WO2002086845A1

WO2002086845A1 - Content monitoring method, content providing device, and content monitoring device

Info

Publication number: WO2002086845A1
Application number: PCT/JP2001/007556
Authority: WO
Inventors: Hideto Yamakawa
Original assignee: U's Communications Corp.
Priority date: 2001-04-19
Filing date: 2001-08-31
Publication date: 2002-10-31
Also published as: JP2002318726A

Abstract

A content providing device (10) for providing a content on a web page creates information for monitoring according to the content of a content file and buries the information in the content file. A content monitoring device (20) acquires the content file to be monitored from the content providing device (10), extracts the information for monitoring, and creates another set of information for monitoring according to the content of the content file. By comparing the sets of information, it is judged whether or not the content file is falsified. Thus the third party other than the content provider monitors the content through a computer network to detect alteration if any.

Description

Specification

Content monitoring method, content providing device, and content monitoring device

The present invention particularly relates to a technique for monitoring electronic information content provided on a Web page and detecting tampering.

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With the spread of the Internet, companies and institutions are actively providing electronic information content on Web pages in order to transmit information about the company and the like.

In such a situation, the damage that content is falsified by illegal intrusion into the Web server of companies etc. is increasing. If content is altered and released, erroneous or unpleasant information will be transmitted from the website of the company, etc., which will damage the company's credibility and cause serious damage. . Therefore, companies that provide content need to confirm that their content has not been tampered with.

Falsification of content is performed by a malicious Internet user illegally invading a web server or the like of a company or the like, and rewriting the content of a file constituting the content. For this reason, in addition to observing the content displayed on the web browser, the system administrator etc. confirms whether the content has been tampered with, and the system administrator etc. does not change the content file time stamp or the content file size. This is done by examining whether or not. Disclosure of the invention

By the way, due to the nature of the Internet, tampering may take 24 hours. On the other hand, if tampering has been performed, unless immediate action is taken, the number of in-home users who browse the tampered content will increase, resulting in greater damage. For this reason, system administrators, etc. must respond quickly to tampering. Content must be monitored at all times.

In general, system administrators of companies and the like are not always familiar with Internet technology and may also be engaged in other tasks, so it is not always possible to monitor content. The burden is considered to be too great. For this reason, it would be convenient if the monitoring of the content could be outsourced to a third party. However, it is often undesirable for a company, etc., to have a third party resident to monitor content. On the other hand, when monitoring remotely, it is difficult to determine whether the content change has been updated by the system administrator or has been tampered with.

An object of the present invention is to provide a technology that allows a third party other than the content provider to monitor the content and detect tampering.

In order to solve the above problems, according to a first aspect of the present invention,

A method of monitoring electronic information content,

Generating first unique information based on the monitored content and adding the first unique information to the content;

Obtaining the monitored content;

Extracting first unique information from the acquired monitoring target content; generating second unique information based on the monitoring target content from which the first unique information is extracted;

Comparing the first unique information with the second unique information,

As a result of the comparison, when the first unique information is different from the second unique information, it is determined that the monitoring target content has been tampered with.

Here, the unique information based on the content can be, for example, a file size of the content file, a hash value such as a time stamp, or the like. Also, the unique information can be added to the content by encrypting it using, for example, a public key method.

According to the second aspect of the present invention,

An apparatus for providing electronic information content,

Encrypts information for identifying the monitored content and the unique information of the content Storage means for associating and storing information for conversion,

Means for generating unique information of the content to be monitored by referring to the storage means, encrypting the unique information and adding the encrypted information to the content to be monitored.

Further, according to a third aspect of the present invention,

Storage means for storing information for identifying the content to be monitored and information for decoding the unique information of the content in association with each other;

A means for referring to the storage means to obtain a monitoring target content, and for extracting and decrypting encrypted unique information from the obtained monitoring target content;

Means for generating unique information of the monitored content from which the encrypted unique information has been extracted;

Means for comparing the decrypted unique information with the generated unique information, and determining that the monitoring target content has been tampered with when the two are different from each other. . BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram for explaining an example of a network system to which the present invention is applied.

