JP2008042538A - Device and program for verifying information, and information terminal apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extract inserted watermark information even when contents, where watermark information including an error correction code is inserted, are severely deteriorated and an error being not less than correction ability occurs. <P>SOLUTION: When error correction is performed in the watermark information in the received contents so as to fail the error correction, a watermark verifying server 104-1 acquires user information stored in a user information DB 222 in a user management server 102, rewrites the user information in the watermark information extracted from the contents by a watermark extracting device 242, repeats the error correction by an error correcting device 244-1, and then, raises probability to extract the watermark information from the contents where the error being not less than correction ability occurs. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for verifying watermark information inserted in content such as an image.

  There is known a digital watermark technique that inserts information so that a human eye does not recognize it by making a subtle modification to content such as an image. In this technique, the amount of information that can be inserted is small in order to prevent deterioration due to watermark information insertion. Therefore, only important information regarding content distribution such as user information, time information, and content information is inserted as watermark information. After that, even if processing such as transformation or processing is performed and the watermarked content deteriorates and many errors occur in the inserted watermark information, the watermark information must be correctly verified. For this reason, digital watermarks are often used in combination with error correction codes that enable correction of generated errors (Patent Document 1).

  On the other hand, an error correction code has a limit of error correction capability. When an error exceeding the correction capability occurs, the original information cannot be restored at all. As a method for improving the correction capability, for example, there is a technique disclosed in Patent Document 2 (see paragraphs 0006 to 0010). This is a technique for improving the correction capability by forcibly rewriting standardized known information (fixed value) such as a header and overwriting and removing errors generated in this part.

Japanese Patent Laid-Open No. 10-308867 JP 2005-130277 A

  Digital watermarks are embedded by applying subtle modifications to the content, and the content is likely to deteriorate due to processing such as deformation and processing. It is a conventional error correction theory that assumes digital communication and digital recording. More errors than expected are likely to occur. In addition, since the amount of information that can be inserted in a digital watermark is small, the amount of information assigned to fixed information such as a header is very small (about several bits). For example, even if the technique of Patent Document 1 is applied, It is hard to say that a sufficient effect is obtained because there is little information that can be forcibly rewritten.

  An object of the present invention is to solve the above-mentioned problems inherent to digital watermarking, and to improve error correction capability even when content deteriorates due to processing such as deformation or processing and an error occurs in watermark information. An object is to provide an information verification device, a program thereof, and an information terminal device.

  In order to achieve the above object, in the present invention, in the digital watermark technology, attention is paid to the fact that information such as user information inserted as a watermark can be limited to some extent in the application environment, and not only fixed information such as a header but also user information Provided is an information search apparatus capable of overwriting a main part of information relating to content distribution, ie, watermark information, a program thereof, and an information terminal apparatus.

  That is, in the present invention, in order to achieve the above object, an information extraction unit that extracts watermark information from received content as an information verification device that verifies watermark information that is inserted into content and includes information related to content distribution. And an information acquisition unit that acquires information related to content distribution stored in the data management device, and error correction processing using the watermark information extracted by the information extraction unit and the information related to content distribution acquired from the data management device The information verification apparatus which comprises the processing part which performs and the information output part which outputs the result of the process of this processing part is comprised.

  In the present invention, in order to achieve the above object, there is provided an information verification program executed in an information verification apparatus for verifying watermark information inserted into content and including information related to content distribution, the information verification apparatus A step of extracting watermark information from the received content, a step of performing error correction on the extracted watermark information and outputting a correction result when the error correction is successful, and storing in the data management device when the error correction fails A step of acquiring information related to the distributed content, a step of performing error correction processing using the extracted watermark information and the information related to the acquired content distribution, and a step of outputting a result of the error correction processing step An information verification program for executing is configured.

Furthermore, in the present invention, in order to achieve the above object, as an information terminal device that inserts watermark information into the content, a content storage unit that stores the distributed content;
A watermark information creation unit that calculates an error correction code based on an information sequence including information related to content distribution, obtains a check sequence, and transmits the information sequence and the check sequence as watermark information; Information comprising: a watermark insertion unit that creates content with a content; a content distribution unit that distributes content with a watermark; and a communication unit that transmits user information about the user to be distributed to the data management apparatus when distributing the content with watermark Configure the terminal device.

