JP2002236669A - Contents sales system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate selling and distributing contents while preventing the unauthorized use of the contents. SOLUTION: In a user terminal 2, a purchaser ID is embedded into the contents related to animation as an invisible electronic watermark 1, and a 'sample' which presents trial is embedded as a visible electronic watermark 2. When the contents which are previewed or auditioned are purchased formally, a dedicated secret key is received from the user terminal 2, and the electronic watermark 2 is removed by using the secret key. If the secret key is not obtained, a character of the 'sample' is always displayed on the contents to reduce the commercial value of the contents. If the contents are reproduced and sold even if the contents are purchased properly, the unauthorized purchaser can be identified by detecting the electronic watermark 1 embedded into the contents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to, for example, moving images,
In the sale and distribution of content related to audio signals, etc., while preventing unauthorized use of content,
The present invention relates to a content sales system capable of distribution.

[0002]

2. Description of the Related Art There are three main sales forms for selling contents such as moving images and audio signals.

[0003] In the first sales form, a purchaser requests a content owner by telephone or network.
This is a form in which a purchase application is made, and a medium on which the content is recorded is delivered by mail or the like and sold.

[0004] In a second sales form, for previewing and listening to a purchaser, once the content whose information amount has been reduced is transmitted over a network or the like and the purchase intention can be confirmed,
In this form, all of the original content information is transmitted and sold.

[0005] In a third sales mode, the content can be reproduced only by dedicated software, and only a part of the content can be reproduced at the preview / listening stage. The requested content is transmitted in response to a request for previewing / listening of the purchaser, and when the purchase intention is confirmed, information for removing the restriction is transmitted to the purchaser, and the entire content is used based on the information. (Japanese Unexamined Patent Publication No. 2000-99010)
Reference).

[0006]

However, the conventional contents sales system has various disadvantages.

First, in the first sales form, previewing and auditioning are impossible, and even if returned, the transportation cost is borne by the purchaser. In the second sales form, even if content for previewing and previewing is transmitted with a reduced amount of information, the same content must be transmitted again when purchasing, resulting in a large amount of information transmission. Become.

In the third embodiment, the content can be reproduced only by the dedicated software, and the use of the content may be restricted. As described above, it is necessary to eliminate the inconvenience of these sales forms, identify the content and the person who wants to purchase the content, and facilitate the copy protection.

[0009] The present invention has been made in view of the above points, and it is an object of the present invention to provide a content distribution system capable of easily selling and distributing content while preventing unauthorized use of the content. .

[0010]

Therefore, the content sales system according to the first aspect of the present invention provides an owner terminal used by an owner of a content related to the contents of various types of information, and a purchase terminal used by a content purchaser. And a content terminal, wherein the content terminal is configured to allow the content to be properly sold from a content owner to a content purchase applicant, wherein the owner terminal hides a predetermined first digital watermark. Using the first method of embedding in the content so that it can be detected only by a specific method,
A first digital watermark embedding unit that embeds information for specifying a purchaser of the content as a first digital watermark in the content to be sold, and a predetermined second digital watermark is made visible and audible. In addition, using the second technique of embedding in the content so that the content can be separated only by the dedicated secret key, information indicating trial use is used as the second digital watermark in the content in which the first digital watermark is embedded. And a second digital watermark embedding means for embedding.

[0011] According to this configuration, the information for specifying the purchaser of the content as the first digital watermark is added to the content to be sold relating to the content of various information by the first digital watermark embedding means. Embedded using the method described above. The first digital watermark embedded in this manner is embedded in the content as a hidden watermark, is invisible and inaudible information that cannot be distinguished from the content by human vision or hearing, and is only used in a specific method. This is information that can be detected. Also, since information for identifying a purchaser of the content is embedded in the content as a first digital watermark, if the purchaser illegally copies the purchased content, the first digital watermark is identified by a specific method. , The purchaser of the content is specified.

[0012] Further, information indicating that the content is a trial as a second digital watermark is added to the content in which the first digital watermark is embedded by the second digital watermark embedding means.
Embedded using the method described above. The second digital watermark embedded in this way is visible and audible, and is identified as content by human vision and hearing. The second digital watermark can be separated from the content by using a dedicated secret key, and the second digital watermark can be removed by obtaining the dedicated secret key. However, even if an attempt is made to illegally use the content without obtaining the secret key, the second digital watermark is always displayed or heard along with the content.

[0013] In the content selling system according to the second aspect of the present invention, the purchaser terminal uses the secret key distributed by the copyright holder of the content to embed the first digital watermark and the second digital watermark. Second from content
And a content conversion unit for converting the digital watermark into content in which only the first digital watermark is embedded.

According to this configuration, the secret key is a valid one distributed by the copyright holder of the content, and the content conversion means uses this secret key to
The second digital watermark information is separated and removed from the content in which the first digital watermark information and the second digital watermark information are embedded, and is converted into the content in which only the first digital watermark information is embedded. Therefore, upon receiving this secret key, the purchaser of the content becomes a valid purchase right holder.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment. In FIG. 1, the Internet 1 is a communication path for transmitting moving image / audio signals or content paired with them. Note that this communication path is not limited to the Internet 1, and may be, for example, satellite communication.

The Internet 1 has an owner terminal 2 used by a content owner who is a copyright holder of the content (hereinafter, referred to as “content provider”),
And a purchaser terminal 3 used by a purchaser of the content.

The owner terminal 2 embeds an invisible / inaudible digital watermark 1 (first digital watermark) and a visible / audible digital watermark 2 (second digital watermark), which will be described later, in the content. This is a terminal for transmitting to the purchaser terminal 3. The owner terminal 2 has a database (not shown) for storing moving image / audio signals or content paired with them, and a database for storing a secret key for removing the digital watermark 2 (FIG. (Not shown).

The purchaser terminal 3 previews from the owner terminal 2,
A terminal for receiving preview content, previewing and previewing the content, and receiving a private key at the time of purchase and removing the digital watermark 2. The purchaser terminal 3 has dedicated software for this purpose. Is installed.

Next, the operation will be described. FIG. 2 is a schematic explanatory diagram showing a series of procedures according to the first embodiment. First, the content provider receives the viewing request of the purchaser. In response to the viewing request, the content provider fetches, for example, the content related to the video and audio archives, and adds an invisible / inaudible digital watermark 1,
A visible / audible digital watermark 2 is embedded and transmitted to the purchaser.

[0020] The purchaser previews this content.
When the user wants to audition and purchase, the content provider is requested to purchase the content. The content provider sells the secret key in response to the purchase request of the buyer. Then, the purchaser uses the secret key to remove the digital watermark 2 from the content, and uses the content legitimately.

Next, the operation of the owner terminal 2 and the purchaser terminal 3 for executing such a procedure will be described. FIG. 3 is a flowchart showing the operation of the owner terminal 2. In the step (in the figure, the step is referred to as “S”), a moving image,
Content related to the audio signal is stored in the database.
In this way, the contents relating to the video and audio archives as shown in FIG.

In step 2, the digital watermark 1 invisible and inaudible to humans is embedded as hidden watermark in the contents to be sold. As the digital watermark 1 to be embedded, information for specifying a purchaser of the content, such as a purchaser ID (identifier) shown in FIG. 2, is used.

There are various methods for embedding the digital watermark 1 in the content. For example, the following method is used. That is, when the content is based on a moving image signal, a method of performing frequency conversion, adding watermark information to the frequency domain, and performing inverse frequency conversion is used (for example, Onishi and Matsui, “Multi-resolution analysis and PN Digital watermarking method using sequences ", 1997, IEICE Transactions D-II, Vol. J80-D-II, No. 11pp3020-3028).

When the content relates to an audio signal, for example, Japanese Patent Application No. 2000-245387 (“Acoustic transmission device and audio signal transmission method, and
Data Extraction Apparatus and Data Extraction Method for Extracting Embedded Data of Audio Signal ").

According to this method, first, the digital audio signals of the L and R channels are divided into frames of a fixed time length. Next, the “embedded data” is encoded to create an impulse response function, and the created impulse response function and L
A convolution operation is performed on the channel audio signal, and the result of the convolution operation and the R-channel audio signal are added and synthesized. Thereby, “embedded data” is embedded in the R channel. Finally, the respective frames of the R channel digital audio signal and the original L channel digital audio signal in which the “embedded data” is embedded are synthesized.

By embedding the purchaser ID using such a method, even if the content of this content is viewed or heard, the embedded purchaser ID is invisible and inaudible, The purchaser ID cannot be identified, and the content of the content is not affected. These methods correspond to a first method, and step 2 corresponds to a first digital watermark embedding unit.

In step 3, a visible / audible digital watermark 2 is embedded in the content. In the digital watermark 2 to be embedded, for example, as shown in FIG.
Information indicating that the content is for previewing / listening is used.

There are various methods for embedding the digital watermark 2 in the content. For example, the following method is used. That is, when the content is based on a moving image signal, the method disclosed in Japanese Patent Application Laid-Open No. 2000-216982 (“Image Processing System and Recording Medium”) is used.

According to this method, the original image is subjected to color space conversion, is divided into a luminance plane and other planes, and, for example, a higher-order bit is assigned to each pixel value bit in a specific area of the separated luminance plane. The shift processing is performed from the bit to the lower bit, and the most significant bit is replaced with the bit value of the binary image as the digital watermark 2. Then, the inverse conversion of the color space is performed. Thus, an image in which the digital watermark 2 is inserted is obtained.

When the content is based on an audio signal, for example, the above-mentioned Japanese Patent Application No. 2000-24538 is used.
Using the technique of No. 7, the embedding level when the digital watermark 1 is inserted is changed. This makes it possible to insert the digital watermark 2.

The following is an example of changing the embedding level. That is, first, L,
The R-channel digital audio signal is sequentially divided into frames of a fixed time length (for example, set so that a sufficient pulse train can be estimated at the time of extraction as described later) in an embedding-side frame dividing unit (not shown). I do. Next, the embedded data and the key information are input to an impulse response creation unit (not shown), and an impulse response function is created. The impulse response function is a uniform random number sequence having a predetermined seed number and a delay time based on the first frame, and is composed of pulses corresponding to embedded data having a predetermined amplitude. This seed number is stored as key information for use at the time of extraction. Furthermore, a convolution operation is performed by a convolution operation unit (not shown) on the impulse response function created by encoding the embedded data and the L-channel acoustic signal for each frame divided by the frame division unit. Create an embedded audio signal. By performing the same operation for each frame, the embedding level can be changed.

Since the impulse response function is a pulse train corresponding to the embedded data, the impulse response function corresponding to the embedded data is referred to as a digital watermark 2 at a position temporally separated from the impulse response function of the digital watermark 1. Can be embedded. Thereby, the digital watermark 1
, The digital watermark 2 can be embedded. In order to remove the digital watermark 2, the digital watermark 2
This is achieved by embedding the inverse function of the impulse response function embedded as

It is preferable that the embedding of the digital watermark 2 is an area or a part related to the essence of the content so that the commercial value at the time of preview and preview is reduced. For example, if the content is related to a moving image, the embedding area of the digital watermark 2 is a caption or the like. If the content is related to an audio signal, the embedding part of the digital watermark 2 is described in Japanese commentary. Etc. are the parts that significantly deteriorate the signal. These methods correspond to the second method, and step 3 corresponds to a second digital watermark embedding unit.

In step 4, a secret key is created. This secret key is a dedicated key held by the copyright holder of the content, and is used to generate a digital watermark 2 from the content for previewing and previewing.
Is the key to getting rid of The secret key is, for example, a description of the seed number of the impulse response function, the time position in which the digital watermark 1 is embedded, and the time position in which the digital watermark 2 is embedded. You.

In step 5, the created secret key is stored in the database. In step 6, the content in which the digital watermark 1 and the digital watermark 2 are embedded is transmitted to the purchaser terminal 3 via the Internet 1. In this way,
The content provider provides content for previewing and previewing to the purchaser in response to the purchaser's viewing request.

FIG. 4 is a flowchart showing the operation of the purchaser terminal 3 to which the content is transmitted. Step 1
In step 1, the preview / preview content transmitted from the owner terminal 2 is received. At step 12, the received content is previewed and previewed. Preview of this content
After performing the audition, the user of the purchaser terminal 3 decides whether to purchase or not, and inputs the decision to the purchaser terminal 3.

If it is determined in step 13 that there is no purchase intention, the processing is terminated here without executing steps 14 to 16. At this time, the preview / preview content is discarded by the user of the purchaser terminal 3, but the user of the purchaser terminal 3 that has received the preview / preview content without wishing to purchase the content for the preview / preview. Even if an attempt is made to illegally use the content, since the digital watermark 2 is embedded in the subtitles, Japanese commentary, and other areas related to the essence of the content, the commercial value of the content is reduced, thereby preventing unauthorized use of the content. Is prevented. On the other hand, if it is determined in step 13 that there is a purchase intention, the process proceeds to step 14.

In step 14, a content purchase request is transmitted to the owner terminal 2. The content provider transmits a secret key in response to the purchase request from the purchaser. In this way, the original purpose content is
Since it has already been transmitted for trial use and trial listening, when a purchase request is made by a purchase applicant, only a secret key is transmitted. The purchaser pays a fee necessary for purchasing the content when obtaining the secret key.

In step 15, the secret key transmitted from the owner terminal 2 is received. The secret key is a dedicated key held by the copyright holder of the content, as described above, and a purchaser of the content becomes a valid purchaser of the content when receiving the secret key. .

In step 16, the digital watermark 2 is removed from the content using the secret key. Digital watermark 2
Is removed from the previewed / listened content by the purchaser of the content using dedicated software in accordance with the secret key. As a result, the purchaser of the content can use all of the original purpose, for example, the content for language learning. Step 16 corresponds to a content conversion unit.

Even if the digital watermark 2 is removed from the content, since the invisible and inaudible digital watermark 1 is embedded in the content, the content purchased by the purchaser is illegally copied and sold. In such a case, by detecting the digital watermark 1 from the illegally copied content, the unauthorized user can be traced.

For example, when the technique described in Japanese Patent Application No. 2000-245387 is used, to detect the embedded digital watermark 1, first, the L channel audio signal and the R channel audio signal are synchronized. Then, the synchronized audio signals of both channels are divided into the same frame at the time of embedding using the frame division information at the time of embedding, and the L-channel audio signal and the corresponding R-channel audio signal frame are cross-spectrum-divided. Each impulse response function is estimated using the method.

The detection of the “embedded data” is based on the time of the head frame of the estimated impulse response audio signal, and the “embedded data” is set in accordance with the uniform random number of the seed number whose delay time is known. Is performed by examining whether or not there is a pulse with a delay time corresponding to ".""Embeddeddata" detected in this way
Is the digital watermark 1.

Since the digital watermark 1 is a purchaser ID, the purchaser can be determined based on the purchaser ID. Can be identified.

According to this configuration, the purchaser ID is embedded as invisible / inaudible digital watermark 1 in the content, and information indicating preview / audition is embedded as visible / audible digital watermark 2 in the content. Before purchasing content, you can preview and listen to the same content that you want to purchase in the sale and distribution of content related to moving images, audio signals, etc., and also preview the content. -Listening and purchasing can be performed in one transmission. In addition, no special device is required for the reproduction, and the reproduction can be easily performed without any special restrictions.

If the secret key is obtained from the copyright holder of the content, the digital watermark 2 can be easily removed from the content by using the secret key, so that the authorized purchaser of the content can use the purchased content properly. can do.

On the other hand, if the secret key is not obtained from the copyright holder of the content, the digital watermark 2 cannot be removed from the content, and the digital watermark 2 is visible and audible, and a portion related to the essence of the content. Embedded in the content, the product value of the content is reduced, and illegal copying of the content by unauthorized users who do not have the secret key can be suppressed, so that unauthorized use of the content can be easily prevented. .

