JP2005051735A - Copyright protection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure sufficient security while simply configuring a content distribution system composed of a server and a plurality of clients in finger printing for video or music contents. <P>SOLUTION: A content distribution server divides contents into (n) content elements, inserts (m) kinds of electronic watermarks to the relevant elements, generates and transmits a play list corresponding to a user ID. A video receiving client acquires the play list, receives and reproduces the contents. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a content copyright protection system, and more particularly to a technique for identifying a user by a digital watermark inserted into video or music content.

  Digital watermarking is a technology that inserts information into content made up of digital data, such as video and music, and detects the inserted information from the content. Information is inserted by making minor changes to the content. The information is represented by the changed location and the changed content. Therefore, the original content and the content into which the information is inserted feel the same for human vision and hearing, but are slightly different. In the information detection, the inserted information is detected by reading the changes made to the content.

  The digital watermark has the following characteristics. Embed information directly rather than 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 inserted information can be detected by re-digitization.

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 surveyed content. As a result, since it is determined that the copy is illegal, there is a deterrent effect for a user who considers illegal copy.
(B) Tracking illegal copyrs:
Before distributing the content to the user or viewing the content, 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 inserting the user ID into the content of (B) with a digital watermark has a great deterrent power against the user who tries to copy the content illegally compared to (A).

  In content distribution, the method of using (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 inserted into the content.

(B1) Inserting a digital watermark on the client side In the conventional method, since a watermark embedding device is placed at the user's hand, the digital watermark algorithm is deciphered, and there is a problem that the risk of forgery or tampering appears. there were. For this reason, it has been difficult to ensure security, such as taking tamper resistance measures on the viewing terminal on the client side.

(B2) When inserting a 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 heavy load and cannot cope with simultaneous access by many users.

  Here, there is a technique described in Non-Patent Document 1 as a conventional technique in the case of inserting a digital watermark (B2) on the server side.

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

  On the other hand, there is a technique described in Patent Document 1 as a conventional technique to which Non-Patent Document 1 is applied.

  In the technique described in Non-Patent Document 1 described above, when 2n content elements are prepared on the server side, [C1X, C1Y, C2X, C2Y, ..., CnX, CnY] Encrypt with separate keys. Here, the key that encrypted C1X is described as KC1X, and the key that encrypted C1Y is described as KC1Y. After all this preparation, all the elements [C1X, C1Y, C2X, C2Y, ..., CnX, CnY] are stored on the medium and distributed. A separate key ring is given to each user. When a key ring A (KC1X, KC2X, KC3Y, KC4X, KC5Y,..., KCnX) is passed to a user A who has obtained this medium, the contents A [C1X, C2X, C3Y, C4X, C5Y,. • Only CnX] can be decoded and viewed. Similarly, another key ring B that can decrypt only the content B [C1X, C2Y, C3X, C4X, C5X,..., CnX] is passed to another user B. When distributing the content, by leaving a delivery record of the key ring, the user who decrypted the content can be identified by examining the elements of the content to be investigated.

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.

JP 2003-78520 A

  The technique described in Non-Patent Document 1 described above is intended to provide a technique that prevents illegal cancellation of digital watermark information and embedding of fake digital watermark information, assuming multicast distribution of content. For this reason, encryption technology and digital watermark technology are excessively linked. This technique is equivalent to the process of inserting a digital watermark at the moment the cipher is unwound, and it is difficult for a user who considers illegal copying to obtain content before inserting the digital watermark by digital capture after decryption.

  For this reason, a key ring composed of a plurality of keys is required to unwrap one content, and the key ring itself must be encrypted with another key.

  Furthermore, although the technology described in Non-Patent Document 1 discloses still image content, it does not describe video and music content. Compared to still images, a new technology was needed to deal with problems specific to video and music, such as a dramatic increase in data volume.

  The present invention provides a technology for ensuring sufficient security in a copyright protection system for video and music content, with a simple system configuration.

  The present invention also provides a technology for solving problems unique to video and music in a copyright protection system for video and music content.

