integrator 307
Comparator and the like for determining which of three voltage sections the analog signal from c belongs to by a predetermined positive threshold voltage and a preset negative threshold voltage.

FIG. 49 is a diagram for explaining the operation of threshold decision section 307d, and shows an example of an analog signal waveform inputted from integrator 307c to threshold decision section 307d. The threshold value judging section 307d includes an 8-bit counter 3
At the time point (immediately before) the reset signal is input from 07e, if the signal voltage from the integrator 307c is larger than the positive threshold value, it is set to 1, and if it is smaller than the negative threshold value, it is set to 0. The code string of the format is output to the encryption key reproducing circuit 308.

Although the threshold voltage can be reliably exceeded (with an extremely high probability) when the jitter modulation according to the present invention is performed, it cannot be exceeded (with an extremely high probability). Integrator 3 with low probability)
The output voltage value is set to 07c. Specific values include the jitter modulation degree during recording (the delay amount of the delay unit 107a of the phase modulator 107), the number of bytes input to the integrator 307c (256), the average number of edges per byte, and the natural (random) Is determined by the standard deviation in the jitter distribution.

As described above, the code string output from threshold determination section 307d indicates a change in the polarity (positive or negative) of the correlation observed for each 256-bit pseudorandom number. Such a change in polarity is generated for each 256-bit pseudo-random number sequence.
This is information corresponding to a bit string indicating whether the pseudo-random number sequence was recorded by jitter modulation without logical inversion or recorded after logical inversion.

The encryption key reproducing circuit 308 includes the synchronous detector 3
An encryption key for encrypting each content is read out based on the code string transmitted from 07, and a plurality of encryption keys are stored in an encryption key selector.

FIG. 50 is a block diagram showing a detailed configuration of the encryption key reproducing circuit 308. Encryption key reproducing circuit 30
8 includes a shift register 308a, a counter 308b, an encryption key selector 308c, and an encryption key storage unit 308d.

The shift register 308a includes the synchronous detector 3
The shift register is a 56-stage (bit) shift register that stores the code string from the synchronous detector 307 while shifting it using the reset signal from the shift register 07 as a shift clock. Immediately after the 56-bit code string is input to the shift register 308a, the counter 308b outputs a load pulse to the encryption key selector 308c. At this time, the encryption key selector 30
8c receives the value of the shift register.

The encryption key selector 308c has a counter 3
08b at the same time as receiving the load pulse from the controller (not shown), and receiving the encryption key ID signal indicating the current i-th encryption key, the value input from the shift register corresponds to the encryption key ID. Store in the location where the encryption key is stored.

This operation is performed for encryption keys 1 to n, and n encryption keys are read from the information control area.
Each encryption key is stored in the encryption key selector 308c.

Next, the operation of decrypting and reproducing the content based on the encryption key will be described. The encryption selector 308c outputs the i-th content (content ID = i
(I = 1, 2,..., N)), decoding and reproduction of main digital information (hereinafter, such an operation is referred to as “main digital information decoding & reproduction mode”) is started. When a notification that the content ID is to be received and a content ID signal for identifying the content ID = i are received from a controller (not shown), an encryption key i is selected and the encryption key storage unit 3 is selected.
08d and output to the reproduction signal processing circuit 304.

[0276] The demodulation section 304 a
A demodulation circuit corresponding to the modulation section 102a of No. 00, which demodulates to a channel code A by sampling a read signal from the reproduction channel 303 in synchronization with a channel bit clock from the clock extractor 305,
The data is converted into 16-bit recording data corresponding to each channel code (16-8 conversion) in synchronization with the byte clock from the clock extractor 305, and the recording data sequence is sent to the decoding decoder 304b and the data selector 304c.

The decryption decoder 304b subtracts the value Q of the encryption key i from the 8-bit data P of the recording data, and outputs the decrypted data R to the data selector 304c. For example, when the encryption key i is 1, the recording data 8b
Subtract 1 from it data. At this time, the data selector 3
04c selects the decoded data R and outputs it as a reproduced signal. As a result, the read signal is decrypted according to the encryption key i.

As a result, for a DVD from which the encryption key cannot be read, the encrypted recording data cannot be decrypted, thereby preventing unauthorized reading of the recording data. Therefore, even if a new DVD is created by dead-copying a legitimate DVD including an encryption key, the DVD cannot be reproduced by a playback device unless the encryption key embedded by jitter modulation is also copied. The copyright is protected because the encrypted primary digital information cannot be decrypted.

In the conventional DVD encryption method, since the disk key and the title key are recorded on the disk as data, the key may be read illegally. However, in this embodiment, since the encryption key is embedded by the jitter modulation, it is difficult to decipher the encryption key and the encryption key can be concealed.