  In this specification, the main information of watermark information such as user information and log management ID may be referred to as “information related to content distribution”. It goes without saying that “distribution” includes not only electronic distribution via a network but also cases via a physical medium. The content is a general term for general electronic data such as documents as well as images. Furthermore, in this specification, each functional block constituting a watermark insertion client that is an information terminal device, a user management server that is a data management device, a watermark verification server that is an information verification device, and the like is mainly referred to as “device”. However, this “device” may be used as “part”. For example, it should be noted that “content storage device” may be read as “content storage unit”, and “watermark extraction device” may be read as “watermark extraction unit”.

  According to the present invention, it is possible to verify the inserted watermark information with a high success rate even when the watermarked content is greatly deteriorated and an error exceeding the correction capability occurs.

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

  The first embodiment introduces a data management device that manages user information, which is information related to content distribution, and forcibly overwrites the main part of watermark information such as user information in addition to fixed information such as headers. In this embodiment, the error verification is repeated to increase the watermark verification success rate.

  FIG. 1 is an overall system configuration diagram including a watermark verification server which is an information verification apparatus. A watermark insertion client 100-1 configured by an information terminal device such as a personal computer (PC) inserts watermark information into a content such as an image and distributes the watermarked content 120-1. The watermarked content 120-1 is not only electronically transferred to a third party via the Internet (not shown) but also stored electronically on a hard disk drive (HDD) or CD ROM (CD-ROM). , Paper, and the like can be recorded and distributed in their respective forms.

  The user management server 102, which is a data management device, manages user information regarding the user who operates the watermark insertion client 100-1. The user information is information that identifies the device or person that delivered the watermarked content 120-1, such as an identifier (ID) identifying the client 100-1 and the name of the user who has logged in to the client 100-1. This user information is registered in the user management server 102 via the network 140 from the client 100-1. Alternatively, it is manually registered by the administrator of the watermark insertion client 100-1. These registration operations are performed periodically regardless of the watermark insertion process.

  The watermark verification server 104-1 as the information verification apparatus acquires the distributed watermarked content 120-1 and verifies the watermark information. If the content 120-1 is a physical medium such as paper, it needs to be read and digitized by a scanner in advance. In the case of this scanner reading, there is a high possibility that the watermark information will deteriorate.

  FIG. 2 is a functional block diagram showing an embodiment of the watermark insertion client 100-1, the user management server 102, and the watermark verification server 104-1 in FIG.

  The watermark insertion client 100-1 includes a content storage device 200, a watermark insertion device 202-1, a watermark information creation device 204-1, a content distribution device 206-1 and a user information transmission device 208. The content storage device 200 stores content electronically. The watermark insertion device 202-1 is activated at the time of content distribution or when the user gives an instruction to insert a watermark, takes in predetermined content from the content storage device 200, and acquires watermark information from the watermark information creation device 204-1 And insert it into the content. The watermark information creating apparatus 204-1 creates user watermark information by collecting, connecting, and encoding user information, time information, and content information. The content distribution device 206-1 distributes the watermarked content 120-1 created by the watermark insertion device 202 to the outside. The content distribution device 206-1 corresponds to a communication device when electronically delivering the content 120-1, and corresponds to a printer driver when printing on paper.

  The user information transmission device 208 transmits user information to the user management server 102 via the network 140. If the administrator of the watermark insertion client 100-1 manually registers user information, the user information transmitting device 208 and the network 140 are not necessary.

  In the case where the watermark insertion device 202-1 is activated at the time of content distribution, watermark information is inserted into all content to be distributed. In this case, even if the content 120-1 is lost to the outside, as long as the content 120-1 is found, it is possible to verify when and who delivered it from the watermark information inserted into the content 120-1. Leads to prevention of leakage.

  In this embodiment, the user management server 102 which is a data management device includes a user information communication device 220 and a user information database (DB) 222. User information of the watermark insertion client 100-1 is periodically collected via the user information communication device 220 and stored in the user information DB 222.

