JPH1186435A - Data control method, data control information embedding method, data control information detection, data control information embedding device, data control information detector and recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control copying propriety and the number of copying times and to protect a copyright by embedding prohibition information into data, such as videos and voices. SOLUTION: The prohibition information 31 is embedded into the videos and permission information 32 is embedded therein by using digital signature, etc., if N times of copying is okay. At the time of reproduction of the data, the presence or absence of the permission information 32 is investigated and a permission flag is set at a 1 or 0. If the permission flag is 1, the permission information 32 is deleted and the copying of the data is made possible. If the permission flag is 0, the prohibition information 31 is detected. A prohibition flag is then made 1 or 0. If the prohibition flag is 1, a copying okay or denial flag is set at the 0 and the copying of the data is prohibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recording of data to be protected by copyright, such as audio software and video software, in order to prevent copying (copying) or data processing (editing). Data control information embedding method and apparatus for adding copy control information for permitting or prohibiting data duplication, data control information detecting method and apparatus for extracting the information, data control information embedding method and data The present invention relates to a data control method combined with a control information detection method.

[0002]

2. Description of the Related Art As a method of embedding copy control information in an image and a method of detecting copy control information, there is a method called patchwork. This method is described in Nikkei Electronics February 24, 1997 issue (No. 683), 149p-16.
2p "Data hiding technology supporting digital watermarking (above)" (and W. Bender, D. Gruhl, N. Morimoto, A. Lu.
“Techniques for data hiding”, IBM Systems Journa
l, Vol 35, NOS 3 & 4, 1996). Hereinafter, a copy control information embedding method and a copy control information detection method for extracting the information according to the related art will be described.

As a conventional copy control information embedding method, 1
A procedure for embedding a copy permission / prohibition bit (1 bit) in one video will be described. The copy permission / prohibition bit is set to 1 when copying is permitted, and is set to 0 when copying is not permitted. Two points (Ai, Bi) are selected from the video by using pseudorandom numbers. Next, when the bit to be embedded is 1, the luminance level Yai of Ai is increased by d and the luminance level Ybi of Bi is decreased by d. Conversely, when the bit to be embedded is 0, the luminance level of Ai is set to d.
And increase the luminance level of Bi by d. At this time, the value of d is an integer between 1 and 5. These processes are repeated n times (n is usually about 10,000).

Next, a conventional copy control information detecting method will be described. First, the luminance levels (pixel information) of two points at the same position as that at the time of embedding information from a video, that is, (Yai +
d, Ybi-d) or (Yai-d, Ybi + d). Then, the difference between these two points is calculated. These processes are repeated n times for each position, and the average of these differences is determined. If the average is equal to or greater than d, the embedded bit is assumed to be 1, and if it is equal to or less than -d, the embedded bit is assumed to be 0. Average is -d or more, d
It is assumed that information is not embedded in the following cases.

Here, the expected value of Yai-Ybi is estimated to be zero. The expected value of (Yai + d)-(Ybi-d) is 2d, and the expected value of (Yai-d)-(Ybi + d) is -2d. Thereby, the determination is made assuming that the threshold value of the deviation from the average value 0 is d and -d. In order to make a more accurate determination, a statistical distribution of the difference is obtained, and the difference can be detected from the deviation from the estimated value.

As described above, according to the conventional copy control information embedding method and copy control information detection method, it is possible to embed and detect a 1-bit copy enable / disable flag. As a further method, instead of uniformly adding or subtracting the level d to the selected pixel, the level to be embedded is changed for each pixel according to the characteristics of the image, and these levels are subtracted from the luminance of each pixel. Or add them and the average of them is level d
By embedding the information in such a manner, it is possible to suppress the deterioration of the image after embedding, and to make the fraud more difficult.

[0007]

However, in the copy control information embedding method and the detection method, it is possible to control not only the permission or prohibition of copying but also the number of times of copying such that the copying is permitted only N times. Has been requested.
In order to control the number of copies, it is necessary to rewrite the copy control information at the time of copying. For example, copy control information indicating that copying is possible once is embedded in software that can be copied once. At the time of copying, this must be rewritten to copy control information indicating that copying is prohibited.

[0008] Such rewriting of copy control information is performed by:
In order to realize the conventional copy control information embedding method and copy control information detection method, both the copy control information embedding method and the copy control information detection method must be executed at the time of user copying. Since the conventional copy control information embedding method is more difficult to process than the copy control information detection method, realization by the user leads to an increase in cost.
Further, since the method of embedding the copy control information is disclosed to the user, there is a possibility that an illegal act is easily executed.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and not only permits or prohibits copying but also controls the number of times of copying, and embeds data control information which is difficult to illegally process. It is an object of the present invention to implement a method and an apparatus thereof, and a data control information detecting method and an apparatus thereof.
It is another object of the present invention to implement a data control information embedding method and apparatus for restricting data processing such as data editing and display, and a data control information detection method and apparatus.

[0010]

In order to solve such a problem, a data control method of the present invention embeds prohibition information in data when copying data is prohibited, and sets the copy of the data to N ( When N is a natural number), the prohibition information is embedded in the data, and N pieces of permission information are embedded in the data, and the permission information is detected from the data prior to copying the data. In the case where at least one of the permission information of the data is invalidated and the copy of the data is permitted, and prior to the copy of the data, the permission information is not detected from the data and the prohibition information is detected. Prohibits copying of the data.

In one embodiment, the permission information is a digital signature f (M), and the digital signature f (M)
Is obtained based on the digital code M by extracting a digital code M from the data.