Further, as a conventional technique, there has been a method in which a discrimination circuit determines the discrimination between an authorized disk and an unauthorized disk, and in the case of an authorized disk, outputs an enable signal to a playback signal processing circuit to permit playback. However,
In this method shown in FIG. 51, an illegal enable signal is output to the reproduction signal processing circuit due to the modification, and there is a possibility that reproduction of an illegal disk cannot be prevented.

In this embodiment, the optical disk reproducing apparatus reads an encryption key corresponding to the content to be reproduced from the sub-digital information recorded in the information control area, and reads the main digital information encrypted with the encryption key. It needs to be deciphered. Therefore, even in the case of the above-mentioned illegal modification, the copyright is protected because the optical disk reproducing apparatus cannot decrypt the encrypted main digital information.

Further, in the method of allowing the discrimination circuit to output an enable signal to the reproduction signal processing circuit and permit reproduction, if an optical disc reproducing apparatus having no discrimination function as shown in FIG. It may not be possible to prevent playback of the disc.

In this embodiment, the optical disk reproducing apparatus reads an encryption key corresponding to the content to be reproduced from the sub-digital information recorded in the information control area, and reads the main digital information encrypted with the encryption key. It needs to be deciphered. Therefore, the optical disk reproducing apparatus having no function of detecting the sub digital information cannot decrypt the encrypted main digital information, so that the copyright is protected.

When an unauthorized encryption key is input from outside or software as shown in FIG. 53 and data is read from an authorized disk, the encryption key must be decrypted for all contents. No. Therefore, the amount of work for decrypting the encryption key can be enormous, and reading data can be made difficult in practice.

Although the recording medium and the recording / reproducing apparatus relating to the encryption of the main digital information by the sub-digital information according to the present invention have been described based on the embodiments, the present invention is not limited to this embodiment. Of course.

For example, in the present embodiment, 256.times.56 logically inverted for one 56-bit encryption key.
Although a pseudo random number sequence of bits is embedded in continuous recording data of 256 × 56 bytes, the present invention is not limited to such numerical values. For the number of bytes related to the physical recording structure such as an ECC block, a sector, and a frame, and the recording data of a specific area, not only one kind but also two
A method of embedding a pseudo-random number sequence starting from an initial value of a kind or more in a plurality of areas may be adopted.

In the present embodiment, the user information is composed of a plurality of contents, and each of the contents is encrypted with an encryption key corresponding to each of the contents. However, the present invention is not limited to this form. Not done. For example, the user information is divided into a plurality of recording data aggregates in units of a number of bytes related to a physical recording structure such as a radial position, a track, an ECC block, and a sector, and an aggregate of recording data in a specific area. Each set of recording data may be encrypted with an encryption key corresponding to the set of recording data. The greater the number of encryption keys, the more confidential the user information becomes.

In the present embodiment, one encryption key is provided for each content, and each content is independently encrypted. However, the present invention is not limited to this mode. For example, if a single encryption key is shared by an aggregate of a plurality of recording data, the capacity of the main digital information for recording the encryption key can be reduced.

In the present embodiment, the n-th encryption key from the first encryption key is recorded in a predetermined area of the control information area in ascending order, but the present invention is limited to this form. Not done. The order in which the encryption keys are recorded may be scrambled, or the order of the encryption keys recorded based on a certain rule may be determined.

Also, in the present embodiment, the encryption key is recorded as sub-digital information by phase modulation that displaces the edge position of the recording mark by a very small amount in the track direction. It is not limited to.
For example, modulation to vary the recording mark by a small amount in the radial direction, modulation to locally narrow the track pitch,
In addition, it is also possible to record the sub-digital information by giving the pit shape or signal a very small change, such as signal amplitude, tracking error signal, focus error signal, asymmetry, and modulation degree.

In this embodiment, the initial value for generating the pseudo-random number sequence is secretly stored in advance in formatter 102 of optical disk recording apparatus 100 and reproduction signal processing circuit 304 of optical disk reproduction apparatus 300. However, the present invention is not limited to this mode. For example, the optical disc recording device records an initial value used for recording the sub-digital information in the control information area of the DVD, and the optical disc reproducing device inserts the disc into the drive and then controls the control information area during the lead-in operation. Alternatively, the initial value may be read from and stored in the initial value storage unit.

The area in which the initial value is recorded is not limited to the control information area, but may be a predetermined area in the user data area. Furthermore, if a plurality of initial values are defined and a pseudo-random number sequence is defined corresponding to each set of recording data, stronger concealment of user information is possible.

In the present embodiment, the encryption encoder adds the value of the encryption key to the 8-bit data of the input recording data. However, the present invention is limited to such an encryption mode. Not something.

