JP2002368985A - Method and device for embedding id information into digital content and reading it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide content distribution technology by considering illegal copy. SOLUTION: A digital content is loaded on an information terminal such as PC 4, and ID information inherent to the viewer or the user of PC 4 is embedded into the content. ID information is embedded in the prescribed position of the content, or it can be embedded into the whole content in the shape of a spatial frequency. The content into which ID is embedded can be used in terminals thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method and an apparatus for embedding ID information in digital content and reading the same.

[0002]Background of the Invention  Information supervision in the United States in 1991
-After the Highway Initiative was proposed,
As shown, the distribution of information through networks is new
The social infrastructure. This new network
In the society, fields such as electronic commerce
Interest in transaction security is growing at the center, and it is difficult to break
Research on issues and certification has been actively conducted.

[0003] On the other hand, in the distribution of digital content (hereinafter, simply referred to as "content") such as still images, moving images, and music, "free (free)" information is basically disclosed on the Internet. For this reason, even valuable content such as works of cultural value can be easily copied and redistributed without permission at present. The charging of the use of content on the Internet, the prevention of piracy and alteration, and the protection of rights in copyrighted works are issues that need attention and solutions. These are extremely important issues in the healthy mutual development of a networked society and culture in the future.

[0004] Against this background, there is a need for a design of a general-purpose method for tracking illegally copied digital content.

[0005]Summary of disclosure  Object of the present invention is applicable to existing content
An object of the present invention is to provide an identification information (ID) embedding method.

Another object of the present invention is to provide an ID that can embed an ID even in a content that does not play a role in the content and that does not have a comment area.
It is to provide an embedding method.

It is still another object of the present invention to provide an ID embedding method capable of suppressing a large decrease in content quality due to embedding of an ID.

It is still another object of the present invention to provide an ID embedding method that can easily detect an embedded ID.

It is still another object of the present invention to provide an ID reading method for easily detecting an ID embedded in content and interpreting the ID information.

[0010] A method according to an embodiment of the present invention comprises the steps of loading the content into an information terminal utilizing the content, and providing the information terminal or a user thereof at a predetermined position of a perceivable portion of the loaded content. Embedding the associated ID information. (The content may be any collection of digital data or may be in the form of an array of data values. The perceivable part is the content, not the reserved or commented areas that do not play a role in the content. The content is first loaded into the information terminal. Subsequently, the ID information is embedded in a predetermined position of the content. The user who created the illegal copy of the content is specified by the ID information embedded in the content. Since the ID information is embedded at a predetermined position, it is not necessary to search for a character string. Since there is no need to prepare special data blocks in advance, this method can be applied to existing content.

In another aspect of the present invention, ID information is embedded in the form of spatial frequency information in the entire content loaded on the information terminal. “Spatial frequency information” is information related to a spatial frequency in some way. In this aspect,
For example, ID information is converted into spatial frequency information by inverse orthogonal transform, and this is reflected in content data. The inverse orthogonal transform may be an inverse fast Fourier transform (IFFT), an inverse discrete cosine transform (IDCT), or the like. This method can also be applied to existing content.

According to the ID reading procedure of the present invention, first, a content is obtained, for example, via a network, and ID information is read from a predetermined position of the content. This ID information is uniquely associated with the information terminal or its user. In another aspect, spatial frequency information is extracted from the acquired content and subjected to orthogonal transform. Through this conversion, the ID information embedded in the content is restored. The orthogonal transform may be a fast Fourier transform (FFT), a discrete cosine transform (DCT), or the like.

[0013]Detailed description of the embodiment  According to the present invention, as shown in FIG.
9 consisting of a client-side device connected to
Work system. In the figure,
As devices on the client side, PCs 4 and 8 as information terminals and
Includes Personal Digital Assistance (PDA) 6
You.

The content is supplied from the server 2 to the client device, and embedding of the ID is performed on the client side. Here, as an example, it is assumed that the PC 4 has an ID embedding function.