According to the data control information embedding method of the present invention, when data copying is prohibited, prohibition information is embedded in the data, and when the data copying is permitted N times (N is a natural number), the prohibition information is used. Is embedded in the data, and N pieces of permission information are embedded in the data.

In one embodiment, the permission information is a digital signature f (M) for a digital code M uniquely obtained from the data. According to the data control information detecting method of the present invention, prior to copying the data, When the predetermined permission information is detected from, the permission information is invalidated and the copy of the data is permitted, and before the data is copied, the permission information is not detected from the data, and the predetermined If the prohibited information is detected,
Copying of the data is prohibited.

In one embodiment, prior to copying the data, if the digital signature f (M) in the data can be authenticated, the copying of the data is permitted, and the copying of the data is performed prior to the copying of the data. Digital signature f (M)
Is not authenticated, the copying of the data is prohibited, and the signature f (M) is authenticated based on the digital code M obtained from the data.

The data control information embedding device according to the present invention comprises a prohibition information embedding means for embedding at least prohibition information indicating prohibition of copying of data into the data, and permitting the data copy N times (N is a natural number). A permission information embedding means for embedding N pieces of permission information in the data in accordance with embedding of the prohibition information by the prohibition information embedding means.

In one embodiment, the permission information embedding means has a code extracting means for extracting a digital code M from the data.

In one embodiment, the permission information embedding means includes a digital signature f () based on the digital code M extracted by the code extraction means and a first encryption key held by a creator of the data. M), and a signature embedding unit for embedding the digital signature f (M) generated by the signature unit as the permission information in the data.

The data control information detecting device of the present invention is a data control information detecting device for extracting prohibition information and permission information embedded in data, wherein the permission information detecting means detects the permission information from the data; Permission information invalidating means for invalidating the permission information of the data, prohibition information detecting means for detecting the prohibition information from the data, and determining whether or not copying is permitted when the permission information is detected by the permission information detection means. The flag is enabled and output, and the permission information is not detected by the permission information detecting means,
When the prohibition information is detected by the prohibition information detection means, a determination means for disabling the copy permission flag and outputting the result is provided.

In one embodiment, the permission information detecting means has a code extracting means for extracting a digital code M from the data.

In one embodiment, the permission information detecting means includes: a signature extracting means for extracting a digital signature f (M) embedded in the data; and a digital code M extracted by the code extracting means. A digital signature f (M) is generated based on the encryption key of the above, and the generated digital signature f (M) is compared with the digital signature f (M) extracted by the signature extracting means. An authentication means for validating and outputting a copy permission flag when the digital signature f (M) is authenticated.

A recording apparatus according to the present invention is a recording apparatus for recording data on a recording medium, comprising: permission information detecting means for detecting the permission information from the data; and permission information for invalidating the permission information of the data. An invalidating means; a prohibition information detecting means for detecting the prohibition information from the data; and if the permission information is detected by the permission information detecting means, a copy permission / inhibition flag is permitted and output, and the permission information detection is performed. Means for detecting the prohibition information by the means and detecting the prohibition information by the prohibition information detection means, disabling and outputting the copy permission / prohibition flag, and outputting the copy permission / prohibition flag by the determination means. Data recording means for recording data when permitted, and not recording when the copy permission / prohibition flag is disabled. It is.

According to the data control method of the present invention, when data processing is prohibited, prohibition information is embedded in the data.
When the processing of the data is permitted N times (N is a natural number), the prohibition information is embedded in the data, and N pieces of permission information are embedded in the data. When permission information is detected, the processing of the data is permitted by invalidating at least one of the permission information of the data, and prior to the processing of the data, the permission information is not detected from the data. When the prohibition information is detected, the processing of the data is prohibited.

In the data control information embedding method of the present invention, when data processing is prohibited, the prohibition information is embedded in the data, and when the data processing is permitted N (N is a natural number) times, the prohibition information is used. Is embedded in the data, and N pieces of permission information are embedded in the data.

According to the data control information detecting method of the present invention, prior to data processing, when predetermined permission information is detected from the data, the permission information is invalidated to permit the processing of the data. Prior to processing said data,
If the permission information is not detected from the data and predetermined prohibition information is detected, the processing of the data is prohibited.

The data control information embedding device according to the present invention wants to prohibit information embedding means for embedding prohibition information indicating prohibition of data processing in the data, and to permit the processing of the data N times (N is a natural number). When the prohibition information embedding means embeds the prohibition information, the apparatus further comprises permission information embedding means for embedding N pieces of permission information in the data.

The data control information detecting device of the present invention is a data control information detecting device for extracting prohibition information and permission information embedded in data, and detects N (N is a natural number) permission information from the data. When the permission information is detected, a permission information detection / deletion means for invalidating at least one of the permission information of the data and validating and outputting a permission flag;
Prohibition information detection means for validating and outputting a prohibition flag when prohibition information is detected from the data; and outputting the prohibition information with a permission / prohibition flag enabled when the permission flag is valid or the prohibition flag is not valid. Determining means for disabling and outputting the permission flag when the permission flag is not valid and the prohibition information is valid.

[0027]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1) A data control method according to Embodiment 1 will be described. FIG. 1 is an explanatory diagram showing an outline of the data control method according to the first embodiment. The data control referred to in the first embodiment means copy control. As shown in FIG. 1A, the signal CI is a signal distributed over the entire screen, and indicates copy prohibition information 31. The signal CE is a signal inserted at a specific portion of the screen, and indicates permission information 32 for one copy. To permit copying N times, the permission information 32 is inserted into N screens.

The signal CI is distributed, for example, over the entire screen,
They cannot be seen. On the other hand, the signal CE is inserted, for example, at a predetermined corner of the screen, and may or may not be visually recognized.