FIG. 2 is a block diagram for explaining a functional configuration of the content providing apparatus 10. FIG. 3 is a block diagram for explaining the functional configuration of the content monitoring device 20. FIG. 4 is a diagram for explaining an example of the data structure of the content management database 14.

FIG. 5 is a diagram for explaining an example of the data structure of the monitoring database 23. FIG. 6 is a flowchart for explaining a process in which the content providing apparatus 10 adds monitoring information to the monitoring target content.

FIG. 7 is a flowchart for explaining a process in which the content monitoring device 20 monitors the monitoring target content.

FIG. 8 is a diagram for explaining an example of a content file. FIG. 8A shows an example of a content file before the monitoring information is added, and FIG. 8B shows an example of the monitoring information. Shows an example of a content file after "."

BEST MODE FOR CARRYING OUT THE INVENTION

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

FIG. 1 is a block diagram for explaining an example of a network system to which the present invention is applied. In this figure, a content providing device 10, a content monitoring device 20, and a plurality of content browsing devices 50 (only one is shown in this diagram) are connected via a computer network 60. The network system. The computer network 60 can be typically the Internet, but the present invention is not limited to this.

The content providing device 10 is a device that has a Web Serno function and provides electronic information content on a Web page. Electronic information content (contents) refers to information such as characters and images displayed on the web page, computer programs and other information that can be obtained from the web page, whether paid or free. It shall be.

The content monitoring device 20 is a device that monitors the content provided by the content providing device 10 via the computer network 60 and detects whether the content has been tampered with.

The content browsing device 50 is a terminal device used by an unspecified number of users of the computer network 60, and has a Web browser function. The user can access the content providing device 10 using the web browser function of the content browsing device 50 and browse the content provided by the content providing device 10. The present embodiment relates to a technology for detecting, when a malicious user alters the content provided by the content providing device 1 ◦ using the content browsing device 50, the alteration.

FIG. 2 is a block diagram for explaining a functional configuration of the content providing apparatus 10. As shown in the figure, the content providing device 10 includes a web server control unit 11, a monitoring information processing unit 12, a network interface unit 13, and a content management database 14. And a content file storage unit 15. However, the configuration of the content providing device 1◦ is not limited to this.

The web server control unit 11 uses the content providing device 10 as a web server. The control for the function is performed. Specifically, in response to a request from a Web browser, a process for transmitting contents such as an HTML (Hypertext Markup Language) file and an image file using HTTP (Hypertext Transfer Protocol) is performed. Furthermore, by providing an extension function called Common Gateway Interface (CGI), it is possible to provide interactive content.

The content file storage unit 15 stores an HTML file, an image file, and the like for constituting the content provided by the content providing device 10 in a URL.

(Umiform Resource Locator) and is stored in association with an address on the computer network 60. When the Web server control unit 10 receives a transmission request for the content whose URL is specified from the Web browser, the Web server control unit 10 obtains the file associated with the URL from the content file storage unit 15 and, as a response to the transmission request, Send to browser.

The monitoring information processing unit 12 performs a process of adding information for falsification monitoring to the content file stored in the content file storage unit 15. In the present embodiment, the monitoring information processing unit 12 includes a hash value calculation unit 12a, a monitoring information generation unit 12b, and a monitoring information addition unit 12c.

The hash value calculation unit 12a refers to the monitored content file and calculates a hash value of the data based on the content file (hereinafter, also simply referred to as “content file hash value”). The data based on the content file can be, for example, a file size. When a content file is tampered with, the file size is also generally changed. can do. As a hash function for calculating a hash value, MD5, MASH, SHA-1 and the like are standard, but are not limited to these.

In addition, the data size based on the content file used to calculate the hash value is not limited to the file size. For example, data on file modification date and time, file name, etc. may be used. Furthermore, in the present embodiment # 1, the hash By using the value, the data amount of the tamper monitoring information is compressed, and the tamper monitoring process is performed efficiently.However, it is not always necessary to use the hash value in determining the identity of the content. . For example, the file size itself may be used for content file identity determination.