For example, as shown in FIG. 55, the value of the lower 8 bits of the encryption key is La, and the value of the lower 9 to 16 bits is L.
b, when the value of the lower 17 to 24 bits is Lc, the encryption encoder first adds La to the 8-bit data J of the recording data and sets it to Ka. Lb from the lower part of Ka
Starting from the bit position defined in
The logical data may be inverted by the number of bits indicated by and the encrypted data K may be output.

As shown in FIG. 56, in the conventional DVD encryption technology, a key obtained by encrypting a master key with a disk key and a title key is further encrypted with an encryption key based on sub-digital information. Alternatively, the content may be scrambled using the key. In addition, the present invention can be applied to any encryption method in which recording data is scrambled with the encryption key by recording the encryption key as sub-digital information.

In this embodiment, the secret key used as the sub-digital information is
Is stored in advance, but may be rewritten by an instruction from a user or secret communication with an external device.

Also, in the present embodiment, the target recording medium is a DVD-ROM, but the present invention is not limited to such a type of recording medium, and a CD-ROM or DVD-R
It can also be applied to AM and the like. If it is possible to write while changing the position and shape of the pit (recording mark) by a small amount, apply it not only to the drilling method but also to other types of recording media adopting the recording method such as phase transition and magnetization. Because it can be.

(Embodiment 4) In this embodiment, an encryption key for encrypting main digital information is recorded on an optical disk in a manner superimposed on main digital information to be encrypted as sub-digital information. .

<Optical Disk> FIG. 56 is a view for explaining an encryption key provided for each block in the optical disk of this embodiment. The user information of each ECC block on the optical disk is encrypted with an encryption key corresponding to each block. An encryption key for encrypting each block is recorded as sub-digital information, superimposed on the recording data itself in the ECC block. This encryption key is
14336 bytes (256 bytes x
It is superimposed on the main digital information (56-bit encryption key) and recorded as sub-digital information.

[0300] Therefore, by adopting a form in which an encryption key for encrypting each ECC block is recorded as sub-digital information on the recording data itself in the ECC block, for example, a regular DVD If the playback device has a function of reading the encryption key from the beginning of the read signal of each ECC block, an unauthorized playback device without this function cannot decrypt the encrypted main digital information. . Therefore, it is possible to avoid infringement of copyright due to an illegal DVD reproducing device becoming available.

<Optical Disk Recording Device> The optical disk recording device of the present embodiment has the same configuration as that of FIG. The operation of encrypting and recording the main digital information while superimposing the sub digital information on the main digital information will be described. ECC
At the time of recording block i (i = 1 to n), the encryption key selector 101a notifies the start of the main digital information encryption & recording mode and the encryption key recording mode, and the content indicating the “ECC block i”. An ID signal is received from a controller (not shown), and an encryption key i is sent to the encryption encoder 101b.

At this time, the encryption encoder 101b encrypts the recording data J of the ECC block i with the encryption key i and outputs the encrypted data to the data selector 101c by the method described in the third embodiment. Data selector 1
01c outputs the encrypted data to the formatter 102. The formatter 102 converts the encrypted data
The signal is subjected to 8-16 conversion by a and output to the phase modulator 107 as a channel signal B.

The encryption key is superimposed on the channel signal B and recorded in the same manner as the sub-digital information recording method described in the third embodiment. The formatter 102 outputs the initial value to the pseudo-random number generator 104, and outputs the encryption key i to the exclusive OR gate 105. The pseudo random number generator 104 outputs a pseudo random number sequence to the exclusive OR gate 105 based on the input initial value and the byte clock. The exclusive OR gate 105 outputs a pseudorandom number sequence D to the PE modulator 106 based on the input pseudorandom number sequence and the encryption key i.
The PE modulator 106 performs PE conversion on the pseudo-random number sequence D input from the exclusive OR gate 105 based on the timing signal from the timing generator 103, and obtains the obtained P
The E modulation signal E is output to the phase modulator 106.

The phase modulator 107 performs phase modulation on the basis of the PE modulation signal E from the PE modulator 106 to determine whether to delay or advance the edge of the channel signal B from the formatter 102 by a predetermined minute time. The modulated channel signal F is output to the recording channel 108. The recording channel 108 generates a control signal for turning on / off a laser beam for exposing the DVD 10 in synchronization with 1/0 of the modulated channel signal F from the phase modulator 107 and sends the control signal to the recording head 109. The recording head 109 cuts by turning a laser beam ON / OFF based on a control signal from the recording channel 108 and spirally applying a spot to the surface of the rotating DVD 10. In this way, the modulated recording mark G composed of optically readable concave or convex pits is
10 is formed.

Thus, it becomes possible to record the encryption key i as sub-digital information while superimposing it on the channel signal B corresponding to 256 × 56 bytes of encrypted data from the head of the ECC block.