FIG. 1B shows an image 33 that cannot be copied. FIG. 1C shows a video 34 that can be copied once, and one permission information 32 is inserted at the lower right of the screen. Fig. 1 (d)
Indicates a copy-enabled image 35, and the prohibition information 31 is displayed on the entire screen.
Is not inserted on the screen.

The copy control aimed at in the first embodiment is to control the output of the video signal in three states: copy free, copy permitted N times (N = 1 in the following description), and copy disabled. Things. When copy-free (copy permitted), copying is unconditionally permitted. When copying is permitted once, copying is permitted only once. If copying is not allowed, copying is prohibited at all, even if video display is allowed.

The prohibition information 31 is embedded in the non-copyable video 33 as shown in FIG. When the non-copyable video 33 is input to the recording device, the permission information 32 is not detected, and the prohibition information 31 is detected. In this case video 3
3 is prohibited. For the image 34 that can be copied once, the prohibition information 31 and the permission information 32 as shown in FIG.
Embed both. When copying the video 34, since the permission information 32 is detected, the copying is permitted. The recording device deletes the permission information 32 of the video 34 transferred to the recording device from the transmission path, and
Start copying. Here, when deleting the permission information 32, the permission information 32 may be entirely deleted or a part of the permission information 32 may be deleted. The purpose is to disable it. For example, when the permission information 32 has meaningful information of 8 bits, only one bit may be deleted or all 8 bits may be deleted. Alternatively, when the permission information 32 is composed of a combination of two pieces of information, one of them may be deleted.

Since only the permission information 32 is removed from the copied video, the prohibition information 31 remains, and the video 33 becomes a non-copyable video.

However, an N-times copyable video in which two or more N pieces of permission information have been embedded becomes one (N-1) times copy-enabled video because one piece of permission information is deleted.

The copy-free image 35 includes the prohibition information 3
Neither 1 nor the permission information 32 is embedded. When copying the copy-free image 35, neither the permission information 32 nor the prohibition information 31 is detected, so that copying is unconditionally permitted.

According to the above copy control method, not only control of prohibition and permission of copy but also control of permitting copy N times can be realized. Furthermore, it is not necessary to disclose the method of embedding prohibited information or the method of deleting prohibited information when copying. For this reason, it becomes difficult for an unauthorized person to delete the prohibition information. Also, since the permission information is not embedded at the time of copying, there is no need to disclose the embedding method. Therefore, an unauthorized person cannot embed the permission information.
In the description with reference to FIG. 1, the prohibition information is embedded in the entire screen. However, the present invention is not limited to this, and may be embedded in a specific portion of the screen. Also, in the description with reference to FIG. 1, the permission information is embedded in a specific location. However, when N = 1 is limited, the present invention is not limited to this and may be embedded in the entire screen.

Next, a data control information embedding method and a data control information detection method which are basic techniques for realizing the data control method of the first embodiment will be described with reference to FIGS.

FIG. 2 is a flowchart showing the data control information embedding method according to the first embodiment. FIG. 4 is a flowchart illustrating the data control information detection method according to the first embodiment.

First, in the data control information embedding method shown in FIG.
A variable Status indicating which of (2) copy once and (3) copy free is set is set. First, in step S1, it is determined whether or not the status is copy free. If the status is copy free, the process ends. If the status is not copy free, the process branches to step S2. In step S2, the prohibition information 31 is embedded in the video.

This embedding process may be any embedding method for embedding one or more bits of information in a video, such as the embedding method of copy control information of the prior art. In particular, it is even better if the embedding method is more complicated than the detection method, and the effects of the present invention are not impaired by the embedding method under the limitation. . A method of embedding information in such an image is a digital watermark (Watermark).
Mark), and many other methods are known in addition to the methods shown in the prior art. For example, there is a method introduced in the February 24, 1997 issue of Nikkei Electronics (digital watermarking protects the multimedia age).
In the next step S3, it is determined whether or not the status is copy once. If the copy is not possible once, the process is terminated. If the copy is permitted once, the process branches to step S4.

In step S4, the permission information 32 is embedded in the video. This step S4 is, for example, a process as shown in the flowchart of FIG. 3, and the permission information embedding process of step S4 will be described in detail with reference to this flowchart.

First, in step S21, a code M uniquely corresponding to the video is extracted from pixels of the video in which information is to be embedded. The extraction processing of the code M can be realized by, for example, a method of selecting k predetermined pixels from the video and setting the MSB (most significant bit) of the data of these pixels to a k-bit code M. However, it is not limited to this.
Digital data is uniquely identified from a video, such as a method of selecting k blocks of × 8 pixels and setting the luminance value of these blocks to a k-bit code M, a method of calculating a frequency component of the video and using its low frequency component, and the like. Any method can be used as long as it can be extracted.

In the next step S22, a digital signature f (M) is created using the code M. Here, the digital signature will be described in detail. Consider a case where user A is a video sender and user B is a video recipient, and user A converts video code M into signature C = f (M) and transmits it to user B. At this time, the user A creates the signature C and transmits the video, and the user B authenticates the signature, that is, verifies whether the signature is correct.

The digital signature required in the first embodiment may be anything as long as the following performance is satisfied.

(1) The user B can easily authenticate the signature C.

(2) The user A can easily create the signature C, but it is difficult for anyone other than the user A to create the signature C.