  The watermark verification server 104-1 as an information verification device includes a content reception device 240, a watermark extraction device 242, an error correction device 244-1, a user information acquisition device 246, an information replacement device 248, and an information output device 250-1. The content receiving device 240 receives the watermarked content 120-1 and transfers it to the watermark extracting device 242. The watermark extraction device 242 extracts watermark information from the watermarked content 120-1. When the content 120-1 is deteriorated, an error often occurs in the watermark information. The error correction device 244-1 performs error correction on the watermark information, and notifies the information output device 250-1 of the correction information when the error correction is successful. The information output device 250-1 extracts and outputs information 260 such as user information, time information, and content information from the correction information. Alternatively, the correction information may be output as it is.

  When the error correction device 244-1 in the watermark verification server 104-1 fails to correct the error because the generated error exceeds the limit of the correction capability, the user information acquisition device 246 is activated and the user of the user management server 102 User information is acquired from the user information DB 222 via the information communication device 220. The information replacement device 248 overwrites part of the watermark information with the user information and sends it to the error correction device 244-1. The error correction device 244-1 performs error correction again on the information in which the user information is rewritten, and if successful, notifies the information output device 250 of the correction information. The two blocks of the information replacement device 248 and the error correction device 244-1 constitute a processing unit that performs error correction processing on the extracted watermark information and the watermark information replaced with the user information obtained from the corresponding part. To do. Until the error correction is successful or the user information in the user management server 102 is exhausted, each device (unit) 240, 242, 244-1, 246, 248, 250-1 in the watermark verification server 104-1 is These operations are repeated. If error correction is not successful for all user information, the information output device 250-1 outputs information indicating that watermark verification has failed. Details of this operation flow will be described later with reference to FIG.

  FIG. 3 shows an embodiment of watermark information inserted into the content in the first embodiment. The watermark information includes a real information sequence including fixed information 300, user information 302, time information 304, and content information 306, and a test sequence 308-1 calculated from the real information sequence for error correction. In digital watermarking, error correction codes such as BCH codes and Reed-Solomon (RS) codes with low decoding error probabilities are used in order to prevent decoding errors that erroneously decode unintended information by correction processing. Many. Since these codes have restrictions on the combination of the number of bits of the actual information sequence and the number of bits of the check sequence, padding is required to adjust the number of bits of the entire watermark information. Fixed information 300 plays the role of this padding. In this embodiment, the user information 302 is information related to content distribution that specifies who has distributed the content, and includes the identification ID of the client 100 and the name of the logged-in user. The time information 304 is information specifying when the content is distributed. The content information 306 is information about the distributed content, and includes a machine name, a file name, and the like.

  As a specific example, a case where 127-bit watermark information is inserted will be described. As the error correction code, a BCH code of 71 bits of real information and 56 bits of check string that can correct up to 9 errors is used. In this case, if the fixed information 300 is 7 bits, the user information 302 is 40 bits, and the time information 304 is 24 bits, the first 5 alphanumeric characters of the login user name and the time information in units of about 4 years are watermarked. Can do. By verifying the watermark by the watermark verification server 104 based on the present embodiment, information about the content cannot be obtained, but it is possible to specify when and who distributed the content from the watermarked content 120-1.

  FIG. 4 shows not only the first embodiment but also the internal structure of the watermark insertion client, user management server, watermark verification server, and log management server in the third embodiment, which will be described later in the second and third embodiments. It is a block diagram which shows one specific example. Each of these computers includes a display device 400, an input device 402, a communication interface 404, a processing unit (CPU) 406, a ram (RAM) 408, a ROM 410, and a storage 412. The display device 400 is an apparatus that discloses content, error-corrected watermark information, and the like to the user. The input device 402 is a device that transmits user operations to the CPU 406 via a keyboard and a mouse. A communication interface 404 controls communication between computers, and controls the content distribution device 206, the user information communication device 210, the content reception device 220, and the log communication devices 1200 and 1220 in FIG.