The monitoring information generation unit 12b performs a process of generating monitoring information by encrypting the hash value generated by the hash value calculation 12a. The encryption method is arbitrary, but in this embodiment, a public key encryption method is used. As the public key and the secret key used for the public key cryptosystem, for example, a public key and a secret key issued by a certificate issuing device 30 of a certificate authority, which is a third party, can be used. The monitoring information generator 12b encrypts the hash value using a secret and a secret key. Hereinafter, the encrypted hash value is referred to as monitoring information.

The content providing device 10 stores and manages the public key and the private key issued by the certificate issuing device 30 in the content management database 14. FIG. 4 is a diagram for explaining an example of the data structure of the content management database 14. In this figure, the content management database 14 manages the content URL 14a, the public key 14b, the secret key 14c, and the storage location 14d as one record.

The content URL 14a stores an address on the combination network 60 for identifying the content file. If the content file is an image file, etc., and is linked from an HTML file, etc., and displayed on the Web page, store the URL of the link source. The public key 14b and the secret key 14c store keys used for encryption and decryption in the public key cryptosystem. The storage location 14 d stores information for specifying the storage location of the content file in the content providing device 10. The storage location of the content file can be specified by, for example, a predetermined path and file name in the content file storage unit 15. In the example of this figure, a public key and a secret key are set for each content file. However, a common public key and a secret key may be used for all or some of the content files. Good.

The monitoring information adding unit 1 2c stores the command generated by the monitoring information generating unit 1 2b. The file monitoring information is added to the content file or the link source content file of the call. The specific processing contents of the monitoring information adding unit 12c will be described later.

The network interface unit 13 performs processing for controlling transmission and reception of data via the computer network 60.

As the content providing device 10, a general information processing device including a central processing unit, a main storage device, an input / output processing device, an auxiliary storage device, and the like, for example, a server computer can be used. The information processing device implements the above-described monitoring information processing unit 12 and the like by the central processing unit and the like performing processing in accordance with a predetermined combination program stored in the main storage device. It will be able to function as 0. A computer program for causing the information processing device to function as the content providing device 10 can be distributed by recording it on a portable recording medium such as a CD-ROM. Then, by storing this recording medium in, for example, an auxiliary storage device, it can be installed in the information processing device. Also, for example, it can be installed via a computer network 60 or the like.

FIG. 3 is a block diagram for explaining a functional configuration of the content monitoring device 20. As shown in the figure, the content monitoring device 20 includes a content monitoring control unit 21, a network interface unit 22, and a monitoring database 23. However, the configuration of the content monitoring device 20 is not limited to this.

The content monitoring control unit 21 monitors the content provided by the content providing apparatus 10 for falsification, for example, at a predetermined time interval or according to a predetermined monitoring schedule or the like. In the present embodiment, the content monitoring control unit 21 includes a content acquisition unit 21a, a content 'monitoring information separation unit 21b, a monitoring information decryption unit 21c, a hash value calculation unit 21d, and a hash. It is configured to include a value comparison unit 21 e.

The content acquisition unit 21a refers to the monitoring database 23 to specify the monitoring target content, and via the computer network 60, monitors the monitoring target content. 'To get.

FIG. 5 is a diagram for explaining an example of the data structure of the monitoring database 23. In this figure, the monitoring database 23 manages the monitoring target content URL 23 a, the public key 23 b, and the monitoring history 23 c as one record.

The monitored content URL 23 a stores the URL of the content to be monitored. The public key 23 b stores the public key applied to the content set in the public key 14 b of the content management database 14. The monitoring result 23 stores the monitoring result (whether or not tampered) of the monitoring target content. For example, the monitoring result 23 can store a history of the monitoring result by storing the monitoring date and time 23 c1 and the result 23 c2 in association with each other.

The content / monitoring information separation unit 21b separates the acquired monitoring target content into a content part and a monitoring information part. That is, in the present embodiment, monitoring information is added to the content file to be monitored by the monitoring information processing unit 12 of the content providing apparatus 10. The content-'monitoring information separation unit 2 lb extracts the added monitoring information and separates it into a content part and a monitoring information part.

The monitoring information decryption unit 21c decrypts the separated monitoring information using the public key 23b recorded in the monitoring database 23. That is, the separated monitoring information is obtained by encrypting the hash value of the content file by the monitoring information processing unit 12 of the content providing apparatus 10. The monitoring information decryption unit 21c decrypts the monitoring information by using the public key corresponding to the secret key used for the encryption, thereby obtaining the hash value of the content file at the time when the monitoring information is generated. Can be obtained.