  In other words, in the video content, there is a possibility that the commercial video of the sponsor according to the region may be sandwiched in the middle of the distribution route, and in the net distribution, the commercial is dynamically sandwiched according to the user's preference. Sometimes. The present invention provides a copyright protection system that can cope with a case where another video is inserted into the video content as described above.

  In addition, since video content is large-capacity data composed of a plurality of frames, frames may be dropped or block noise may occur during playback depending on the communication path and the load on the player. The present invention provides a copyright protection system in which the value of an embedded user ID does not go wrong even when such a video failure occurs.

  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.

In a preferred embodiment of the present invention, the video copyright protection system includes a video distribution server device, a video reception client device, and a fingerprint detection device.
(1) The video distribution server includes the following steps.
(A) Advance preparation-Step of dividing video content into n video elements-Step of creating m video elements with different digital watermarks inserted for each video element-N * m video elements with the same key Step of encryption with (user ID can be expressed as m to the power of n)
(B) A step of receiving a license / content distribution / user request and transmitting a license including the key / a step of generating and transmitting a playlist corresponding to the user ID / a sequence of encryption according to the distribution order of the playlist The step of transmitting the video element that has been made may be associated with information related to the client (request time, request content, etc.) regarding the generation of the playlist.
(2) In response to the video distribution server, the video reception client transmits a content request, acquires a license, acquires a playlist, and receives the content. Further, the obtained license is used to decrypt the video element so that it can be viewed.
(3) The fingerprint detection device receives the video content to be investigated, divides it into n video elements, and detects digital watermark information that becomes a fingerprint from each of the n elements. The user ID embedded from the detected information is restored, and the unauthorized copy outflow source is specified. Hereinafter, the fingerprint detection device is referred to as a digital watermark detection device.

  According to the present invention, it is possible to ensure sufficient security while simplifying a content distribution system for video and music content, and to solve problems unique to video and music.

  An embodiment relating to the present invention will be described below.

  FIG. 1 is a diagram showing a schematic configuration of the present embodiment. As shown in FIG. 1, the application form of the present embodiment is a video distribution server device (hereinafter referred to as a server) 101 and a plurality of video reception client devices (hereinafter referred to as clients). As an example, this embodiment has a client A 102 and a client B 103).

  Note that each device according to the present embodiment includes, for example, a CPU, a memory, a removable reading medium such as a CD-ROM or DVD-ROM, and a reading device that reads information from a portable storage medium, via 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 when the CPU executes a program stored in an external storage device or memory. The program may be stored in advance in the information processing apparatus, and when necessary, the program may be a removable storage medium that can be used by the information processing apparatus or a network or a carrier wave that propagates over the network. The information processing apparatus may be introduced via a usable communication medium. Also, some or all of the functions of each device may be realized by hardware.

  FIG. 4 is a diagram showing a schematic configuration of the video distribution server apparatus 101 (hereinafter referred to as a server) of the present embodiment. As shown in FIG. 4, the server 101 of this embodiment can be 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. it can.

  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 CPU 301 executes the user identification unit 110, the management unit 111, the content creation unit 112, the playlist issue unit 113, the content distribution unit 114, and the playlist concealment unit 115 in the memory 206. A program to be realized on the server 101 is stored.

  FIG. 5 is a diagram showing a schematic configuration of the video reception client device 102 (hereinafter referred to as a client) of the present embodiment. As shown in FIG. 5, 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.

  In addition, the client 102 stores a program that realizes the playlist control unit 130 and the content reproduction unit 131 on the client 102 by being executed by the CPU 301.

  As shown in FIG. 1, as a preliminary preparation, the server 101 divides video content into n video elements, creates m video elements into which different digital watermarks are inserted for each video element, and creates n * m video elements. Are stored in the content storage unit 116 in the storage area 207. The video element may be stored after being encrypted with the same key. To create m types of video elements, m types of watermark information may be inserted according to one digital watermark algorithm, or one watermark information may be inserted according to m types of different watermark algorithms. These may be used together.

  A processing flowchart of the server 101 is shown in FIG. Hereinafter, the processing flow of the server 101 will be described with reference to FIGS.