Therefore, even if the entire contents of a DVD on which such an encryption key is recorded are read out as it is using an ordinary reproducing apparatus and then recorded on another DVD, only the original main digital information remains. The sub-digital information (encryption key) copied and buried in the jitter is not copied. Therefore, the illegally copied D
The VD cannot decrypt the encrypted main digital information in the playback device. This gives you a pirated DVD
Can avoid infringement of copyright due to the circulation of.

In the present embodiment, the target recording medium is an optical disk. However, the present invention is not limited to such a type of recording medium, and the present invention is not limited to this type of recording medium.
M, DVD-ROM, CD-R, CD-RW, DVD-
It is also applicable to RAM, DVD-RW, MO, and the like. That is, the present invention can be applied to recording not only on uneven pits but also on phase change films, magnetic films, and the like. If the pit (recording mark) position can be written by jitter modulation, it can be applied not only to the drilling method but also to other types of recording media that use a recording method such as phase transition (phase change) or magnetization. Because you can. Note that the configuration and operation shown in FIG. 35 can be applied to the recording apparatus.

<Optical Disk Reproducing Apparatus> An optical disk reproducing apparatus according to the present invention has the same configuration as that of FIG. 44, and has a configuration in which the internal configuration of the encryption key reproducing circuit is replaced as shown in FIG. The operation of decoding and reproducing the main digital information while extracting the sub-digital information superimposed on the main digital information will be described.

At the time of reproducing the ECC block i (i = 1 to n), the reproduction signal processing circuit 304 notifies the start of the encryption key read mode and the content decryption & reproduction mode and the "ECC block i". The demodulation unit 304a receives the content ID signal from the controller (not shown), demodulates the read signal input from the reproduction channel by 16-8, and demodulates the demodulated signal P to the decoding decoder 304.
b and the data selector 304c. Further, the reproduction signal processing circuit 304 outputs the initial value held in the initial value storage section 304d to the pseudo-random number generator 306. The pseudo random number generator 306 generates a pseudo random number sequence (M sequence) based on the input initial value.

The synchronous detector 307 includes the clock extractor 30
5 is a circuit for detecting the correlation between the early phase error signal H and the late phase error signal I output from the pseudorandom number generator 306 and the pseudorandom number sequence from the pseudorandom number generator 306. (Positive correlation, negative correlation, no correlation)
Is transmitted to the encryption key reproducing unit 800.

[0311] The encryption key reproducing circuit 800 reads out the encryption key based on the input reset signal and code string. The shift register 800a uses the reset signal from the clock extractor 305 as a shift clock to
Is a shift register of 56 stages (bits) that stores the code string while shifting it. Shift register 800a
Immediately after a 56-bit code string is input to
00b outputs a load pulse to the encryption key storage unit 800c. At this time, the encryption key storage unit 800c stores the value of the shift register 800a. The encryption key storage unit 800c outputs the encryption key i to the reproduction signal processing circuit 304 immediately after the encryption key i is stored.

[0312] The decoding decoder 304b converts the 8-bit data of the demodulated signal input from the reproduction channel 303 from
The value of the encryption key i input from the encryption key storage unit 800c is subtracted and output to the data selector 304c. For example, when the encryption key i is 1, the recording data 8b
Subtract 1 from it data. At this time, the data selector 304c selects the output of the decoding decoder 304b and outputs it as a reproduction signal. Thus, the demodulated signal is decrypted according to the encryption key i.

In the fourth embodiment, in addition to the effect of the first embodiment, an encryption key for encrypting each ECC block is recorded so as to be superimposed on the encrypted data of each ECC block. Therefore, in reproducing data, it is necessary to reproduce each ECC block, read the encryption key embedded in the main digital information, and decrypt the encrypted data. Therefore, a DV without an encryption key decryption function
With respect to D, unauthorized reading of data is prevented.

Further, when an unauthorized encryption key is input from outside or from software and data is to be read from an authorized disk, the encryption key must be decrypted for all ECC blocks. Therefore, the amount of work for decrypting the encryption key can be made extremely large, and it becomes practically difficult to read data.

In the present embodiment, each block is encrypted with an encryption key corresponding to each block. However, the present invention is not limited to this mode. For example, the user information is divided into a plurality of recording data aggregates in units of a number of bytes related to a physical recording structure such as a radial position, a track, an ECC block, and a sector, and an aggregate of recording data in a specific area. Each set of recording data may be encrypted with an encryption key corresponding to the set of recording data. The greater the number of encryption keys, the more confidential the user information becomes.