FIG. 2 is a flowchart showing the operation when the PC 4 receives the content. PC4 first
The content is downloaded from the server 2 via the network 9 (S0). At this time, a program for decoding (decrypting) or decrypting the content is also downloaded from the server. This program is
It may be included in the downloaded viewer or browser, which returns the encrypted content to a usable form. User ID information unique to the PC 4 or its user is embedded in the viewer. I
D is embedded in the content when decoding the content with this viewer (S2). After embedding the ID, use such as displaying the content on a screen or copying the content is permitted.

FIG. 3 shows a configuration of the PC 4 related to embedding an ID. In the following examples, content is considered an image. First, the user requests a content manager or a provider (not shown) operating the server 2 to distribute the content. After authenticating the user, the content manager sends the content and the viewer 12 to the PC 4 via the network as shown in FIG. These are received by the communication unit 10 of the PC 4.

The viewer 12 received in the PC 4 is used to decode and display the received content. As shown in FIG. 3, the content is input to the viewer 12. The viewer 12 includes an image decoding unit 14 that decodes an image compressed or encrypted by the content manager before transmission to the PC 4, an ID holding unit 16 storing an ID, and an ID holding unit 16. An ID embedding unit 18 for reading out the ID and embedding it in the decoded image is provided. The image decoding unit 14 has a built-in decoding algorithm. When transmitting the viewer 12, the content manager stores and provides an ID unique to the user who has requested the content in the ID holding unit 16. The viewer 12 can be provided as a plug-in type device for existing browsers on the Internet, for example.

In order to prevent the image before the ID embedding from being read and used, for example, the memory area of the PC 4 for storing the image without the ID embedded is protected by the ID embedding unit 18 and has no ID. Reading of the content is prevented. When a read access occurs to a memory area in which content having no ID is stored, for example, the system is configured to be interrupted or reset. When the embedding of the ID is completed, this protection is removed, and free use of the image is permitted.

As shown in FIG. 3, the image containing the ID is sent to the display control unit 20. The image is now converted to a display format for display 24. The storage device control unit 22 writes data to a storage device 26 such as a hard disk unit, and stores a decoded image in the storage device 26.

FIG. 4 shows an internal configuration of the ID embedding section 18 of FIG. 3 according to one embodiment of the present invention. The ID embedding unit 18 includes an ID reading unit 30 that reads an ID from the ID holding unit 16 and a decoded image reading unit 32 that reads a decoded image.
And a combining unit 34 that embeds an ID at a predetermined position in the data sequence of the decoded image, for example, at the beginning, center, or end of the data sequence. If the ID is n bits and the luminance of each pixel is represented by multi-scale, for example, the synthesizing unit 34 replaces the least significant bit (LBS) of the luminance with each bit of the ID in order from the first pixel to n pixels. To go.

In the actual operation, first, the user of the PC 4 requests the server 2 of the content manager to distribute a certain content. After the content is encrypted on the server 2 side, the content is sent to the PC 4 via the network together with the viewer 12. The communication unit 10 of the PC 4 receives the transmitted content, and this is passed to the viewer 12, which is also received from the network. In the viewer 12,
The image decoding unit 14 decodes the content and passes it to the ID embedding unit 18. The ID reading unit 30 of the ID embedding unit 18
D is read from the ID holding unit 16 and given to the synthesizing unit 34. The decoded image is read by the decoded image reading unit 32 and passed to the synthesizing unit 34. After receiving the ID and the decoded image, the synthesizing unit 34 calculates the LSB of the luminance according to the method described above.
The ID is embedded in the image by replacing. The image with the ID is displayed on the display 24. In addition, the storage device 2
6 may be sent. Thereafter, if unauthorized modification or duplication is performed on the image with the ID stored in the storage device 26, the modified or duplicated copy is embedded in the image stored in the storage device 26. ID
Information will be included.

FIG. 5 shows an ID according to another embodiment of the present invention.
This is another configuration of the embedding section 18. 4, the same reference numerals are given to the members equivalent to those in FIG. 4, and the description will be omitted. The configuration of FIG. 5 is based on the inverse fast Fourier transform (IF
An IFFT unit 40 that performs FT) and a combining unit 42 that combines the converted ID (that is, the output of the IFFT unit 40) with the decoded image.

In this embodiment, the ID information is represented as a signal in the frequency domain. When embedding such an ID, inverse orthogonal transform is performed on the frequency signal indicating the ID information, and a bit pattern is formed in the content area. This bit pattern is embedded in the digital content. In this specification, the term "content area" refers to an area representing data included in digital content, and the "frequency domain" refers to a mapping area obtained by performing orthogonal transformation on the content area. If the content is a two-dimensional image (illustrated below)
The content domain becomes a two-dimensional spatial domain, and the corresponding frequency domain becomes a two-dimensional spatial frequency domain. When the content is audio, the content domain is, for example, a time domain, and the frequency domain is, for example, a one-dimensional frequency domain.

FIG. 6 shows an example in which ID information is represented as a signal in the frequency domain. A two-dimensional image is used as an example of the content. The rectangle 52 represents a two-dimensional spatial frequency domain corresponding to the two-dimensional spatial domain. Arrows 54a, 5
4b represents the x and y directions of the space area, respectively, and arrows 56
Reference numerals a and 56b denote directions in which the frequency increases in the frequency domain corresponding to the x and y directions of the sky listening area. In this frequency domain, three users A, B, and C
Signals indicating the ID information of (xa, ya),
(Xb, yb) and (xc, yc) are plotted. For example, in the case of user A, the frequency signal is (xa, y
A sharp peak is taken around a). The steep peak may have a finite width or a delta function. Thus, the user ID information is represented by one point in the two-dimensional frequency domain.

FIG. 7 shows a state where the ID information of the user A is converted into an actual bit pattern in the spatial domain by the IFFT unit 40. The value of the pixel of the bit pattern in FIG. 7 is “1” in the hatched portion and “0” in the other portions. In this example, since the frequency signal indicating the ID information of the user A is substantially at the center of the spectrum region in both the x and y directions (FIG. 6), the spatial frequencies of the hatched portion and other portions in FIG. The values are almost equal in the directions. In the case of the user B, the frequency signal indicating the ID information has a higher frequency in both directions, so that the bit pattern formed in the hatched portion and the other portion becomes thin (not shown).

FIG. 8 shows a decoded image (digital content) obtained by converting a bit pattern including ID information as shown in FIG.
FIG. 4 is a diagram for explaining a method of embedding in a file. In this example, the luminance of the pixel of the decoded image is represented by 8-bit binary data. By replacing the LSB of the luminance of the decoded image with the value of the corresponding pixel in the bit pattern including the ID information,
D information is embedded in the decoded image. Therefore, in this example, if a certain pixel exists in the shaded portion of FIG. 7 in the decoded image, its LSB is replaced with “1”, and if it exists in other portions, it is replaced with “0”. The 7 bits other than the LSB of the pixel luminance are left as the original data of the decoded image. Thus, according to this embodiment, I
D can be embedded in the entire image, or in a certain divergent portion therein. This method is effective as a countermeasure against cutting off part of the content. Because I
This is because, by properly taking the above-mentioned spread portion in which D is to be embedded, even if that portion is cut off, it is possible to effectively impair the usability of the content. A specific embodiment has been described for embedding ID information of the present invention. Various modification techniques are conceivable for these embodiments. Hereinafter, some of them are shown.

First, in the above-described embodiment, the content is distributed via a network. However, the content is distributed and stored in a storage medium such as a CD-ROM or a flexible disk.
It may be loaded into C. The embodiments described above are also applicable to the case where such another method is used for content distribution.

Second, in the above embodiment, a still image is considered as an example of digital content, but the method of the present invention can be applied to other types of digital content such as moving images (eg, video) and audio. It is. In the case of a moving image, the ID information may be divided into a plurality of parts, and different parts may be embedded in different image frames. In the case of audio content, the image decoding unit 14 in FIG. 3 may be changed to an audio decoding unit, the display control unit 20 may be changed to an audio output control unit, and the display 24 may be changed to a speaker. Since the audio is one-dimensional data unlike the image, the IFFT may be one-dimensional. In the case of an image, ID information is inserted in bits relating to luminance, but in the case of audio, it may be inserted in an LSB of frequency data or the like.

Third, the place where the ID is inserted need not be limited to the LSB of the content. Of the quantized data,
Any bit may be placed in the range that does not significantly affect the perceived content quality. In addition,
It is also possible to adopt a method in which the watermark is intentionally embedded as a visible watermark.

Fourth, in the above-described embodiment, the ID is inserted in the lower bit irrespective of the upper bit. However, an offset may be added to the lower bit so that the entire data including the upper bit includes the ID. Good.

FIG. 13 is a diagram showing 3 items in content such as an image.
In the example of a × 3 pixel area, the luminance of each pixel is “10,
8,0 ... ". FIG. 14 shows the luminance of the same 3 × 3 pixel area, but here, the luminance is represented by a remainder system of three. With this remainder system, for example, a value corresponding to a pixel having a luminance of “10” is “1”. FIG. 15 shows a sample data pattern generated by the above-described method and representing ID information, which is to be embedded in the 3 × 3 pixel area of FIG. This ID pattern is also represented by a remainder system of three. In this example, the user wants to put “0” in the first row, “1” in the second row, and “2” in the third row. FIG. 16 shows that the luminance of each pixel in the 3 × 3 pixel area shown in FIG. 14 is offset by 1, to obtain each pixel value in the 3 × 3 pixel area shown in FIG.
This shows how 0 or 1 is added. In fact, Figure 1
According to the calculation shown in FIG.
And the ID information is embedded in the 3 × 3 pixel area of the image shown in FIG. That is, this method adds an offset to the entire luminance data,
The entire data including the upper bits includes the ID.

According to this method, as in the case of embedding the ID in the lower bits, it is possible to avoid a state in which the ID is directly visible in the lower bits of the data, thereby improving the security. It is also advantageous that data such as "2" as well as "0" and "1" can be embedded. Here 3
Is considered, but this may be another number.
Also, any other mathematical, Boolean, or cryptographic method may be employed.

Fifth, in the above embodiment, the synthesizing unit 3
No. 4 (FIG. 4) has an ID embedded at a predetermined position such as the head of the data string. However, the predetermined position may be a position in the content data in which the influence of a slight shift given to the data value is difficult to recognize. In that case, the quality of the content (the quality of still images, moving images, sound, text, etc.) is not significantly affected.

Sixth, in the embodiment shown in FIG. 3, the image decoding unit 14 and the ID embedding unit 18 have different configurations. These configurations may be integrated, and the ID may be embedded simultaneously with the restoration of the image.

Seventh, in the embodiment shown in FIG. 3, a program for decrypting (decoding) and / or decoding (decoding) is built in the viewer or the browser. However, this program may take any form as long as it can restore the content to a format that is easy for the user to use.

Eighth, the ID information of one user is represented by one point in the frequency domain (FIG. 6), but this may be another method. For example, the ID information of one user may be represented by a set of a plurality of discrete points, a two-dimensional area, or the like.

Ninth, the two straight lines 100 and 102 in FIG.
, The reference information may be included in a frequency domain expression as shown in FIG. Since the position of the reference information is fixed and known in the frequency domain, the reference information can be used when reading the ID information from the content. With the help of reference information, for example, rotation, enlargement, etc.
Even if the content is deformed, the position of the ID can be specified with higher accuracy, and the user represented by the ID can be identified.

The above is the method of embedding ID information. Next, a method of reading the embedded ID information will be described.

When content is illegally copied or altered (hereinafter referred to as cheating), it is desired to identify the fraudster. This becomes possible by reading the ID information embedded in the content. A device that reads out the ID (hereinafter referred to as a “detection device”) may exist in any part of the network, and for example, a proxy server or the like may include the detection device.

FIG. 10 is a flowchart showing the operation of the detection device. The detecting device loads the content from the storage device or the storage medium (S10), and the ID embedded therein.
The information is read (S12). If any wrongdoing is found, take appropriate measures, such as notifying the content owner to the content manager.

FIG. 11 shows an embodiment of the detecting device for reading out the ID information embedded in the content. Detector 6
0 (may be included in the PC) are a communication unit 62 for acquiring content from the network, an ID reading unit 64 for reading ID from the acquired content,
A display control unit 66 that controls a display 68 to display D is provided.

In this embodiment, the ID reading section 64
Is a predetermined position in the data string of the acquired content,
For example, the head LSB of the data string is extracted, and the ID is reconstructed. As a result of the extraction, if ID information that can identify the user significantly does not appear, it is determined that the content is the original, that is, the content in which the ID information of the user is not embedded. On the other hand, if the content in which the ID of a certain user is embedded is found on the network, there is a possibility that the user identified by the ID information has illegally distributed the content. In this way, the wrongdoing is tracked based on the ID.

FIG. 12 shows another ID reading section according to another embodiment of the present invention. The ID reading unit operates to read an ID embedded as spatial frequency information in the content. The ID reading unit 64 extracts an LSB of the acquired content data to form a bit pattern, and an LSB extraction unit 72. The ID reading unit 64 performs a fast Fourier transform (F) on the bit pattern formed based on the extracted LSB.
An FFT unit 74 for performing FT) is provided.

The operation according to this configuration is equivalent to reversing FIGS. First, L representing embedded ID information
SB is extracted (FIG. 8). Subsequently, a bit pattern formed by the LSB in the content is detected (FIG. 7). Thereafter, the FFT unit 74 calculates the spatial frequency in each of the x and y directions from the bit pattern. FIG.
In the case of this bit pattern, the ID of the user A in FIG. 6 is found as a result of the FFT calculation. Now the fraudster is User A
Is identified.

According to this method, it is also advantageous that it is not necessary to compare the suspicious content with the original content in order to detect the ID.

Many modification techniques are conceivable for the method of reading the ID information described above. The modification techniques of the ID embedding method already described in this specification have corresponding modification techniques of the ID reading method. For example, when an offset is added to the lower bits by the method described with reference to FIGS. 13 to 16, the ID can be read. In addition, a predetermined position of the content (for example, a position where shifting the data value does not have a perceptible effect) is
When D is embedded, there is an ID reading method that detects the same position in conformity with the ID embedding method. In general, as long as the embedding and reading devices employ the same embedding / reading rules, I
Reading of D is possible.

In the above embodiment, the detection device is connected to the network. However, if only the content stored in the storage medium is to be inspected, this device may be an offline stand-alone type.

Further, in the above-described embodiment, the embedding of the ID is performed on the information terminal using the content, that is, on the user side. However, as will be apparent to those skilled in the art, the various methods described above for embedding ID information in content similarly apply to content distribution designs in which ID embedding is performed by the content provider. it can.

Of course, modifications to the present invention will become apparent to those skilled in the art when viewing the present invention from various angles. Other embodiments are possible, as particular designs will occur depending on the particular application. Therefore, the scope of the present invention should not be limited by the embodiments described herein, but should be determined only by the appended claims.

[Brief description of the drawings]

FIG. 1 is a diagram showing a network system to which a preferred embodiment of the present invention is applied.

FIG. 2 is a flowchart showing an operation when a PC receives content for embedding an ID.

FIG. 3 is a diagram showing a configuration related to embedding of an ID in a PC.

FIG. 4 is an internal configuration diagram of an ID embedding unit of FIG. 3;

FIG. 5 is a diagram showing another configuration of the ID embedding unit of FIG. 3;

FIG. 6 is a diagram showing the relationship between ID and spatial frequency by using a spectral domain.

FIG. 7 shows an ID of a certain user by the IFFT unit of FIG. 5;
FIG. 8 is a diagram showing a result of converting the image data into an actual image data pattern.

8 is a diagram illustrating a method of embedding the bit pattern of FIG. 7 in a decoded image.

FIG. 9 is a diagram illustrating a state where fixed reference information is superimposed on the spectral region of FIG. 6;

FIG. 10 is a flowchart illustrating an operation of the inspection device that reads an ID embedded in content.

FIG. 11 is a diagram showing a configuration of an ID reading unit in the detection device.

FIG. 12 is a diagram illustrating another configuration of the ID reading unit of FIG. 11;

FIG. 13 is a diagram showing a 3 × 3 pixel area.

14 is a diagram showing the luminance of 3 × 3 pixels in FIG. 13 in a modulo 3 system.

FIG. 15 is a diagram showing a data pattern to be embedded as an ID in a 3 × 3 area of FIG. 13;

FIG. 16 is a diagram showing a state where an offset 0 or ± 1 is added to the luminance of each pixel in order to obtain the state of FIG. 15 from the state of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 communication unit 12 viewer 14 image decoding unit 16 ID holding unit 18 ID embedding unit 20 display control unit 22 storage device control unit 24 display 26 storage device 30 ID reading unit 32 decoded image reading unit 34 synthesis unit 40 IFFT unit 42 synthesis Unit 60 detection device 62 communication unit 64 ID reading unit 66 display control unit 68 display 72 LSB extraction unit 74 FFT unit

Continued on front page F-term (reference) 5B017 AA06 BA09 CA07 CA16 5B057 AA20 CB19 CE08 CG05 CG07 DA07 DA16 DA17 5C076 AA14 BA06

Claims (33)