As a specific method of this digital signature,
There is a method using public key encryption. The user A prepares a signature function D (first encryption key) as a function for performing a signature,
An authentication function E (second encryption key) is prepared as a function for performing authentication. Here, the authentication function E is set to be the inverse function of the signature function D. The user A uses the signature function D to create a signature C from the code M by C = D (M). User B verifies whether E (C) matches M using authentication function E. That is, since the authentication function E is the inverse function of the signature function D, if C is a correct signature, E (C) = E (D
(M)) = M, and if C is not a valid signature, E
(C) and M do not match.

Here, in the public key cryptosystem, a mechanism in which it is difficult to obtain a secret signature function D from a public authentication function E is realized by using a mathematical method. Examples of this realization include RSA encryption, Elgamal
Some use encryption or the like. In the RSA encryption, the signature function D is defined by the following equation (1). D (M) = M ^d mod n (1)

The authentication function E is defined by the following equation (2). E (C) = C ^e mod n (2)

Here, modn means a remainder operation by n, that is, an integer of the remainder when divided by n. N, e, and d in the equations (1) and (2) are selected so that E is an inverse function of D. Is done. That is, it is selected so that the following equation (3) is satisfied. E (C) = C ^e mod n = (M ^d ) ^e mod n = M ^de mod n = M (3) User A prepares large prime numbers p and q, and sets n = p × q . Next, Euler's function φ (n) is defined as (p−1) × (q−1) = φ (n). Next, an integer e which is relatively prime to the function φ (n) is appropriately set. That is, φ (n)
And e have the greatest common divisor of one. And the next (4)
D is determined so that the equation is satisfied. e × dmod φ (n) = 1 (4) If the thus determined e and d are used, the aforementioned equation (3) is satisfied.

User A publishes n and e, and d, p, q
Secret. Thus, the authentication function E is made public while the signature function D is kept secret. User A who knows p and q
Can determine d from e using equation (4).
However, the user B who does not know p and q has difficulty obtaining d from n and e.

For easy understanding, a very simple numerical example will be shown. For example, if p = 5 and q = 11 are selected as prime numbers,
n = 55 and φ (n) = 40. Next, if e = 7 is selected, from equation (4), 7 × 23 mod 40 = 1, and d
= 23 is obtained. User A publishes n = 55 and e = 7, and keeps p = 5, q = 11, and d = 23 secret.

For example, the signature for M = 42 is calculated as in the following equation (5). D (M) = 42 ²³ mod 55 = 3 (5)

From this, C = 3. The user B calculates the following equation (6) using a public authentication function. E (C) = 3 ⁷ mod 55 = 42 (6)

As a result, since E (C) matches the initial M = 42, it is verified that the signature is correct.

Here, for the sake of simplicity, small values are selected as the prime numbers p and q constituting n. However, in order to enhance the security of encryption, the actual value of n is about 512 bits. Even if the values of p and q are 256 bits wide, the size becomes a huge value of about 77 to 78 digits when converted to a decimal number.

Although the above description is about digital signatures using public key cryptography, there are other digital signatures based on the knapsack problem and digital signatures to which zero-knowledge conversational proof is applied. It is described in a book by Tsujii and Kasahara, "Encryption and Information Security" (published by Shoshodo).

Now, the flow charts of FIGS. 2 and 3 will be described. After creating a digital signature f (M) using the code M in step S22 in FIG. 3, the signature f (M) is embedded in the video in step S23. As a method of embedding the signature f (M) in the video, 0 is white, 1
There is a method of embedding at the edge of the image with a visible pattern such as black. However, without being limited to this method, the LSB (least significant bit) of the pixel selected from the video is signed by the signature f (M).
, Embedding in the blanking interval of the video, using a digital watermark that can be easily deleted, etc.
Any method can be used as long as it can embed a code of a plurality of bits.

In such a process of embedding permission information, since a digital signature based on a code M that can be uniquely derived from a video is used as permission information, a third party creates the same signature without a secret key d. It is difficult to do so, and new permission information cannot be embedded.

According to the copy control information embedding method of the first embodiment, nothing is embedded in a video when copy is free, and prohibition information and one permission information are embedded in a video when copying is allowed once. Embed. If copying is not possible, only the prohibition information is embedded in the video.

Next, a data control information detecting method according to the first embodiment for detecting copy control information from an image will be described with reference to FIG.

First, in step S5, the permission information 32 is detected from the video. This step S5 is performed, for example, in FIG.
The processing for detecting permission information in step S5 will be described in detail with reference to this flowchart.

In step S24 of FIG. 5, the signature f (M) embedded in the video is detected. Next step S2
In 5, the code M is extracted from the video. The extraction of the code M can be performed by the same process as the extraction of the code M in step S21 in FIG.

In the next step S26, the digital signature is authenticated. This digital signature authentication is performed in step S2.
This is the authentication of the signature created in step 2. For example, in the case of RSA encryption authentication, public information n and public key e are used. Signature f
Assuming that (M) is C, a function for signature authentication is expressed by the above-described equation (2). If the result is M as shown in equation (3), authentication is possible, and if it does not match M, authentication is impossible.

If the authentication is permitted, the permission information is embedded, so the process proceeds to step S27, and 1 is substituted for the permission flag. If authentication is not possible in step S26, since permission information is not embedded, the process proceeds to step S28, and 0 is substituted for the permission flag. In the first embodiment, the permission flag is generated as described above, but any signal may be used as long as it can distinguish between a state where permission information is embedded and a state where permission information is not embedded.

After detecting the permission information in step S5 in FIG. 4, the process proceeds to step S6, and the permission flag is determined. If the permission flag is 1, the flow branches to step S7,
If it is 0, the flow branches to step S8. In step S7, the permission information is deleted. The deletion of the permission information is processing for removing the permission information embedded in step S4 from the video, and deletes at least a part of the permission information as described above. After the processing in step S7, step S1
Proceed to 1 to set the copy permission flag to 1.