Further, in this embodiment, the encryption key corresponding to a certain block is recorded so as to be superimposed on the column of the recording data of the block itself, but the present invention is not limited to this. is not. As shown in FIG. 58, if the encryption key for encrypting a certain set of recording data is recorded so as to be superimposed on the recording data of the immediately preceding collection of recording data, then When the aggregate is continuously reproduced, when reproducing the aggregate of the desired data, the encryption key has already been read at the time of reproducing the aggregate of the immediately preceding data. Decoding (without waiting for time). In this manner, the encryption key for encrypting a certain aggregate of recording data may be recorded in a manner superimposed on the recording data of the aggregate of recording data different from the aggregate of the recording data.

According to the optical discs of the third and fourth embodiments, the encryption key is embedded in the main digital information as sub-digital information in a manner that is difficult to read. Is
Because the encryption key is not copied, it is possible to prevent the encrypted primary digital information from being decrypted,
It is possible to prevent copyright infringement caused by illegally copying a digital work on an optical disk as it is.

Further, according to the optical disks of the third and fourth embodiments, since the encryption key is embedded by jitter modulation, it is difficult to decipher the encryption key and the encryption key is highly concealed.

According to the optical disk reproducing apparatuses of the third and fourth embodiments, since the encrypted recording data cannot be decrypted for the optical disk from which the encryption key cannot be read, the recorded data is read illegally. Is prevented. Therefore, even if a new optical disk is created by dead-copying a legitimate optical disk including an encryption key, the optical disk can be used in a playback device unless the encryption key embedded by jitter modulation is also copied together. The copyright is protected because the encrypted primary digital information cannot be decrypted.

[0320]

According to the present invention, since the sub-digital information is embedded in the main digital information in a manner that is difficult to read, the sub-digital information is not copied when the optical disk is copied only based on the presence or absence of the recording mark. .
This makes it possible to prevent the digital work on the optical disk from being illegally copied in its entirety, and to prevent decryption of the main digital information. This can prevent copyright infringement.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an area of an optical disc according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of an identification area of the optical disc in the first embodiment.

FIG. 3 is a diagram illustrating pits that are phase-modulated and recorded and that form sub-digital information according to the first embodiment.

FIG. 4 is a block diagram of an optical disc reproducing device according to the first embodiment.

FIG. 5A shows a track on which sub-digital information is recorded, FIG. 5B shows an output signal waveform of a phase comparator when reproducing the track shown in FIG. 5A, and FIG. 5C shows a waveform when reproducing the track shown in FIG. The figure which showed the output signal waveform of the LPF, and the output signal waveform of the amplitude detector at the time of reproducing | regenerating the track of (d) and (a).

FIG. 6 is a diagram illustrating another optical disk area according to the first embodiment of the present invention.

FIG. 7 is a view for explaining still another optical disk area according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating still another optical disc area according to the first embodiment of the present invention.

FIG. 9 is an exemplary view for explaining an example of a relationship between identification information of a content included in an optical disc and an identification area in which the content is stored.

FIG. 10 is a view for explaining modulation for shifting pits in the radial direction in order to record sub-digital information.

FIG. 11 is a diagram illustrating still another optical disc area according to the first embodiment of the present invention.

FIG. 12 is a diagram illustrating still another optical disc area according to the first embodiment of the present invention.

FIG. 13 is a block diagram of an unauthorized copying apparatus in a conventional example.

FIG. 14A is a diagram illustrating an area of an optical disc;
(B) A diagram illustrating a modulation method of sub-digital information, (c)
The figure explaining the content of management information.

FIG. 15 is a block diagram showing a configuration of an optical disk recording apparatus according to a second embodiment.

FIG. 16 is a block diagram illustrating a detailed configuration of a formatter in the printing apparatus according to the second embodiment.

FIG. 17 is a block diagram illustrating a detailed configuration of a phase modulator in the recording apparatus according to the second embodiment.

FIG. 18 is a block diagram showing a detailed configuration of a sub digital information generator in the recording device according to the second embodiment.

FIG. 19 is a graph showing the frequency distribution of jitter for pits formed by the recording apparatus of the second embodiment.

FIG. 20 is a timing chart of main signals in the recording apparatus according to the second embodiment.

FIG. 21 is a diagram showing a correspondence relationship between a secret key, a pseudo-random number sequence, and recorded data.

FIG. 22 is a timing chart of main signals in the recording apparatus according to the second embodiment.

FIG. 23 (a) is a diagram illustrating an area of an optical disk,
(B) The figure explaining the content of management information.

FIG. 24A is a diagram illustrating an area of an optical disc;
(B) The figure explaining the content of management information.

FIG. 25 is a block diagram showing a configuration of an optical disc reproducing device according to the second embodiment.

FIG. 26 is a block diagram showing a detailed configuration of a clock extractor of the reproduction device according to the second embodiment.

27A is a circuit diagram showing a detailed configuration of a phase error signal separator in a clock extractor, and FIG. 27B is a timing chart of each signal for explaining the operation of the phase error signal separator.