  After the above-described advance preparation is completed, the server 101 receives a content distribution request from the user (S701).

  Next, the user identification unit 110 in the server 101 receives the user ID (uid = A) 124 and the password (pwd) 125 from the client A102, and the user ID in the management data 120 registered in the management unit 111 in advance. And a password are identified, and a user is identified (identified as uid = A in this case) (S702). After specifying the user, the server 101 accepts the user request. When the video element is encrypted at the time of advance preparation, a license including the encryption key may be transmitted to the client A102.

  Next, the management unit 111 calls watermark information (in this case, WM = 110...) Uniquely corresponding to the user ID from the management data 120 based on the identified user ID 124 and transmits it to the playlist issuing unit 113 ( S703).

  The playlist issuing unit 113 receives the user ID 124 and the watermark information 126, and generates a playlist 121 of the video element from the information. The playlist 121 is represented by the playback order of video elements and information (for example, URL on the Internet) that identifies video elements that are played back in each order. The generated playlist 121 is transmitted to the playlist concealment unit 115 (S704).

  The playlist concealment unit 115 receives the playlist 121 and conceals the playlist based on the user ID 124. As an example of concealment, there is encryption of information for specifying video elements to be reproduced in each order in a playlist. A key generated based on the user ID may be used as a key at the time of encryption. The playlist concealment unit 115 generates the concealed playlist 122 by the concealment process and transmits it to the client A102 (concealed playlist transmission 140) (S705).

  Here, regarding the concealment of the play list 121 and the transmission to the client, the play list 121 may be stored in the server without performing the processing. In this case, when a video content reproduction request is made from the client, the user authentication is performed, the playlist corresponding to the user ID 124 is selected, and the video element selected according to the playlist is transmitted to the user.

  On the other hand, after receiving the concealed playlist 130 in response to the server 101, the client A102 makes a video content playback request (request 141). When the video element is encrypted on the server side, in addition to the concealed playlist, a license including the encryption key is also received. Details of the reception and playback request are executed by the playlist control unit 130 in the client A 102 receiving the hidden playlist 122 and transmitting the hidden playlist 122 together with the playback request to the server 101. When user information is necessary for canceling the concealment of a playlist, user authentication information may be transmitted in addition to the transmission information when a reproduction is requested.

  Next, the server 101 receives the concealed playlist 122 together with the reproduction request from the client A102 (S706). The playlist concealment is canceled by the playlist concealment unit in the server 101. As described above, when user information is required to cancel the concealment of the playlist, user authentication information (user ID, password) is received from the client A102, and the concealment of the playlist is canceled based on the authentication information. As a result of the release of the concealment, the playlist 121 is restored, and information specifying the playback order of the video elements in the playlist and the video elements to be played back in each order is transmitted to the content distribution unit 114.

  The content distribution unit 114 selects a video element from the content storage unit 116 based on the information relating to the video element, and distributes the selected series of video elements to the client as video content 123 ( S707).

  That is, consider content C that forms one content with n elements [C1, C2,..., Cn]. For each of these n elements, two types of watermark information (watermark information X, watermark information Y) are inserted to create two element groups that look the same for humans. An element group similar to C1 is defined as C1X and C1Y, and similarly, a total of 2n elements are prepared on the server side. When delivering content from the server, the content is delivered by combining either X or Y elements for each of the n elements according to the user ID of the delivery destination. According to the above method, it is not necessary to insert an individual user ID by digital watermark at the time of content distribution, and it is possible to reduce the processing at the time of distribution.

  The client A 102 receives the video content 123 distributed from the server 101, reproduces the video content with the content reproduction unit 103 in the client A 102, and allows the user to view it. If a series of video elements constituting the content is encrypted, the content reproduction unit 103 decrypts the video elements based on the license information received from the server 101 first, and then Reproduce.

  Similarly, another client (for example, client B103 in the figure) responds to the server 101 to transmit a content request, acquire a license, acquire a playlist corresponding to the user ID, and receive the content.