In step S8, prohibition information is detected.
This is to detect the prohibition information embedded in step S2. Here, the prohibition flag is set to 1 when there is prohibition information, and to 0 when there is no prohibition information. Thereafter, the process proceeds to step S9, and the prohibition flag is determined. If the prohibition flag is 1, the process branches to step S10. If the prohibition flag is 0, the process branches to step S11. The method of generating the prohibition flag is not limited to the above method, and any signal may be used as long as the signal can identify the state where the prohibition information is embedded and the state where the prohibition information is not embedded.

In step S10, the copy permission flag is set to 0.
In step S11, the copy permission flag is set to 1. Here, the copy permission flag is set to 0 for copy inhibition,
1 is a signal indicating that copying is permitted. Note that the copy permission flag may be in any form as long as it is a signal that can identify prohibition and permission of copying.

According to the data control information detection method of the first embodiment, copying of a video in which permission information is embedded is permitted after the permission information is deleted. A video in which neither permission information nor prohibition information is embedded is permitted to be copied. Copying of a video in which permission information is not embedded and in which prohibition information is embedded is prohibited.

As described above, in the first embodiment, the change from the single copy permitted state to the non-copyable state is realized by embedding and deleting permission information. Further, the embedding of the permission information is based on the digital signature and can be easily deleted and detected, but it is difficult for those who do not know the secret key d to embed the permission information. Therefore, it is difficult to illegally change (rewrite) the copy permission. Furthermore, the prohibition information is embedded by a method different from the permission information, and only the detection method need be disclosed or provided to the user B. Therefore, the user A can keep the embedding and deletion methods secret.

According to the first embodiment, not only prohibition and permission of copying but also control of permitting copying once can be realized. For this reason, it is possible to realize a data control method, a data control information embedding method, and a data control information detection method, which are more difficult to cheat than in the past.

In the first embodiment, the method of realizing once-permitted copying has been described. However, when embedding the copy control information, the permission information is embedded N times (N is an integer of 2 or more), and when the copy control information is detected, the permission information is embedded. No matter how many pieces of information are detected, by deleting only one piece of information, it is possible to realize a control that copying can be performed N times.

In the above description, copy prohibition, 1
The data control method of permitting N times and permitting N times has been described. However, the present invention is not limited to this, and controls such as prohibition of video reproduction, permission once, and permission N times, and data processing such as editing or processing of video, The display of an image can be controlled in the same manner.

Although the video signal is processed, an audio signal or a document may be processed, and the same effect can be obtained.

Further, a digital signature based on a code M uniquely obtained from a video is used as a permission signal.
The embedding method is not limited to this, and any embedding method can be used. That is, only the deletion and detection methods need to be disclosed to the user B without disclosing the embedding method. If the method of embedding cannot be inferred from the method of deletion or detection, or the amount of calculation of the embedding process is large compared to deletion or detection, or if the circuit size is complicated, the method is even more illegal. Can be stronger. At this time, by generating the permission information based on the code M uniquely obtained from the video, the video and the permission information can be made to correspond one-to-one, making unauthorized generation of the permission information difficult.

As another example of the method of embedding permission information, the permission information is composed of two pieces of first permission information and second permission information, and the first permission information is written using the first embedding method. There is a method of embedding the second permission information in the video at the same time as embedding it in the video using the second embedding method.
Here, the first embedding method is a method that is difficult to delete, that is, embedding is performed by the same method as that used for embedding the prohibition information, and the second embedding method is a method of visually embedding at the edge of the screen. Embed in an easy way. When copying a video, copying is permitted only when both the first permission information and the second permission information are detected together, and only the second permission information is deleted. Thus, by combining the first permission information and the second permission information,
An embedding method that is easy to detect and delete, but difficult to embed, can be realized. The first embedding method shown here may be exactly the same as the embedding method of the prohibition information, or may be a different method.

As a method of forming the first and second permission information, a result obtained by converting the code M using a conversion coefficient and one of the conversion coefficients are used as the first permission information.
There is a method of using the other as the second permission information. here,
The conversion processing includes arithmetic operations such as addition, subtraction, multiplication, and division with the conversion coefficient, logical operations with the conversion coefficient, encryption processing using the conversion coefficient as a key, and delay processing using the conversion coefficient as a delay amount. Any method can be adopted as long as the processing result changes depending on the value. In particular, a conversion process in which it is difficult to obtain a conversion coefficient from the code M and the conversion result is desirable, and has an effect of being resistant to fraud. This can be realized by keeping the conversion processing method secret.

(Embodiment 2) As Embodiment 2 of the present invention, a data control system for realizing the data control method described in Embodiment 1, and a data control information embedding device and data control in the system 1 shows an information information detection device.

FIG. 6 is a configuration diagram of a data control system according to the second embodiment. The data control system includes a data control information embedding device 41, a data control information detection device 42, a transmission unit 43, a recording unit 44, and a recording medium 45.

The data control information embedding device 41 inputs a video signal, embeds copy control information, and outputs the video signal with this information embedded to the transmission section 43.

As a transmission method by the transmission unit 43, there is radio digital transmission or analog transmission using a satellite, a terrestrial wave, or the like. Further, there is a digital transmission or an analog transmission by wire using a telephone line, a coaxial cable, a twisted pair cable, an optical cable, or the like. Furthermore, digital or analog recording media such as magnetic disks, optical disks, CDs, DVDs, DVCs, and VCRs are also considered to be the transmission unit 43 because video signals are reproduced as bit streams from the recording media.