FIG. 28 is a block diagram showing a detailed configuration of a reproduction signal processing circuit of the reproduction device according to the second embodiment.

FIG. 29 is a circuit diagram showing a detailed configuration of a synchronous detector of the reproducing apparatus according to the second embodiment.

FIG. 30 is a diagram showing an example of an analog signal waveform output from an integrator of the reproducing apparatus according to the second embodiment.

FIG. 31 is a block diagram showing a detailed configuration of a verification unit of the playback device according to the second embodiment.

FIG. 32 is a timing chart of a displacement pattern gate.

FIG. 33 is a diagram illustrating a recording area of a conventional optical disc.

FIG. 34 is a view for explaining a control information area and a user information area on the optical disc of the third embodiment.

FIG. 35 is a block diagram illustrating a configuration of an optical disc recording device according to a third embodiment.

FIG. 36 is a timing chart of main signals in the recording apparatus according to the third embodiment.

FIG. 37 is a block diagram illustrating a detailed configuration of an encryption device of the recording device according to the third embodiment.

FIG. 38 is a block diagram illustrating a detailed configuration of a formatter of the printing apparatus according to the third embodiment.

FIG. 39 is a diagram showing a correspondence relationship between an encryption key, a pseudo-random number sequence, and recording data.

FIG. 40 is a circuit diagram showing a detailed configuration of a pseudo-random number generator of the recording apparatus according to the third embodiment.

FIG. 41 is a block diagram illustrating a detailed configuration of a phase modulator of the recording apparatus according to the third embodiment.

FIG. 42 is a view showing the surface of a DVD on which pits have been formed by the recording apparatus of the third embodiment.

FIG. 43 is a graph showing the frequency distribution of jitter for pits formed by the recording device of the third embodiment.

FIG. 44 is a block diagram showing a configuration of an optical disc reproducing apparatus according to a third embodiment.

FIG. 45 is a block diagram showing a detailed configuration of a clock extractor of the playback device of the third embodiment.

46A is a circuit diagram showing a detailed configuration of a phase error signal separator in a clock extractor, and FIG. 46B is a timing chart of each signal for explaining the operation of the phase error signal separator.

FIG. 47 is a block diagram showing a detailed configuration of a reproduction signal processing circuit of the reproduction device of the third embodiment.

FIG. 48 is a circuit diagram showing a detailed configuration of a synchronous detector of the playback device of the third embodiment.

FIG. 49 is a view showing an example of an analog signal waveform output from the integrator of the reproducing apparatus according to the third embodiment.

FIG. 50 is a block diagram showing a detailed configuration of an encryption key reproducing circuit of the reproducing device of the third embodiment.

FIG. 51 is a view for explaining that an invalid enable signal is externally input to the optical disc reproducing apparatus.

FIG. 52 is a diagram showing an optical disk reproducing apparatus having no discrimination function between an authorized disk and an unauthorized disk.

FIG. 53 is a view showing that an unauthorized encryption key is externally input to the optical disc reproducing apparatus.

FIG. 54 is a diagram showing a detailed configuration of an encryption encoder.

FIG. 55 is a view showing an example of an encryption method.

FIG. 56: ECC recorded as sub digital information
FIG. 4 is a diagram for explaining an encryption key provided for each block.

FIG. 57 is a block diagram showing a detailed configuration of an encryption key reproducing circuit of the optical disc reproducing device according to the fourth embodiment;

FIG. 58: ECC recorded as sub digital information
FIG. 4 is a diagram for explaining an encryption key provided for each block.

[Explanation of symbols]

10, 20 optical disk (DVD) 12 control area 13, 13a, 13b identification area 14, 14a, 14b data area 100, 100a optical disk recording device 101 encryptor 102 formatter 103 timing generator 104 pseudorandom number generator 107 phase modulator 108 Recording channel 109 Recording head 121 Secondary digital information generator 207, 227, 247 Management information 208, 228, 248 Disk management information 209, 229, 249 Secondary digital information management information 210, 220, 250 Threshold information 212, 232, 252 Secondary digital Information arrangement position information 213, 233, 253 Sub-digital information displacement pattern information 214, 234, 254 Pseudo random number generator initial value information 300, 1200 Optical disk reproducing device 302 Reproducing head 303 Raw channel 304 reproduction signal processing circuit 305 clock extractor 306 pseudorandom number generator 307 coherent detector 308 encryption key reproducing circuit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takashi Ishida 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hirodori Ishibashi 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Haruharu Miyashita 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd.