  The CPU 406 executes and controls programs that implement the functional blocks (apparatuses) shown in FIG. The RAM 408 stores temporary data necessary for implementing the present invention. The ROM 410 stores a program executed by the CPU 406. The storage 412 is a device that stores a large amount of information such as content and user information, and constitutes a content storage device 200 and a user information DB 222. It is also possible to store a program as the device group described above. In this case, the computer need not have the ROM 410. Needless to say, the program for realizing the functional blocks of each of the embodiments can be provided using a storage medium or provided via a communication medium.

  FIG. 5 is a flowchart showing an example of the operation of the watermark verification server 104-1 in the first embodiment. This flowchart shows the program executed by the CPU 406 in FIG. 4 and the operation flow of the apparatus group in the watermark verification server 104-1 in FIG.

Each step of this flowchart will be described in association with the operation of each apparatus in FIG.
(500) The watermark extraction device 242 extracts watermark information from the content 120-1. The watermark information to be extracted is not subjected to error correction.
(502) The error correction device 244-1 performs error correction on the watermark information.
(504) If error correction is successful, the process proceeds to step 506;
(506) The error correction device 244-1 notifies the information output device 250-1 of the correction information. Proceed to step 522.
(508) The variable i is initialized to 1.

(510) The information replacement device 248 acquires the i-th user information stored in the user information DB 222 in the user management server 102 via the user information acquisition device 246, and rewrites the fixed information 300 and the user information 302. .
(512) The error correction device 244-1 corrects the error of the information rewritten in step 510.
(514) If error correction is successful, the process proceeds to step 506;
(516) Increase variable i by one.
(518) If the variable i is greater than the number of user information stored in the user information DB 222, the process proceeds to step 520. If not, return to Step 510.
(520) The error correction apparatus 244-1 notifies the information output apparatus 250-1 that error correction has failed.
(522) When the correction information is notified in step 506, the information output device 250 extracts the user information 302, the time information 304, and the content information 306 from the correction information and outputs them. When the notification is received from step 520, the information output device 250 outputs that the watermark verification has failed.

  In this embodiment, since the watermark information is composed of fixed information, user information, time information, etc., many errors occur other than the fixed information 300 and the user information 302, and it is rewritten with correct user information in step 510. Note that error correction may also fail. In this case, the fact that the watermark information could not be verified is output in step 520 and the process is terminated.

  Note that in the flow of this embodiment, user information is sequentially extracted using only the variable i. However, when the user information is managed hierarchically in units of departments, the variable i for the department and the variable j for the section. It is also possible to extract user information by rotating the users belonging to the section in multiple loops such as with the variable k.

  In the above embodiment, the user information is registered regardless of the watermark insertion process. However, when distributing the watermarked content 120-1, the content distribution device 206-1 activates the user information transmission device 208, The present embodiment can also be extended so that the user information transmitting apparatus 208 collects the information of the user who delivered the content in the watermark insertion client 100-1 and transmits it to the user management server 102. In this case, since only the user information that the watermark insertion client 100-1 distributed the watermarked content 120-1 is stored in the user information management server 102, there is no useless search for user information in the watermark verification server 104-1. The entire verification process can be speeded up.

  In addition, when distributing the content 120-1, the content distribution device 206 can transmit, for example, content data itself, which is not inserted into the content as a watermark, to the user management server 102 via the user information transmission device 208. These pieces of information are stored in the user information DB 222. When user information and content information can be identified by extracting watermarks from the lost content 120-1, more detailed information about the content 120-1, such as content data, can be obtained by referring to the user information DB 222 based on such information. Information can be acquired.

  The second embodiment introduces a server that manages user information on the premise that the watermark information is composed only of fixed information and user information, concatenates and encodes all user information and fixed information, It is an Example of the information verification apparatus which raises a watermark verification success rate by comparing with the extracted information.

  That is, in this embodiment, unlike the first embodiment, an actual information string can be configured only by the fixed information 300 and the user information 302 as information related to content distribution. Therefore, if the inspection string 308-2 is calculated and added, Thus, information having the same length as the inserted watermark information (hereinafter referred to as a code word) can be calculated. Even if the watermark information contains many errors, the codeword generated from the user information inserted as information related to content distribution is more similar to the watermark information than other codewords. Compared with the information calculated and extracted from the content, there is a high possibility that the user information giving the most similar code word is the user information inserted into the content. A second embodiment based on this fact will be described in detail below.