The video signal transmitted or reproduced via the transmission section 43 is input to the data control information detection device 42. The data control information detecting device 42 detects the copy control information, outputs a record enable / disable flag indicating whether the copy is permitted or prohibited and the video information, and these information are input to the recording unit 44.

The recording section 44 permits recording of video information on the recording medium 45 when the recording permission flag indicates copy permission, and does not perform recording when the recording permission flag indicates copy prohibition. Here, the recording medium 45 is a magnetic disk, optical disk, CD, D
Any medium that records data, such as a digital or analog recording medium such as VD, DVC, or VCR, may be used.

The data control information embedding device 41 has a prohibition information embedding means 411 and a permission information embedding means 412.

In the data control information embedding device 41, the prohibition information embedding means 411 embeds the prohibition information in the input video signal when it is desired to embed the information of copy once or copy prohibition. This embedding process is the same as the process of step S2 in FIG. Next, the permission information embedding means 41
Reference numeral 2 embeds permission information in a video signal when copying is permitted once. The operation of the permission information embedding means 412 will be described later. Due to such an operation of the data control information embedding device 41, nothing is embedded in the video when the copy is free, and the prohibition information and the permission information are embedded in the video when the copy is permitted once, and when the copy is not permitted. The prohibition information is embedded in the video.

The data control information detection device 42 has a prohibition information detection means 421, a permission information detection / deletion means 422, and a judgment means 423.

In the data control information detecting device 42, the permission information detecting / deleting means 422 detects and deletes permission information from the video signal. 1 if permission information is detected
Is not detected, a permission flag indicating 0 is output. The operation of the permission information detecting / deleting means 422 will be described later.

When the prohibition information detecting means 421 receives the video signal from the permission information detecting / deleting means 422, it checks the presence or absence of embedded prohibition information. Here, a prohibition flag indicating 1 is output if prohibition information is detected, and 0 if not detected. The values of the permission flag and the prohibition flag are input to the determination unit 423. When the permission flag is 1 or the prohibition flag is 0, the determination unit 423 outputs a record permission flag indicating copy permission. If the permission flag is 0 and the prohibition flag is 1, a recording permission flag indicating copy prohibition is output.

By the operation of the data control information detecting device 42 described above, copying of the video in which the permission information is embedded is permitted after the permission information is deleted. In addition, copying of a video in which neither permission information nor prohibition information is embedded is permitted. Further, copying is prohibited for videos in which permission information is not embedded and prohibition information is embedded.

Next, the configuration and operation of the permission information embedding means 412 and permission information detection / deletion means 422 will be described with reference to FIGS.

As shown in FIG. 7, permission information embedding means 412
Is configured to include a signature embedding unit 51, a code extraction unit 52, and a signature unit 53.

In the permission information embedding means 412, the code extracting means 52 first generates a code M which can be uniquely derived from the video signal, and outputs it to the signature means 53. The signature unit 53 converts the code M into a digital signature f (M) and outputs the digital signature to the signature embedding unit 51. Next, the signature embedding unit 51 embeds the digital signature f (M) in the video signal. If the permission information is not embedded, the digital signature f (M) is not embedded. Here, the method of generating the code M in the code extracting means 52 and the signature f in the signature means 53
The method of generating (M) and the method of embedding the signature in the signature embedding unit 51 are described in steps S21, S22, and S23 in FIG.
The processing is the same as the above.

As shown in FIG. 8, the permission information detecting / deleting means 422 includes the signature extracting / deleting means 54, the code extracting means 5
5. It includes the authentication means 56.

In the permission information detecting / deleting means 422, the signature extracting / deleting means 54 extracts the digital signature f (M) from the video signal and outputs the digital signature f (M) from the video signal.
(M) is deleted at least in part. Next, the code extracting means 55 generates a code M from the video signal in the same manner as the code extracting means 52, and outputs it to the authentication means 56. Next, the authentication unit 56 authenticates the digital signature f (M) based on the code M, and outputs a recording permission flag indicating recording permission. If the authentication is not successful, a recording permission flag indicating recording prohibition is output. Here, the signature extraction method in the signature extraction / deletion means 54, the code M generation method in the code extraction means 55, and the authentication method in the authentication means 56 are shown in FIG.
These are the same as those described above.

As described above, according to the second embodiment, not only prohibition and permission of copying but also control of permitting copying once can be realized, and illegality is more difficult than the conventional method. And a data control information embedding device and a data control information detecting device in the system.

Although the second embodiment has been described with respect to a method of realizing one-time copying, the permission information is embedded N times (N is a natural number of 1 or more) when the copy control information is embedded, and when the copy control information is detected, the permission information is embedded. No matter how many pieces of information are detected,
By deleting only one, copying is enabled N times.

Although the method of embedding and detecting the copy prohibition information has been described, the method of embedding and detecting the reproduction prohibition information can be similarly realized, and the reproduction can be controlled. Furthermore, control of copying and control of reproduction can be realized at the same time.

Although the copy control information embedding device 41 has the configuration as shown in FIG. 6, it is not limited to this. Prohibition information embedding means 411 and permission information embedding means 4
The order of 12 may be reversed, and it can be realized by an apparatus having an arbitrary configuration that embeds at least prohibition information in a video that cannot be copied and embeds both prohibition information and permission information in a video that can be copied once.

The copy control information detecting device 42 has the configuration as shown in FIG. 6, but is not limited to this. A configuration may be such that the video signal at the previous stage of the permission information detection / deletion means 422 is input to the prohibition information detection means 421, or the permission information detection / deletion means 422 is separated into permission information detection means and permission information deletion means. The present invention can be realized by an apparatus having an arbitrary configuration such that copying is permitted and permission information is deleted when permission information is detected, and copying is prohibited when prohibition information is detected.