The hash value calculation unit 2Id calculates an overnight hash value based on the separated content. This makes it possible to obtain the hash value of the content file at the time of monitoring. The hash value calculation method used by the hash value calculation unit 21 d is the same as the hash value calculation method used by the hash value calculation unit 12 a of the content providing device 10.

The hash value comparison unit 21 e transmits the monitoring information acquired by the monitoring information decoding unit 21 c. The hash value of the content file at the time of generation is compared with the hash value of the content file at the monitoring time obtained by the hash value calculation unit 21d. If they match, it is determined that the content file has not been tampered with, and if they do not match, it is determined that the content file has been tampered with. The hash value comparison unit 21e records this determination result in the monitoring result 23c of the monitoring database 23. ,

The network interface section 22 performs processing for controlling transmission and reception of data via the computer network 60.

Note that, like the content providing device 10, a general information processing device including a central processing unit, a main storage device, an input / output processing device, an auxiliary storage device, and the like can be used as the content monitoring device 20. Further, the information processing device can function as the content monitoring device 20 by executing a predetermined computer program.

Next, the processing operation of the present embodiment in the above configuration will be described.

First, as a premise of the content monitoring process, a process for setting a content to be monitored will be described. This process is performed by, for example, the administrator of the content providing apparatus 10.

The content providing device 10 records, in the content management database 14, information on the content file to be monitored among the content files stored in the content file storage unit 15. In other words, the content URL 14a of the monitored content, the public key 14b and the private key 14c obtained from the certificate issuing device 30, and the storage location 14d are stored on a content management data base. Record in 14. If the content file to be monitored is an image file or the like and is displayed on a web page linked from an HTML file or the like, the URL of the link source is changed to the content UR L 14 a as described above. To be stored.

Then, the content monitoring device 20 is notified of the content URL recorded in the content management database 14 and the public key. The content monitoring device 20 records the notified content URL and the public key in the monitoring target content URL 23 a of the monitoring data base 23 and the public key 23 b. Thus, the process for setting the content to be monitored ends. Next, a process in which the content providing apparatus 10 adds monitoring information to the monitoring target content will be described. This process is basically performed when the content to be monitored is created or modified. That is, whether or not the content has been falsified is determined based on the content at the time of performing this processing, based on whether or not the content has been changed. FIG. 6 is a flowchart for explaining this processing.

Monitoring 甩 The hash value calculation unit 12 a of the information processing unit 12 refers to the storage location 14 d of the content management database 14 and refers to the monitoring target recorded in the content file storage unit 15. The content file 150 is obtained (S101). Then, the hash value of the content file 150 is calculated by a predetermined hash value calculation method (S102).

Next, the monitoring information generation unit 12 b acquires the secret and secret key 14 c corresponding to the content file 150 from the content management database 14. Then, monitoring information is generated by encrypting the calculated hash value using the secret key 14c (S103). By encrypting the hash value as monitoring information in this way, the falsification of the hash value itself can be prevented.

Next, the monitoring information adding unit 12c attaches the generated monitoring information to the content or the content that is a link source of the content ;!] (S104). This processing will be described below.

In general, a content file can be distinguished into a text-based file described in HTML or the like and a file recorded in binary or the like of image data. Of these, most text-based files allow monitoring information to be added to the file without affecting the display format of the web browser. On the other hand, a file recorded in binary or the like may be affected by the addition of monitoring information in the file, such as a distorted image displayed on a web browser.

For this reason, in the present embodiment, two methods are provided for attaching the monitoring information to the content file. The first method is to add content monitoring information to the content file. This method uses text-based It is preferable to apply this to a content file to which monitoring information can be added without affecting the display form of the web browser, such as files. The second method is to add the content monitoring information to the link tag of the link source content file of the content. This method applies to files other than those to which the first method applies. Which method is to be applied can be determined for each file type in advance. Also, monitoring information may be added to the content file by using a so-called digital watermarking technique. In this case, a method of adding monitoring information can be selected based on whether or not a digital watermark can be embedded.