  FIG. 7 is a block diagram illustrating an example of a detailed configuration of the watermark verification server 104-2 according to the second embodiment. The watermark verification server 104-2 includes a content reception device 240, a watermark extraction device 242, an error correction device 244-2, an information output device 250-2, a user information encoding device 700, and an information comparison device 702. The content receiving device 240 receives the watermarked content 120-2 and transfers it to the watermark extracting device 242. The watermark extracting device 242 extracts watermark information from the watermarked content 120-2. The error correction device 244-2 performs error correction on the watermark information, and notifies the information output device 250-2 of the error correction information when the error correction is successful. The information output device 250-2 extracts the user information 302 from the correction information and outputs it. Alternatively, the correction information may be output as it is.

  When the generated error exceeds the limit of the correction capability and the error correction fails, the user information encoding apparatus 700 is activated and acquires the user information 720 from the user management server 102. Furthermore, the user information encoding device 700 calculates a check string 308-2 from the fixed information 300 and the acquired user information 720 to create a code word. The information comparison device 702 compares the codeword with the watermark information and calculates a different number of bits. The user information encoding device 700 and the information comparison device 702 repeat this operation for all users stored in the user management server 102, and the code word with the smallest number of different bits is inserted into the content. The information output device 250-2 is notified as a probable code word. The information output device 250-2 extracts the user information 302 from the codeword and outputs it. Alternatively, the correction information may be output as it is.

  Including the encoding processing function of the user information encoding device 700, the blocks of the information comparison device 702 and the error correction device 244-2 include a processing unit that performs error correction processing on the extracted watermark information or user information. It is composed. As in the first embodiment, the error correction device 244-2, the user information encoding device 700, and the information comparison device 702 are preferably stored in the ROM 410 or the storage 412 of FIG. Consists of.

FIG. 8 is a flowchart showing an example of the operation of the watermark verification server 104-2 in the second embodiment. Each step will be described in association with the operation of the device group in FIG.
(500) The watermark extracting device 242 extracts watermark information from the content 120-2. Even in this embodiment, the watermark information to be extracted is not subjected to error correction.
(502) The error correction device 244-2 performs error correction on the watermark information.
(504) If error correction is successful, the process proceeds to step 506;
(506) The error correction device 244-2 notifies the correction result to the information output device 250-2. Proceed to step 522.
(508) The variable i is initialized to 1.

(800) The user information encoding device 700 acquires the i-th user information stored in the user information DB 222, calculates the check string 308-2 from the fixed information 300 and the user information, and creates a code word Ci. To do.
(802) The information comparison device 702 compares the codeword Ci with the extracted watermark information and calculates a different number of bits Di.
(804) Increase the variable i by one.
(806) If the variable i is greater than the number of user information stored in the user information DB 222, the process proceeds to step 808. If not, go to Step 800.
(808) The information comparison apparatus 702 notifies the information output apparatus 250 of the code word Ci that gives the minimum Di as watermark information.
(522) The information output device 250-2 extracts the user information 302 from the received information and outputs it.

  Since the second embodiment is based on comparing the codeword and information extracted from the content, it should be noted that the most probable user information is always output unlike the first embodiment. Further, in the flow shown in FIG. 8, user information is sequentially extracted using only the variable i. However, when user information is managed hierarchically in units of departments, as in the first embodiment, a multiple loop is used. It is also possible to extract user information by turning.

  It should be noted that, as in the first embodiment, if the user information transmitting device 208 is activated in conjunction with the distribution of watermarked content, it is possible to eliminate users not related to watermark insertion and speed up the entire verification process. Yes.

  Next, as a third embodiment, an information verification device that uses a log management server instead of a user information management server, inserts a log management ID as watermark information, and compares it with any log management ID and information extracted from content Examples will be described. That is, the log management ID is used as information related to content distribution to be inserted into the watermark information. The reason why the apparatus of the second embodiment described above can surely output the most probable watermark information is that the codeword can be calculated only from the fixed information and the user information as the information related to the content distribution. The third embodiment further expands the second embodiment by introducing a log management server and inserting a log management ID instead of user information as information related to content distribution.