Claims (50)

[Claims] An optical disc having main digital information recorded by an optically readable recording mark and sub-digital information superimposed and recorded by displacing a position or a shape of the recording mark by a very small amount. An optical disc, wherein a plurality of areas for storing the same sub-digital information are provided for one content recorded by the main digital information. 2. An optical disc having main digital information recorded by an optically readable recording mark and sub-digital information superimposed and recorded by displacing the position or shape of the recording mark by a very small amount. An optical disc, wherein a plurality of areas for storing different sub-digital information are provided for one content recorded by the main digital information. 3. The optical disk according to claim 1, wherein the plurality of areas are provided in units of a predetermined radial position. 4. The optical disk according to claim 1, wherein the plurality of areas are provided in predetermined address units. 5. The optical disc according to claim 1, wherein a displacement amount differs for each area. 6. An optical disc having main digital information recorded by an optically readable recording mark and sub-digital information superimposed and recorded by displacing a position or a shape of the recording mark by a very small amount. An optical disc, wherein different sub-digital information is provided for different contents recorded by the main digital information. 7. Sub-digital information is superimposed and recorded on an optical disk on which main digital information is recorded by optically readable recording marks by displacing the position or shape of the recording marks in the track direction by a very small amount. An optical disc, wherein the sub-digital information is formed in an area different from a data area in which content is recorded by the main digital information. 8. An optical disk in which sub-digital information is superimposed and recorded on an optical disk on which main digital information is recorded by optically readable recording marks by displacing the position or shape of the recording marks by a very small amount. An optical disc, wherein the sub-digital information is formed in an area different from a data area in which content is recorded by the main digital information and a control area in which control information is recorded. 9. The optical disk according to claim 1, wherein the sub-digital information is information for determining that the disk or the content is legitimate. 10. The optical disc according to claim 1, wherein a pattern correlated with a pattern formed based on the sub-digital information is recorded. 11. The optical disk according to claim 1, wherein information indicating a location of an area where the sub-digital information is formed is recorded. 12. Sub-digital information is superimposed and recorded on an optical disk on which main digital information is recorded by optically readable recording marks by displacing the position or shape of the recording marks in the track direction by a very small amount. An optical disc reproducing method, comprising: forming a pattern based on the sub-digital information, comparing the pattern with predetermined key information, and reproducing a content recorded by the main digital information when no correlation is found. A method for reproducing an optical disk, comprising: 13. The method according to claim 12, wherein the sub-digital information is reproduced every predetermined reproduction time. 14. The method according to claim 12, wherein the key information is obtained through a network. 15. An optical disc on which main digital information and sub digital information are recorded by optically readable recording marks, wherein sub digital information management information necessary for extracting the sub digital information is recorded in advance. An optical disk characterized in that: 16. The sub-digital information is recorded by phase modulation for displacing the edge position of the recording mark by a very small amount in the track direction, and the edge position of the recording mark is determined when only the main digital information is recorded. 16. The optical disk according to claim 15, wherein the optical disk is formed at a position where the phase is advanced or delayed by a certain small amount with respect to the edge position of the recording mark. 17. The optical disc according to claim 15, wherein an initial value of the random number sequence is recorded on the optical disc in advance as the sub-digital information management information. 18. The recording mark is integrated with an advance amount and a send amount for a fixed-length random number sequence, and sub-digital information is determined based on whether the magnitude of the integrated value is larger or smaller than a predetermined threshold. 17. The optical disc according to claim 15, wherein the threshold is generated and the threshold is recorded in advance as the sub-digital information management information. 19. The optical disk according to claim 15, wherein an arrangement position of the sub digital information is recorded in advance as the sub digital information management information. 20. The optical disk according to claim 15, wherein the sub-digital information is recorded while switching ON / OFF of the phase modulation according to the length of the recording mark. 21. The optical disk according to claim 15, wherein length information of said recording mark for determining ON / OFF of said phase modulation is recorded in advance as said sub digital information management information. . 22. The optical disc according to claim 15, wherein the sub-digital information management information is recorded in a control data area on the optical disc in advance. 23. The optical disc according to claim 15, wherein the sub-digital information management information is recorded in a user data area on the optical disc in advance. 24. The optical disk according to claim 15, wherein the sub-digital information management information is recorded in advance on a BCA on the optical disk. 25. The main digital information is recorded by an optically readable recording mark, and the sub-digital information is recorded by phase modulation in which the edge position of the recording mark is displaced by a very small amount in the track direction. In the case where only the main digital information is recorded, it is formed at one of a position where the phase is advanced by a certain small amount with respect to the edge position of the recording mark and a position where the phase is delayed, and is necessary for extracting the sub-digital information. An optical disc reproducing apparatus comprising: reproducing means for reproducing main digital information from an optical disc in which sub-digital information management information is recorded in advance; and sub-digital information extracting means for extracting sub-digital information. 