FIG. 8 is a diagram for explaining an example of a content file. FIG. 8A shows an example of a content file before the monitoring information is added. FIG. 8B shows an example of the content file before the monitoring information is added. The example of the content file after addition is shown.

In FIG. 8B, the portions indicated by * and * 2 are the portions added as monitoring information. * Indicates monitoring information for this content file. In this diagram, it may be the monitoring information of this content file! --Content- 1 ""> The monitoring information “YYYYYYYYYY” is added. *? Is monitoring information of “sample.gif”, which is an image file linked from this content file. In other words, since it is not desirable to add monitoring information in the image file “sample.gif”, this monitoring 'f helmet bulletin' is included in the evening instructing a link to “sample.gif”. Has been added. In the figure, "=" indicates that the information is monitoring information of a linked content file, and monitoring information "XXXXXXXX" of "sample.g" is added. This monitoring information “XXXXXXXX” is information generated from the hash value of “sample.gif” and the secret key. The code indicating that the information is monitoring information is not limited to K !! Content-ID = ""> and AUTH, ".

In accordance with such monitoring information loading [I rule, the monitoring information adding unit 12c adds the generated monitoring f green information to the content or the content of the link source of the content. Then, the content file 150 ′ to which the monitoring information has been added is stored in the content file storage unit 15 (S 105), and the process of adding the monitoring information to the monitoring target content ends. Next, a process in which the content monitoring device 20 monitors the monitoring target content will be described. This process is performed periodically, for example, every 5 minutes or 10 minutes, or according to a predetermined monitoring schedule. In this way, for example, by performing monitoring processing at intervals of 5 minutes, it is possible to quickly detect when content has been tampered with. By performing falsification processing such as stopping the Web server function and restoring contents, damage due to falsification can be reduced. FIG. 7 is a flowchart for explaining a process in which the content monitoring device 20 monitors the monitoring target content.

The content acquisition unit 21 a of the content monitoring control unit 21 refers to the monitoring target content UR L 23 a of the monitoring database 23, and monitors the content file 150 5 via the computer network 60. (S 2 0 1) o Next, the content 'monitoring information separation unit 2 lb converts the acquired content file 150' into content 150 a and monitoring information 150 b Separation (S202): ₀ This separation processing is performed, for example, by using the code indicating the monitoring information added by the monitoring information adding unit 12c of the content providing apparatus 10 as the key to the content 150a. And monitoring information 150b.

'Next, the hash value calculation unit 21d calculates a hash value of the separated content 150a (S203). This hash value is the hash value of the content file at the time of monitoring. If the monitoring information is, for example, information for monitoring a linked content file as indicated by AUTH = "", the linked content file is acquired and the hash value of the content file is changed. calculate.

Also, the monitoring information decryption unit 21c refers to the public key 23b of the monitoring database 23 to decrypt the separated or obtained monitoring information 150c (S204). . As a result, the hash value 152b of the content file to be monitored at the time when the monitoring information is generated is acquired.

Then, the hash value comparison unit 21e compares the hash value 152a of the content file at the time of monitoring with the hash value 152b of the monitoring target content file at the time of generating the monitoring information (S2 0 5). And two houses If the menu values match, it is determined that the content file has not been tampered with; otherwise, it is determined that the content file has been tampered with. Thus, when the content file has been tampered with, it can be detected via the computer network 60 that the content file has been tampered with. The hash value comparison unit 21 e records this determination result in, for example, the monitoring result 23 c of the monitoring data base 23 together with the monitoring date and time, and ends the process of monitoring the monitoring target content. Note that the present invention is not limited to the above embodiment. For example, although the case has been described above in which the content monitoring device 20 monitors one content providing device 10, the content monitoring device 20 can also monitor a plurality of content providing devices. In this case, by monitoring the URL of the content to be monitored of each content providing device, a public key, and the like in the monitoring database 23, a plurality of content providing devices are monitored by the same processing as described above, and the content is tampered with. Can be detected.