  FIG. 9 is an overall system configuration diagram of a third embodiment having a log management server. As in the first and second embodiments, the watermark insertion client 100-3 inserts watermark information into content such as an image and distributes the watermarked content 120-3. The log management server 900 acquires log information about content distribution such as user information, time information, and content information from the watermark insertion client 100-3 via the network 140, and associates this log information with a log management ID. It is a device to manage. The watermark insertion client 100-3 in the present embodiment inserts the log management ID into the content as information related to content distribution in the watermark information, as will be described in detail later. The watermark verification server 104-3 is a device that acquires the distributed watermarked content 120-3 and verifies the watermark information. The watermark verification server 104-3 transmits the verified log management ID to the log management server 900, and receives and outputs log information corresponding to the log management ID.

  FIG. 10 shows an example of watermark information in the third embodiment. The watermark information inserted into the content by the watermark insertion client 100-3 includes the fixed information 300, the log management ID 1000 as information related to content distribution, and the error correction check column 308-3 that can be calculated from these. Compared with the watermark information of the second embodiment shown in FIG. 6, a log management ID 1000 is inserted instead of the user information 302 as information relating to content distribution.

  As a specific example, a case where 127-bit watermark information is inserted will be described. As an error correction code, a BCH code having 71 bits of actual information and 56 bits of check string, which can correct up to nine errors, is used, as in the first embodiment. In this case, if the fixed information 300 is 7 bits and the log management ID 1000 is 64 bits, 2 64 power can be allocated as the log management ID. Even if 100 million users deliver 10,000 contents every day, this value is not depleted for about 50,000 years, and it can be said that there is no practical problem.

  FIG. 11 shows an example of log information managed by the log management server 900. In the log 1100, for example, user information AAAAAAA, time information 2000/1/1 0:00:00, and content information BBBBBBB are acquired from the watermark insertion client 100-3, and managed in association with the log management ID 0000001.

  FIG. 12 is a block diagram showing an example of detailed configurations of the watermark insertion client 100-3, the log management server 900, and the watermark verification server 104-3 in the third embodiment.

  The watermark insertion client 100-3 includes a content storage device 200, a watermark insertion device 202-3, a watermark information creation device 204-3, a content distribution device 206-3, and a log communication device 1200. The content storage device 200 stores content electronically. The watermark insertion device 202-3 is activated at the time of content distribution, takes in predetermined content from the content storage device 200, acquires watermark information from the watermark information creation device 204-3, and inserts it into the content. The watermark insertion apparatus 202-3 activates the log communication apparatus 1200 simultaneously with its activation in order to acquire watermark information. In the third embodiment, the watermark information creating apparatus 204-3 creates the watermark information by acquiring the log management ID 1000 from the log communication apparatus 1200 and encoding it by concatenating with the fixed information. The content distribution device 206-3 distributes the watermarked content 120-3 created by the watermark insertion device 202-3 to the outside.

  On the other hand, the log communication device 1200 is activated in response to an instruction from the watermark insertion device 202-3, and displays the user information of the watermark insertion client 100-3, distribution time information, information about the content to be distributed, and the like. Is acquired and transmitted to the log management server 900. At this time, the log management server 1000 issues a log management ID 1000 for associating these pieces of information. This is received and transmitted to the watermark information creating apparatus 204-3.

  The log management server 900 includes a log communication device 1220 and a log management DB 1222. The content distribution log information is collected from the watermark insertion client 100-3 via the log communication device 1220, and the log management DB 1222 stores the log management ID 1000 in association with the log information. In addition to collecting log information, the log communication device 1220 can also transmit a log management ID and log information.

  The watermark verification server 104-3 includes a content reception device 240, a watermark extraction device 242, an error correction device 244-3, an information comparison device 702, a log display device 1240, and a log management ID encoding device 1242. The content receiving device 240 receives the watermarked content 120-3 and transfers it to the watermark extracting device 242. The watermark extracting device 242 extracts watermark information from the watermarked content 120-3. The error correction device 244-3 performs error correction on the watermark information, and notifies the log display device 1240 of the error correction information when the error correction is successful. The log display device 1240 extracts the log management ID 1000 from this correction information, inquires the log management server 900, acquires the corresponding log information 260 from the log management DB 1222, and displays it.