Further, even if a purchaser who has just purchased the content once illegally copies or sells the content, the invisible / inaudible digital watermark 1 can be obtained.
Is embedded in the content, and therefore, by detecting this digital watermark 1 by a specific method, it is possible to easily identify a purchaser who has illegally copied, sold, or the like.

The method of embedding the digital watermark 1 in the content is not limited to the above-described one. If the invisible and inaudible digital watermark 1 can be embedded in the content,
Any method may be used. The same applies to the digital watermark 2, and any method may be used as long as a visible and audible digital watermark 2 can be embedded in the content.

The digital watermarks 1 and 2 are not limited to the above-mentioned information, but can be used to specify a purchaser of the content and to know that the content is for previewing / listening. Information may be used.

[0051]

As described above, according to the content sales system of the first aspect of the present invention, information for specifying a purchaser of the content is added to the content related to the various types of information by the first digital watermark. Embedded as a hidden watermark, and information indicating that it is a trial
The digital watermark is embedded so that it is visible and audible, so in the sale and distribution of content, the same content as the one you want to purchase can be previewed and previewed before purchasing the content. Previewing / listening and purchasing can be performed in one transmission. In addition, no special device is required for the reproduction, and the reproduction can be easily performed without any special restrictions.

Also, if a dedicated secret key is obtained, the digital watermark 2 can be removed from the content and the content can be used properly. If the secret key is not obtained, the digital watermark 2 is removed from the content. As a result, the merchandise value of the content is reduced, so that unauthorized use of the content can be easily prevented. In addition, if the content is illegally copied by the buyer who obtained the private key,
By detecting the first digital watermark embedded in the content, it is possible to track the purchaser who has been illegally copied.

According to the content selling system of the second aspect, the second digital watermark is removed using the secret key distributed by the copyright holder of the content. Applicants can be identified as legitimate buyers.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing a series of procedures according to the first embodiment.

FIG. 3 is a flowchart illustrating an operation of the owner terminal according to the first embodiment.

FIG. 4 is a flowchart illustrating an operation of a purchaser terminal according to the first embodiment.

[Explanation of symbols]

 1 Internet 2 Owner terminal 3 Buyer terminal

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G10K 15/02 G10K 15/02 5C076 G10L 11/00 H04N 1/387 H04N 1/387 7/173 640Z 7 / 08 G10L 9/00 E 7/081 H04N 7/08 Z 7/173 640 (72) Inventor Seiichi Koshi 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Technical Research Institute (72) Inventor Hitoshi Ogawa 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Research Institute (72) Inventor Hajinobu Mizutani 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation F-Term (Reference) 5B017 AA06 BA09 CA16 5B057 AA20 BA01 CE08 CE09 CG07 CG09 DA08 5B085 BE07 5C063 AA01 AB03 AC01 AC05 AC10 CA23 CA36 DA07 DA13 DB09 5C064 BA07 BB02 BC06 BC18 BC22 BC23 BD02 BD 08 BD09 5C076 AA14 AA40 BA06

Claims (2)

[Claims] Claims 1. A content terminal having an owner terminal used by a content owner and a purchaser terminal used by a content purchaser related to the content of various information, wherein the content is valid from the content owner to a content purchaser. The owner terminal, wherein the owner terminal embeds in the content such that the predetermined first digital watermark is concealed as a hidden watermark and can be detected only by a specific method. A first digital watermark embedding unit that embeds information for specifying a purchaser of the content as a first digital watermark in the content to be sold, and a predetermined second digital watermark that is visible and audible And a second method for embedding the first digital watermark in the content so that the first digital watermark can be separated only by a dedicated secret key. Content sales system characterized by comprising a content that is a second electronic watermark embedding means for embedding the information as a second electronic watermark indicating the trial, the. 2. The purchaser terminal separates a second digital watermark from the content in which the first digital watermark and the second digital watermark are embedded, using a secret key distributed by a copyright holder of the content. 2. The content sales system according to claim 1, further comprising a content conversion unit that converts the content into a content in which only the first digital watermark is embedded.