In the above description, a digital signature based on a code M uniquely obtained from a video is used as the permission signal. However, the present invention is not limited to this, and any embedding method can be used. That is, only the deletion and detection methods need to be disclosed to the user B without disclosing the embedding method. If the method of embedding cannot be inferred from the method of deletion or detection, or the amount of calculation of the embedding process is large compared to deletion or detection, or if the circuit size is complicated, the method is even more illegal. Can be stronger. At this time, by generating the permission information based on the code M uniquely obtained from the video, the video and the permission information can be made to correspond one-to-one, making unauthorized generation of the permission information difficult.

As another example of the method of embedding permission information, the permission information is composed of two pieces of first permission information and second permission information, and the first permission information is written using the first embedding method. There is a method of embedding the second permission information in the video at the same time as embedding it in the video using the second embedding method.
Here, the first embedding method is a method that is difficult to delete, that is, embedding is performed by the same method as that used for embedding the prohibition information, and the second embedding method is a method of visually embedding at the edge of the screen. Embed in an easy way. When copying a video, copying is permitted only when both the first permission information and the second permission information are detected together, and only the second permission information is deleted. Thus, by combining the first permission information and the second permission information,
An embedding method that is easy to detect and delete but difficult to embed can be realized. The first embedding method shown here may be exactly the same as the embedding method of the prohibition information, or may be a different method.

As a method of forming the first and second permission information, a result obtained by converting the code M using a conversion coefficient and one of the conversion coefficients are used as the first permission information.
There is a method of using the other as the second permission information. here,
The conversion processing includes arithmetic operations such as addition, subtraction, multiplication, and division with the conversion coefficient, logical operations with the conversion coefficient, encryption processing using the conversion coefficient as a key, and delay processing using the conversion coefficient as a delay amount. Any method can be adopted as long as the processing result changes depending on the value. In particular, a conversion process in which it is difficult to derive a conversion coefficient from the code M and the conversion result is desirable, and an effect of being illegally strong can be obtained. This can be realized by keeping the conversion processing method secret.

In each of the first and second embodiments, the data control information embedding method or the data control information embedding apparatus does not embed neither prohibition information nor permission information when the status is copy-free. Not something. When the status indicates copy free, information indicating copy free may be embedded,
Similar effects can be obtained.

In the data control information detection method or data control information detection apparatus, copying is permitted when no copy control information is detected, but the present invention is not limited to this. When no information is detected, copying may be prohibited. Further, a configuration may be adopted in which copying is permitted when information indicating copy free is detected, and the same effect is obtained.

[0105]

As described above, according to the present invention, not only copy free and copy prohibition, but also, when permission information is detected in data, only N times of copying can be permitted. In addition, a data control method in which fraudulent acts are difficult can be realized.

According to the embodiment, since the creator of the data inserts the permission information using the digital signature, it is impossible for the person who obtained the data to falsify the permission information.

According to the embodiment, not only the control of copy free and copy prohibition, but also information for permitting N copies can be embedded.

According to the first embodiment, since the permission information is generated based on a code uniquely obtained from the data, the permission information has one-to-one correspondence with the data, making it difficult to falsify the permission information. You can do it.

According to the first embodiment, since the permission information is inserted by using the digital signature, it is impossible to modify the permission information on the side that has obtained the data.

According to one embodiment, when data into which permission information is inserted is input, the number of copies is limited to N, and when data into which only prohibition information is inserted is input, copying is prohibited. be able to.

According to one embodiment, copying is permitted only when permission information based on a code uniquely obtained from data is detected.

According to one embodiment, copying is only permitted when the digital signature has been authenticated.

According to the embodiment, when permission information is detected from data, the data can be recorded on a recording medium.

According to the embodiment, when only the prohibition information is detected in the data, the data processing is prohibited, and when the permission information is detected, N data processings can be permitted.

According to the embodiment, not only control of prohibition of data processing but also information for permitting data processing of N times can be embedded.

According to one embodiment, when data into which permission information is inserted is input, the number of data processing is limited to N, and when data into which only prohibition information is inserted is input, data processing is stopped. Can be banned.

According to one embodiment, when data into which permission information is inserted is input, the number of times of data processing is limited to N, and when data into which only prohibition information is inserted is input, data processing is stopped. Can be banned.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an outline of a data control method according to a first embodiment.

FIG. 2 is a flowchart illustrating a data control information embedding method according to the first embodiment;

FIG. 3 is a flowchart showing one process of a data control information embedding method of FIG. 2;

FIG. 4 is a flowchart illustrating a data control information detection method according to the first embodiment.

FIG. 5 is a flowchart showing one process of the data control information detection method of FIG. 4;

FIG. 6 is a configuration diagram of a data control system according to a second embodiment.

FIG. 7 is a configuration diagram of permission information embedding means in the data control system of FIG. 6;

FIG. 8 is a configuration diagram of permission information detection means in the data control system of FIG. 6;

[Explanation of symbols]

 41 Data Control Information Embedding Device 42 Data Control Information Detecting Device 43 Transmitting Unit 44 Recording Unit 45 Recording Medium 51 Signature Embedding Means 52, 55 Code Extracting Means 53 Signature Means 54 Signature Extraction / Delete Means 56 Authentication Means 411 Prohibition Information Embedding Embedding means 412 permission information embedding means 421 prohibition information detecting means 422 permission information detecting / deleting means 423 judging means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 1/387 H04L 9/00 675B 5/91 H04N 5/91 P 7/08 7/08 Z 7/081

Claims (18)