  When the error that has occurred exceeds the limit of the correction capability and the error correction fails, the log management ID encoding device 1242 is activated and the log management ID 1000 is obtained from the log management DB 1222 via the log communication device 1220 of the log management server 900. get. Further, the log management encoding device 1242 calculates a check string 308-3 from the fixed information 300 and the acquired log management ID 1000 to create a code word. The information comparison device 702 compares the codeword with the watermark information and calculates a different number of bits. The log management ID encoding device 1242 and the information comparison device 702 repeat this operation for all users stored in the log management DB 1222, and log the code word having the smallest number of different bits as the most probable log management ID 1000. The display device 1240 is notified. The log display device 1240 acquires the log information 260 corresponding to the log management ID 1000 from the log management server 900 and displays it.

  The log communication devices 1200 and 1220 are controlled by the communication interface 404 in FIG. 4 as described above. The log management DB is stored in the storage 412. As in the previous embodiment, including the encoding processing function of the log management ID encoding device 1242, the blocks of the information comparison device 702 and the error correction device 244-3 have errors in the extracted watermark information or log management ID. The log management ID encoding device 1242 is preferably composed of a program stored in the ROM 410 or the storage 412 and is executed and controlled by the CPU 406.

  The operation flow of the watermark verification server 104-3 in the present embodiment is the same as FIG. 8 except that in step 800, the i-th log management ID is obtained instead of the user information and the code word Ci is created. In this embodiment, since the log management ID is inserted as watermark information, unlike the second embodiment, a feature is that various information related to contents other than user information can be acquired from the log management server 900.

The figure which shows the structure of the watermark insertion client concerning 1st Example of this invention, a user management server, and a watermark verification server. The block diagram which shows one Example of a structure of the watermark insertion client of 1st Example, a user management server, and a watermark verification server. The figure which shows one Example of the watermark information of a 1st Example. The block diagram which shows an example of a structure of the watermark insertion client in each Example, a user management server, a watermark verification server, and a log management server. The figure which shows the flowchart which shows one Example of the operation | movement of the watermark verification server of a 1st Example. The figure which shows one Example of the watermark information of a 2nd Example. The block diagram which shows one Example of a structure of the watermark verification server of a 2nd Example. The figure which shows the flowchart which shows one Example of the operation | movement of the watermark verification server of a 2nd Example. The figure which shows the structure of the watermark insertion client concerning a 3rd Example, a log management server, and a watermark verification server. The figure which shows one Example of the watermark information of a 3rd Example. The figure which shows one Example of the log of a 3rd Example. The block diagram which shows one Example of a structure of the watermark insertion client of 3rd Example, a log management server, and a watermark verification server.

Explanation of symbols

100-1, 100-3: watermark insertion client, 102: user management server, 104-1, 104-3 ... watermark verification server, 120-1, 120-2, 120-3 ... watermarked content, 140 ... network, 200 ... content storage device, 202-1, 202-3 ... watermark insertion device, 204-1, 204-3 ... watermark information creation device, 206-1, 206-3 ... content distribution device, 208 ... user information transmission device, 220 ... User information communication device, 222 ... User information DB, 240 ... Content reception device, 242 ... Watermark extraction device, 244-1, 244-2, 244-3 ... Error correction device, 246 ... User information acquisition device, 248 ... Information replacement device, 250-1, 250-2 ... Information output device, 260 ... Information related to content distribution or error correction information, 300 ... Fixed information, 302 ... User information, 304 ... Time information, 306 ... Content information, 308 -1,308-2, 308-3 ... Inspection row, 400 ... Display device, 402 ... Input device, 404 ... Communication interface, 406 ... CP U, 408 ... RAM, 410 ... ROM, 412 ... storage, 700 ... user information encoding device, 702 ... information comparison device, 720 ... user information, 800, 802, 804, 806, 808 ... processing steps, 900 ... log management Server, 1000 ... log management ID, 1100 ... log, 1200, 1220 ... log communication device, 1222 ... log management DB, 1240 ... log display device, 1242 ... log management ID encoding device.