  When the video content distributed to the client is illegally leaked from the client, the digital watermark detection apparatus 104 receives the content to be investigated and identifies the illegal copy leak source from the content. Examples of unauthorized leakage of content by the client 102 include an act of extracting the content developed in the memory 306 (an act of storing the content in another storage medium or another device) or an output to the monitor via the output device 304 One example is the distribution of acquired content via a network through an action of capturing content (monitor shooting with a digital camera).

  FIG. 6 is a diagram showing a schematic configuration of the digital watermark detection apparatus 104 of the present embodiment. As shown in FIG. 6, the digital watermark detection apparatus 104 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 104. 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 memory 606 stores a program for executing the content reception processing unit 150, the digital watermark detection processing unit 151, and the detection information processing unit 152 on the digital watermark detection device 104 by being executed by the CPU 601. .

  A processing flowchart of the digital watermark detection apparatus 104 is shown in FIG. The processing flow of the digital watermark detection apparatus 104 will be described below with reference to FIG.

  The content reception processing unit 150 receives the content to be investigated and stores it in the storage area 607 (S801).

  The digital watermark detection processing unit 151 divides the video content into n video elements according to the digital watermark detection method shown in FIG. 3, and detects a digital watermark from each of the n elements (S802).

  Based on the management data 120 stored in the storage area 607 in advance, the detection information processing unit 152 identifies the user ID of the video content, that is, the user ID of the illegal leak source from the information detected by the digital watermark detection processing unit 151. (S803). The user ID is not necessarily specified by the digital watermark detection apparatus 104. The digital watermark detection apparatus 104 may transmit the detection information to the server 101, and the server 101 may specify the user ID.

  The watermark detection processing unit transmits the specified user ID information or all the detected information to the server 101 (S804).

  In addition to the above-described identification of the unauthorized person's user ID, the digital watermark detection apparatus 104 may also specify the distribution server of the video content. In this case, in the server 101, as advance preparation, in addition to the process of inserting m types of digital watermarks into n video elements constituting the video content, a digital watermark that can identify the server ID is additionally inserted. It is necessary to keep it.

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

It is a figure which shows schematic structure and the process sequence of the copyright protection system of this embodiment. It is a figure explaining the digital watermark insertion method of this embodiment. It is a figure explaining the digital watermark detection method of this embodiment. It is a figure which shows schematic structure of the server 101 of this embodiment. It is a figure which shows schematic structure of the client 102 of this embodiment. It is a figure which shows schematic structure of the digital watermark detection apparatus 104 of this embodiment. It is a figure which shows the processing flow of the server 101 of this embodiment. It is a figure which shows the processing flow of the digital watermark detection apparatus 104 of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Server, 102 ... Client A, 103 ... Client B, 110 ... User identification part, 111 ... Management part, 112 ... Content creation part, 113 ... Playlist issue part, 114 ... Content distribution part, 115 ... Playlist concealment part 116 ... Content storage unit 120 ... Management data 121 ... Playlist 122 ... Hidden playlist 123 ... Content 130 ... Playlist control unit 131 ... Content playback unit

Claims (16)