[Claims] When data copying is prohibited, prohibition information is embedded in the data. When copying of the data is permitted N times (N is a natural number), the prohibition information is embedded in the data. Embedding permission information in the data, and prior to copying the data, if the permission information is detected from the data, at least one of the data
Two of the permission information are invalidated to permit copying of the data. Prior to the copying of the data, when the permission information is not detected from the data and the prohibition information is detected, the copying of the data is performed. A data control method characterized by prohibiting. 2. The permission information includes a digital signature f (M)
The data control method according to claim 1, wherein the digital signature f (M) is obtained based on the digital code M by extracting a digital code M from the data. 3. When the copying of data is prohibited, the prohibition information is embedded in the data. When the copying of the data is permitted N times (N is a natural number), the prohibition information is embedded in the data. Embedding permission information in the data. 4. The data control information embedding method according to claim 3, wherein the permission information is a digital signature f (M) for a digital code M uniquely obtained from the data. 5. When a predetermined permission information is detected from the data before copying the data, the permission information is invalidated to permit the copying of the data, and prior to the copying of the data, A method for detecting data control information, wherein, when the permission information is not detected from the data and predetermined prohibition information is detected, copying of the data is prohibited. 6. If the digital signature f (M) in the data can be authenticated before copying the data, the copying of the data is permitted, and the digital signature in the data is copied prior to the copying of the data. When f (M) cannot be authenticated, copying of the data is prohibited, and the signature f (M) is authenticated based on a digital code M obtained from the data. Method. 7. A prohibition information embedding means for embedding at least prohibition information indicating prohibition of copying of data in said data, and said prohibition information embedding means for permitting N (N is a natural number) copies of said data. And a permission information embedding means for embedding N pieces of permission information in the data in accordance with the embedding of the prohibition information by the data control information. 8. The data control information embedding device according to claim 7, wherein said permission information embedding means includes a code extracting means for extracting a digital code M from said data. 9. The permission information embedding means generates a digital signature f (M) based on the digital code M extracted by the code extraction means and a first encryption key held by a creator of the data. 9. The data control information according to claim 8, further comprising: signature means for generating; and signature embedding means for embedding the digital signature f (M) generated by the signature means in the data as the permission information. Implanting device. 10. A data control information detecting device for extracting prohibition information and permission information embedded in data, wherein the permission information detecting means detects the permission information from the data, and invalidates the permission information of the data. Permission information invalidating means, prohibition information detecting means for detecting the prohibition information from the data, and when the permission information is detected by the permission information detecting means, outputs a copy permission / prohibition flag, and outputs And determining means for disabling and outputting the copy permission flag when the permission information is not detected by the permission information detection means and the prohibition information is detected by the prohibition information detection means. A data control information detection device characterized by the above-mentioned. 11. The data control information detecting device according to claim 10, wherein said permission information detecting means has a code extracting means for extracting a digital code M from said data. 12. The permission information detecting means includes: a signature extracting means for extracting a digital signature f (M) embedded in the data; a digital code M and a second encryption key extracted by the code extracting means. Digital signature f (M) based on
Is generated, and the generated digital signature f (M) and the digital signature f extracted by the signature extracting means are generated.
(M), whereby the digital signature f
12. The data control information detecting device according to claim 11, further comprising: an authentication unit for validating and outputting a copy permission flag when (M) is authenticated. 13. A recording apparatus for recording data on a recording medium, comprising: permission information detecting means for detecting the permission information from the data; permission information invalidating means for invalidating the permission information of the data; Prohibition information detecting means for detecting the prohibition information from data, and when the permission information is detected by the permission information detecting means, a copy permission / prohibition flag is permitted and output, and the permission information is detected by the permission information detecting means. Is not detected, the prohibition information is detected by the prohibition information detection means, and the copy permission / prohibition flag is disabled and output by the determination means; and the copy permission / prohibition flag is permitted by the determination means. A data recording unit that records data, and does not record when the copy permission / prohibition flag is disabled.
A recording device comprising: 14. When prohibiting data processing, embed prohibition information in the data. When permitting N (N is a natural number) processing of the data, embed the prohibition information in the data. Embedding the permission information in the data, and prior to processing the data, if the permission information is detected from the data, invalidate at least one of the permission information of the data to perform the processing of the data. Prior to the processing of the data, when the permission information is not detected from the data and the prohibition information is detected,
A data control method, wherein processing of the data is prohibited. 15. When prohibiting data processing, embed prohibition information in the data. When permitting N (N is a natural number) times of data processing, embed the prohibition information in the data. Embedding permission information in the data. 16. When predetermined permission information is detected from the data prior to the processing of the data, the permission information is invalidated to permit the processing of the data, and prior to the processing of the data, A method for detecting data control information, wherein the processing of the data is prohibited when the permission information is not detected from the data and predetermined prohibition information is detected. 17. A prohibition information embedding means for embedding prohibition information indicating prohibition of data processing in the data, and when the processing of the data is to be permitted N times (N is a natural number), the prohibition information embedding means is provided. A data control information embedding device, comprising: permission information embedding means for embedding N pieces of permission information in the data in accordance with embedding of prohibition information. 18. A data control information detecting apparatus for extracting prohibition information and permission information embedded in data, wherein when N (N is a natural number) permission information is detected from the data, at least one of the data is detected. Permission information detection / deletion means for disabling one permission information and validating and outputting a permission flag; prohibition information detection means for validating and outputting a prohibition flag when prohibition information is detected from the data; When the permission flag is valid or the prohibition flag is not valid, the permission flag is enabled and output. When the permission flag is not valid and the prohibition information is valid, the permission flag is disabled. Determination means for outputting
A data control information detection device comprising: