JP2007207051A - Electronic watermark embedding/distributing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that due to unefficient watermark embedding/detection processing for video content, there is possibility of the increase and erroneous detection of data access in finger printing of video or music content. <P>SOLUTION: This video element combination technology is provided to restore user ID regardless of the extraction start position of content elements by integrating the embedding analysis processing of content and watermark embedding processing to embed a plurality of pieces of information, and allowing processing independent of embedding information to be shared. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a content copyright protection system, and more particularly to a fingerprinting technique for embedding a digital watermark for identifying a user in multimedia data.

  Digital watermarking is a technique for embedding information in content such as multimedia data, for example, video and music, and detecting the embedded information from the content. Information is embedded by making minor changes to the content. Information is expressed by the changed location and the changed content. Therefore, the original content and the content in which information is embedded feel the same for human vision and hearing, but are slightly different. In the information detection, the embedded information is detected by reading the changes made to the content.

  The digital watermark has the following characteristics. Embed information directly rather than writing it in external data such as content headers. Therefore, as long as the characteristics of the content itself do not change, the embedded information survives and can be detected later. Therefore, even after once converted into an analog signal, the embedded information can be detected by re-digitizing.

For the purpose of protecting the copyright of contents, there are roughly two types of uses of digital watermarks: (A) copyright claim and (B) illegal copy tracking.
(A) Copyright claim First, the author ID information is embedded in the content using a digital watermark. Then, after content distribution or after content distribution, it is possible to identify the copyrighted work of a specific author by detecting the author ID from the content to be investigated. As a result, it becomes clear that the copy is an unauthorized copy, which has a deterrent effect on a user who considers an unauthorized copy.
(B) Before distributing the tracking content of the unauthorized copy person to the user or before the user views it, the user ID information is embedded in the content using a digital watermark. Then, by detecting the user ID from the content to be investigated, it can be specified that the specific user has illegally leaked the content.

  In particular, the method of embedding the user ID with the digital watermark in the content (B) has a great deterrent power against the user who intends to illegally copy the content, compared with (A).

  In content distribution, the usage method (B) is further divided into two types (B1) on the client side and (B2) on the server side, depending on where the user ID is embedded in the content.

(B1) Embedding a digital watermark on the client side Since a watermark embedding device is placed at the user's hand, the digital watermark algorithm is deciphered and there is a risk of forgery or tampering. For this reason, it has been difficult to ensure security, such as taking tamper resistance measures on the viewing terminal on the client side. Therefore, the following (B2) is often used.

(B2) When embedding digital watermark on the server side After authenticating the accessing user, the user ID information must be embedded in the content in real time at the time of distribution. This has a problem that the server processing has a large load and cannot cope with simultaneous access by many users.

  There is a technique described in Non-Patent Document 1 as a conventional technique for embedding a digital watermark on the server side (B2).

  Non-Patent Document 1 states that “the content is divided into a plurality of parts, a plurality of digital watermarks are prepared for each of the divided parts, and the digital watermark for each user is extracted as the digital watermark value of the extracted divided part. It is a technology that adopts a configuration of “combination of”.

  With the above technology, it is not necessary to embed individual user IDs with digital watermarks when distributing content, and the processing during distribution can be reduced.

  In addition, when the content distributed by the above technology is illegally leaked from the user, watermark detection is performed from each of the n elements of the distributed content to detect the user ID at the time of embedding and to detect the unauthorized person. Identify.

Roland Parviainen et al., “Large Scale Distributed Watermarking of Multicast Media through Encryption,” International Federation for Information Processing Communications and Multimedia Security Joint working conference IFIP TC6 and TC11, May 21-22, 2001.

  The technology described in Non-Patent Document 1 has two problems.

  The first problem is the efficiency of the embedding process.

  The technology described in Non-Patent Document 1 eliminates the need to embed individual user IDs with digital watermarks when distributing content, but it is necessary to create watermark-embedded content for one content in advance for the number of watermark information. Therefore, an efficient digital watermark embedding process has been demanded.

  The second problem is accurate detection of embedded information.

  In the technology described in Non-Patent Document 1, according to the user ID of the distribution destination, for each of the n divided content elements, an ID is expressed by combining any element of X or Y, and the content is distributed. In the case where the content is extended over a long period of time, the ID is generally expressed repeatedly for a certain number of continuous content elements. When such use is assumed, the conventional technology does not know which content element is the starting point of information, and may detect an incorrect ID. Also, even if the watermark embedding / detector side determines the first content element on the time axis as the start point of information, if the content is cut out in the time axis direction, an incorrect ID can be detected. There is sex.

  Accordingly, there is a need for a more practical digital watermark embedding technique that can cope with such problems.

  In the content creation processing of the present invention, the content embedding analysis processing and the watermark embedding processing for embedding a plurality of information are integrated, and the processing independent of the embedding information is made common, thereby reducing the number of times data is loaded from the disk and the disk capacity. Provide technology that can reduce the amount of waste.

  Further, the content distribution processing of the present invention provides a video element combination technique that can restore the user ID regardless of the extraction start position of the content element at the time of watermark detection.

In a preferred embodiment of the present invention, the video copyright protection system includes a video distribution server, a video receiving client, and a fingerprinting detection machine.
(1) The video distribution server includes the following steps.
(A) Content creation / Steps of extracting video elements of a predetermined length from video content at predetermined time lengths / Steps of repeatedly embedding m kinds of digital watermarks in the number of video elements for every n video elements (b) Content distribution Step of accepting a user request, selecting a video element corresponding to the user ID, and delivering in combination with the video content (2) The video receiving client transmits a content request in response to the video delivery server, Receive.
(3) The digital watermark detection apparatus receives video content to be investigated, extracts n video elements having a predetermined length for each predetermined time length, and detects digital watermark information from the extracted n elements. The user ID embedded from the detected information is restored, and the unauthorized copy outflow source is specified. Here, the number of video elements extracted by the fingerprint detection machine is not necessarily n, and may be larger than n.

A first aspect of the present invention is a method for distributing content distributed from a transmission side to a reception side,
Generating digital watermark embedding information based on information on the receiving side;
A content element having a predetermined length is extracted from the content every predetermined time length, and m types (m is an integer of 1 or more) of electronic watermarks are embedded in the content element to generate m types of content elements. Steps,
Generating one content by combining the content and a content element in which the digital watermark is embedded based on the embedded information of the digital watermark;
And transmitting the generated content to the receiving side.

Further, the step of generating the content element includes:
Generating m types of digital watermark patterns independent of content;
Extracting a unit element from the content element, and performing a digital watermark embedding strength analysis of the unit element;
The method may include embedding a digital watermark in the unit element from the m types of digital watermark patterns and the intensity analysis result.

Further, the step of generating the embedded information of the digital watermark includes:
There may be a step of generating embedded information having a bit configuration based on the bit arrangement order without depending on the starting point of the embedded information bits.

A second aspect of the present invention is content generated according to the above aspect,
Generating digital watermark embedding information based on information on the receiving side;
Extracting a content element of a predetermined length from the content every predetermined time length;
Embedding m types (m is an integer of 1 or more) of electronic watermarks for one content element to generate m types of content elements;
Based on the embedded information of the digital watermark, the content is generated by the step of combining the content element with the content embedded with the digital watermark.

A third aspect of the present invention is an information detection method for detecting digital watermark information from content distributed from a transmission side to a reception side,
Extracting a content element of a predetermined length from the content every predetermined time length;
Detecting digital watermark information from each of the content elements;
And a detection information processing step for identifying information on the content receiving side according to claim 1 from the detected digital watermark information.

Further, the detection information processing step for identifying information on the content receiving side from the detected digital watermark information includes:
The method includes a step of specifying information on the content receiving side based on the bit arrangement order without depending on the detected starting point of the information bits.

  In the following, video content is taken as a specific example, but the present invention is not limited to video content and can be applied to music content.

  According to the present invention, it is possible to ensure sufficient security in fingerprinting multimedia data even with a simple system configuration.

  FIG. 1 is a diagram showing a schematic configuration of the present embodiment. As shown in FIG. 1, the application form of this embodiment includes a video distribution server 101 and a plurality of video reception clients (in this embodiment, client A 102 is taken as an example).

  Note that each device according to the present embodiment includes, for example, a CPU, a memory, a removable device such as a CD-ROM and a DVD-ROM, and a reading device that reads information from a portable storage medium, and a network. General information processing in which a communication device for communicating with a partner device, an external storage device such as an HDD, and an input / output device such as a keyboard, mouse, and display are connected via an internal communication line such as a bus In the apparatus, it can be realized by the CPU executing a predetermined program loaded in the memory.

  Furthermore, each processing unit of each device is embodied in the information processing device by the CPU executing a program stored in an external storage device or memory. The program may be stored in the information display device in advance, or a storage medium that can be attached and detached and used by the information processing device or a network or a carrier wave that propagates on the network when necessary. The information processing apparatus may be introduced via a communication medium that can be used. Also, some or all of the functions of each device may be realized by hardware.

  FIG. 2 is a diagram showing a schematic configuration of the video distribution server apparatus (server 101) of the present embodiment. As shown in FIG. 2, the video distribution server apparatus 101 of this embodiment is configured using an information processing apparatus having a CPU 201, a ROM 202, an input device 203, an output device 204, a communication device 205, and a memory 206. can do.

  The CPU 201 is a device that controls the operation of the entire server 101. The memory 206 is a storage device that stores various processing programs and data for controlling the operation of the entire server 101. The input device 203 is a device that performs various inputs for inputting content. The output device 204 is a device that performs various outputs accompanying content output. The communication device 205 is various devices that perform communication and control with other processing devices via a network such as the Internet or an intranet, or a dedicated interface such as SCSI, RS422, or IEEE1394.

  In addition, the server 101 executes the user identification unit 110, the watermark information generation unit 111, the management unit 112, the watermark content creation unit 113, the distribution content control unit 114, and the content distribution unit 115 by being executed by the CPU 301. A program to be realized is stored in the memory 206.

  FIG. 3 is a diagram showing a schematic configuration of the video reception client device (client 102) of the present embodiment. As shown in FIG. 3, the client 102 according to the present embodiment can be configured using an information processing apparatus having a CPU 301, a ROM 302, an input device 303, an output device 304, a communication device 305, and a memory 306. it can.

  The CPU 301 is a device that controls the operation of the entire client 102. The memory 306 is a storage device that stores various processing programs and data for controlling the operation of the entire client 102. The input device 303 is a device that performs various inputs for inputting content. The output device 304 is a device that performs various outputs accompanying content output. The communication device 305 is various devices that perform communication and control with other processing devices via a network such as the Internet or an intranet, or a dedicated interface such as SCSI, RS422, or IEEE1394.

  Further, the client 102 has a program in the memory 306 that realizes the content decrypting unit 130 and the content reproducing unit 131 by being executed by the CPU 301.

  As shown in FIG. 1, the watermark content creation unit 113 in the server 101 extracts n video elements having a predetermined length from video content at predetermined time lengths and prepares m kinds of digital watermarks for each element as advance preparation. The embedded n * m video elements are stored in a storage area such as an HDD. For example, when the video content is an MPEG compressed stream file, there is a method in which video elements from a predetermined key frame to a key frame are cut out every predetermined time length, and m kinds of electronic watermarks are embedded in the elements. In addition, the user ID (uid = A) and password (pwd) are registered in the management data 120, and the watermark information uniquely corresponding to the user ID (in this case, WM = 110 ...) This is determined based on the generated watermark information.

  After the advance preparation is completed, the server 101 receives a content distribution request from the user. First, the user identification unit 110 in the server 101 receives the user ID (uid = A) and password (pwd) from the client A102, and the user ID and password in the management data 120 registered in the management unit 112 in advance And specify the user (in this case, specify uid = A). After specifying the user, the server 101 receives the user's request.

  Next, the management unit 112 calls watermark information uniquely corresponding to the user ID from the management data 120 based on the identified user ID, and transmits the watermark information to the distribution content control unit 114. The distribution content control unit 114 receives the user ID and watermark information, specifies the playback order of the video elements in which the watermarks are embedded, and the video elements to be played back in each order, and the original video and the video elements in which the watermarks are embedded. And the content distribution unit 115 transmits video address information so that a series of videos can be distributed to the user.

  The content distribution unit 115 distributes the video specified by the distribution content control unit 114 to the user. The content distribution unit 115 may distribute the video content after encrypting the video content with a key or the like generated based on the user ID when the video is distributed.

  The client A 102 receives the video content 123 distributed from the server 101 and plays back the video content in the content playback unit 131 so that the user can view it. When the video content is a compressed stream file, the content decoding unit 130 in the client A 102 decodes the file, and then transmits the decoded file to the content reproduction unit 131. If the video content is encrypted, the content playback unit 131 decrypts the video element based on the license information received from the server 101 first, and then plays the video content.

  When the video content distributed to the client is illegally leaked from the client, the digital watermark detection apparatus 103 receives the content to be investigated and, based on the method described in FIG. N pieces of video elements are extracted, and digital watermark information is detected from each of the extracted n elements. The user ID embedded from the detected information is restored, and the user ID of the video content, that is, the user ID of the illegal outflow source is specified from the information detected based on the management data 120. The identification of the user ID is not necessarily performed by the fingerprint detection machine, and the apparatus may transmit the detection information to the server 101, and the server 101 may identify the user ID.

  In addition to the above-described identification of the unauthorized person's user ID, the digital watermark detection apparatus 103 may also specify the distribution server of the video content. In this case, as a preliminary preparation, the server 101 extracts n video elements having a predetermined length from video content for every predetermined time length and inserts m kinds of digital watermarks, and in addition, the server ID can be specified. It is necessary to insert a digital watermark separately.

  FIG. 4 is a diagram showing a schematic configuration of the digital watermark detection apparatus 103 of this embodiment. As shown in FIG. 4, the digital watermark detection apparatus 103 of the present embodiment is configured using an information processing apparatus having a CPU 601, a ROM 602, an input device 603, an output device 604, a communication device 605, and a memory 606. can do.

  The CPU 601 is a device that controls the overall operation of the digital watermark detection apparatus 103. The memory 606 is a storage device that stores various processing programs and data for controlling the operation of the entire digital watermark detection apparatus 104. The input device 603 is a device that performs various inputs for inputting content. The output device 604 is a device that performs various outputs accompanying content output. The communication device 605 is various devices that communicate with and control other processing devices via a network such as the Internet or an intranet, or a dedicated interface such as SCSI, RS422, or IEEE1394.

  The digital watermark detection apparatus 103 also has a program in the memory 606 that implements the content reception processing unit 150, the digital watermark detection processing unit 151, and the detection information processing unit 152 by being executed by the CPU 601.

  FIG. 5 is a diagram illustrating an example of a processing flow of the watermark content creation unit 113 in the video distribution server 101. The watermark content creation unit 113 generates m different types of watermark embedded content from the original content. For m types of different watermark generations, the creation unit may input m types of watermark information and related external parameters.

  As shown in the figure, in step S701, the watermark content creation unit 113 generates m types of digital watermark patterns that do not depend on the content in advance before embedding the digital watermark. In step S702, the watermark content creation unit 113 reads unit elements of the original content (eg, MPEG GOP unit, frame image, etc.) from a storage area such as an HDD. When the original content is a compressed stream such as MPEG, a part of the original content is decoded in this step, and a frame image generated by decoding may be used as a unit element. In step S703, the watermark content creation unit 113 analyzes the ease of embedding a digital watermark based on the image content of the unit element, and creates an embedding strength map of the unit element.

  Here, the intensity map is common to m types of watermark patterns, and one type of intensity map is generated. However, m types may be created depending on the m types of watermark patterns.

  In step S704, the watermark content creation unit 113 embeds a digital watermark in the unit element based on the m types of watermark patterns generated in step S701 and the one type of intensity map generated in step S703, and generates m types of watermarks. Generate an embedding unit element. In step S705, the m types of unit elements are stored in a storage area such as an HDD. When the original content is a compressed stream such as MPEG, the m types of watermark embedding unit elements may be encoded in this step and then stored in the storage area. In step S706, the watermark content creation unit 113 determines whether all reading of the original content has been completed. If the reading has been completed, the processing of the watermark content creation unit 113 is terminated, and the reading has not been completed. In step S707, the reading destination of the original content is moved, and the reading destination is set to the address of the next unit element.

  This process requires only one reading of the original content when generating m watermark-embedded contents, and the embedded intensity map is also created sequentially, so that the intensity map writing process and reading process are minimal. Therefore, the disk capacity can be reduced.

  FIG. 6 is a diagram illustrating an example of a processing flow of the watermark information generation unit 111 in the video distribution server 101. The watermark information generation unit 111 determines watermark information uniquely corresponding to the user ID (uid) and adds it to the management data 120.

  As shown in the figure, in step S801, the watermark information generation unit 111 reads the user ID, and checks in step S802 whether the user ID overlaps with the user ID in the management data 120. If they overlap, this is output and the processing of the watermark information generation unit 111 is terminated. If not, in step S803, the watermark information generation unit 111 selects one piece of watermark information from the watermark information list and associates it with the user ID.

  Regarding the watermark information list generation processing in step S803, in the above-described conventional technology, according to the user ID of the distribution destination, for each of the n divided content elements, an ID is obtained by combining any of m types of watermark embedding elements. To deliver content.

  However, when the content is extended over a long period of time, the ID is generally repeatedly expressed for every fixed number of content elements. Assuming such use, the above-described conventional technology does not know which content element is the starting point of information, and may detect an incorrect ID. Also, even if the watermark embedding / detector side determines the first content element on the time axis as the start point of information, if the content is cut out in the time axis direction, an incorrect ID can be detected. There is sex.

  Therefore, the watermark information list generation process according to the present embodiment provides a watermark information generation process that can restore the user ID regardless of the content element extraction start position at the time of watermark detection. Specifically, regardless of the content element detection start position, watermark detection is performed from each of the n elements of the distributed content, and one ID is detected when any of the m types of watermarks is detected from each element. Provide a method that can identify

  In the present embodiment, the watermark information list is generated by reducing this process to a process for obtaining a pattern in which the vertices of a regular n-gon are painted in m colors. That is, the bit configuration is based on the bit arrangement order without depending on the starting point of the embedded information bits. Here, the number of watermark information is the number of patterns in which the vertices of a regular n-gon are painted with m colors.

  In step S804, the watermark information generation unit 111 checks whether the watermark information associated with the user ID overlaps with the watermark information in the management data 120. If they overlap, this is output and the processing of the watermark information generation unit 111 is terminated. If there is no overlap, the user ID and the watermark information are added to the management data 120 in step S805. At the same time, user-related information such as user affiliation and password may be added.

  FIG. 7 is a diagram illustrating an example of a processing flow of the detection information processing unit 152 in the digital watermark detection apparatus 103. The detection information processing unit 152 receives n pieces of watermark information from the digital watermark detection processing unit 151, and identifies a user ID from the watermark information. As described in the description of the watermark information generation unit 111, the detection information processing unit performs watermark detection from each of the n elements of the distributed content, regardless of the detection start position of the content element. When one of the types of watermarks is detected, it is possible to specify one ID. That is, the information on the content receiving side is specified based on the bit arrangement order without depending on the detected starting point of the information bits.

  7, in step S901, the detection information processing unit 152 reads n pieces of watermark information, accesses the management data 120 in the server 101 in step S902, and stores the watermark information in the management data 120. Check if the corresponding user ID exists. In this step, when the management data 120 in the server 101 is stored in the storage area of the detected information processing unit 152, the detected information processing unit 152 does not access the server 101 and performs confirmation processing in the processing unit. Do. If there is a corresponding user ID in step S902, the corresponding user ID is output in step S906, and the process of the detection information processing unit 152 is terminated. If there is no corresponding user ID, it is determined in step S903 whether n watermark information has been shifted a predetermined number of times (n times).

  Here, the watermark information shift processing is composed of n bits, each of which is composed of m kinds of elements, is shifted to the right (or left) by 1 bit, and the rightmost (left) end bit. Is the leftmost (right) bit. For example, when the watermark information is expressed as n = 6 elements and m = 2 types of watermark information = {100110}, the watermark information subjected to the right shift processing is {010011}, and the left shift processing is performed. The watermark information is {001101}. If the shift process is shifted by the watermark information length (n bits), the original watermark information is restored. In this step, whether the process of S902 has been performed on all of the assumed watermark information from the detected watermark information. Check.

  When n watermark information has been shifted a predetermined number of times (n times) in this step, in step S904, the fact that there is no corresponding user ID is output and the processing of the watermark information generating unit 111 is terminated. If n watermark information is not designated to be shifted a predetermined number of times (n times) in this step, the watermark information is shifted in step S905, and then the user corresponding to the management data is again in step S902. Check if there is an ID.

  As described above, according to the copyright protection system of the present embodiment, it is possible to ensure sufficient security while making the content distribution system simple in fingerprinting video and music content, and It is possible to solve problems specific to video and music.

It is a figure which shows schematic structure and the process sequence of the copyright protection system of this embodiment. It is a figure which shows schematic structure of the video delivery server apparatus (server 101) of this embodiment. It is a figure which shows schematic structure of the video reception client apparatus (client 102) of this embodiment. It is a figure which shows schematic structure of the digital watermark detection apparatus 103 of this embodiment. It is a figure which shows the processing flow of the watermark content production | generation part 113 in the video delivery server 101 of this embodiment. It is a figure which shows the processing flow of the watermark information generation part 111 in the video delivery server 101 of this embodiment. It is a figure which shows the processing flow of the detection information processing part 152 in the digital watermark detection apparatus 103 of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Server, 102 ... Client A, 103 ... Digital watermark detection apparatus, 110 ... User identification part, 111 ... Watermark information generation part, 112 ... Management part, 113 ... Watermark content creation part, 114 ... Distribution content control part, 115 ... Content distribution unit, 120 ... management data, 130 ... content decoding unit, 131 ... content reproduction unit, 150 ... content reception processing unit, 151 ... potential watermark detection processing unit, 152 ... detection information processing unit

Claims (11)

In the distribution method of content distributed from the transmission side to the reception side,
Generating digital watermark embedding information based on information on the receiving side;
A content element having a predetermined length is extracted from the content every predetermined time length, and m types (m is an integer of 1 or more) of electronic watermarks are embedded in the content element to generate m types of content elements. Steps,
Generating one content by combining the content and a content element in which the digital watermark is embedded based on the embedded information of the digital watermark;
And a step of transmitting the generated content to a receiving side. The content distribution method according to claim 1,
The step of generating the content element comprises:
Generating m types of digital watermark patterns independent of content;
Extracting a unit element from the content element, and performing a digital watermark embedding strength analysis of the unit element;
A content distribution method comprising: m types of digital watermark patterns; and embedding a digital watermark in the unit element from the intensity analysis result. The content distribution method according to claim 1,
The step of generating embedded information of the digital watermark includes:
A content distribution method comprising a step of generating embedded information having a bit configuration based on a bit arrangement order without depending on a starting point of embedded information bits. Generating digital watermark embedding information based on information on the receiving side;
Extracting a content element of a predetermined length from the content every predetermined time length;
Embedding m types (m is an integer of 1 or more) of electronic watermarks for one content element to generate m types of content elements;
Content generated by the step of combining the content and a content element embedded with a digital watermark based on the embedded information of the digital watermark. In an information detection method for detecting digital watermark information from content distributed from a transmission side to a reception side,
Extracting a content element of a predetermined length from the content every predetermined time length;
Detecting digital watermark information from each of the content elements;
A content distribution method comprising: a detection information processing step for identifying information on the content receiving side according to claim 1 from the detected digital watermark information. In the information detection method of Claim 5,
A detection information processing step for identifying information on the content receiving side from the detected digital watermark information,
A content distribution method comprising a step of identifying information on a content receiving side based on a bit arrangement order without depending on a detected starting point of information bits. In a content distribution apparatus that distributes data from a transmission side to a reception side,
A watermark information generating unit that generates embedded information of a digital watermark based on information on the receiving side;
A content element having a predetermined length is extracted from the content every predetermined time length, and m types (m is an integer of 1 or more) of electronic watermarks are embedded in each content element to generate m types of content elements. A watermark content creation unit;
A distribution content control unit that generates one content by combining the content and a content element in which the digital watermark is embedded based on the embedded information of the digital watermark;
And a content distribution unit that transmits the generated content to a receiving side. The content distribution apparatus according to claim 7,
The watermark content creation unit that generates the content element includes:
A watermark pattern generation unit that generates m types of digital watermark patterns independent of content;
An embedding strength analysis unit that extracts a unit element from the content element and performs an electronic watermark embedding strength analysis of the unit element;
A content distribution apparatus comprising: the m types of digital watermark patterns; and a digital watermark embedding processing unit that embeds a digital watermark in the unit element based on the strength analysis result. The content distribution apparatus according to claim 7,
The watermark information generating unit for generating the embedded information of the digital watermark is:
What is claimed is: 1. A content distribution apparatus comprising: a generation unit that generates embedded information that has a bit configuration based on a bit arrangement order without depending on a starting point of embedded information bits. A content reception processing unit for extracting a content element of a predetermined length from the content in a certain time length in the information detection apparatus for detecting digital watermark information from the content distributed from the transmission side to the reception side;
A digital watermark detection processing unit for detecting digital watermark information from each of the content elements;
A content distribution apparatus comprising: a detection information processing unit that identifies information on a content receiving side according to claim 1 from the detected digital watermark information. The information detection device according to claim 10,
A detection information processing unit that identifies information on the content receiving side from the detected digital watermark information,
What is claimed is: 1. A content distribution apparatus comprising: a processing unit that identifies information on a content receiving side based on a bit arrangement order without depending on a detected starting point of information bits.

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