In a content distribution method for distributing content from a transmitting device to a receiving device,
Dividing the content into n content elements (n is an integer greater than or equal to 1);
Inserting m types (m is an integer of 1 or more) of electronic watermarks into the content element to generate n × m types of content elements;
Selecting a content element corresponding to the information on the receiving device and generating a list for identifying the selected element;
Identifying a content element based on the list, and delivering the identified content element to the receiving device. The content distribution method according to claim 1,
Generating the content element comprises:
A content encryption step for encrypting the content element with the same key after generating the content element;
An encryption information transmission step of transmitting information related to the encryption key to the receiving device;
And an encrypted content transmission step of transmitting the encrypted content element to the receiving device. The content distribution method according to claim 1,
The step of generating the content element specific list includes:
A list hiding step for hiding information in the list so that the content element cannot be identified from the list after the list is generated;
A concealment list transmission step of transmitting the concealed list to the receiving side device;
Receiving the list from the receiving side device; and, if the list is concealed, has a list receiving and concealment releasing step for releasing concealment In a method for receiving content distributed from a transmitting device to a receiving device,
A request information transmission step for transmitting information specifying the receiving device and information relating to a content transmission request to the transmitting device;
The content distribution method according to claim 1, further comprising: a content element reproduction step of receiving and reproducing the specified content element transmitted from the transmission side device. The content receiving method according to claim 4, wherein:
The request information transmission step includes:
An encrypted information receiving step for receiving encrypted information of the content according to claim 2 after transmitting the request information;
In the content element playback step,
A content decrypting step of decrypting the encrypted content based on the encrypted information after receiving the encrypted content according to claim 2;
A decryption content element reproduction step for reproducing the decryption content element. The content receiving method according to claim 4, wherein:
The request information transmission step includes:
A concealment list receiving step for receiving the concealment list according to claim 3 after transmitting the request information;
A concealment list transmission step of transmitting the received concealment list to the transmission side device. The content receiving method according to claim 6,
The hidden list receiving step includes:
Receiving in addition to the concealment list from the transmitting side device information related to concealment of the concealment list;
A concealment list releasing step for canceling concealment of the concealment list based on the information concerning the concealment;
A list transmission step of transmitting the list from which the concealment has been released to the transmission side device. In an information detection method for detecting digital watermark information from content distributed from a transmission side device to a reception side device,
A content receiving step for receiving the content;
Dividing the content into n content elements (n is an integer greater than or equal to 1);
A receiving-side device specifying step for detecting digital watermark information from each of the content elements and specifying information on the receiving-side device according to claim 1. In a content distribution device distributed from a transmission side device to a reception side device,
A content dividing unit that divides the content into n (n is an integer of 1 or more) content elements;
A content creation unit that inserts m types (m is an integer of 1 or more) of electronic watermarks into the content element and generates n × m types of content elements;
A list issuing unit for selecting a content element corresponding to the information on the receiving side device and generating a list for identifying the selected element;
A content distribution unit that identifies content elements based on the list and distributes the identified content elements to the receiving-side apparatus. The content distribution device according to claim 9,
The content creation unit that generates the content element includes:
A content encryption unit that encrypts the content element with the same key after generating the content element;
An encrypted information transmitting unit for transmitting information related to the encryption key to the receiving side device;
And an encrypted content transmission unit that transmits the encrypted content element to the receiving device. The content distribution device according to claim 9,
The list issuing unit that generates the content element specific list includes:
A list concealment unit that conceals information in the list so that the content element cannot be identified from the list after the list is generated;
A concealment list transmission unit for transmitting the concealed list to the reception side device;
A list receiving unit configured to receive the list from the receiving side device and to release the concealment if the list is concealed; In the content receiving device delivered from the transmitting device to the receiving device,
A request information transmitting unit that transmits information specifying the receiving device and information related to a content transmission request to the transmitting device;
And a content element reproduction unit that receives and reproduces the specific content element transmitted from the transmission side device. The content receiving device according to claim 12,
The request information transmission unit
An encrypted information receiving unit that receives information related to the encrypted information of the content according to claim 10 after transmitting the request information;
The content element playback unit
A content decrypting unit that decrypts the encrypted content based on the encrypted information after receiving the encrypted content;
And a decrypted content element playback unit that plays back the decrypted content element. The content receiving device according to claim 12,
The request information transmission unit
A concealment list receiving unit that receives the concealment list according to claim 11 after transmitting the request information;
A concealment list transmission unit for transmitting the reception concealment list to the transmission side device. The content receiving device according to claim 14,
The concealment list receiver
A list concealment information receiving unit for receiving information related to concealment of the concealment list in addition to the concealment list from the transmission side device;
A concealment list releasing unit for canceling concealment of the concealment list based on the concealment information;
And a list transmission unit that transmits the list whose concealment is released to the transmission side device. In an information detection device for detecting digital watermark information from content distributed from a transmission side device to a reception side device,
A content receiver for receiving the content;
A content element dividing unit that divides the content into n (n is an integer of 1 or more) content elements;
10. The receiving apparatus specifying unit that detects digital watermark information from each of the content elements and specifies information on the receiving apparatus according to claim 9.

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