[Claims] 1. A method for embedding identification information (ID) in digital content including a data value, comprising the steps of: loading the digital content into an information terminal in which the digital content is to be used; Embedding an indication of an ID associated with the information terminal or its user in a perceivable part playing a role in the set content. 2. The method of claim 1, wherein the indication of the ID is embedded at a predetermined position in the loaded content. 3. The method of claim 2, wherein said embedding step is performed by manipulating lower bits of a data value at a predetermined position of the loaded content. 4. The indication of the ID includes a plurality of bits, and the step of manipulating comprises replacing each least significant bit of the array of data values at a predetermined position of the loaded content with a corresponding bit of the indication of the ID. 4. The method according to claim 3, comprising the step of replacing in order. 5. The method of claim 2, wherein said embedding step comprises the step of adding an offset to each of the array of data values at a predetermined position in the content. 6. The indication of the ID includes a plurality of digits each of which can take N values (N is a predetermined integer), and the offset added to the data value is expressed by adding the sum of the data value and the offset by N. 6. The method of claim 5, wherein the remainder is determined by a remainder and a corresponding digit in the display of the ID. 7. The method of claim 2, wherein the predetermined location is a location in digital content where embedding of an ID has little perceptual effect. 8. The method according to claim 1, wherein embedding of the indication of the ID is performed on a spread portion of the loaded content. 9. The method according to claim 8, wherein the certain extent defines a content area, and the indication of the ID is expressed in a frequency domain related to the content area. 10. The frequency domain is a mapping of a content area by orthogonal transform, and the embedding step includes:
10. The method of claim 9, comprising inversely transforming the frequency domain representation of the ID into a content domain representation of the ID by inverse orthogonal transformation, and embedding the inversely transformed ID in the content. 11. The method of claim 10, wherein said embedding step is performed by manipulating lower bits of data of the content. 12. The inversely transformed ID includes a plurality of bits, and the manipulating step comprises: replacing a least significant bit of each of a plurality of data values of the content with a corresponding bit of the inversely transformed ID. 12. The method according to claim 11, further comprising the step of: 13. The method of claim 10, wherein said embedding step comprises adding an offset to each of a plurality of data values of the content. 14. The inversely transformed ID includes a plurality of digits each of which can take N values (N is a predetermined integer), and the offset added to each data value is the data value and the offset. 14. The method of claim 13, wherein the sum is determined by the remainder of dividing the sum of N by N and the corresponding digit in the inversely transformed ID. 15. The method according to claim 8, wherein the reference information is embedded in the digital content in the form of reference information in the frequency domain. 16. The loaded content is encrypted, and the embedding step includes a step of decrypting the loaded content and an ID of the decrypted content.
Embedding the display of the information. 17. The method of claim 1, wherein the loaded content is encrypted, and the embedding step includes the steps of simultaneously decrypting the content and embedding an ID indication in the content. the method of. 18. The method of claim 1, further comprising, after embedding the ID information, authorizing use of the digital content at the information terminal. 19. A method for reading out an ID from digital content in which the ID is embedded by using the method according to claim 4, wherein a least significant bit is extracted from an array of data values at a predetermined position of the content. Obtaining an ID from the extracted bits. 20. A method for reading an ID from digital content in which the ID is embedded using the method according to claim 5, wherein an offset is extracted from an array of data values at a predetermined position of the content. Obtaining an ID from the offset obtained. 21. An ID using the method according to claim 10.
Extracting the ID from the digital content embedded in the content, extracting the inversely converted ID embedded in the content from the content;
A method comprising: converting the extracted inversely transformed ID to an ID display in the frequency domain through orthogonal transform; and obtaining the ID from the converted frequency domain display. 22. An ID using the method according to claim 12.
Extracting the ID from the digital content embedded in the content by extracting the inverse-converted ID embedded in the content from the least significant bit of the data value of the content; A method of converting the converted ID into an ID display in the frequency domain through orthogonal transform, and obtaining the ID from the converted display in the frequency domain. 23. An ID using the method according to claim 13.
Extracting the ID from the embedded digital content by extracting an inversely converted ID embedded in the content by extracting an offset from the content; and extracting the inversely converted ID from the content. Transforming the generated ID into an indication of an ID in a frequency domain through orthogonal transform, and obtaining the ID from the indication of the ID in the frequency domain. 24. The digital content includes identification information (I
D) a device that embeds the encrypted digital content and ID information, and decrypts the encrypted content and acts to embed the ID information in the decrypted content. Including a communication unit that receives a program for decrypting content, and a unit that uses the program for decryption to generate decrypted content in which ID information is embedded from the received encrypted content. . 25. The apparatus according to claim 24, further comprising a display control unit for displaying the decrypted content in which the ID information is embedded. 26. The apparatus of claim 25, further comprising means for preventing the decrypted content from being displayed before the ID is embedded. 27. The apparatus of claim 24, further comprising a memory for storing the decrypted content with embedded ID information. 28. Identification information (I
An apparatus for embedding D), comprising: a communication unit that receives digital content; and an embedding unit that embeds an ID in a perceptible portion of the received content. 29. The apparatus according to claim 28, wherein the embedding section embeds an ID in a predetermined position of the content. 30. The apparatus according to claim 28, wherein the ID is displayed in a frequency domain, and the frequency domain is associated with a content area determined by content. 31. A display control unit for displaying content,
Means for preventing content from being displayed before the ID is embedded. 32. The apparatus of claim 28, further comprising a protector that prevents the digital content from being used before the ID is embedded. 33. A method for embedding identification information (ID) in digital content including a data value,
Loading the digital content into an information terminal where the digital content is to be used, and, in the loaded content, excluding a reserved area and a comment area, the information terminal includes Or embedding an indication of an ID associated with the user.