Claims (10)

An information verification device for verifying watermark information inserted into content and including information related to content distribution,
An information extraction unit for extracting the watermark information from the received content;
An information acquisition unit for acquiring information related to content distribution stored in the data management device;
A processing unit that performs an error correction process using the watermark information extracted by the information extraction unit and information related to the content distribution acquired from the data management device;
An information verification apparatus comprising: an information output unit that outputs a processing result of the processing unit. The information verification device according to claim 1,
The information related to the content distribution includes user information for identifying a user who has distributed the content,
The processor is
An information replacement unit that rewrites the user information of the extracted watermark information with the user information acquired by the information acquisition unit;
An error correction unit that performs error correction using the watermark information extracted by the information extraction unit or the watermark information rewritten by the information replacement unit,
The information output device, wherein the information output unit outputs correction information when error correction in the error correction unit is successful, and outputs information indicating failure when error correction fails. The information verification device according to claim 1,
The information relating to the content distribution is user information for identifying a user who has distributed the content,
The processor is
An error correction code calculated using the user information acquired by the information acquisition unit and the extracted watermark information, and an information comparison unit that outputs the most similar correction code;
An error correction unit that performs error correction on the extracted watermark information and outputs a correction code;
The information verifying device that outputs the correction code output from the error correction unit or the information comparison unit. The information verification device according to claim 1,
The information related to the content distribution is a log management ID indicating log information about the content distribution,
The processor is
Comparing the error correction code calculated using the log management ID acquired by the information acquisition unit with the extracted watermark information, and an information comparison unit that outputs the most similar correction code;
An error correction unit that performs error correction on the extracted watermark information and outputs a correction code,
The information verifying device that outputs the correction code output from the error correction unit or the information comparison unit. An information verification program executed in an information verification apparatus for verifying watermark information including information related to content distribution inserted into content,
In the information verification device,
Extracting the watermark information from the received content;
Performing error correction on the extracted watermark information and outputting a correction result when the error correction is successful;
A step of acquiring information related to content distribution stored in the data management device when error correction fails;
Performing an error correction process using the extracted watermark information and the acquired information relating to content distribution;
An information verification program that executes a step of outputting a result of the error correction processing step. An information verification program according to claim 5,
The information related to the content distribution is user information related to a user who has distributed the content, and the acquisition step acquires all of the user information,
The error correction processing step includes
Calculating an error correction code corresponding to each of the acquired user information;
Comparing the error correction code with the extracted watermark information, and obtaining the error correction code with the smallest difference,
An information verification program for outputting the error correction code having the smallest difference in the output step. An information verification program according to claim 5,
The information related to the content distribution is a log management ID indicating log information about the content distribution, and the acquisition step acquires all of the log management ID,
The error correction processing step includes
Calculating an error correction code corresponding to each acquired log management ID;
Comparing the error correction code with the extracted watermark information, and obtaining the error correction code with the smallest difference,
The output step includes
Extracting the log management ID from the error correction code having the smallest difference; and
An information verification program comprising: acquiring log information corresponding to the extracted log management ID from the data management apparatus and outputting the log information. An information terminal device that inserts watermark information into content,
A content storage unit for storing the content to be distributed;
A watermark information creating unit that calculates an error correction code based on an information sequence including information related to content distribution to obtain a check sequence, and transmits the information sequence and the check sequence as watermark information;
A watermark insertion unit that inserts the watermark information into the content to create a watermarked content;
A content distribution unit for distributing the watermarked content;
An information terminal device comprising: a communication unit that transmits user information about a user to be distributed to the data management device when distributing the watermarked content. The information terminal device according to claim 8, wherein
An information terminal device in which the information related to the content distribution is the user information about a user who distributes the content. The information terminal device according to claim 8, wherein
The communication unit receives a log management ID associated with the user information issued every time the data management device receives the user information,
The watermark information creating unit is an information terminal device that uses the log management ID as information related to the content distribution.

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