If the public key and the private key issued from the certificate issuing device 30 have an expiration date, the content monitoring device 20 sends the expired public key and a new public key to the content monitoring device 20. If the hash values do not match regardless of which key is used to perform decryption, it may be determined that tampering has been performed. : As described above, according to the present invention, a third party other than the content provider can monitor the content via the convenience network and detect tampering.

Claims

1. A method of monitoring electronic information content,

Acquiring the monitoring target content;

Extracting first unique information from the acquired monitoring target content; andgenerating second unique information based on the monitoring target content from which the first unique information is extracted.

Having a step of comparing the first unique green report with the second unique information,

A content monitoring method, characterized in that when the first unique information and the second unique information are different as a result of the comparison, it is determined that the monitoring target content has been falsified. ·

2. A method of monitoring electronic information content,

A step of generating first unique information based on the monitoring target content and adding the first specific information to a reference source content referencing the content;

A step of acquiring the monitoring target content and the reference source content; and a step of extracting first unique information from the acquired reference source content;

-A step of generating second unique information based on the obtained monitored content; and

Comparing the first unique information and the second unique information. If the result of the comparison is that the first unique information differs from the second unique information, A content monitoring method characterized by determining that the monitored content has been tampered with.

3. A method of monitoring electronic information content,

Generating first unique information based on the monitoring target content, encrypting the first unique information, and adding the first unique information to the content;

Obtaining the monitored content;

Extracting the encrypted first unique information from the obtained monitored content; and Decrypting the first unique information from the extracted encrypted first unique information;

The encrypted first unique information is extracted based on the extracted monitored content.

(2) a step of generating unique information;

Comparing the decrypted first unique information with the second unique information.If the result of the comparison is that the decrypted first unique information is different from the second unique information, A content monitoring method characterized by determining that the monitored content has been tampered with.

4. A method for monitoring electronic information content,

Generating first unique information based on the monitored content, encrypting the first unique information and attaching the content to a reference source content that refers to the content, and acquiring the monitored content and the reference source content Extracting the encrypted first unique information from the acquired reference source content;

Decrypting the first unique information from the extracted encrypted first unique information;

Generating a second unique information based on the acquired monitored content; and comparing the first unique information with the second unique information. If the result of the comparison indicates that the decrypted first unique information is different from the second unique information, it is determined that the monitoring target content has been tampered with.

5. The content monitoring method according to claim 3 or 4, wherein

A content monitoring method, wherein the encryption and decryption use a public key method.

6. The content monitoring method according to any one of claims 1 to 5,

A content monitoring method, wherein the first unique information and the second unique information based on the content are hash values of values based on the content of the content.

7. A device for providing electronic information content,

Storage means for storing information for identifying the content to be monitored and information for encrypting the unique information of the content in association with each other;

Means for referring to the storage means, generating unique information of the monitoring target content, encrypting the unique information, and adding the encrypted unique information to the monitoring target content.

8. The content providing device according to claim 7, wherein the unique information is a hash value of a value based on the content of the monitoring target content.

9. storage means for storing information for identifying the monitoring target content and information for decoding the unique information of the content in association with each other;

Means for referring to the storage means to obtain monitoring target content, extracting encrypted specific information from the obtained monitoring target content and decrypting the same, and monitoring target content from which the encrypted specific information is extracted. Means for generating unique information of

A content monitoring device comprising: a unit that compares the decrypted unique information with the generated unique information and determines that the monitoring target content has been tampered with when the two are different. ''

10. The content monitoring apparatus according to claim 9, wherein the unique information is a hash value of a value based on the content of the content to be monitored. .

1 1. A process of storing information for identifying the monitoring target content and information for generating unique information of the content in association with each other;

A program for causing a computer to execute a process of generating unique information of monitoring target content with reference to the stored information and adding the information to the monitoring target content.

1 2. A process of storing information for identifying the monitoring target content and information for extracting unique information from the content in association with each other, and

A process of referring to the stored information to obtain monitoring target content, and extracting unique information from the obtained monitoring target content;

A process of generating unique information of the monitored content from which the unique information is extracted; A program for comparing the extracted unique information with the generated unique information, and determining that the monitoring target content has been tampered with if the two are different from each other. ,

13. A computer-readable recording medium on which the program according to claim 11 or 12 is recorded.