26. The optical disc reproducing apparatus according to claim 25, wherein said sub-digital information extracting means extracts sub-digital information based on information read from sub-digital information management information on said optical disc. 27. An apparatus for recording main digital information by forming an optically readable recording mark, wherein the sub-digital information is shifted by a phase modulation for displacing an edge position of the recording mark by a very small amount in a track direction. A sub-digital information recording unit for recording information, wherein the sub-digital information recording unit, based on the sub-digital information, sets the phase of the edge position of the recording mark corresponding to the main digital information by a predetermined small amount. An optical disc recording apparatus, comprising: means for forming on one of an advanced position and a delayed position, and recording, on the optical disk, sub-digital information management information necessary for extracting the sub-digital information. 28. An optical disc on which main digital information is recorded by optically readable recording marks, wherein sub-digital information is recorded by changing the position or shape of the specific recording mark by a very small amount. An optical disc, wherein the main digital information is encrypted by the sub digital information. 29. The main digital information is divided into a plurality of recording data aggregates in units of a predetermined recording data aggregation, and each of the recording data aggregations corresponds to the recording data aggregations. 29. The optical disk according to claim 28, wherein the optical disk is encrypted with the sub-digital information. 30. The optical disk according to claim 28, wherein the sub-digital information is recorded in an area where main digital information to be encrypted is recorded. 31. The optical disk according to claim 28, wherein the sub-digital information is recorded in an area different from an area in which main digital information to be encrypted is recorded. 32. The optical disk according to claim 28, wherein the main digital information is divided into a group of a plurality of recording data in units of contents. 33. The optical disk according to claim 28, wherein the main digital information is divided into a plurality of sets of recording data in units of a radial position. 34. The optical disc according to claim 28, wherein the main digital information is divided into a plurality of recording data sets in units of tracks. 35. The optical disk according to claim 28, wherein the main digital information is divided into a plurality of recording data sets in units of ECC blocks. 36. The optical disk according to claim 28, wherein said main digital information is divided into a plurality of sets of recording data in units of sectors. 37. An aggregate of recording data that is not encrypted exists in an aggregate of a plurality of recording data constituting the main digital information. Optical disk. 38. The optical disk according to claim 28, wherein some of the recording data in the collection of recording data to be encrypted includes recording data that is not encrypted. 39. The optical disk according to claim 28, wherein there are two or more pieces of sub-digital information for encrypting the one set of recording data. 40. An apparatus for recording main digital information by forming a recording mark on an optical disk, wherein the sub-digital information is recorded by changing the edge position or shape of the recording mark by a small amount. An optical disc recording apparatus comprising: a recording unit; and a main digital information encrypting unit that encrypts main digital information based on the sub digital information. 41. The optical disk recording apparatus according to claim 40, wherein the sub-digital information recording means records the sub-digital information by phase modulation for displacing the edge position of the recording mark by a very small amount in the track direction. . 42. The optical disk recording apparatus according to claim 40, wherein said sub digital information recording means records sub digital information in an area where said encrypted main digital information is recorded. 43. The optical disk according to claim 40, wherein the sub-digital information recording means records the sub-digital information in an area different from an area where the main digital information to be encrypted is recorded. Recording device. 44. An apparatus for reproducing main digital information by detecting a recording mark formed on an optical disk, comprising: extracting sub-digital information from a channel signal corresponding to a row of the detected recording marks; An optical disc reproducing apparatus comprising: a main digital information decoding unit for decoding encrypted main digital information based on the sub digital information extracted by the sub digital information extracting unit. 45. The sub-digital information extracting means includes clock extracting means for extracting, from the channel signal corresponding to the detected row of recording marks, a channel bit clock synchronized therewith, wherein the channel signal and the channel bit are extracted. The optical disc reproducing apparatus according to claim 44, wherein the sub-digital information is extracted based on a phase difference from a clock. 46. The sub-digital information extracting means extracts the sub-digital information from a channel signal corresponding to a row of recording marks in an area where the encrypted main digital information is recorded. Item 45. The optical disc reproducing apparatus according to Item 44 or 45. 47. The sub-digital information extracting means extracts the sub-digital information from a channel signal corresponding to a row of recording marks in an area different from the area where the encrypted main digital information is recorded. Claim 44.
45. An optical disk reproducing apparatus according to 45. 48. An optical disk having main digital information recorded by an optically readable recording mark and sub-digital information superimposed and recorded by displacing the position or shape of the recording mark by a very small amount. An optical disc having a plurality of areas having sub-digital information according to a linear velocity at the time. 49. The optical disk according to claim 48, having different sub-digital information. 50. An optical disk having main digital information recorded by an optically readable recording mark and sub-digital information superimposed and recorded by displacing the position or shape of the recording mark by a very small amount. An optical disc having sub-digital information and provided with a plurality of areas having different displacement amounts.